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W O RLD M ETEO RO LO GI CAL O RGAN IZATIO N

WMO-No. 544

Secretariat of the World Meteorological Organization Geneva Switzerland

2003

MANUAL

on the Global Observing System

VOLUME I(Annex V to the WMO Technical Regulations)

GLOBAL ASPECTS

2003 edition

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2003, World Meteorological Organization

ISBN 92-63-13544 -4

NOTE

The designations employed and the presentation of material in this publication do not

imply th e expression of any op inion whatsoever on t h e part of th e Secretariat of th e World

Meteorological Organization con cernin g th e legal status of any coun try, territory, city or

area, or of its auth orities, or concernin g the d elim itation o f its fron tiers or bou n daries.

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Supplement

No.Dated

Inserted in the publication

by date

1

2

3

4

56

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

TABLE FOR NOTING SUPPLEMENTS RECEIVED

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EDITORIAL NOTE

The following typograph ical practice has been followed:

Standardpractices and procedures have been printed in semi-bold roman.

Recommendedpractices an d procedures have been prin ted in ligh t face roman .

(Definitions appear in a bigger type.)

Notes h ave been printed in smaller type, light face rom an , and preceded by th e in dication NOTE.

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Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

PART I GENERAL PRINCIPLES REGARDING THE ORGANIZATION AND

IMP LEMENTATION OF TH E GLOBAL OBSERVING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . I-1

1 . Purpose o f the Global Observ ing System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1

2 . O rga n iza tio n a n d d esign o f th e G lo ba l O b ser vin g Sy st em . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1

3 . Im p le m en t a tio n o f t h e Glo ba l O b ser vin g Sy st em . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1

PART II REQUIREMENTS FOR OBSERVATIONAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1. Classi ficat ion of requiremen ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1 .1 Global requ ir ements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1 .2 Regiona l r equ ir ements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1 .3 Nat iona l r equ ir ements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-11 .4 Applicat ion a rea observat iona l r equ ir ements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1 .5 Specia l r equ ir ements fo r env ironm ental emergency r esponse ac tiv it ies . . . . . . . . . . . . . . II-1

1 .6 Requirements in the even t o f vo lcan ic act iv ity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

2. Procedure for elaborat ion of requiremen ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

3 . Systems fo r meet ing r equ ir ements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-2

Attachm ent II.1Classification of scales of meteorological ph enom ena . . . . . . . . . . . . . . . . . . . . . . II.1-1

Attach m ent II.2Special observational requirements for environmental emergency response activities II.2-1

Attachm ent II.3Observational requirements in th e event of volcanic activity . . . . . . . . . . . . . . . . II.3-1

PART III SURFACE-BASED SUBSYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

1. Composit ion of the subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

2 . Implementa t ion o f e lements o f the subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

2.1 Networks of observing stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

2.1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

2.1.2 Global networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1

2 .1 .3 Regiona l ne tworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-2

2 .1 .4 Nat iona l ne tworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-2

2.2 Observing stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-2

2.3 Surface synopt ic stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-3

2.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-3

2 .3 .2 Land st a tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-3

2.3.3 Sea stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-4

2.4 Upper-air synopt ic stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-6

2.5 Aircraft meteorological stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-7

2.6 Aeronaut ical meteorological stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-8

2.7 Research and special -purpose vessel stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-82.8 Climatological stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-8

2.9 Global Climate Observing System Surface Network (GSN) stat ions . . . . . . . . . . . . . . . . . . III-9

2.10 Global Climate Observing System Upper-air Network (GUAN) stat ions . . . . . . . . . . . . . . III-10

2.11 Agricultural meteorological stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-10

2.12 Special stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-11

2.12.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-11

2.12.2 Weather radar stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-12

2.12.3 Radiation stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-12

2.12.4 Wind profiler stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-13

2.12.5 Atm ospherics detection stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-13

2.12.6 Meteorological reconn aissance aircraft stations . . . . . . . . . . . . . . . . . . . . . . . . . . III-13

2.12.7 Meteorological rocket stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-13

2.12.8 Global Atmosphere Watch (GAW) stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-142.12.9 Planetary boundary-layer stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-15

2.12.10 Tide-gauge station s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-15

CONTENTS

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MANUAL ON THE GLOBAL OBSERVING SYSTEMvi

3. Equipment and m ethods of observation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-15

3.1 General requirements of a meteorological stat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-15

3.2 General requirements of inst ruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-16

3.3 Surface observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-16

3.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-16

3.3.2 Atmospheric pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-16

3.3.3 Air temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-17

3.3.4 Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-17

3.3.5 Surface wind . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-17

3.3.6 Clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.7 Weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.8 Precipi tat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.9 Sea temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.10 Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.11 Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.12 Soil temp erature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.13 Soil m oisture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.14 Evapotranspiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-18

3.3.15 Evaporation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-193.3.16 Sunshine durat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-19

3.4 Upper-air observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-19

PART IV SPACE-BASED SUBSYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1. Composit ion of the subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1.1 Space segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1.1.1 Polar-orbi t ing satel li tes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1.1.2 Geostat ionary satel li tes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1 .1 .3 Research and development sa tell it es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

1.2 Ground segmen t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

2. Imp lemen tat ion of the subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

2.1 Space segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1

2 .1 .1 Number, d ist ribu t ion and ava ilab ility o f operat iona l spacecraft . . . . . . . . . . . . . . IV-1

2.1.2 Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2

2 .1 .3 Cont ingency a rr angements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

2 .1 .4 Research and development sa tell it es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

2.2 Ground segmen t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

2.2.1 Central stat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

2.2.2 Users stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

2.2.3 Archiving st rategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-4

2 .2 .4 Educa t ion and t r ain ing st ra t egy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-4

PART V QUALITY CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

1. Basic characterist ics of quali ty control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

2. General pr inciples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

2.1 Respons ibil ity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

2.2 Relay of data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-12.3 Minim um standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

APPENDIX DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . App.-1

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PURPOSE AND SCOPE

1. Th e Man ual is design ed:

(a) To f ac il it a t e cooperat ion in observat ions

between Members;

(b) To specify obligations of Members in th e imp le-

men tation of th e World Weather Watch (WWW)

Global O bserving System (GOS);

(c) To ensure adequate uniformity and s tandardiza-

tion in the practices and procedures employed

in achieving (a) and (b) above.

2. Th e first edition of th eManual on th e Global

Observing System was issued in 1980 in accordance withthe decisions of Seventh Congress. Since then it has

undergone a number of revisions and amendments.

These have been consolidated into this new revised

edition approved by Resolution 8 (EC-LV).

3. Th e Man ual is com posed of Volum es I an d

II, which con tain th e regulatory m aterial for th e global

and regional aspects, respectively. The regulatory

material s tems from recommendations of the

Com m ission for Basic System s (CBS) and resolution s of

regional associations, as well as from decisions taken

by Co n gress (Cg) an d th e Executive Cou n cil (EC).

4. Volum e I of th e Man ual Global Aspects

forms part of the WMO Technical Regulations and is

referred to as An nex V to th e WMO Techn ical Regulations.

5. Volum e II of th e Man ual Regional Aspects

does no t form part of th e WMO Techn ical Regulations.

6. In essen ce, th e Man ual specifies wh at is

to be observed wh ere and when in order to meet th e

relevant observational requirements of Members. The

Guide on the Global Observing System (WMO-No. 488 )

provides detailed guidance on h ow to establish , oper-

ate and manage networks of stations to make these

observations. While some regulatory materialconcerning instrum ents and m ethods of observation

is cont ained in a special sh ort section of the Man ual,

a full description of how and with what observations

are made is contained in the Guide to Meteorological

Instruments and Methods of Observation (WMO-No. 8).

Th e International Cloud Atlas (WMO-No. 407)

describes the classification of clouds. The subsequent

step of how observations are to be reported and

encoded is specified in the Manual on Codes (WMO-

No. 306). Further guidance on observations for

special applications is given in WMO publications

such as the Guide on Meteorological Observation and

Information Distribution Systems at Aerodromes (WMO-

No. 731), Guide to Marine Meteorological Services

(WMO-No. 471), Guide to Clim atological Practices

(WMO-No. 100), Guide to Agricultural Meteorological

Practices (WMO-No. 134) an d various pub lications of

the Global Atmosphere Watch Programme.

TYPES OF REGULATION

7. Volum e I of th e Man ual com prises stan-

dard practices and procedures and recomm ended

practices and procedures. The definitions of these

two types are as follows:

Th e standardpractices and procedures:

(a) Are those practices and procedures which it isnecessary that Members follow or implement;

and therefore

(b) Have the status of requirements in a technical

resolution in respect of wh ich Article 9(b) of th e

Convention is applicable; and

(b) Are invariably distinguished by the use of the term

shallin th e English text and by suitable equivalent

term s in th e French , Russian an d Span ish t exts.

Th e recom m endedpractices an d p rocedures:

(a) Are those practices and procedures which it is

desirable that Members follow or implement;

and therefore

(b) H a ve t h e st a t u s o f r ec om m e n d a t io n s t o

Members to which Article 9(b) of the

Convention shall not be applied; and

(c) Are dist inguished by the use of the term should

in the English text (except where specifically

oth erwise provided b y decision of Con gress) an d

by suitable equivalent terms in the French,

Russian an d Spanish t exts.

8. In accordan ce with th e above defin ition s,

Members shall do th eir utm ost to im plement th e stan-

dard practices and procedures. In accordance with

Article 9 (b) of the Con vention an d in conformity withthe provisions of Regulation 127 of the General

Regulations, Members shall formally notify the

Secretary-General, in writing, of their intention to

apply the standard p ractices and procedures of the

Manual, except those for which they have lodged a

specific deviation. Members shall also inform the

Secretary-General, at least three months in advance,

of any change in the degree of their implementation

of a standard practice or procedure as previously

n otified and of the effective date of the ch ange.

9. With regard to th e recomm endedpractices

and procedures, Members are urged to comply with

these, but it is not necessary to notify the Secretary-

General of non-observance.

INTRODUCTION

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10. In order to clarify th e status of th e

various regulatory material, the standard practices

and procedures are distinguished from the recom-

mended practices and procedures by a difference in

typographical practice, as indicated in the editorial

note.

NOTES, ATTACHMENTS (VOLUME I) AND

VOLUME II

11. Certain n otes are in cluded in th e Man ual

for explanatory purposes. They d o n ot h ave the status

of the annexes to the WMO Technical Regulations.

12. A n um ber of sp ecificatio ns an d form ats of

observing practices an d procedu res are in cluded in th e

Manual. Taking int o account the rapid d evelopmen t of

observin g techn iques and t he increasing requiremen ts of

th e WWW an d oth er WMO program m es, these specifica-

tion s, etc., are given in attachments to the Manual and

do not have the status of the annexes to the WMO

Techn ical Regulation s. Th is will enable th e Com m ission

for Basic Systems to up date th em as n ecessary.

13. Th e words shall an d should i n the

attachm ents, notes and Volum e II have their dictionary

meanings and do not have the regulatory character

m ention ed in paragraph 7 above.

MANUAL ON THE GLOBAL OBSERVING SYSTEM2

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1. PURPOSE OF THE GLOBAL

OBSERVING SYSTEM

1.1 The purpose of the Global Observing

System (GOS) shall be to provide, from all parts of

the globe an d from outer space, high-quality stan-

dardized observations of the state of the

atmo sphere, land and ocean surface for the p repa-

ration of w eather analyses, forecasts and w arnin gs

and for other applications in support of WMO

programmes and re lated environmental

programm es of oth er organizations.

1.2 Th e GOS sh ould p rovide supplem en tary

observa t ions r equ i r ed in t e rna t iona l ly fo r spec ia l

purposes, provided th is would n ot be detrimen tal to

a c h i e v i n g t h e p r i m a r y p u r p o s e s o f t h e W o r l d

Weather Watch (WWW).

2. ORGANIZATION AND DESIGN OF

THE GLOBAL OBSERVING SYSTEM

2.1 The GOS shall be organized as part of

the WWW, in conjunction with the Global Data-

processing System (GDPS) and the Global

Telecommunication System (GTS).

2.2 The GOS shall be con stituted as a coo rdi-

nated system of m ethod s, techniqu es and facilities for

m aking observation s on a worldwide scale and as one

of the main components of

the WWW, taking into account to the ex tent feasible

the requirem ents of oth er internation al programm es.

2.3 The GOS shall consist of facilities and

arrangem ents for makin g observation s at station s

on land and at sea, from aircraft, from environ-

m ental observation satellites and oth er platform s.

2.4 For convenience in the planning and

coordinating of the system, taking into account

various criteria for observational data require-

ments, the GOS shall be considered as composed

of th ree levels: global, region al and nation al.

2.5 The GOS shall be designed as a flexible

and developing system capable of continuous

improvement, on the basis of the latest achieve-

m ents of techno logical and scientific progress and

in accordance with changing requirements for

observation al d ata.

2.6 The plann ing and coordination of the

GOS shall be realized through recommendations

of the WMO Commission for Basic Systems (CBS)

and approved by the Executive Coun cil, in consul-

tation and coordination with Members, regional

associations and other technical commissions

concerned.

2.7 The GOS shall consist of two subsys-

tems: the surface-based subsystem and the

space-based subsystem.

2.8 The GOS surface-based subsystem shall

be composed of surface synoptic land and sea

stations, upper-air stations, clim atolo gical stations,agricultural meteorological stations, aircraft mete-

orological stations, aeronautical meteorological

stations, research and special-purpose vessel

stations an d special station s as detailed in Part III,

paragraph 1 (a ) to (h) of this Manual.

2.9 The m ain elem ents of the GOS surface-

based subsystem shall consist of networks of

surface synoptic stations on land and at sea and

aircraft meteorological stations as detailed in Part

III, paragraph 1 (a ) to (c) of this Manual.

2.10 Other elements of the GOS surface-based

subsystem shall con sist o f aeron autical meteorological

stations, climatological stations, agricultural meteoro-

logical stations, research and special-purpose vessel

stations and special stations as listed in Part III, para-

graph 1 (d) to (h) of this Manual.

2.11 The GOS space-based subsystem shall

comprise satellites of three types: operational polar-

orbiting and operational geostationary satellites and

research an d developm ent (R&D) satellites.

3. IMPLEMENTATION OF THE

GLOBAL OB SERVING SYSTEM

3.1 All activities co nn ected with th e im p le-

m ent ation of th e GOS on th e territories of ind ividual

countries should be the responsibility of the coun-

tries th em selves an d sh ould, as far as possible, be m et

from nat ional resources.

3.2 Im plem en tation of th e GOS on th e terri-

tory of developing countries should be based on the

principle of the u tilization of n ation al resources but,

wh ere necessary and so requested, assistance m ay be

provided in part th rough:

(a) The WMO Voluntary Cooperat ion Programm e

(VCP);

PART I

GENERAL PRINCIPLES REGARDING THE ORGANIZATION AND

IMPLEMENTATION OF THE GLOBAL OBSERVING SYSTEM

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(b) Other bilateral or mu l t ilateral ar rangements

including the Uni ted Nat ions Development

Programm e (UNDP) wh ich should be used to th e

m axim um extent possible.

3.3 Im plem en tat ion of th e GOS in region s

outside the territories of individual countries (e.g.

outer space, oceans, the Antarctic) should be based

on the principle of voluntary participation of coun-

tries that desire and are able to contribute by

providing facilities and services, either individually

or jointly from th eir nation al resources, or by h aving

recourse to collective financing. The assistance

sources described in 3.2 above m ay also be used.

3.4 In th e im plem en tat ion of th e GOS, m axi-

mu m use sho uld be m ade of existing arrangements,

facilities and personn el.

NOTES:(1) The set t ing up and operat ion of the new and improved

facilities and services require a con siderable amo un t of

scientific research, development engineering, coordi-

nation of procedures, standardization of methods and

implementation coordination.

(2) The further development of the GOS is an important

feature of the WWW plan that provides for:

(a) Continued development of the GOS as a cost-effec-

tive composite system comprising operationally

reliable surface-based and space-based (satellite)

subsystem s. It is expected th at, within th e surface-

based subsystem , new system s measuring both large

and local scales of atmospheric phen om ena will be

deployed operationally on a wider scale. Increasing

use will be made of the rapidly growing fleet of

aircraft with automated observing and reporting

system s to supply observation of data at cruising

levels and d uring ascent an d descent. Mobile sea

stations will continue to be the main source for

surface synoptic observations over the oceans.

Through in creased use of automat ic observing and

(satellite) transmission equ ipmen t, th e quality and

quan tity of the data will increase. The nu mb er of

ships equipped with au tom ated upper-air soun ding

facilities (within the Automated Shipboard

Aerological Programm e (ASAP)) will increase and th e

deploym ent of more cost-effective systems will be

accelerated. Drifting bu oys, deployed outside th e

main shipping routes, will continue to supply

surface atmosph eric and oceanographic parameters

from th e data-void ocean areas. It is also expected

that the operational space-based subsystem will

include a new generation of polar-orbiters and

geostationary satellites with improved and new

sensing systems.

(b) Coordinat ion , in tegrat ion and susta inab il ity o f

comp osite surface- and space-based system s and

developm ent of observing n etworks th at are adapt-

able to chan ging requirement s. This will include th e

plann ing for a new com posite upper-air observing

system m aking the m ost effective use of new an d

emerging techn ology, in order to d evelop a cost-

effective, truly global system with the density ofin

situ observations required for operation al purposesas well as to com plement and calibrate observations

from satellites. The new composite system will

utilize a range of techn ologies and tech niques some

of which could become operational only after a

long-term developmen t effort. The in troduction of

new techn ology should be as and wh en proven an d

must be consistent with existing systems and

supporting structures.

(c) Development of new strategies to faci li tate closer

cooperation between Meteorological Services and

research programmes so that the available observ-

ing systems and programmes can be of use to

operational meteorology and the research

community.

(d) Exploring new ways for Members to contr ibute to

th e GOS, includin g joint fund ing and inn ovative

arrangemen ts to ensure adequate observations in

remote and data-sparse areas.

3.5 Existing elemen ts of the GOS, as defined in

Part III, shall no t be removed before the reliability of a

new elemen t has been proven, an d relative accuracy

and representativeness of the o bservational data have

been exam ined and foun d acceptable.

MANUAL ON THE GLOBAL OBSERVING SYSTEMI2

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PART II

REQUIREMENTS FOR OBSERVATIONAL DATA

1. CLASSIFICATION OF

REQUIREMENTS

NOTE: A classification of th e scales of meteorological

phen omen a is given in Attachm ent II.1.

1.1 Gl ob a l r eq u i r e m e n t s

Global requirements shall refer to observational

data needed by Members for a general description

of large-scale and planetary-scale meteorological

phenomena and processes.

1.2 R eg i on a l r e q u i re m e n t s

Regional requiremen ts shall be related to the observa-

tion s needed by tw o or mo re Members to describe in

greater detail the large- and planetary-scale atmo-

spheric phen om ena, as well as to describe the smaller

ones on the mesoscale and small scale as may be

agreed by region al associations.

1.3 N at i on a l r eq u i r e m e n t s

National requirem ents shall be determined by each

indiv idual Member in the light of its own in terests.

1.4 A p p l i ca t i on ar ea ob s e rva t i on a l

r e q u i r e m e n t s

Observation al data requiremen ts for specific app lica-

tion areas such as Global Numerical Weather

Prediction, Nowcasting and Very Short Range

Forecasting, etc. are defined, reviewed and updated

as part of the Rolling Review of Requirements (RRR)

Process as described in the Guide on the GlobalObserving System (WMO-No. 488).

1.5 Specia l requ iremen ts for

e n v i ro n m e n t a l e m e r g en c y

respon se ac t iv i t i e s

In o rder fo r th e des igna ted Regiona l Spec ia li zed

Meteorological Centres (RSMCs) to be in a po sition to

provide Members with transport model products for

environm ental em ergency response, meteorological

a n d n o n - m e t e o r o l o g i c a l ( r a d i o l o g i c a l ) d a t a

requiremen ts need to be m et. Th ey are specified in

Attach m en t II.2. Th ese data, part icularly from th e site

of an accident, are also n eeded by Memb ers so that

they may take appropriate preventive and remedial

action in case of an acciden tal release of radioactive

m aterial into th e environm ent. Data shou ld be made

a v a i l a b l e p r o m p t l y i n a c c o r d a n c e w i t h t h e

C o n v e n t i o n o n E a r l y N o t i f i c a t i o n o f a N u c l e a r

Acciden t (Article 5(e)).

1.6 R eq u i r e m e n t s i n t h e e ve n t o f

vo l c an i c ac t i v i t y

Requiremen ts in t h e even t of volcanic activity poten -

tially hazardous to aviation should be related to theobservational data needed by Members for taking

appropriate action; these data are specified in

Attachment II.3.

2. PROCEDUR E FOR ELABORATION

OF REQUIREMENTS

2.1 Th e form ulat ion of observation al data

requiremen ts is a com plicated process which con sists

of several stages. At various levels this process

involves groups of end-users, regional associations,

WMO technical commissions and other bodies. In

order to rationalize the formulation of the observa-

tional data requirements, the following procedures

(schematically shown in Figure II.1) are applied. The

process is called the Rolling Review of Requirements

(RRR) Process and is described in detail in the Guide

on the Global Observing System (WMO-No. 488).

2.2 Users presen t to WMO Mem bers th eir

needs for observational data for various application

areas (e.g. meteorological services for aviation,

marine navigation, industry, agriculture, climate

research, etc.). Meteorological data might be used in

two w ays: directly in th e provision of m eteorological

services, and in the preparation of meteorologicalprodu cts (weath er analysis and progn oses) by Global

Data-processing System (GDPS) centres. In the latter

case, GDPS cen tres are con sidered as users.

2.3 W MO tech n ical com m ission s are resp on si-

ble for the consolidation of data needs presented by

Memb ers an d for the formu lation, on th eir basis, of a

statemen t on observational data requirements/goals

(usually in the form of tables) in various WMO

Program m es. Th is shou ld in clude explanatory n otes and

a ration ale for th e requirem ent s/goals an d, if possible, a

statem ent on th e increm ental value of partially meeting

th ese goals (in term s of accuracy, den sity, frequ ency, etc.).

Often th is will in clude a feedback process with users to

ensure that enough information and understanding

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about u sersn eeds are available. If a statem ent on require-

m en ts/goals is add ressed to th e World Weath er Watch ,

and in particular to its Global Observing System, it

should be presen ted to th e Com m ission for Basic System s

(CBS) for con sideration .

2.4 Th e Com m ission for Basic System s:

(a) Evaluates the feasibility of stated requiremen ts/

goals. Th e evaluation of techn ical and instrumen tal

feasibility should be con ducted in collaboration

with th e Comm ission for Instrumen ts and Methods

of Observation (CIMO), the W MO bod y respon sible

for th e In strumen ts and Meth ods of Observation

Programme (IMOP). The evaluation process will

result in th e form ulation (in th e form o f tables) of

wh at portion of the statem ent of requiremen ts/goals

is feasible an d can be ach ieved. As part of th e RRR

Process, a Statem ent of Guidan ce will be prepared to

indicate the feasibility of achieving the statedrequirements;

(b) Formula tes system requ ir emen ts to p rov ide

observational data to meet the requirements/

goals defin ed by th e techn ical com m ission s;

(c) Develops any amendm ents to the WMO regula-

tory and guidance publications on the basis of

system requiremen ts and submits them (in case of

regulatory publications) to th e Executive Coun cil.

NOTE: The primary responsibility for the evaluation of the

feasibility of meeting stated observational data

requirements related to the Global Atmosphere

Watch, and for the developmen t of associated guid-

ance material, rests with the Commission for

Atm osph eric Sciences.

2.5 Th e Execu tive Cou ncil ap p roves th e

amendments and requests the Secretary-General to

incorporate th em in appropriate WMO Manuals.

2.6 Th e Mem bers will be advised on th e

performance of observing systems and programmes

through updated WMO Man uals and Guides to m eet

users n eeds for observation al data.

3. SYSTEMS FOR MEETING

REQUIREMENTS

The surface-based subsystem and the space-based

subsystem shall com plem ent each oth er in provid-

ing the observational data required.

MANUAL ON THE GLOBAL OBSERVING SYSTEMII2

2

Review

and

update

1

Review

and

update

4

Review

and update

Guidance on

feasibility

New

initiatives

Descript ion of proposed systems

System specifications

Description of present/planned

systems

Plan and

implement

systems

Other

inputs

Space and in situ

observing syst em

operators

Users

2

Summary of

present/planned/proposed

system capabilities

1

User requirements

(technology free)

For each application:

Statement of maximum

and minimum

3

Critical

review

3

Statement of conformance

of present/planned/proposed

system capabilities to

maximum/minimum

requirements

4

Statement of Guidance

on feasibility of meeting

requirements

OPAG IOS*Feedback to users and

technical commissions

5

5

Expertise on each application

* Open Programme Area Group (OPAG) on Integrated Observing Systems (IOS)

Figure II.1Rolling Review of Requirements Process

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ATTACHMENT II.1

CLASSIFICATION OF SCALES OF METEOROLOGICAL PHENOMENA

The scales of meteorological phenomena are as

follows:

(a) Small scale (less than 100 km; for examp le,

thunderstorm, local winds, tornadoes);

(b) M eso sca le (1 001 000 km; for exam ple, fron ts

an d cloud clusters);

(c) La rge sca le (1 0 005 000 km; fo r example ,

depressions an d an ticyclones);

(d) Pl an e t a ry sc al e (m o r e th a n 5 0 0 0 k m ; fo r

exam ple, lon g upp er-troposph ere waves).

NOTE: The requirements for observational data shall be deter-

mined in part by these scales of meteorological

phen omen a. Many phen omen a overlap between two

of the classes ind icated, and t here is also dynam ic in ter-

action between th e phen om ena in different scales.

Scales (b) and (c) should be considered as roughly

correspon ding to t h e regional level within th e World

Weather Watch (WWW), and (c) and (d) can be

combined within the global level.

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ATTACHMENT II. 2

SPECIAL OBSERVATIONAL REQUIREMENTS FOR ENVIRONMENTAL

EMERGENCY RESPONSE ACTIVITIES

A. METEOROLOGICAL DATA

REQUIREMENTS

1. Data n eeded to run tran sport m odels are

the same as specified for the production of weather

forecasts based on numerical weather prediction

(NWP) models and are given in the Manual on

the Global Data-processing System (WMO-No. 485),

Volume I Global Aspects, Appendix II.2 and the

Guide on the Global Observing System (WMO-No. 488),

Attachment II.1.

2. Addition al data1 are desirable from the

accident site2 and potentially affected area3 an d

should be available to the designated Regional

Specialized Meteorological Centre (RSMC) to

improve the q uality of information about th e trans-

port of pollutan ts. These shou ld include:

(a) Wind, temperature and h umidity, upper-air data;

(b) Prec ip it a tion da ta (type and amount ) ;

(c) Surface air temperature data;

(d) Atmospheric p ressure data ;

(e) Wind direct ion and speed (surface and stack

height) data;

(f) Hu m id ity d ata.

3. Th e data n eeded from th e acciden t site

m ay be provided by the following system s in com bi-

n ation as necessary an d p ossible:

(a) At least one r ad iosonde s ta t ion should be

located at a suitably safe distance to enable

continued operation in an emergency situation

and to be represent ative of cond itions at or near

th e acciden t site;

(b) In an emergency si tuat ion, at two or three

stations closest to the site of the accident

(within 500 km) frequency should be increased

to every three hours for the duration of the

emergency. Stocks of consumables should be

stored for use in em ergen cy situation s;

(c) At least one surface stat ion should be located at

the accident site or, if not possible, at a nearby

site. It should be convertible to an hourly auto-

mated mode fo r bo th opera t ions and

telecommunications in case of emergency;

(d) Addi t ional informat ion should be provided at orn ear the acciden t site by in strumen ted towers or

masts (up to 100 km) and conventional or

Doppler radars, Sodars and boundary layer

sondes with automatic transmission of data.

4. Th e data n eeded from th e poten tially-

affected area should be provided as follows:

(a) All upper-air s tations within the potentially-

affected area should make observations every six

ho urs of the em ergency;

(b) Where possible, one or more addit ional observ-

ing systems, including wind profilers, mobile

radiosounding equipment, and ascent/descent

data from aircraft shou ld be provided;

(c) Al l su r face st a t ions with in th e po ten t ia lly-

affected area including those which are not

normally exchanged data internationally on a

routine basis should provide observational data

to designated RSMCs. Platforms and buoys

shou ld also provide observational data to en sure

adequate coverage over sea areas;

(d) A series of best estim ates of precipitation sho uld

be m ade by combinin g inform ation from direct

m easurem ent s (autom ated or man ual) of surface

stations, composite radar information extend-

ing over the whole WMO Region, andsatellite-derived data.

B. NON-METEOROLOGICAL DATA

REQUIREMENTS

1. In case of em ergen cy, n on -m eteorologi-

cal data to be provided to designated RSMCs from

the accident site should include:

(a) Start of release (date, t ime);

(b) Du ration ;

(c) Radionuclide species;

(d) Total release quant ity or pollutan t release rate;

(e) Effect ive height of release.

1 The words additional data are used with their usual

mean ing an d n ot as in Resolution 40 (Cg-XII).

2 Due to the highly variable types of nuclear accidents, a

precise definition of accident site is not possible. The

accident site should be understood as the location where

the accident occurred and the immediate surrounding

zone with in a ran ge of a few kilom etres.

3 The poten tially affected area is depen den t on t he state and

evolution of th e atmosphere over an extended area around

th e accident site, as well as on th e nu clear event itself and

cannot be precisely defined in advance. It should be

understood as the area where, using all the information

available including the air transport pollution products if

already issued, th e nu clear pollutan ts are likely to be trans-

ported in the air or on the ground at a significant levelover th e n atural (backgroun d) radioactivity. Advice in t his

area may be obtain ed from th e RSMC concerned.

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MANUAL ON THE GLOBAL OBSERVING SYSTEMII.22

Points (a) and (b) are necessary information for

running transport models, while (c), (d) and (e) are

desirable additional information.

2. In order to calibrate an d validate th e atm o-

sph eric transport m odel forecasts processed, radiological

data from potentially affected areas are needed. The

most suitable radiological data required are:

(a) Time-integrated air pol lutant concentrat ion;

(b) To t al d ep o sit io n .

3. Th e requ ired data from th e acciden t site

and potentially-affected area may be obtained by the

following means:

(a) Fixed radiological m onitoring stations;

(b) Mobi le sur face un i ts;

(c) Radio logical sounding/or;

(d) Ins trumenta l airc ra ft .

The frequency of observations should be increased

from one hour to ten minutes during the accident

(routine frequen cy of observations varies from on e to

six hours).

C. EXCHANGE OF METEOROLOGICAL

AND NON-METEOROLOGICAL DATA

1. Non -m eteorological data an d, to som e

extent , addition al meteorological data are likely to be

provided by non-meteorological national authorities.

The Nation al Meteorological or Hydrom eteorological

Services (NMSs) should encourage the provision of

these data by non-meteorological agencies/operators

to National Meteorological Centres (NMCs) for

on ward t ransm ission to th eir associated RSMCs.

2. For th e exch an ge of relevan t m eteorolog-

ical and non-meteorological (radiological) data, a

complete l is t of abbreviated heading bulletins,

including all the regional meteorological and radio-

logical observations, should be sent by Members to

the WMO Secretariat for insertion into Weather

Reporting (WMO-No. 9), Volume C1 Catalogue of

Meteorological Bulletins.

3. Radiological data available in th e early

phase of a nuclear accident (containment radiation

reading, on-site radiation levels, etc.) which assist in

characterizin g th e n uclear accident, shou ld be provided

by national authorities to the International Atomic

Energy Agency (IAEA) as soon as practicable via themost reliable communication means. The IAEA will

verify and assess the information and then provide

these data to the appropriate RSMC, which should

distribute them to NMCs via the Global

Telecommunication System (GTS). In case of environ-

m ent al emergencies, all relevan t ob servational (meteo-

rological and non-meteorological) data should be

transm itted to bot h RSMCs an d NMSs through th e GTS

as qu ickly as possible.

4. En d-to-en d testin g of p rocedu res for data

acquisition, quality control, communication use and

product dissemination should be carried out periodi-

cally to assure system performan ce.

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ATTACHMENT II.3

OBSERVATIONAL REQUIREMENTS IN THE EVENT OF VOLCANIC ACTIVITY

The International Airways Volcano Watch (IAVW) is

coordinated and developed by th e International Civil

Aviation Organization (ICAO) Secretariat with the

assistance of the Volcanic Ash Warnings Study

Group. The Handbook on the International Airways

Volcan o Watch (IAVW) describes th e operat ion al

procedures and th e contact l ist for the implementa-

tion of the IAVW in th e event of th e occurrence of

pre-eruption volcanic activity1, volcanic eruptions

and volcanic ash clouds.

A. METEOROLOGICAL DATA

REQUIREMENTS

The data n eeded to run transport m odels are the same

as specified for the production of weather forecasts

based on numerical weather prediction (NWP) for

mod els and are given in the Manual on the Global Data-

Processing System (WMO-No.485), Volume I Global

Aspects, Appendix II.2 and the Guide on the Global

Observing System (WMO-No.488), Attachment II.I.

1. Addition al data2 are desirable from the

area in the vicinity of the volcano and should be

made available to the designated Meteorological

Watch Offices and Volcanic Ash Advisory Centre

(VAAC)3 to imp rove the quality of information about

th e transport of volcanic ash. These data are the same

as specified for th e special observation requiremen ts

for en vironm ent al emergency respon se activities and

are given in Attach m ent II.2 of this Manual.

2. Im agery d a t a fro m geo st a t io n ary an d

polar-orbit in g satel li tes are required by th e des ig-

n a ted VAAC to a scer t a in w h eth er a vo lcan ic ash

c lo u d i s id e n t i fi a b le a n d t o d e t e r m i n e i t s e x t e n t

(vertical and horizontal) [Reference: The Handbook

on th e IAVW, Section 4.1.1 (c) and Section 4 .5.1(b)].

These data are also required to validate th e transpo rt

mo del trajectory forecast an d to d eterm ine wh en th ev o l c a n i c a s h h a s d i s si p a t e d . Th e i m a g e r y d a t a

should:

(a) Be m ulti-spectral covering visible and infrared

wavelengths;

(b) Have adequate spat ial resolut ion to detect small

volcanic ash clouds [5 km or less];

(c) Have global coverage to provide data for all the

VAACs;

(d) Have a frequent repeat cycle (30 minu tes or less for

th e detection o f volcanic ash an d at least every six

ho urs for tracking volcanic ash for transport m odel

validation ) [Referen ce: The Han dbo ok on th e IAVW,

Section 4.4.1 (c), Section 4.5.1 (d) an d (e)];

(e) Be processed and d elivered to th e VAAC with a

minimal delay.

3. Addition al satellite data th at can assist in

the detection of pre-eruption volcanic activity, a

volcanic eruption, or a volcanic ash cloud should be

made available to the designated VAAC. This may

include satellite data that can be used to detect

volcanic ho t-spots or sulph ur dioxide em ission s.

4. Data obtain ed from surface-based radar

within range of the volcano should be made available to

th e designated VAAC. Th ese data can be used to d etect th e

presence of a volcanic ash cloud an d m easure its heigh t.

B. NON-METEOROLOGICAL DATA

REQUIREMENTS

1. Th e occurren ce of p re-erup tion volcan ic

activity, volcanic eruption s and volcanic ash clouds,

because of the pot ential hazard to aviation, sh ould be

reported without delay to th e designated Area Cont rol

Centres, Meteorological Watch Offices and VAAC as

described in t h e Han dboo k on th e IAVW. Th e report in

plain language sho uld be m ade in th e form o f a volcanic

activity report com prising th e following in form ation, if

available, in t h e order in dicated:

(a) Message typ e, VOLCANIC ACTIVITY REPORT;(b) Stat ion ident i fier, locat ion indicator or name of

station;

(c) D at e/ t im e o f m e ssa ge ;

(d) Loca t ion o f vo lcano and n ame if known;

(e) Concise descrip t ion o f even t inc lud ing , as

approp riate, level of inten sity of volcan ic activ-

ity, occurrence of an eruption and its date and

time, th e existence of a volcanic ash cloud in t h e

area with th e direction of ash cloud m ovement

and height as best estimated.

2. Available geological d ata th at in dicates

th e occurrence of pre-erupt ive volcan ic activity or a

volcanic eruption should be passed immediately to

th e design ated Area Con trol Cent res, Meteorological

1 Pre-eruption volcanic activity in this context means

unusual and/or increasing volcanic activity, which could

presage an eruption.

2 The words additional data are used with their usual

mean ing an d n ot as in Resolution 40 (Cg-XII).

3 Volcanic Ash Advisory Centres (VAACs) are designated by

th e Intern ational Civil Aviation O rganization (ICAO) andWMO to issue advisories on the presence and forecasted

trajectory of volcanic ash.

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MANUAL ON THE GLOBAL OBSERVING SYSTEMII.32

Watch Offices and VAAC [Reference: The Handbook

on th e IAVW, Section 4.1.1 (a)]. These data include:

(a) vulcanological observations;

(b) seism ological activity reports.

3. Pilot reports of p re-erup t ion volcan ic

activity, volcanic eruptions and volcanic ash clouds

should be reported without delay to the designated

Area Control Centres, Meteorological Watch Offices

and VAAC [Reference: The Handbook on the IAVW,

Section 4.1.1 (a)].

C. EXCHANGE OF METEOROLOGICAL

AND NON-METEOROLOGICAL DATA

The exchan ge of all the above dat a is described in th e

Handbook on the International Airways Volcano

Watch (IAVW).

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PART III

SURFACE-BASED SUBSYSTEM

1. COMPOSITION OF THE SUBSYSTEM

The m ain elem en ts of th e surface-based subsystem are:

(a) Surface synopt ic stat ions :

(i) Lan d station s:

Man n ed surface station s;

Automatic surface stations;*

(ii) Sea stat ion s:

Fixed sea station s:

Ocean weather stations;

Lightship stations;

Fixed p latform stations;

Anchored platform stations;

Island an d coastal station s;

Mobile sea stations:

Selected ship stations;

Supplementary ship stations;

Auxiliary ship stations;

Ice-floe station s;

Automatic sea stations:*

Fixed sea stations;

Mobile sea stations;

Drifting bu oy station s;

(b) Upper-air synopt ic stat ions :

Rawinson de stations;

Radiosond e station s;

Radiowind stations; Pilot-balloon stations;

(c) Aircraft meteorological s tat ions ;

Oth er elem ent s of th e subsystem are:

(d) Aeronaut ical m eteorological s tations ;

(e) Research an d special-purpose vessel stations;

(f) C limato logical st a tions;

(g) Agricultural m eteorological s tations;

(h) Special stat ions , which include:

(i) Weat h er rad ar st at io n s;

(ii) Rad iat io n st at io n s;

(iii) W in d p ro filers;

(iv ) Atmospherics de tect ion st a tions;(v ) M et eo ro lo gic al r ec on n a issa n c e a irc ra ft

stations;

(v i) Meteoro logica l rocke t st a tions ;

(v ii) Global Atmosphere Watch st a tions ;

(vi ii ) Planetary boundary-layer stat ions ;

(ix ) Tid e-ga u ge st at io n s.

NOTES:

(1) Definitions of stations listed above will be found in th e

Appendix to this Manual.

(2) Any stat ion may fall under more than on e of the above

categories.

2. IMPLEMENTATION OF ELEMENTS

OF THE SUBSYSTEM

2.1 N et w or k s o f ob s e rv i n g s t a t i on s

2.1.1 Gen er a l

2.1.1.1 Corresponding to the three levels of

requirements for observational data, three types

of networks of observing stat ions global ,

regional and national shall be established.

2 .1 .1 .2 Th e n et wo rks sh o u ld b e in t erd ep en d en t

with selected stations of the national networkswithin a Region compris ing the corresponding

regional network, and with selected stations of the

regional network forming the global network.

Therefore, a station of th e global network is part of a

regional network and a n ational network.

2 .1 .1 .3 Th e fre qu en c y a n d sp acin g of t h e o b ser -

vations should be adjusted to the physical scales of

the meteorological phen om ena to be described.

NOTE: See t he Guide on the Global Observing System

(WMO-No. 488), Figure II.1.

2.1.2 Gl ob a l n e t w o r k s

2.1.2.1 A global synoptic network shall be

established, based upon the Regional Basic

Syno ptic Netw orks (RBSNs).

NOTE: See 2 .1 .3 below.

2 .1 .2 .2 Th e o bse rva tio n al p ro gra m m e o f t h e

global synoptic network should provide meteorolog-

ical data which have the necessary accuracy, spatial

and temporal resolutions to describe the state of

temporal and spatial changes in the meteorologicalph enom ena an d processes occurring on the large and

planetary scales.

NOTE: Guidance as to the determination of requirements

for accuracy and time an d spatial resolution of the

observational data is given in the Guide on the

Global Observing System (WMO-No. 488).

2 .1 .2 .3 Th e glo b al sy n o pt ic n e tw ork sh o u ld b e a s

h om ogeneou s and as un iform as possible all over th e

globe, and the observations should be made at the

main standard times of observation.

2 .1 .2 .4 M em b ers sh o u ld im p lem e n t t h e G lo ba l

Climate Observing System (GCOS) Surface Network* Data m ay be asynop tic when collected via satellite

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(GSN) th e global reference network of som e 1 000

selected surface observation stations established to

m on itor d aily global an d large-scale climate variability.

2 .1 .2 .5 M em b ers sh o u ld im p lem e n t t h e G CO S

Upper-air Network (GUAN) the global baseline

network of about 150 selected upper-air stations

established with relatively homogenous distribution

to m eet requiremen ts of GCOS.

2 .1 .2 .6 M em b ers sh o u ld a lso est ab lish a n e t wo rk

of Global Atm osph ere Watch (GAW) station s

designed to meet the need for monitoring, on a

global and regional basis, the chemical composition

and related ch aracteristics of the at m osph ere.

NOTE: For fur ther information on the location of GAW

stations, see the Technical Regulations (WMO-No.

49), Volume I General Meteorological Standards

and Recommended Practices, Chapter B.2, as well asthe appropriate Global Atmosphere Watch techni-

cal publications, and the Guide on the Global

Observing System (WMO-No. 488).

2.1.3 Regiona l ne tw orks

2.1.3.1 Regional netw orks shall be established

in relation to the regional requirem ents.

NOTE: Regional associations are responsible for the deter-

mination an d coordination of the comp osition of

these networks within the general framework

established by th e Com mission for Basic Systems

(CBS).

2.1.3.2 Regional Basic Synoptic Networks of

both surface and upper-air stations shall be estab-

lished to meet the requirements laid down by the

regional association s.

2.1.3.3 Togeth er, the RBSNs shall fo rm the m ain

part of the surface-based global synoptic network.

NOTES:

(1) The regional associations will continue to examine th eir

plans to meet any new internation al requirements.(2) Details of known regional requiremen ts are given in

Volum e II of this Manual.

2.1.3.4 Members shall implement the RBSNs.

2 .1 .3 .5 Th e h o r izo n t a l sp a cin g o f o b se rv in g

stations and the frequency of their reporting should

be in accordance with the requiremen ts laid down in

Volume I, Part II, and Volume II of this Manual.

2.1.4 Na t i o n a l n e t w o r k s

National networks shall be established by

Members to satisfy their ow n requiremen ts. When

implementing these national networks, Members

shall take into account the needs to complete the

global and regional n etwo rks.

NOTE: A complete list of all surface and u pper-air stations

in op eration wh ich are used for syno ptic purposes

is given in W eather Reporting (WMO-No. 9),

Volum e A Observing Stations.

2.2 Observing s tat ions

General

2.2.1 Th e im p lem en tatio n an d o peratio n o f

each of the above elem ent s shou ld be as laid down by

decisions of Congress, the Executive Council, the

technical commissions and regional associations

concerned.

NOTE: These decisions are reflected in th e Technical

Regulations (WMO No. 49) and its annexes (e.g.

this Manual, the Manual on Codes (WMO-No. 306)

and in oth er relevant WMO publications such as

th e Guide on the Global Observing System (WMO-

No. 488) and the Guide to Meteorological

Instruments and Methods of Observation (WM0-No.

8) which set forth the technical and meteorologi-

cal aspects in detail.

2.2.2 In im p lem en tin g t he Glo bal Observin g

System (GO S) surface-based subsystem , Memb ers

should ensure that the observing system meets the

requirements placed on the subsystem.

2.2.3 In im p lem en t in g t he su rface-b ased

subsystem, Mem bers should strive to meet th e provi-

sions indicated in 2.2.1 above as closely as possible,

in particular as regards the main elements of the

surface-based subsystem.

2.2.4 Each st at io n sh o uld be lo cat ed at a sit e

that permits correct exposure of the instruments and

satisfactory no n -in strumen tal observation s.

2.2.5 In general, observing stations shall be

spaced at an interval and with observations takenfrequently enough to permit an accurate descrip-

tion of the atmosphere for users of the

observations fo r the p urpose in tended.

2.2.6 If in cert ain d esert an d ot h er sp arsely

populated areas i t is not possible to establish

networks with the recom men ded d ensities, networks

with densities as near as possible to those recom-

m end ed sho uld b e established. Special efforts sh ould

be made to establish an adequate network in such an

area when it borders a pop ulated area or is traversed

by a regularly used air route.

2.2.7 Asyn o pt ic ob servat io n s sh o uld b e t aken

when necessary to supplement observation s from the

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synoptic n etworks and in a m ann er which increases

th eir spatial or tem poral frequen cy.

2.2 .8 O bservat io n s sh o uld be t aken in areas

where special phenomena are occurring or expected

to develop. As many elements of standard observa-

tions as possible should be reported. Information

sho uld be comm un icated in real t ime.

NOTE: Drifting buoys and aircraft may also report at

asynoptic times.

2.2.9 Members shall ensure that a record of all

surface and upper-air observations is made and

preserved.

2.3 Su r f ac e s yn op t i c s t a t i on s

2.3.1 Gen er a l

2.3.1.1 Surface synoptic stations may be

manned or partly or fully automated and shall

include land stations and fixed and mobile sea

stations.

2.3.1.2 Each synoptic station shall be located

so as to give m eteorological data representative of

the area in w hich it is situated.

2.3.1.3 The main standard times for surface

synoptic observations shall be 0000, 0600, 1200

and 1 800 UTC.

2.3.1.4 The intermediate standard times for

surface synoptic observation s shall be 0300, 09 00,

1500 and 2100 UTC.

2 .3 .1 .5 At m o sp h e ric p re ssu re o b se rv at io n s

should be made at exactly the standard time while

the observation of other elements should be made

within th e ten m inutes preceding th e stand ard tim e.

2.3.1.6 Every effort should be made to obtain surface

syno ptic observations four tim es daily at the m ain stan-

dard times, with priority being given to th e 0000 and 1200

UTC observation s requ ired for global exchan ges.

2 .3 .1 .7 W h e n it is d ifficu lt fo r a n y re aso n t o

provide sufficient s taff for 24-hour operations,

partially or fully automated stations should supple-

ment or replace manned surface stations including

th ose in th e basic syno ptic netwo rk to provide obser-

vations at least at the main standard times.

2.3.2 La n d s t a t i o n s

General

2.3.2.1 A syno ptic station on land shall be iden-

tified by a station index number assigned by the

Member concerned w ithin the allocations m ade to

that Member, in compliance with the scheme

prescribed in the Manual on Codes (WMO-No. 306).

2.3.2.2 When a Member establishes a syno ptic

station on land (or a fixed weather station at sea)

the Member shall send the following information

to the Secretariat at least two months before the

station becomes operational:

(a) Name, and where appropriate, station index

number (stating whether the station is auto-

matic or manned and, if both, the time of

each);

(b) Geographical coordinates in degrees and

minutes of arc and elevation of the station in

whole metres above mean sea level;

(c) Geopotent ia l of the datum level in whole

metres to which the pressure is reduced, or

the reference isobaric surface the geopotentialof w hich is reported;

(d) Times at which synoptic observations are

m ade and reported;

(e) Topographical s ituation;

(f) Any other information required for comple-

tion of the entries in Weather Reporting

(WMO-No. 9), Volu m e A Observing Stat ions.

2.3.2.3 Members shall send the necessary

amendments to the information supplied under

2.3.2.2 (a ) (f) above to the Secretariat as soon as

possible.

2 .3 .2 .4 An y ch a n ge in in d ex n u m ber o f syn o pt ic

stations included in the international exchanges

should be notified to the Secretariat at least six

m on th s before becomin g effective.

2 .3 .2 .5 Ea ch M em b er sh o u ld p u blish a d escr ip -

tion , in sufficient detail to enable departu res from th e

representativeness of observations to be assessed, of

each of its synoptic stations whose reports are

included in international exchanges.

2.3.2.6 All changes in the stat ion index

number of a synoptic station shall be effective

from 1 Janu ary or 1 July each year.

2.3.2.7 Each Member of WMO shall designate a

national focal point to communicate with the

WMO Secretariat on matters regarding the contents

of Weather Reporting (WMO-No. 9), Volume A

Observing Sta tions . The n ational focal po int shall be

authorized to act in these matters on behalf of the

Perm anen t Representative co ncerned.

Location an d composition

2 .3 .2 .8 Su rfa ce la n d st at io n s, in c lu d in g t h o se in

th e RBSN, shou ld be spaced at in tervals n ot exceed-

ing the minimum horizontal resolution required by

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applications areas supported by the network and as

described in the Rolling Review of Requirements

Process. During the first decade of the twenty-first

century, the interval, in general, should not exceed

250 km (or 300 km in sparsely pop ulated areas).

2.3.2.9 Surface synoptic observations recorded

at a manned synoptic land station shall consist of

observations of the following elements:

(a) Present weather;

(b) Past w ea th e r;

(c) Wind direct ion and speed;

(d) Clo ud am o un t;

(e) Ty pe o f cl ou d;

(f) He igh t o f c lou d b ase ;

(g) Visi bi li ty ;

(h) Air temperature;

(i) Hum idity;

(j) Atmospheric pressure ;

together with such of th e follow ing elem ents as are

determined by regional association resolutions:

(k) Pressure tendency;

(l) Characteristic of pressure tendency;

(m ) Extreme temperature;

(n) Amount of precipi tation;

(o) St at e o f grou n d;

(p) Direct ion of cloud movement;

(q) Sp ec ia l p h en om e n a.

2.3.2.10 A surface synoptic observation at an

automatic land station shall consist of observa-

tions of the following elements:

(a) Atmospheric pressure;

(b) Wind direct ion and speed;

(c) Air t emperature ;

(d) Hum idity ;

(e) Precipitation, yes or no (at least in tropical

areas);

together with the fol lowing e lements which

should be in cluded if possible:

(f) Am ou n t o f pre ci pi ta ti on;(g) Intensity of precipitation;

(h) Vi si bi li ty ;

(i) Optical extinction profile (height of cloud base)*;

(j) Sp ec ial p h en o m en a.

Frequency and tim ing of observations

2.3.2.11 At synopt ic land stat ions the frequency of

surface synop t ic observat ions sh ould be m ade an d

r e p o r t e d e i g h t t i m e s p e r d a y a t t h e m a i n a n d

intermediate stand ard times in extratropical areas and

four t im es per day at the m ain standard times in the

tropics.

2.3.2.12 At a (manned or automatic) land

station, surface synoptic observations shall be

made and reported at least at the main standard

times.

2 .3 .3 Sea s t a t ion s

General

2.3.3.1 W h en m o re eco n om ical m e an s a re n ot

ava il ab le , ocean weather s t a t ions and some o th er

f ix e d s e a s t a t i o n s s h o u l d p r o v i d e e s s en t i a l a n d

detailed meteorological and oceanograph ic data from

critical locations or ocean areas.

NOTES:

(1) In this role, these stations are an integral part of

regional and national networks.

(2) Fixed sea stations also provide reference level data and

a basis for calibration of soundings by remote sensing

from satellites and are thu s im portan t in th e analysis of

phenomena on a large or planetary scale.

(3) A fixed sea station other than an ocean weather station

or a moored buoy may be identified by a station index

number if considered to be in the same category as a

land station.

2.3.3.2 Members shall recruit as mobile ship

stations as many ships as possible that traverse

data-sparse areas and regularly follow routes

throug h areas of p articular interest.

2.3.3.3 Members concerned shall provide the

Secretariat, no t later than 1 March each year, wi th

a list of their selected and supplementary ship

stations in operation at the beginning of the year

or with amendments to the previous list giving

the name, call sign and route or route designator

of each ship.

2.3.3.4 Members shall include in the lists ofselected and supplem entary ship stations info rm a-

tion on the method of obtaining sea surface

temperature, type of barometer, psychrometer,

barograph, radio equipment and other instru-

ments aboard the ship and radiowatch hours.

2 .3 .3 .5 M em b e rs sh o u ld co n sid er usin g fix ed o r

mobile automatic sea stations or drif t ing buoy

stations in th e data-sparse areas of persisten t cloudi-

ness, where remote sounding by satelli te is

hampered.

NOTE: These stat ions are located on f ixed or mobile

ships, fixed or anchored platforms an d on drifting

platforms an d ice floes.


* Height of cloud base and cloud extent could be derived

directly from the optical extinction profile without

further measurement, using one-minute time series.

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2.3.3.6 Environmental data buoy stations shall

be identified by the International Identifier System.

NOTE: This iden t i fier system i s used by the

Intergovernmental Oceanographic Commission

and WMO u niversally.

Location and composition

2 .3 .3 .7 Ea ch f ix ed se a st at io n sh o u ld b e lo ca ted

so as to provide data which are representative of the

marine area. As a minimum, observations should be

taken at the main synoptic times. The observations

should include as many elements of a full synoptic

report as possible.

2 .3 .3 .8 M em b er s sh o u ld e st ab lish , e it h er in d iv id -

ually or jointly, ocean weather stations or other

suitable observational facilities in ocean areas whereth ere are large gaps in th e global network.

NOTE: Information describing the stat ion should be sent

to t he Secretariat as for syno ptic land stations (see

paragraph 2.3.2.2).

2.3 .3.9 In i ts recru it m en t p ro gra m m e, e ach

Member should aim at making the maximum possi-

ble contribution from mobile sea stations towards

attaining an adequate density of observations in all

oceanic areas.

NOTE: An adequate density of surface reports in oceanic

areas is one p er 250 km.

2.3.3.10 It shall be possible to determine the

position of a fully automated mobile sea station.

2.3.3.11 At ocean weather stations, a surface

synoptic observation shall consist of observations

of the following elements:

(a) Present weather;

(b) Past w ea th e r;

(c) Wind direct ion and speed;

(d) Clo ud am o un t;

(e) Ty pe o f cl ou d;(f) He igh t o f c lou d b ase ;

(g) Visi bi li ty ;

(h) Air temperature

(i) Hum idity;

(j) Atmospheric pressure ;

(k) Pressure tendency;

(l) Characteristic of pressure tendency;

(m ) Sh ips course and speed;

(n) Sea surface temperature;

(o) Direct ion of movement of waves;

(p) Wav e perio d;

(q) Wa ve h eig ht;

(r) Sea ice and/ or icing of ship superstructure,

wh en appropriate;

(s) Sp ec ial p h en o m en a.

2 .3 .3 .12 At a se lected sh ip st a t ion , a su r face

synoptic observation should consist of observations

of elemen ts (a) to (r) in 2.3.3.11 above.

2 .3 .3 .13 At a supplementary sh ip st a tion , a su r face


of elemen ts (a) to (h), (i) and (r) in 2.3.3.11 above.

2 .3 .3 .14 At an aux ilia ry sh ip st a tion , a su r face


of elements (a) to (d), (g), (h) (j) and (r) in 2.3.3.11

above.

2 .3 .3 .1 5 At a ligh t sh i p , a m a n n e d p la tfo rm , a n d

c o a s t a l a n d i s l a n d s t a t i o n s , a s u r f a c e s y n o p t i c

o b s e r v a t i o n s h o u l d c o n s i s t o f o b s e r v a t i o n s o f

e l em e n t s (a) to (r) , w i t h t h e e x c ep t i o n o f (m ), in

2.3.3.11 above.

2.3.3.16 At a fixed automatic sea station,surface synoptic observations shall consist of

observations of the following elements:


(b) Wind direct ion and speed;

(c) Air t emperature ;

(d) Sea surface temperature;

In addition to the elemen ts listed above, a surface

synoptic observation m ade at a fixed autom atic sea

station should include, if possible, the following

elements:

(e) Precipitation, yes or no (especially in tropical

areas);

(f) Waves.

2.3.3.17 At a dr ift ing automat ic sea stat ion (dri ft -

ing buoy), a surface synoptic observation should

consist of as many as possible of elements (a) to (d)

and (f) in 2.3.3.16 above.

NOTE: The position of the drifting buoy shall also have to

be determined.

2 .3 .3 .1 8 M em b e rs sh o u l d e n d ea vo u r t o e q u ip

mobile ships to make subsurface observations andrepor t them in th e BATHY/TESAC code form.

NOTE: Guidance on steps to be taken while recruit ing a

selected, supplementary or auxiliary observing

ship, on the organization needed to collect ships

weather reports and on the use of marine meteo-

rological logs on board ships, is contained in the

Guide to Marine Meteorological Services (WM0-

No. 471).


2.3.3.19 At an ocean weather station, surface

synop tic observations shall be m ade and reported

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at least four times per day and preferably h ou rly at

the main and intermediate standard times.

2.3.3.20 At l ightship stat ions , f ixed and

anchored platform stations, and at automatic sea

stations, surface synoptic observations shall be

made and reported at least four times per day at

the main standard times.

2.3.3.21 At a mobi le sea stat ion, surface synopt ic

observations should be made and reported at least

four t imes per day at th e m ain standard times.

2 .3 .3 .22 When opera t iona l d ifficu lt ies on board

ship m ake it impracticable to make a surface synopt ic

observation at a m ain standard time, th e actual t im e

of observation should be as near as possible to the

main standard time.

2 .3 .3 .2 3 W h e n ev er st or m c on d it io n s th r ea te n o rprevail, surface synoptic observations should be

made and reported from a mobile sea station more

frequently than at the m ain stand ard tim es.

2.3.3.24 When sudden and dangerous weather devel-

opments are encountered at sea stations, surface

observations should be mad e and reported as soon as possi-

ble with out regard to the stand ard time of observation.

NOTE: For specific instructions relative to the furnishing

by ships of special reports, in accordan ce with t he

Internat ional Co nven tion for Safety of Life at Sea,

see Weather Reporting (WMO-No.9).

2 .3 .3 .25 Members should ar range fo r timely t rans-

m ission of observation s.

NOTE: Details of observing and reporting programm es are

described in the Guide to Marine Meteorological

Services (WM0-No. 471), Chap ter 5. In case of diffi-

culties resulting from fixed radiowatch hours on

board single-operator ships, the procedures given

in the Manual on the Global Telecommunication

System (WMO-No. 386), Volum e I Global Aspects,

Part I, Attachment I-1, should be followed.

2.4 Upper-air syno pt ic s tat ion s

General

2.4.1 Upper-air synoptic stations shall be id en-

tified as provid ed un der 2.3.2.1 to 2.3 .2.7 above.

2.4.2 The standard times of upper-air synop-

tic observations shall be 0000, 0600, 1200 and

1800 UTC.

2.4.3 As u pp er-air d at a fro m th e o cean a reas

are particularly sparse, Members should give consid-

erat ion to equipping sui table ships to make

sound ings and, if possible, to m easure upper wind s.

2.4.4 In t h e t ro pics p rio rit y sh o uld be given t o

upper-wind observations.

2.4.5 Up per-air st at io n s m akin g ob servat io n s

of pressure, temperature, humidity and wind should

be spaced at intervals not exceeding the minimum

horizontal resolution required by applications areas

supported by the network and as described in the

Rolling Review of Requirements Process. During the

first decade of the twenty-first century, the interval,

in general, sho uld not exceed 250 km or 1 000 km in

sparsely populated an d ocean areas.

Location an d composition

2.4.6 An upper-air synoptic observation

shall consist of observations of o ne o r m ore of the

following elemen ts:


(b) Air temperature;

(c) Hum idity;

(d) Wind direct ion and speed.


2 .4 .7 At an u pp er-air syn o pt ic st at io n , t h e

frequency of synoptic observations should be four

per day at the standard times of upper-air synoptic

observations.

2.4.8 At an upper-air synoptic station,

upper-air observations shall be made and reported

at least at 0000 UTC and 1200 UTC.

2.4.9 At o cean weat h er st at io n s, u pp er-air

synoptic observations should comprise rawinsonde

observat ions at 0000 and 1200 UTC and/or

radiowind o bservations at 0600 an d 1800 UTC.

2 .4.1 0 Th e act ua l t im e o f regu la r u p per-a ir

synoptic observations should be as close as possible

to (H-30) and sh ould n ot fall outside the tim e range

(H-45) to H.

NOTE: The actual time of a pilot-balloon observation

may deviate from the range indicated above if, by

doing so, wind observations to considerably

greater heights can be expected.

2 .4 .1 1 In a rea s w h er e it is n o t po ssib le t o m e et

the frequency requiremen ts men tioned above, every

effort shou ld be mad e to obtain at least the following

observations:

(a) Upper-air observation s from th e RBSNs and

other networks of stations on land and at sea,

twice daily, at 0000 and 1200 UTC;

(b) In th e t ropics, at stat ions where two complete

radiosonde/radiowind observat ions are not


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m ade, priority should be given t o th e implemen -

tation of one complete radiosonde/radiowind

observation and one radiowind observation

daily.

2.5 A ir c ra f t m e t e oro l og i c a l s t a t i on s

General

2.5.1 Each Member shall arrange for obser-

vations to be made by aircraft of its registry

operating on international air routes and for the

recording and reporting o f th ese observation s.

NOTE: Further information on aircraft observations

and reports may be found in th e Technical Regulations

(WMO-N0.49), Volume II Meteorological Service for

International Air Navigation [C.3.1.] 5.

2.5.2 Members accepting responsibility for

collecting aircraft reports for synoptic purposes

shall promptly make these available, in agreed

code fo rm s, to o ther Members.

2 .5 .3 M em b ers sh o u ld give sp ecial co n sid era -

t ion to the use of an automated ai rcraf t

m eteorological observing an d reportin g system.

2.5.4 Aircraft reports shall, at a minimum,

satisfy the requirements of International Air

Navigation (f

w o r l d m e

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