TECO-2006 Geneva, Dec. 3-5, 2006 1

Improvements in the Upper-Air Improvements in the Upper-Air Observation Systems in JapanObservation Systems in Japan

M. Ishihara, M. Chiba, Y. Izumikawa, N. Kinoshita, and M. Ishihara, M. Chiba, Y. Izumikawa, N. Kinoshita, and N. TsukamotoN. Tsukamoto

Japan Meteorological AgencyJapan Meteorological Agency

WMO Technical Conference on Meteorology and WMO Technical Conference on Meteorology and Environmental Instruments and Methods of ObservationEnvironmental Instruments and Methods of Observation

TECO-2006TECO-2006GenevaGeneva

December 3-5, 2006December 3-5, 2006

TECO-2006 Geneva, Dec. 3-5, 2006 2

OutlineOutline

Background

Operations of wind profilers and Doppler radars

Automatic upper-air observation systems

Experiment on ground-based microwave

radiometers for operational use

Operation of GPS-derived IWV Measurement

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Improvement of observations and monitoring

Modernization of upper-air observation

systems

Improvement of forecasting

Non-hydrostatic mesoscale model with

4D-VAR data assimilation

Enhancement of warning issue

Decreasing size of warning areas and

extension of warning lead-time

Strategy of JMA for Severe Weather EventsStrategy of JMA for Severe Weather Events

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1. 1. Mesoscale Mesoscale Wind ProfilerWind Profiler Network Network 31 wind profilers are being operated at 1357MHz-band, and provide winds aloft from near the surface to about 5 km in height every 10 minutes.

Wind Profiler Network and Data Acquisition System

(WINDAS)

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2. Replacement of conventional radars 2. Replacement of conventional radars with Doppler radarswith Doppler radars

A replacement project from conventional radars to D

oppler radars is started in the radar network.

The main purpose of introducing Doppler radars is t

he assimilation of Doppler velocity data to the numer

ical weather prediction model, for increasing the acc

uracy of prediction for mesoscale severe weathers.

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• Existing conventional radars • Doppler radars being installed in 2006-2007 , and 2008 • Doppler weather radars being operated for aviation weathers

Replacement Plan of Weather Radars in JMA Replacement Plan of Weather Radars in JMA

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Impact of Doppler Velocity Data to Impact of Doppler Velocity Data to Numerical Weather ForecastNumerical Weather Forecast

Assimilation of Doppler velocity data to the mesoscale numerical model using the 4D-VAR was started in 2004.

Verification of 3-hour accumulated rainfall forecasts starting from 1800 UTC on 1 Feb 2004. (a) 12-15 hour forecast without the assimilation of Doppler velocity data, (b) observation, and (c) forecast with the assimilation (Ishikawa and Koizumi, 2006). Circles indicate heavy rainfall areas.

Tokyo

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3. Introduction of Automatic Upper-air 3. Introduction of Automatic Upper-air Observation SystemsObservation Systems

• Manned stations • Automatic radiosonde observation systems bein

g started in 2003-2006 , and 2007

120°

120°

140°

140°

30° 30°

40° 40°

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Automatic Upper-air Observation SystemsAutomatic Upper-air Observation Systems

Station (year of installation) Manufacturer Type Radiosonde Ground System

47678 HACHIJOJIMA (2003) VAISALA AUTOSONDE RS92-AGP DigiCORA III

47945MINAMIDAITOJIMA

(2005)VAISALA AUTOSONDE RS92-AGP DigiCORA III

47918 ISHIGAKIJIMA (2006) MEISEI ARS RS-01GM RD-01G

47909 NAZE (2007) MEISEI ARS RS-01GM RD-01G

HACHIJOJIMA (2003)

MINAMIDAITOJIMA (2005)

ISHIGAKIJIMA (2006)

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Automatic Radiosonde Observation Systems Automatic Radiosonde Observation Systems Being Suitable for Our OperationBeing Suitable for Our Operation

The ballon-launching gear of the system was improved after the installation to endure to strong wind and high humidity at 47678.

600g balloons with internal parachutes are used at 47918.

Some balloons had been tore in the storage room of the system due to surface ozone at 47918. An air- filter was installed stop the inflow of ozone from the outside, and then the problem was resolved.

An unmanned hydrogen generator will be used at 47909 from 2007.

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4. Experiments of Ground-based Microwave 4. Experiments of Ground-based Microwave Radiometers for Operational UseRadiometers for Operational Use

• JMA starts a project for operational use of ground-based microwave radiometers.

• Field experiments are being made in some different climate conditions of Japan; in sub-tropics, in summer and winter at the mid-latitudes.

• Two methods; the built-in algorisms and the 1D-VAR with the mesoscale model, are being tested to retrieve temperature and humidity profiles.

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Field Experiments of ground-based Field Experiments of ground-based Microwave Radiometers in 2006-2007Microwave Radiometers in 2006-2007

Radiometric TP/WVP-3000

Naha

Tsukuba

Niigata Morioka

Sendai

Oct. to Dec., RPG HATPRO

June to July, RDX WVP-3000July to Sep., RPG HATPRO

August to Dec., RDX WVP-3000

July to Dec., RDX WVP-3000

April to May and Jan. 2007, RDX WVP-3000Jan. 2007., RPG HATPRO

Radiometer Physics GmbH HATPRO

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• A topic in the field experiment; the radiometer measurements with the rainfall mitigation system, and in this case, temperature and water vapor profiles was obtained in good accuracy even in strong rain as well as in light rain.

strong rain light rain

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• The operational measurement of integrated water vapor (IWV) measurement using the GPS receiver network (GEONET) of the Geophysical Survey Institute (GSI) has been planned.

• However, the information on the orbits and the clocks of the GPS satellites, which are needed to calculate IWV, are not available in real-time.

5. Operational Measurement5. Operational Measurement of of GPS-derived GPS-derived Integrated Water Vapor (IWV)Integrated Water Vapor (IWV)

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• The meteorological Institute of JMA (MRI) has

developed a near-real time processing scheme.

Using the ultra-rapid information and the GPS clocks

corrected by the accurate clock of an International

Global Navigation Satellite System Service (IGS)

station.

• The scheme provides enough accuracy of integrated

water vapour (IWV) for assimilation to NWP.

• JMA is going to make a contract with the Geophysical

Survey Institute (GSI) to obtain the GPS network data

in real-time probably in 2007.

NearNear--real Time Processing of IWVreal Time Processing of IWV

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NearNear--real Time Processing of IWVreal Time Processing of IWV

Ultra-Rapid Orbit

(Predicted half)

before 24 hours

Ultra-Rapid Orbit (observed half)

after 2 - 8 hours

Rapid Orbit

after 12 - 36 hours

Final Orbit

after 2 weeks

Accuracy

1) Using the rapid orbit, the error on the most accurate clock in a GPS station of Japan (Usuda) is estimated. The error is extrapolated in the next 24 hours.

2) Using the corrected time of Usuda, errors on the clocks of the GPS satellites are corrected.

3) Using the corrected GPS satellite clocks and the ultra-rapid orbit, IWV is estimated at the each GPS stations.

Rapidity

(Shoji and Kunii, 2006)

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• Convection nowcasting using horizontal water vapor flux convergence using GPS integrated water vapour (IWV) and surfade winds from the AWS network (AMeDAS).

FLUX CONV (kg m-2s-1)

Radar Echo IWV Flux Convergence

05UTC 05UTC

06UTC 06UTC

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Issues and Future PlansIssues and Future Plans

• Re-construction of radiosonde observation netwoRe-construction of radiosonde observation network using automatic systems including positive anrk using automatic systems including positive and negative targeting,d negative targeting,

• Vertical profiling of water vapor from microwave rVertical profiling of water vapor from microwave radiometers, GPS occultation method, wind profileadiometers, GPS occultation method, wind profilers,rs,

• Upper-air observations over the ocean.Upper-air observations over the ocean.