Teddy Allen and Dr. Scott CurtisTeddy Allen and Dr. Scott Curtis
Atmospheric Science Program Atmospheric Science Program
Department of GeographyDepartment of Geography
East Carolina UniversityEast Carolina University
Dr. Douglas Gamble Dr. Douglas Gamble
Department of Geography and GeologyDepartment of Geography and Geology
University of North Carolina at University of North Carolina at WilmingtonWilmington
Jamaica’s Mid-Summer “Dry Jamaica’s Mid-Summer “Dry Spell”Spell”
March 6, 2008March 6, 20082008 Climate Prediction Applications Science Workshop
OUTLINEOUTLINE
• Economic MotivationEconomic Motivation
• Defining the Mid-Summer “Dry Spell”Defining the Mid-Summer “Dry Spell”
• MSD variability and patternsMSD variability and patterns
• Modified Pressure IndexModified Pressure Index
• Vegetation ResponseVegetation Response
• Future WorkFuture Work
Dataset grid box nearest Montego Bay
$0
$10,000
$20,000
$30,000
$40,000
$50,000
GDP per capita
MOTIVATIONMOTIVATION
0
25
50
75
100
% GDPAgriculture% Labor inAgriculture
Jamaica is a relatively Jamaica is a relatively poor* nation that poor* nation that largely depends on its largely depends on its agricultural yields for agricultural yields for both export and both export and domestic consumption. domestic consumption. An improved An improved understanding of the understanding of the mechanisms of the Mid mechanisms of the Mid Summer “Dry-Spell” Summer “Dry-Spell” can have significant can have significant impacts upon impacts upon agricultural agricultural productivity and productivity and economic prosperity.economic prosperity.* Definition of poor neglects significant cultural
wealth that Jamaica possesses.
( CIA World FactBook 2007 )
Data SetsData Sets
• NCEP NCAR monthly ReanalysisNCEP NCAR monthly Reanalysis 2.5 degree gridded dataset2.5 degree gridded dataset
• NASA Global Precipitation NASA Global Precipitation
Climatology Project (GPCP) V2Climatology Project (GPCP) V2
• Terra MODIS spectral Terra MODIS spectral imageryimagery
0
1
2
3
4
5
6
JAN
FEB
MAR AP
RMAY JU
NJU
LAU
GSE
POCT
NOVDEC
Montego Bay18N, 80W
mm
day
-1GPCP CLIMATOLOGY 1979 - GPCP CLIMATOLOGY 1979 - 20072007 Mid Summer “Dry-Spell” Mid Summer “Dry-Spell”
SignatureSignature
Mid-Summer “Dry Spell” Mid-Summer “Dry Spell” Conceptual ModelConceptual Model
divergence
upwelling
NAM
H
MSD timing
MayJuly
Mid-Summer “Dry Spell” Mid-Summer “Dry Spell” PatternPattern
Mean pentad gauge precip. Apr. - Nov. 1979-2007
Mid-Summer “Dry Spell” Mid-Summer “Dry Spell” Inter-Annual VariabilityInter-Annual Variability
1998 1999 2000
2001 2002 2003
2004 2005 2006
Average Sea Level Pressure (NCEP NCAR Average Sea Level Pressure (NCEP NCAR Reanalysis)Reanalysis)
Apr.–Nov. 1979 - 2007Apr.–Nov. 1979 - 2007APRIL MAY JUNE
JULY AUGUST SEPTEMBER
OCTOBER NOVEMBER
Monthly Caribbean Low Level Jet Averages Monthly Caribbean Low Level Jet Averages (925mb) Apr.-Nov. 1979-2007(925mb) Apr.-Nov. 1979-2007
APRIL MAY JUNE
JULY AUGUST SEPTEMBER
OCTOBER NOVEMBER
Monthly GPCP Caribbean Precip. Averages Monthly GPCP Caribbean Precip. Averages Apr.-Nov. 1979 - 2007Apr.-Nov. 1979 - 2007
APRIL MAY JUNE
JULY AUGUST SEPTEMBER
OCTOBER NOVEMBER
Average 925mb Divergence Average 925mb Divergence 1979-20071979-2007
JUNE JULY
AUG. SEPT.
Average DifferencesAverage DifferencesJuly minus MayJuly minus May
increase in NASH
increase in CLLJ
decrease in precip.
+4mb
-2 mm / day
+5 ms-1
Modified Bermuda High IndexModified Bermuda High IndexP P Montego BayMontego Bay – P – P 30N, 40W30N, 40W
Montego Bay
30N, 40W
MBHI
BHI
MBHI Monthly ClimatologiesMBHI Monthly Climatologies
Montego Montego BayBay
30N, 40W30N, 40W MBHIMBHI
JanuaryJanuary 1015.261015.26 1022.601022.60 -7.34-7.34
FebruaryFebruary 1015.121015.12 1021.891021.89 -6.77-6.77
MarchMarch 1014.291014.29 1021.151021.15 -6.86-6.86
AprilApril 1013.521013.52 1021.081021.08 -7.56-7.56
MayMay 1012.831012.83 1022.411022.41 -9.58-9.58
JuneJune 1013.51013.5 1023.691023.69 -10.19-10.19
JulyJuly 1014.511014.51 1024.811024.81 -10.30-10.30
AugustAugust 1013.691013.69 1022.731022.73 -9.04-9.04
SeptembeSeptemberr
1012.261012.26 1020.681020.68 -8.42-8.42
OctoberOctober 1011.771011.77 1019.421019.42 -7.65-7.65
NovembeNovemberr
1012.621012.62 1019.211019.21 -6.59-6.59
DecembeDecemberr
1014.421014.42 1020.461020.46 -6.04-6.04
0
2
4
6
8
10
12
Modified BHIModified BHI 20020022
MBHIMBHI
Jan.Jan. -8.21-8.21
Feb.Feb. -5.8-5.8
Mar.Mar. -8.78-8.78
Apr.Apr. --10.1410.14
19819833
MBHIMBHI
Jan.Jan. --10.8910.89
Feb.Feb. -3.08-3.08
Mar.Mar. -7.16-7.16
Apr.Apr. -6.67-6.67
2002 GPCP Montego Bay
1983 GPCP Montego Bay
0
2
4
6
8
10
JAN FEB MAR APR
20021983AVG
Early Season MBHI
Vegetation Response Via Vegetation Response Via Remote SensingRemote Sensing
Terra MODIS (Moderate Resolution Imaging Spectrometer)
36 Spectral Bands covering the Earth every 1-2 days
250m resolution
Jamaican Region Imagery delivered every 16 days
Normalized Difference Vegetation Index (NDVI) Classification through ERDAS Imagine software
April 2006April 2006
OctoberOctober 2006
NDVI = NIR - red
NIR + red
________
FUTURE WORKFUTURE WORK
NDVI TIME SERIES CLASSIFICATION ENSO
FORCINGS
FARMING PERSPECTIVE
For more info: [email protected]
AcknowledgementsAcknowledgements
• Dr. Scott Curtis Dr. Scott Curtis
• Dr. Douglas GambleDr. Douglas Gamble
• Dr. Rosana Nieto-FerreiraDr. Rosana Nieto-Ferreira
• ECU Geography DepartmentECU Geography Department
• Dr. Peter Robinson and the SERCCDr. Peter Robinson and the SERCC
• National Science FoundationNational Science Foundation