precipitation climatology of costa rica and its variability atmospheric, oceanic and topographic...
TRANSCRIPT
Precipitation Climatology ofCosta Rica and its Variability
Atmospheric, Oceanic and Topographic Interactions
Characters in The Play
• Topography
• Oceans
• Northeast Trade Winds (aka Los Alisios)
• Caribbean Low Level Jet (aka Veranillos de
San Juan)
• Inter-tropical Convergence Zone
• Cold Fronts (aka Los Nortes)
• ENSO (El Niño y La Niña)
Act 1: November - April “Los Alisios”
LOW LOW LOW
LOW LOW
LOW LOW
HIGH HIGH HIGH
HIGH HIGH HIGH
HIGH
HIGH
~0°
~30°S
~30°N
~45-60°S
~45-60°N
~90°S
~90°N
NortheastTrades
Hadley Cell
Costa Rica~ 8-11.5°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICALPICTURE
Source: NASA
Source: Instituto Merteorologico Nacional and Instituto Costarricense de Electricidad
Act 2: May - October “ITCZ”
ITCZ Feb3°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICALPICTURE
Peru-HumboldtCurrent
ITCZ Feb3°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICALPICTURE
Cross-EquatorialWesterlies
10°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICALPICTURE
ITCZ Sep
Cross-equatorialWesterlies
Act 3: July - August “Veranillo de San Juan”
Lat
itu
de
(° N
ort
h)
2
4
6
8
10
12
2
4
6
8
10
12
Mean Position
J F M A M J J A S O N D
Costa RicaCosta Rica
Mean Monthly Position of ITCZ inEastern Equatorial Pacific
VERANILLOS DE SAN JUAN OR CANICULAMid-Summer Drought
Month
Ave
rage
Lat
itud
e (°
N)
of I
TC
Z
in E
aste
rn E
quat
oria
l Pac
ific
Hastenrath, 1991
San Andrés orCaribbean Low
Level JetCoolUpwelling
GAP IN CENTRAL AMERICAN CORDILLERA
DJF1000hPa
m/s
NCEP-NCARRE-ANALYSIS
Source: Kalnay et al., 1996
80°W
Caribbean Low Level Jet (CLLJ)
SEASONAL STRENGTHS OF CLLJWesterly Component of Wind Velocity at 80°WMAM
JJA
SON DJF
Source: NCEP-NCAR Reanalysis, Kalnay et al., 1996
CLLJ
Latitude Latitude
Pre
ssur
e (m
m)
~Alt
itud
e
GAP IN CENTRAL AMERICAN CORDILLERA
JUNE JULY
AUGUST SEPTEMBER
EVIDENCE OF VERANILLOS ?
Source: Mejiaand Poveda2003
Meso-ScaleConvectiveSystems1998 as detected by TRMM
Act 4: November - April “Los Nortes”
H
HRockies etc.
Appalachians
North America as Funnel of Cold Air in Boreal Winter
Surges of Cold Air over Gulf of Mexico and Caribbean
ITCZ Feb3°N
NortheastTrades
ColdFronts
Andes
STANDARD CLIMATOLOGICALPICTURE
Act 4: ENSO “El Niño y La Niña”
ITCZ Feb3°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICAL PICTURE EL NIŇO
Peru-HumboldtCurrent
1. Warmer surface waters appear in Eastern Equatorial Pacific November onwards
ITCZ Feb3°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICAL PICTURE EL NIŇO
Peru-HumboldtCurrent
1. Warmer surface waters appear in Eastern Equatorial Pacific November onwards
2. ITCZ shifts south and west of normal position
ITCZ Feb3°N
NortheastTrades
Andes
STANDARD CLIMATOLOGICAL PICTURE EL NIŇO
Peru-HumboldtCurrent
1. Warmer surface waters appear in Eastern Equatorial Pacific November onwards
2. ITCZ shifts south and west of normal position
3 Northeast Trades intensify
Positive = More Westerly (Less Easterly)Negative = More Easterly (Less Westerly)
Difference in Velocities (Warm – Cold Phase of ENSO)
MAM
Poveda et al., 2001
“In El Niño, trades weaker (less easterly) than in La Niña.”
Spring:
JJA
Poveda et al., 2001
“In El Niño, trades stronger (less westerly) than in La Niña.”
Summer:
Positive = More Westerly (Less Easterly)Negative = More Easterly (Less Westerly)
Difference in Velocities (Warm – Cold Phase of ENSO)
SON
Poveda et al., 2001
“In El Niño, trades stronger (less westerly) than in La Niña, but not as marked as in summer.”
Fall:
Positive = More Westerly (Less Easterly)Negative = More Easterly (Less Westerly)
Difference in Velocities (Warm – Cold Phase of ENSO)
DJF
Poveda et al., 2001
“In El Niño, trades much weaker (less easterly) than in La Niña.”
Winter:
Positive = More Westerly (Less Easterly)Negative = More Easterly (Less Westerly)
Difference in Velocities (Warm – Cold Phase of ENSO)
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
?
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
?
Act 5: Epilogue “The Atlantic”
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño
SeasonalPrecipitation as a Normalized deviate
Standard Deviations above/below mean
La Niña El Niño