View
217
Download
1
Tags:
Embed Size (px)
Citation preview
Sensitivity of Simulated Philippine Rainfall to Model Resolution and
Convective Closure Scheme
JOSEFINA ARGETE
Institute of Environmental Science and Meteorology
University of the Philippines
ELLA CECILIA CASTILLO
Climate Studies Division
Manila Observatory
ANA LIZA SOLIS
Climatology & Agrometeorology Branch
PAGASA, Weather Bureau
ObjectivesObjectives
• To test the sensitivity of RegCM3 to different domain resolutions on Philippine rainfall
• To test the sensitivity of the model to 2 convective closure schemes
• To validate the model output with observed values (station data, CRU and XA)
Brief Brief ClimatologyClimatology
Northeast Monsoon Season – (Oct-Mar)
brings relatively warm & humid air masses e.g. much rainfall in northern and eastern part of the country.
Southwest Monsoon Season – (May-September)peak in August, deep current up to 10,000m highAlmost all parts of the island receive high rainfall, max. at coasts and slopes directly exposed to the monsoon.
North Pacific Trades – (Mar-Apr) NE monsoon weakens, islands under influence of trades, easterlies bring warmest air in the Phils.
NCEP REANALYSIS
NCEP REANALYSIS
Input data: ET42, L15 (ECWCRP)
GTOPO30_10MIN
GLCC10MIN_BATS
OISST
Start date=1997052500
End date=1997070100
clat = 14 clon= 120
iproj=“ROTMER”
MethodologyMethodology
60 km 45 km 20 km
No. of grids 55 x 45 63 x 53 163 x 133
ds 60 45 20
nspgx 6(12) 8(16) 18(36)
dt 200 100 60
igcc FC/AS FC FC
Validation dataValidation data
• CRU monthly precip
• Xie-Arkin monthly precip rate
• Observed daily/monthly station rainfall
Observed vs. Simulated rainfall
0
5
10
15
20
25
30
35
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
days
rr a
mo
un
t (m
m)
observed 20 km 45 km FC
Closure Scheme, 60 km
0
5
10
15
20
25
30
35
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
days
rr a
mo
un
t (m
m)
observed FC AS
CONCLUSIONSCONCLUSIONS::
• 60 & 45km res. runs captured the spatial pattern of rr ; details are more evident in 20km res.run
• The run using Arakawa-Schubert Scheme simulated the Philippine rainfall better than the Fritsch-Chappel Scheme
• In general, the model’s prca compared relatively well with the observed rainfall values but tended to overestimate
• The same is true for convective precip (prcc)