PEMANFAATAN WRF-VAR 3.2.1 UNTUK
PRAKIRAAN CUACA
FATKHUROYAN, ST
.
POKOK BAHASAN
•
PENDAHULUAN
•
PHYSIC AND DYNAMIC OPTIONS
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INPUT DATA
•
HASIL
Pendahuluan
WRF ( Weather Research and Forecasting ) ialah
model NWP ( numerical Weather Prediction ) yang
dipakai baik untuk kebutuhan operasional
forecasting maupun untuk riset atmosfer ( real data
dan idealized case ).
WRF dikembangkan oleh :
National Center for Atmospheric Research (NCAR)
The National Centers for Environmental Prediction
(NCEP)
Forecast Systems Laboratory (FSL)
Air Force Weather Agency (AFWA)
Naval Research Laboratory
Oklahoma University
History of WRF Model
–
2000: V1.0 (beta release of EH core)
– 2001: V1.1
–
2002: V1.2 (beta release of EM core
)
– 2003: V1.3
–
2004: V2.0 (first official release)
Core WRF
Model yang berbeda dengan arsitektur sama tapi berbeda
core-code nya.
–
ARW (Advanced Research WRF) at NCAR
– NMM (Non-Hydrostatic Mesoscale Model) at NCEP
• Based on Eta Model’s code
Alur WRF-Var
Sumber :
m
mm.uca
PHYSIC AND DYNAMIC OPTIONS
1. Microphysics (mp_physics)
a. Kessler scheme: A warm-rain (i.e. no ice) scheme used commonly in idealized cloud modeling studies (mp_physics = 1).
b. Lin et al. scheme: A sophisticated scheme that has ice, snow and graupel processes, suitable for real-data high-resolution simulations (2).
2.1 Longwave Radiation (ra_lw_physics)
a. RRTM scheme: Rapid Radiative Transfer Model. An accurate
scheme using look-up tables for efficiency. Accounts for multiple bands, trace gases, and microphysics species (ra_lw_physics = 1).
b. GFDL scheme: Eta operational radiation scheme. An older multi-
PHYSIC AND DYNAMIC OPTIONS
2.2 Shortwave Radiation (ra_sw_physics)
a. Dudhia scheme: Simple downward integration allowing efficiently for clouds and clear-sky absorption and scattering. When used in high- resolution simulations, sloping and shadowing effects may be
considered (ra_sw_physics = 1).
b. Goddard shortwave: Two-stream multi-band scheme with ozone from climatology and cloud effects (2).
3.1 Surface Layer (sf_sfclay_physics)
a.MM5 similarity: Based on Monin-Obukhov with Carslon-Boland
viscous sub-layer and standard similarity functions from look-up tables (sf_sfclay_physics = 1).
PHYSIC AND DYNAMIC OPTIONS
3.2 Land Surface (sf_surface_physics)
a. 5-layer thermal diffusion: Soil temperature only scheme, using five layers (sf_surface_physics = 1).
b. Noah Land Surface Model: Unified NCEP/NCAR/AFWA scheme with soil temperature and moisture in four layers, fractional snow cover and frozen soil physics. New modifications are added in Version 3.1 to
better represent processes over ice sheets and snow covered area.
3.3 Urban Surface (sf_urban_physics – replacing old switch
ucmcall)
a. Urban canopy model (1): 3-category UCM option with surface effects for roofs, walls, and streets.
PHYSIC AND DYNAMIC OPTIONS
4. Planetary Boundary layer (bl_pbl_physics)
a. Yonsei University scheme: Non-local-K scheme with explicit entrainment layer and parabolic K profile in unstable mixed layer (bl_pbl_physics = 1).
b. Mellor-Yamada-Janjic scheme: Eta operational scheme. One- dimensional prognostic turbulent kinetic energy scheme with local vertical mixing (2).
5. Cumulus Parameterization (cu_physics)
a. Kain-Fritsch scheme: Deep and shallow convection sub-grid scheme using a mass flux approach with downdrafts and CAPE removal time scale (cu_physics = 1).
Input Data
Sumber :
m
mm.uca
Alur WRF
Sumber :
m
mm.uca
System requirement
Required libraries (WRF and WPS):
• FORTRAN 90/95 compiler
• C compiler
• Perl
• netCDF
• NCAR Graphics (optional, but recommended – used by
graphical utility programs)
Optional libraries* for GRIB2 support (in WPS):
• JasPer (JPEG 2000 “lossy” compression library)
• PNG (“lossless” compression library)
Data Hasil WRF-ARW
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Disebut Fg ( first Guess )
Sumber Data Observasi
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NCEP prebufr files
: real- time dan archived
ob_format = 1
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NCAR archived observation data files
( Format Little_R via obsproc)
ob_format = 2
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NOAA / ESRL / GSD MADIS files
: real-time dan
archived
Data Observasi
Sumber :
m
mm.uca
Data Observasi Prebufr NOAA
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Real-time data
Download dari NCEP NOAA, yaitu :
gdas1.thhz.prebufr.nr dan
gdas1.thhz.gpsro.tm00.bufr_d
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Archived data
Observation Pre-processor
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Tujuannya :
Mengubah data observasi yang berbentuk format
Little_R agar dapat dipakai kedalam WRF-Var.
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Fungsi dasar :
Menyaring data observasi konvensional ( time
window, domain, duplikasi, dll ) untuk keperluan
asimilasi Wrf-Var.
Data Observasi NCAR
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Data udara atas sejak 1972
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Data Observasi permukaan sejak 1975
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Lalu di konversi kedalam bentuk format Little_R.
•
Kemudian di proses kedalam observation pre-processor
( obsproc.exe ).
Data Observasi NCAR ( cont'd)
Sumber :
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mm.uca
Data Observasi MADIS
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Perlu software konverter
.
•
Belum sepenuhnya di tes.
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Data Observasi sejak 2001, yaitu Metar, ACARS,
satwnd, marine, radiosonde.
Data Satelit
Sumber :
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Cakupan satelit NOAA
Sumber :
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Sumber :
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Data yang dipakai
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Data radiasi satelit NCEP global bufr format ( total 15
sensor dari 6 satelit )
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4 HIRS dari NOAA 16, 17, 18, metop-2
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5 AMSU-A dari NOAA 15,16,18, EOS-Aqua, metop-2
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3 AMSU-B dari NOAA 15, 16, 17.
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2 MHS dari NOAA 18, metop-2
Radiative Transfer Model
• Berfungsi untuk menghitung radiasi dan tingkat kecerahan temperatur
1=RTTOV (Radiative Transfer for TOVS)
EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites)
http://www.metoffice.gov.uk/research/interproj/nwpsaf/rtm/index.html
Latest released version: RTTOV_9_3,
Version used in WRF-Var: RTTOV_8_7 (no plan/resource to update to RTTOV_9)
2=CRTM (Community Radiative Transfer Model)
JCSDA (Joint Center for Satellite Data Assimilation)
ftp://ftp.emc.ncep.noaa.gov/jcsda/CRTM/
Kondisi saat ini
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Single Computer, Fedora 12
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physics and dynamic option
mp_physics = 4, WSM-5 Class Scheme
ra_lw_physics = 1, RRTM Scheme
ra_sw_physics = 1, Dudhia Scheme
sf_sfclay_physics = 2, Eta Similarity
sf_surface_physics = 1, 5-Layer thermal diffusion
bl_pbl_physics = 2, MYJ Scheme
cu_physics = 3, Grell-Devenyi Ensemble
Resolusi Topografi = 36 km
Resolusi Grid = 10 '.
Validasi
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Resolusi 60 km
Validasi
Suhu Permukaan, Medan
0 5 10 15 20 25 30 35
20 27
20-30 April 2011
oC
WRF OBS
Validasi
Suhu Permukaan, Cengkareng
0 5 10 15 20 25 30 35
20 22 25 28
20-30 April 2011
oC
WRF
OBS
Suhu Permukaan, Makassar
0 5 10 15 20 25 30 35
20 21 26 30
20-30 April 2011
oC
WRF OBS
Validasi
Validasi
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Resolusi 36 km.
RH Medan
0 20 40 60 80 100 120
2 5 9
2-9 Mei 2011
% WRF
OBS
Suhu Permukaan, Cengkareng 0 5 10 15 20 25 30 35 40 2 4
2-9 Mei 2011
oC
WRF
OBS
Validasi
RH Cengkareng 0 10 20 30 40 50 60 70 80 90 100 2 4
2 -9 Mei 2011
% WRF
OBS
Suhu Permukaan Makassar
0 5 10 15 20 25 30 35
2 6 8
2-9 Mei 2011
% WRF
OBS
RH Makassar
0 20 40 60 80 100 120
2 6 8
2-9 Mei 2011
% WRF
OBS
Hasil
Hasil
Hasil
Kesimpulan
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Data hasil Observasi baik synop, pilot, rason, dll
dapat dipakai sebagai inputan WRF-Var
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Data hasil Observasi satelit juga dapat dipakai untuk
input WRF-Var
Saran
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Perlu dibangun Cluster untuk instalasi WRF-Var
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Validasi model dengan MET ( Model Evaluation Tool )
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Pemilihan Fisik dan dinamik yang tepat untuk wilayah
Terima
