Mesoscale NWP Model Intercomparisonfor The Maritime Continent :

Preliminary Results and Future Plans

Tri Wahyu Hadi

Atmospheric Science Research GroupFaculty of Earth Sciences and Technology

Institut Teknologi BandungINDONESIA

Acknowledgement

• Kyoto University Active Geosphere Investigationfor The 21st Century COE Program (KAGI 21) :Profs. T. Tsuda and S. Yoden

• Institute for Research and Community Services (LPPM), ITB : Prof. Emmy Suparka

• MEXT Special Coordination Funds for PromotingScience and Technology

• Research assistants and students : Nurjanna Joko T.,I Dewa G. A. Junnaedhi, Amry Widyatmoko

• Other supporting agencies and research collaborators

Outline

1.Background and Motivation

2.Previous works and some results :• Near real-time downscaling experiments• A numerical study on strong convective

system

3. Current works • Mesoscale NWP model intercomparison• Another study on strong convective system

4. Future Plans

Background and Motivation :Meteorological Disasters in The Maritime Continent of Indonesia

Small “twister” in Yogyakarta (http://www.detik.com and other web sites)

“Extreme” Winds

• Small scale but relatively strong transient weather disturbance

• Torrential rain due to mesoscale convective system

• Increasing frequency and intensity (?)

• Effort to reduce these disaster necessitates a high resolution NWP system

“Extreme” Rainfall

Flooding over wide area (Aceh 2006, Central Java 2008)

Severe floods in Jakarta, Jan/Feb 2002, Feb. 2007, Feb 2008

Previous Works and Some Results :Near Real-Time Downscaling Experiments (1)

Global domain

Data freely available on the internet,NCEP GFS global model output :• Horizontal resolution : 0.5° & 1° available• Vertical resolution : 24 sigma levels • Time resolution : 3 hr (downloaded at 6 hr

interval)• Prediction range : up to 384 hr (var. res.)• Number of output parameters : 128 • GRIB ver. 2 data format

Targetted regional model characteristics

• Coarse grid res. : 30 km x 30km• Finer grid res. : 10 km x 10 km• Vertical resolution : 32 sigma levels • Time resolution : 3 hr• Two-way nesting between coarse and

finer domain

(figure by JMA)

Regional Model domains

Previous Works and Some Results :Near Real-Time Downscaling Experiments (2)

NOAA

Dept. Inf. ScienceKochi University

Space Science and Engineering Center(SSEC) University of Wisconsin

Block A :Internet Resources

Dept. Atm. Sci. University of Wyoming

GFS Data

SondeData

MTSAT IR mages

MTSAT/GOESlatest images

Block B :Download Server

Regional model Preprocessing(if data is adequate)

Daily rainfall estimation

Model runup to 48-hour lead time prediction

Topgraphyand land-use data (fixed)

Post processing of regional model output

-Monitoring-Prediction -Nowcasting-Forcast Verification

Block D : Web Server

Postprocess

Block C : PC Cluster

??

Previous Works and Some Results :Near Real-Time Downscaling Experiments (3)

MM5 modeling system :Non-hydrostaticPrimitive equationsDeveloped by PSU/NCARFree software Parallel version with MPIModel Setup

- boundary-layer parameterization : MRF

- cumulus parameterization :Grell (30 km) & KF (10 km)

Downscaling without additional

input except refinement of tropography

Previous Works and Some Results :Near Real-Time Downscaling Experiments (4)

1200 UTC

0000 UTCThe system hasrecently beenupgraded resulting in reduced latency

NCEP-GFS Forecast Run at 1200 UTC

Download Time

2100 UTC

MM5 Forcast Run

1200 UTC

MM5 Regional Prediction effective forecast lead time

Data downloaded at 6 hr fcst interval

PC Cluster assembledinhouse : 8 nodesAMD Athlon 64;10 GB total memory4 TB total data storage

Previous Works and Some Results :Near Real-Time Downscaling Experiments (5)http://weather.geoph.itb.ac.id/

Previous Works and Some Results :Near Real-Time Downscaling Experiments (6)

pure downscaling

not much improvementin average error

Previous Works and Some Results :A Numerical Study of Strong Convective System (1)

Pwat (kg/m2)

TBB (K)

Synoptic scale conditionrelated to Jakarta flood event of Jan/Feb 2002

• Southward migrationof monsoon trough

• Appearance of cyclonicvortex over the Indian Oceansouth-west of Jakarta

Data : NCEP global tropospheric analysis and GMS IR imageries(daily averaged TBB)

Northern coastal plain of Java Island is prone to heavy rainfall during end of Jan.-beginning of Feb.

Previous Works and Some Results :A Numerical Study of Strong Convective System (2)

Rc (mm)

• MM5 daily accumulated rainfall

• 3 km horizontal resolution

• NCEP-FNL initial and boundary condition

Concentration of heavy rainfall over Jakarta area

Previous Works and Some Results :A Numerical Study of Strong Convective System (3)

TBB (K)

From Edvin Aldrian (BPPT), Courtesy of BMG

Characterized by North-Southmovement of convectivesystem

Previous Works and Some Results :A Numerical Study of Strong Convective System (4)

Clw (g/kg)

27 Jan 2002, 0200 LT 27 Jan 2002, 0300 LT

27 Jan 2002, 0400 LT 27 Jan 2002, 0500 LT

Convectivemechanism :

cold pooladvection

Previous Works and Some Results :A Numerical Study of Strong Convective System (4)

Clw (g/kg)

Convectivemechanism :

mixed layerblocking

Previous Works and Some Results :Anticipated Problems in NWP Application

• Model accuracy High resolution simulation using NWP model hasrevealed a detailed structure of the convective systemrelated to heavy rainfall events but downscaling alonedoes not seem to significantly improve average forecast error local data assimilation

• Model uncertaintyModel uncertainty is an inherent problem of atmospheric predictability quantification by meansof (multi-model) ensemble forecasting learning from other projects, model intercomparisons is an important step

Current Works :Mesoscale NWP Intercomparison (1)

JMA

CMA

MSC

ZAMG

NCEP

CMAS

BRDP08, Courtesy of Dr. Hiromu Seko (MRI-JMA)

Current Works :Mesoscale NWP Intercomparison (2)

Improvement of Computational Infrastructure

The same look and number of nodes but now with :

• Processor : Intel Core2 Quad Core(2.4 GHz) per node (32 cores in total)

• 32 GB of total memory• OS : Open SuSE 10.2 (free version)

PC Cluster assembled inhouse : • 8 nodes (1 master and 7 diskless nodes)

• Processor : single AMD Athlon (2.0 GHz) per node

• 10 GB total memory• OS : SLES 9.0

MM5 and WRF test runs show that Hybrid SMP-MPI system reduce computational time by a factor of 4 to 6

Current Works :Mesoscale NWP Intercomparison (3)

MM5-WRF output samples

• Apart from accuracies, MM5 andWRF produced quite results at 30 km resolution downscaling

• WRF accumulated rainfall is morecharacterized wih small scale features

Current Works :Mesoscale NWP Intercomparison (4)

WRF 3km simulation of heavy rainfall

WRFMM5

Rc (mm)

Current Works :Mesoscale NWP Intercomparison (5)

WRF with cumulus parameterization WRF explicit

• Convection initiated at the top of PBL• Gravity-wave induced convection (?)• Sensitivity to cumulus parameterization at 3 km resolution

Current Works :Another Study of Strong Convective System (1)

http://foto.okezone.com/

0104 07

Floods in Karawang :• Long duration of inundation (more than 10 days)

• Relatively large area• Seems to be triggered by rainfall event of Feb. 6, 2008

• Less effect of topography(?)

Current Works :Another Study of Strong Convective System (2)

2008/02/06 21:06 2008/02/06 22:062008/02/06 19:06 2008/02/06 20:06

2008/02/07 00:062008/02/06 22:30 2008/02/06 23:06 2008/02/06 23:30

2008/02/07 00:30 C-band Radar Images Courtesy of HARIMAU Project(JAMSTEC-BPPT)

Eastward moving convective cells along the coastal plain

Current Works :Another Study of Strong Convective System (3)

30-hour forecast of 3-hourly convective rainfall (07/02/2008 0100 LT)

MM5 WRF

• New resolution set-up 27-9-3 km nesting (2 online and 1 off-line) • Another type of blocking (land-breeze?) • Too strong blocking in WRF• WRF requires more parameter tuning

Future Plans : Three-model Intercomparisons with JMA-NHM

06 February 2008, JMA-NHM test run 24 and 30 hour forecast of 3-hourly precipitation, 27 km resolution

JMA-NHM has been installed and being tested to run donwscaling forecast with NCEP-GFS data

Future Plans : Coal Mines at Berau as Forecast Test Ground

• Partial funding by PT. Berau Coal

• Installation of 6-7 AWS

• Near real time data transfer to ITB

• Experiments on local data assimilation

• Decision support system in mining opration as apart of research activities

Future Plans : C-Band Radar and GPS/Met over West Java

• Another high-resolutionsimulation and forecast test ground

• Relatively dense GPSnetwork as part of INATEWS

• High possibility to obtain near real-time GPS/Metdata through collaborationwith BAKOSURTANAL (National Survery and MappingAgency)

• More powerful if combined withC-band radar at Serpong through collaboration with JAMSTEC

Courtesy of Cecep Subarya (BAKOSURTANAL)

Concluding Remarks

• Capacity building We have developed an entry-level computational infrastructure to conduct NWP research in SEA(The Maritime Continent of Indonesia). We are setting upan environment for model intercomparison

• Near-real time downscaling experimentsMM5-WRF intercomparison shows that WRF requiresmore model parameter tuning in the tropics

• Process study Strong convections related to heavy rainfall involve complex mechanisms

• Future plan We are trying to setup two ground tests for model intercomparison (Berau and Jakarta)