JOINT WMO TECHNICAL PROGRESS REPORT ON THE GLOBAL DATA
PROCESSING AND FORECASTING SYSTEM AND NUMERICAL
WEATHER PREDICTION RESEARCH ACTIVITIES FOR 2012
Pakistan Meteorological Department - Pakistan
1. Summary of highlights
Pakistan Meteorological Department (PMD) has been running High-resolution Regional Model
(HRM) since 2006. HRM is hydrostatic regional weather forecast model with horizontal grid
resolution flexible between 0.25° - 0.05° (~ 28 to 6 km) and hybrid vertical coordinate, 30 - 60
layers.
Initially model was configured at 22km horizontal grid resolution and forecast was generated two
times a day at 00:00 and 06:00 GMT using initial and boundary conditions from German Global
Model (GME). Later in September 2010 after successful deployment of powerful 256 cores High
Performance Computing Cluster (Blade Servers) having peak performance of about 1.7 TFlops the
HRM has been configured at finer horizontal grid resolution of 11km and now the forecast is
generated three times a day 00:00, 06:00 and 12:00 GMT. The spatial coverage of HRM simulation
has also been extended and now model is simulated using domain size 46oE to 96 oE and 5 oN to
50 oN. From March 2012, the GME data resolution has been shifted from 30km to 20km. PMD has
successfully deployed HRM with new GME data.
PMD has signed license agreement with DWD Germany for use of non-hydrostatic Numerical
Weather Prediction Model COSMO (Consortium for Small-scale Modeling). Cosmo model will be
used for internal scientific and official meteorological service purposes.
Grid point precipitation data is extracted daily for Pakistan which is used as an input to a Flash
Flood Guidance System (FFGS). The FFGS has been developed by Hydrological Research Centre
(HRC) USA, for early warning of flash flood threats.
2.
Equipment in use
Pakistan Meteorological Department acquired High Performance Computing Cluster comprising of
HP rack mount servers in 2006 to cope with the computational needs of numerical models. Later in
September 2010 PMD successfully deployed Powerful 256 cores High Performance Computing
Cluster (Blade Servers) having peak performance of about 1.7TFlops and it is operational now to
simulate regional weather forecast and climate models at very fine grid resolutions. The technical
specifications of existing system and newly acquired Dell blade servers are as under.
High Performance Computing Cluster (HP Rack mount Servers)
HP Proliant DL380 G4
Compute Nodes: Nos 09
Processor: 3.4 GHz Intel Xeon dual process each
RAM: 4 GB each
Hp Proliant DL380 G5
Computer Nodes: Nos 04
Processor: 3.0 GHz Intel Xeon dual core dual processor each
RAM: 4 GB each
Storage
DELL Power Vault MD1000 Director Attached Storage
Capacity: 12 TB (12 SATA Drives of 1TB each)
Connectivity
Gigabit Ethernet
High Performance Computing Cluster (Blade Servers)
Peak Computational Performance 1.7 TFlops
Dell Power Edge M600 Blade Servers
Compute Nodes: 32 Nos
Processor: 3.33GHz 2 x Quad Core Intel Xeon Processors
RAM: 8 GB Each
Connectivity:
Infiniband Interconnect 20Gbps
Fiber Channel 8Gbps
Storage:
SAN Dell/EMC CX4-120 with Fiber Channel 8 Gbps Interconnect
12 TB SATAII (12 drives of 1 TB each)
FC 5.2 TB (13 Drives of 400 GB each)
3.
Data and Products from GTS in use
A GTS link via ftp has been established in 2011 between China Meteorological Agency
(CMA), and PMD Islamabad. NWP products of CMA’s Global Spectral Model (GSM) in Grib1
format are being uploaded to PMD’s ftp server daily at 00:00, 06:00, 12:00, and 18:00 GMT. GSM
has a horizontal resolution of TL639 (0.28125 deg) and is used for Short- and Medium-range
forecast. Outputs of GSM in graphical form are updated daily on website of PMD after post
processing.
4.
Forecasting system
4.1.
System run schedule and forecast ranges
The High Resolution Regional model HRM is simulated three times a day i.e. 00:00, 06:00 and
12:00 GMT to generate 72 hours forecast. The forecast is generated at 11km horizontal grid
resolution on 03 hourly intervals i.e. 00, 03, 06, 09, 12, 15, 18 and 21 GMT.
GFS Model at 0.5o horizontal grid resolution is used to generate one week forecast at 06 hourly
intervals i.e. 00, 06, 12 and 18 GMT.
GSM Model at 0.28125 o horizontal grid resolution is used to generate one week forecast at 00
GMT at 12 hourly intervals.
The forecast is available and regularly updated on Pakistan Meteorological Department Web Portal.
4.2
Short-range forecasting system (0-72 hrs)
4.2.1
Data assimilation, objective analysis and initialization
Several options exist to derive the initial state of the HRM, namely
a) Interpolation of the analysis of DWD‘s global model GME (grid spacing 40 km, 40 layers until 31
January 2010, grid spacing 30 km, 60 layers from 1 February 2010, grid spacing 20 km, 60 layers
from 29 February 2012) to the HRM grid,
b) 3D-Var data assimilation, based on DWD‘s PSAS scheme, ported to the HRM by Hanoi National
University, Vietnam,
c) 3D-Var data assimilation, developed by M. Bonavita and L. Torrisi (CNMCA-UGM, Rome, Italy),
d) LAPS analysis, adapted to HRM and used by INMET, Brazil.
Two options are available for lateral boundary conditions of the HRM, namely
a) Forecasts of DWD‘s global model GME, distributed to HRM users free of charge, or
b) Forecasts of the global model of the ECMWF (Reading, UK), available only to member states or
associated ones.
DWD provides the analyses and forecasts of GME on all 60 model layers and seven soil layers at
a horizontal resolution of 20 km four times per day, namely
a) Up to 78 (120) hours at 3-hourly intervals, based on the initial states for 00 and 12 UTC. These
data are distributed by the DWD via the internet between 02:40 to 03:30 UTC for 00 UTC and
between 14:40 to 15:30 UTC for 12 UTC.
b) Up to 48 hours at 3-hourly intervals, based on the initial states for 06 and 18 UTC. These data
are distributed by the DWD via the internet between 08:40 to 09:10 UTC for 06 UTC and between
20:40 to 21:10 UTC for 18 UTC.
4.3
Model
4.3.1
In operation -HRM (High-resolution Regional Model)
HRM is hydrostatic regional weather forecast model with horizontal grid resolution flexible between
0.25° - 0.05° (~ 28 to 6 km) and hybrid vertical coordinate, 30 - 60 layers.The Deutscher
Wetterdienst (DWD) is the provider of High Resolution Regional Model (HRM) which is a flexible
tool for Numerical Weather Prediction. HRM package is distributed by DWD to Universities,
research institutes, and meteorological services. On the request of HRM users. DWD prepared
topographical datasets for any region of the world containing mesh size between 28km and 6 km.
An important programme “gme2hrm” generates the initial and lateral boundary conditions for HRM
from the analysis and forecast data of Global Model GME. Many post processing programmes are
used to read GRIB1 Code forecast field of HRM. Fortran 95 has been used to implement code and
some C sub routines for GRIB1 coding and decoding. For the rapid completion of simulations by
allowing substantial reduction on programme runtime OpenMP (shared memory) and MPI
(distributed memory) are in practice. The High Resolution Regional model HRM is simulated three
times a day i.e. 00:00, 06:00 and 12:00 GMT to generate 72 hours forecast. The forecast is
generated at 11km horizontal grid resolution on 03 hourly intervals i.e. 00, 03, 06, 09, 12, 15, 18
and 21 GMT. Model is simulated using domain size 46oE to 96 oE and 5 oN to 50 oN.
Prognostic variables
 Surface pressure
ps
 Temperature
T
 Water vapour
qv
 Cloud water
qc
 Cloud ice
qi
 Ozone (optional)
o3
 Horizontal wind
u, v
 Several surface/soil parameters
Diagnostic variables
 Vertical velocity
 Geopotential
 Cloud cover
 Diffusion coefficients
Numerics of HRM:

Regular or rotated latitude/longitude grid

Mesh sizes between 0.25° and 0.05° (~ 28 to 6 km)

Arakawa C-grid, second order cantered differencing


clc
tkvm/h

Hybrid vertical coordinate, 30 to 60 layers (Simmons and Burridge, 1981)

Split semi-implicit time stepping (Burridge, 1975); t = 150s at  = 0.25°

Helmholtz equation solved by a direct method (FFT and Gauss solver)

Lateral boundary formulation due to Davies (1976)

Radiative upper boundary condition as an option (Herzog, 1995)

Linear fourth-order horizontal diffusion, slope correction for temperature

Adiabatic implicit nonlinear normal mode initialization (INMI, Temperton, 1991) or
diabatic (incremental) digital filter initialization (DFI, Lynch, 1997).
Physical Parameterization of HRM:

-two stream radiation scheme (Ritter and Geleyn, 1992) including long- and shortwave
fluxes in the atmosphere and at the surface; full cloud - radiation feedback; diagnostic
derivation of partial cloud cover (rel. hum. and convection)

Grid-scale precipitation scheme including parameterized cloud microphysics (Doms and
Schättler, 2003)

Mass flux convection scheme (Tiedtke, 1989) differentiating between deep, shallow and
mid-level convection or (alternatively) Bechtold (2001) convection scheme

Level-2 scheme (Mellor and Yamada, 1974) of vertical diffusion in the atmosphere,
similarity theory (Louis, 1979) at the surface

Subgrid scale orographic (SSO) effects (blocking and wave breaking) due to unresolved
orography (Lott and Miller, 1997)

Seven-layer soil model including snow and interception storage (Heise and Schrodin, 2002)

Sea ice model (Mironov and Ritter, 2003; Mironov and Ritter, 2004)
4.3.2.

Research performed in this field
Diagnosis and Numerical Simulation of Heavy Rainfall Event in winter over upper parts of
Pakistan.

Numerical simulation of heavy rainfall in South Asia.

Performance Evaluation of HRM for the prediction of heavy rainfall in Pakistan using
different horizontal grid resolutions i.e. 22km and 11km and different domain sizes.

Prediction of Summer Monsoon Rainfall using High-resolution Regional Model HRM.

Evaluation of HRM for different convection schemes i.e. Tiedtke and Bechtold for improved
Summer Monsoon Rainfall prediction.

Heavy Rainfall forecast by High Resolution Regional Model (HRM) and its validation for
Pakistan.
4.3.3
Operationally available NWP products
Output of following variables is generated using HRM forecast.

2 m temperature [K]

2 m maximum temperature [K]

2 m minimum temperature [K]

Surface total cloud cover [%]

Surface pressure [Pa]

Specific humidity [kg/kg]

Surface precipitation amount, rain, convective [kg/m**2]

Surface precipitation amount, rain, grid scale [kg/m**2]

Surface convective snow [kg/(m**2)]

Surface large scale snow [kg/(m**2)]

u-component (zonal) of wind [m/s]

v-component (merdional) of wind [m/s]

Geopotential [(m**2)/(s**2)]

Pressure reduced to MSL [Pa]
5.
Plans for the future (next 4 years)

Up gradation of the High Performance Computing Cluster System to meet the increasing
need of computing resources for the operational use of non-hydrostatic model COSMO at
finer resolutions.

Implementation of a non-hydrostatic limited-area atmospheric model, COSMO (Consortium
for Small-scale Modeling) to be used both for operational and for research applications.

Incorporation of in-situ data in HRM using Data Assimilation techniques for improved
weather forecast.

Development of Model verification software to validate model quantitative forecast on
regular basis.
6.
References
http://www.pmd.gov.pk/rnd/rndweb/rnd_new/numerical.php