JOINT WMO TECHNICAL PROGRESS REPORT ON THE GLOBAL DATA
PROCESSING AND FORECASTING SYSTEM AND NUMERICAL
WEATHER PREDICTION RESEARCH ACTIVITIES FOR 2009
Central Institute for Meteorology and Geodynamics, Austria
1.
Summary of highlights
Work on the limited area model ALADIN focused on the development of a modified cloudiness diagnostics
and the operational implementation of the ALARO-0 prognostic convection scheme (3MT). In April 2009 the
full ALARO-0 physics package was finally put into operations. Special attention was given to the evaluation
of high resolution model versions (ALADIN 5km, AROME 2.5km).
A pre-operational version of an ALADIN-AUSTRIA assimilation system using 3D-VAR for atmospheric fields
and optimum interpolation method for surface field was implemented. Further, work to study the impact of
new observation types like GPS based humidity data and ASCAT soil moisture data in the assimilation
system has started in 2009.
In the field of limited area ensemble prediction the work focused on the creation of surface perturbations and
the optimization of the blending technique for upper air perturbations. Further, experiments were carried out
to evaluate the impact using a clustering method to select representative global EPS members to be coupled
with the LAMEPS.
The work related to nowcasting focused on the parameterization of elevation effects on the precipitation
distribution in mountainous terrain.
2.
Equipment in use
Computers used for the forecasting system are NEC and Linux clusters:
3.
Computer
Memory
Storage
2 NEC SX-8R, 8 CPU each
2 Opteron Linux clusters , 8 cpu each
Opteron Linux cluster, 8 cpu
128GB
16GB
32GB
4.4TB
3.5TB
1TB
Data and Products from GTS in use
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SYNOP
TEMP
AMDAR
SHIP
FAX
GRIB
4.
Forecasting system
4.1
System run schedule and forecast ranges
The operational Limited Area Model ALADIN (named ALADIN-AUSTRIA in the following) is run for times per
day. Forecast range and times for product availability can be read from the table below.
Suite
1
2
3
Analysis time + forecast range
00UTC + 72 h
06UTC + 60 h
12UTC + 72 h
Product availability
3:30 UTC
10:20 UTC
15:30 UTC
4
4.2
18UTC + 60h
22:20 UTC
Medium range forecasting system (4-10 days)
Locally none (ECMWF products are used).
4.3
Short-range forecasting system (0-72 hrs)
4.3.1
Data assimilation, objective analysis and initialization
The operational initialisation of the ALADIN LAM model at ZAMG is still dynamical downscaling of analysis
fields from the French global model ARPEGE and ECMWF IFS model. Meanwhile a pre-operational parallel
run initialised by ALADIN-3DVAR has been conducted. This analysis system contains a 3DVAR part for
upper-air data and the CANARI optimal interpolation part for surface assimilation. The lateral boundary data
and SST are taken from downscaled ARPEGE analyses. After some successful tests of the two individual
assimilation parts, both have been put together and have been run combined in a 6 hourly cycle since
summer 2009. It is planned to initialise the ALADIN short range forecast with the results of this analysis
system in the future. Experiments, related to the impact of individual observation systems on the analysis
system, and the integration of further observation datasets especially GPS data in the ALADIN-3DVAR
analysis are part of the ongoing research at ZAMG. Additionally a new Kalman Filter based surface analysis
system has been tested, which uses satellite derived soil moisture observations from ASCAT.
Observations currently used in the pre-operational 3DVAR
assimilation system; the use of GPS data is tested separately:
Observation system
SYNOP
SHIP
AMDAR/AIRREP
TEMP
WINDPROFILER
GEOWIND
NOAA-AMSU-A
NOAA-AMSU-B
Assimilated fields in the preoperational run at ZAMG
T2m,RH2m,Φ
T2m,RH2m,Φ,U10m,V10m
U,V,T
U,V,T,Q, Φ
U,V
U,V
radiance
radiance
Schematic of the pre-operational assimilation cycle at ZAMG;
Long cutoff (blue) and short cutoff (red):
The research work on GPS ZTD data assimilation has started in the middle of 2009 and is planned to end in
August 2010. This research work is within the framework of Austrian national GNSS-MET project. High
density GPS ZTD data of the whole Austrian domain (about 42 stations) will be delivered by the Technical
University of Vienna to ZAMG. Then they will be assimilated into the ALADIN/Austria 3DVAR system. The
aim is to investigate whether the high density GPS ZTD data which is a function of the pressure, temperature,
humidity can bring any positive impact on regional weather forecast, especially the locally developed
convective precipitation events.
4.3.2
Model
4.3.2.1 In operation
The model system for the short range weather forecast used at ZAMG is ALADIN-AUSTRIA (Wang et al.
2006). The integration domain of ALADIN-AUSTRIA is shown in Figure 1. In April 2009 the full ALARO-0
physics package was put into operations after extensive tests. The main characteristics of the model are:
Horizontal resolution:
Number of levels:
Number of grid points:
Time-step:
Coupling model:
Coupling frequency:
Forecast range:
Output every:
Physics:
Orography:
Grid:
9.6 km
60, pressure-based, hybrid coordinate
300 x 270
415 sec, 2-time-level SLSI time integration
ARPEGE, DFI initialization
3 hours, Davies-Kallberg relaxation scheme
72h / 60h
1 hour
ALARO-0 physics (prognostic large scale cloud and
precipitation scheme + prognostic convection scheme 3MT,
pseudo-prognostic TKE scheme, ...), Boer-type scheme of
gravity wave drag; ISBA surface scheme;
envelope
quadratic
Figure 1: Domain and model topography of ALADIN-Austria.
4.3.2.2 Research performed in this field

During pre-operational testing it was found that the cloudiness diagnostics within the ALARO-0
physics environment shows some deficiencies to forecast overcast skies. A modified cloud
diagnostic version was therefore developed (Wittmann 2009) and finally introduced into the common
ALADIN source code package.
Figures 2+3: Cloud cover “climatology” model (red) vs. synop observation (green) for June 2008. Left:
Original cloud diagnostics, Right: Modified cloud diagnostics

A 4.9km (horizontal resolution) version of ALADIN using ALARO-0 physics package and a 2.5km
AROME model was set into pre-operational status (1 daily run with 48h and 30h forecast range
respectively). During verification special emphasis was given to the evaluation of (convective)
precipitation forecasts using the object based verification method SAL (Wernli et al. 2008).
4.3.3
Operationally available NWP products
4.3.4
Operational techniques for application of NWP products
4.3.4.1 In operation
A so-called ‘META’-forecast system is in operation for short-range forecasts. It utilizes the output of global
and limited-area models (ECMWF, ALADIN, GME, COSMO, UKMO) available at ZAMG to generate biascorrected, optimized, weighted point forecasts of standard meteorological quantities at surface station
locations.
4.3.4.2 Research performed in this field
The META-forecast system has been extended to further parameters and the forecast range has been
increased to +10 days.
4.3.5
Ensemble Prediction System
4.3.5.1 In operation
The operational LAMEPS system at ZAMG, ALADIN-LAEF, was upgraded in February 2009 (Wang et al.
2010). The generation of Initial perturbations in the ALADIN-LAEF system is implemented as follows: 1)
Upper air perturbations to initial conditions are calculated by blending the large scale perturbation generated
by the ECMWF, using the Singular Vector method, with the small scale perturbation generated by ALADINBreeding; 2) NCSB (non-Cycling Surface Breeding) technique is used for perturbations to initial surface
conditions (Wang et al. 2010?). To consider perturbations due to model uncertainties a multi-physics scheme
is applied as well.
Currently ALADIN-LAEF is running under the SMS (Supervisor Monitoring Scheduler) environment on high
computer facility of ECMWF twice per day (00 and 12UTC), consisting of 16 perturbed members and one
control member, on 18 km horizontal resolution, with 37 levels in the vertical. The domain of the perturbed
members and the control run covers Europe and a large part of the North Atlantic (Fig. 3). The output
frequency of the forecast runs has been increased to 1-hourly.
In 2009 a deterministic model, ALADIN-EU has been implemented and is in operational use. The domain of
ALADIN-EU covers whole Europe and large parts of the North Atlantic. It is run twice per day with a
horizontal resolution of 6.5 km and 45 vertical levels. The coupling model of ALADIN-EU is the deterministic
ECMWF run.
ALADIN-LAEF and ALADIN-EU data are operationally archived in MARS system at ECMWF.
Figure 4:
ALADIN-LAEF domain and model topography. The inner limited-area domain in red is the
ALADIN-LAEF post-processing and verification domain, which covers Central Europe and has a resolution of
0.15° x 0.15°.
4.3.5.2 Research performed in this field
LAMEPS is a major field of research in the NWP group at ZAMG. Studies have been done on how to
optimize the way of dealing with uncertainties in the analysis. The Blending technique, where the large scale
perturbations from the ECMWF EPS members generated by Singular Vector are combined with the smallscale uncertainty generated by ALADIN-Breeding, has been further developed. For surface initial
perturbations the NCSB technique has been developed, which generates the surface perturbation by
blending the ALADIN control surface analysis and the very short range surface forecast driven by perturbed
atmospheric forcing, e.g. by the ECMWF EPS members (Wang et al. 2010). Further studies have been
carried out to improve the results by optimizing tuning parameter. Experiments using clustering analysis of
ECMWF EPS to select the member for coupling of ALADIN LAEF in an objective way have been
implemented. It was shown that using representative member from clustering improves the performance of
ALADIN LAEF slightly (Fig. 4 from Weidle et al 2010).
First tests for an increase of resolution up to 11 km and an enlarged domain, covering whole Europe have
been carried out.
Other studies on statistical calibration of LAEF forecast have also been carried out. The non-homogenous
Gaussian regression method is used for performing a statistical correction of the first and second moment
(bias and dispersion) for 2m temperature (Kann et al. 2009).
Figure 5: Continuous Ranked Probability Score of Temperature at 850 hPa for the operational LAEF system
(solid) and LAEF when driven by ECMWF-EPS member selected by clustering analysis (dashed/dotted).
4.3.5.3 Operationally available EPS Products
The following ALADIN-LAEF products are available at 1h time resolution
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Mean/spread/spaghetti/probability/post stamp chart:
2m Temp, 10m Wind, 2m RH, Total Precipitation, Mslp, and 500hPa Geopotential
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EPS-meteogram
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Mean/spread/probability/post stamp chart:
250, 500, 700, 850, 925hPa, T, Wind, Geopotential, RH (lower Level)
4.4
Nowcasting and Very Short-range Forecasting Systems (0-6 hrs)
4.4.1
Nowcasting system
4.4.1.1
In operation
The high-resolution analysis and nowcasting system INCA (Integrated Nowcasting through Comprehensive
Analysis) developed at ZAMG provides three-dimensional fields of temperature and humidity on an hourly
basis, and of wind in 10 min intervals. Two-dimensional fields of precipitation rate, precipitation type, and
cloudiness are provided at 15 minute intervals.
Figure 6: Austrian domain and topography of the nowcasting system INCA.
The system is operated with a horizontal resolution of 1 km and a vertical resolution of 100-200 m on the
region shown in Fig. 5. In addition to this Alpine domain, it is further applied to the neighbouring countries
Czech Republic and Slovakia. INCA combines surface station data, remote sensing data (radar, satellite),
forecast fields of the numerical weather prediction model ALADIN, and high-resolution topographic data
(Haiden et al., 2009).
Table 3: Meteorological fields analyzed and nowcasted in INCA (SFC = surface station data, SAT = satellite
data, RAD = radar data)
Nowcasting field
Required observations
Update
Temperature
SFC: 2m temperature
SAT: MSG cloud types (optional)
1 hour
Humidity
SFC: 2m humidity
1 hour
Wind
SFC: 10m wind and gusts
10 min
Precipitation
Precipitation type
Cloudiness
Global radiation
Convective
diagnostics
SFC: precipitation
RAD: radar precipitation
Derived from precipitation
and temperature nowcast
SAT: MSG cloud types
SFC: sunshine% (optional)
SAT: MSG cloud types
SFC: global radiation
Derived from temperature,
humidity and wind nowcast
15 min
15 min
15 min
1 hour
1 hour
The most important applications of INCA products are flood prediction and warning (Komma et al., 2007),
road weather prediction, and predictions for the energy sector. Verification shows that the average
performance of INCA as measured by MAE significantly exceeds that of NWP models (ALADIN, ECMWF)
during the first 4 hours of the forecast in the case of precipitation (not shown), and 6-8 hours in the case of
temperature (Fig. 6).
Figure 7: Mean absolute error and bias of the INCA temperature forecast for all Austrian non-mountain
stations as a function of lead time for the period 01-01-2008 to 04-04-2009. Also shown, for comparison,
corresponding values for the ALADIN model (ref) and persistency (per)
4.4.1.2 Research performed in this field
Research in nowcasting is concentrated on the parameterization of elevation effects on the precipitation
distribution in mountainous terrain as for the short durations typical in nowcasting (15 min), the intensitydependence of the elevation effect has to be taken into account (Haiden and Pistotnik, 2009).
The INCA analysis system has been combined experimentally with a hydrological model (two-way coupling)
in order to use runoff data as a quality measure for the elevation-precipitation parameterization.
There were also minor developments in the improvement of data filter algorithms, data quality control, wind
analysis and verification issues.
In the framework of the SNOW-V10 (Science & NOWcasting of Olympic Weather for Vancouver 2010)
project, embedded in WMO’s WWRP programme, the INCA application has further been extended to the
Vancouver region. Real time analyses and short range forecasts were made available for local
meteorologists during the Olympics and Paralympics.
4.4.2
Models for Very Short-range Forecasting Systems
4.4.2.1
In operation
The INCA system smoothly combines the nowcast with classical NWP forecasts using a pre-defined
weighting function. For most quantities, this weighting function gives full weight to the nowcast for the first 2
hours, and decreases linearly between +2 and +6 hours.
4.4.2.2
Research performed in this field
4.5
Specialized numerical predictions
4.6
Extended range forecasts (ERF) (10 days to 30 days)
4.6.1
Models
4.6.1.1 In operation
Locally none (ECMWF products are used).
4.6.2
Operationally available NWP model and EPS ERF products
Locally none (ECMWF products are used).
Extended range forecast products are generated with special respect to Austria. 2m temperature, 10m wind
speed, precipitation and cloudiness are visualized for major Austrian cities as a function of forecast
projection (Fig. 7).
Figure 8: 5%, 25%, 50%, 75% and 95% percentiles of ECMWF 2m temperature as a function of forecast
range. Initialization date: 02.04.2009, 00UTC. Forecast for Vienna.
4.7
Long range forecasts (LRF) (30 days up to two years)
4.7.1
In operation
ECMWF’s seasonal forecast system 3 is obtained and post-processed to satisfy local requirements. Among
others, probabilities for negative, neutral and positive temperature anomalies for the coming season are
calculated (see Fig 8).
Figure 9: Probability [%] for predicted mean temperature anomalies for the coming season (MAM) for
Austria: The probabilities for negative (blue box), neutral (green) and positive (red) anomalies are shown.
The anomalies have been calculated with respect to a hindcast period from 1981 onwards
4.7.2 Research performed in this field
4.7.3
Operationally available EPS LRF products
Event probabilities, monthly mean anomalies of 2m temperature and monthly anomalies of precipitation
sums are processed for operational purposes.
5.
Verification of prognostic products
Verification done for the prognostics products of the operational ALADIN-AUSTRIA model and other
experimental model:
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Point forecast vs. synop: 2m temperature, 2m relative humidity, 10m wind speed, 10m wind direction,
10m gust speed, mean sea level pressure, total cloudiness
Precipitation forecast: Verification is done on rectangular domains using INCA precipitation analysis
as a reference. Beside traditional grid-point and areal mean scores (POD, FAR, HSS, etc) the object
based method SAL is used.
Free atmosphere: Verification of model fields (temperature, geopotential, wind speed, relative
humidizy) on several standard pressure heights is done against the models own analysis and
alternatively radiosoundings.
6.
Plans for the future (next 4 years)
6.1
Development of the GDPFS
6.2
Planned research Activities in NWP, Nowcasting and Long-range Forecasting
6.2.1
Planned Research Activities in NWP
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6.2.2
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Further development of ALARO physics in order to be able to switch the operational ALADINAUSTRIA model from 9.6km to 5km horizontal resolution. Special attention will be given to the
prediction of (convective) precipitation, low stratus and screening level diagnostics.
Work on the improvement and validation of ALADIN 3D-VAR and surface assimilation (using
optimum interpolation and/or EKF) will continue.
Further research on the impact of assimilation of new observation types such as GPS and ASCAT
soil moisture data will be carried out.
Tests with increased resolution of the Limited Area Forecasting System ALADIN-LAEF will be
carried out to evaluate the potential benefit with respect to the current operational version of
ALADIN-LAEF.
Planned Research Activities in Nowcasting
Coupling of INCA with AROME: Nowcasting of convective precipitation over Alpine terrain will be a
major topic for research. The benefit of using high resolution AROME forecasts (wind, moisture, etc)
as an input for the nowcasting system INCA for the prediction of convective cells evolution (initiation,
intensification, weakening, dissipation) will be explored.
Further development of the analysis and nowcasting system INCA will continue with special
emphasis on: Gust nowcasting, downburst potential, low stratus, precipitation nowcasting
(improvement of motion vectors).
6.2.3
Planned Research Activities in Long-range Forecasting
7.
References
Haiden, T., and G. Pistotnik, 2009: Intensity-dependent parameterization of elevation effects in precipitation
analysis. Adv. Geosci., 20, 33-38.
Haiden, T., A. Kann, G. Pistotnik, K. Stadlbacher, and C. Wittmann, 2009: Integrated Nowcasting through
Comprehensive
Analysis
(INCA)
System
description.
ZAMG
report,
61p.
http://www.zamg.ac.at/fix/INCA_system.pdf
Kann, A., C. Wittmann, Y. Wang and X. Ma, 2009: Calibrating 2m Temperature of Limited Area Ensemble
Forecasts Using High Resolution Analysis. Mon. Wea. Rev., 137, 3373-3387
Komma, J., C. Reszler, G. Blöschl, and T. Haiden, 2007: Ensemble prediction of floods - catchment nonlinearity and forecast probabilities. Nat. Haz. Earth Syst. Sci., 7, 431-444.
Wang, Y., A. Kann, M. Bellus, J. Pailleux, and C. Wittmann, 2010: A strategy for perturbing surface initial
conditions in LAMEPS, Atmos. Sci. Let., 11, DOI: 10.1002/asl.260
Weidle, F., W. Tian, T. Wang, and Y. Wang, 2010: Strategies for using Clustering Analysis of ECMWF-EPS
for Initial Conditions in LAMEPS, Tellus A, in preparation
Wernli, H, M. Paulat, M. Hagen, and C. Frei, 2008: SAL - A novel quality measure for the verification of
quantitative precipitation forecasts, Mon. Wea. Rev., 136, 4470-4487.
Wittmann, C., 2009: Near maximum overlap version for ACNPART. ALADIN/LACE report, available from
http://www.rclace.eu/File/Physics/2009/wittman_cloud_acnpart_2009.pdf