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Towards Rapid Update Cycling for Short Range NWP Forecasts in the HIRLAM Community WMO/WWRP Workshop on Use of NWP for Nowcasting UCAR Center Green Campus, Boulder, Colorado, USA 24-26 October, 2011
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Towards Rapid Update Cycling for Short Range NWP Forecasts in the HIRLAM Community
WMO/WWRP Workshop on Use of NWP for Nowcasting
UCAR Center Green Campus, Boulder, Colorado, USA
24-26 October, 2011
Magnus Lindskog, Siebren de Haan, Sibbo van der Veen, Sigurdur Thorsteinsson, Shiyu Zhuang, Tomas Landelius and Kristian Pagh Nielsen
HIRLAM 7.3 RCR
(15 km hor res, 60 vertlev)
HIRLAM 7.4 RCR
(7 km hor res, 65 vert lev)
SMHI HARMONIE (ALARO)
(5.5 km hor res, 60 vert lev)
DMI HARMONIE (AROME)
(2.5 km hor res, 65 vertlev)
HIRLAM ref DA: 4D-Var
HARMONIE ref DA: 3D-Var
Focus is moving towards frequently updated short-range km-scale forecasts
Investigate effects of increasing frequency of data assimilation cycles and of shortening observation cut-off time
Utilization of new types of observations
Handling of balances
Algorithmic developmentsTowards Rapid Update Cycling (RUC)On-going data assimilation developments
RADAR radial winds and reflectivities, GNSS (GPS) ZTD, Mode-S, satellite based radiances (IASI, SEVIRI,ATOVS), GPS RO, derived satellite based cloud-products, Scatterometer,…
ASCAT, SMOS, MODIS, GLOBSNOW, …New types of observations
Illustration upper-air observation types
Illustration derived cloud products
(seasonal variation of coupling of humidity background errors with errors of other variables as
derived for km-scale model over Danish domain)
SUMMER (12 UTC)
WINTER ( 12UTC)
T and Ps
Air-mass/flow dependence to be represented
Handling – two step method
Parallel experiments over H11 and U11 domains
Summer period:1 May 2010- 5 September 2010 Winter period:13 January 2011- 28 February 2011
Domains D11/H11/U11: 11 km hor res., 60 vert lev.
Parallel experiments U11 RUC with and without cloud initialization
1. Transfer of MSG cloud cover to 3D cloud cover in HIRLAM model:
2. Translate N to humidity
Cloud forecast Verification scores
Verification results by comparison of Hirlam cloudiness to synoptic observations (bias and standard deviation of errors)
(large verification area over Europe)
REF: Hirlam reference run
MSG: Hirlam run with MSG cloud initialisation
Two parallel exp. for July & August 2009 and January & February. 2010:
Model domain: SMHI pre-oper.
Horizontal resolution: 5.5 km
Vertical levels: 60
LBC: 3 hourly with ECMWF fc
Surface DA: Optimal Interpolation
Upper–air DA: 3D-Var
Observation usage: SYNOP, SHIP, DRIBU, TEMP, PILOT, AIREP, AMDAR, Conv.+ATOVS AMSU-A
Temperature (K) RMS/BIAS of + 12 h forecasts as function of vertical level
Surface pressure (hPa) RMS/BIAS as function of forecast range
Assimilation of ATOVS AMSU-A crucial for positive impact of 3h data assimilation cycle in this parallel experiment
Utilization of observations with high resolution in space and time important for RUC.
Encouraging first results from initializing clouds for RUC, applying a simple approach.
Significant seasonal variations of balances revealed for a km-scale model. Future plans include investigation of air-mass and flow dependent balances. Imbalances and associated spin-up need further investigations.
Algorithmic developments for handling of non-linearities, complex observation types and non-additive errors are on-going.
Co-ordinated impact studies planned to assess the impact of new observation types and to optimize the handling of these.Conclusions and Future Plans