Presentation is loading. Please wait.

Presentation is loading. Please wait.

Assimilation of high-resolution DIAL water vapor data into the MM5 modeling system – Comparison of the performance of different assimilation methods Content:

Similar presentations


Presentation on theme: "Assimilation of high-resolution DIAL water vapor data into the MM5 modeling system – Comparison of the performance of different assimilation methods Content:"— Presentation transcript:

1 Assimilation of high-resolution DIAL water vapor data into the MM5 modeling system – Comparison of the performance of different assimilation methods Content: Scientific questions Case study Methodology First results Summary & Outlook H.-S. Bauer, V. Wulfmeyer, M. Grzeschik and A. Behrendt, IPM Hohenheim University Francois Vandenberghe, NCAR RAP Edward V. Browell, NASA GSFC September 6, 2005 WSNE 2005, Toulouse, France

2 Scientific Questions Is there a significant influence on the water vapor field and its temporal development when only data from one flight track is assimilated ? Are there systematic differences occurring when different assimilation systems are used ? Is the precipitation forecast influenced by the assimilation and if yes how good perform the different assimilation systems ? Does the signal propagate in the model forecast even if data is no longer assimilated ? What is the most appropriate assimilation method for DIAL water vapor ? ? September 6, 2005 WSNE 2005, Toulouse, France

3 Case study during IHOP_2002: May 24
Study of the role of the water vapor field in the initiation of convection Combination of state-of-the-art water vapor instrumentation applied Huge amount of supporting background data and model runs available LASE flight tracks Ideal opportunity for studying the impact of water vapor data assimilation on the forecast quality of mesoscale models. 20:30UT 20:50UT 19:00UT 19:30UT 18:00UT 18:15UT 20:20UT 20:00UT 18:45UT 18:35UT Field campaigns essential for providing detailed data sets for better understanding and prediction of precipitation. IHOP During IHOP, we investigate the case where the improvement of the initial water vapor field could play an important role We selected May 24, 2002: Cold front, dry line triple point, high probability of convection, upper air trough Flight pattern were designed so that the preconvective water vapor field was measured Lase was upstream and downstream there was development of deep convection Initiation of convection September 6, 2005 WSNE 2005, Toulouse, France

4 Assimilation using low horizontal resolution and simplified physics
ECMWF analysis LASE water vapor Assimilation using low horizontal resolution and simplified physics (3DVAR, 4DVAR, FDDA) MM5 3.4 Simple Phys. NESTDOWN Intermediate resolution forecasts using a Horizontal resolution of 10 km MM Sophist. Phys. NESTDOWN High-resolution forecasts using a horizontal horizontal resolution of 3.3 km September 6, 2005 WSNE 2005, Toulouse, France

5 Performance of the assimilation
Example 4DVAR September 6, 2005 WSNE 2005, Toulouse, France

6 Results: 2m mixing ratio
September 6, 2005 WSNE 2005, Toulouse, France

7 Results: Wind September 6, 2005 WSNE 2005, Toulouse, France

8 Results: Precipitation
September 6, 2005 WSNE 2005, Toulouse, France

9 Summary The experiments show a significant influence of the LASE data onto the water vapor field for all used assimilation systems. Improved forecast of the distribution of precipitation for all assimilation systems used. The representation is clearly influenced by the choice of the assimilation system used. The LASE data is of high quality and well suited for data assimilation. Compared to observations 4DVAR shows the best results of the three assimilation systems. September 6, 2005 WSNE 2005, Toulouse, France

10 Thanks for your attention !
September 6, 2005 WSNE 2005, Toulouse, France

11 September 6, 2005 WSNE 2005, Toulouse, France

12 MM5 configuration Assimilation runs (MM5 v3.4):
Anthes-Kuo convection MRF PBL scheme stable precipitation scheme Simple radiation scheme Free forecasts (MM5 v3.6.1): Kain-Fritsch 2 convection MRF PBL scheme GSFC graupel scheme RRTM radiation D01: 40x40x20 grid points, 30km D02: 85x85x36 grid points, 10 km D03: 220x220x36 grid points, 3.3 km September 6, 2005 WSNE 2005, Toulouse, France


Download ppt "Assimilation of high-resolution DIAL water vapor data into the MM5 modeling system – Comparison of the performance of different assimilation methods Content:"

Similar presentations


Ads by Google