1. FE 14 Impact of surface forcing on the diurnal boundary layer development Gerd Vogel, Felix Ament*, Ursula Schubert DWD, FE14 Potsdam Zurich, September 2005 *University Bonn

2. Lindenberg (DWD) Selected point of soil moisture validation within the LM integration area (DWD)

3. Soil moisture (0-10cm)

8. sand sandy loam loam

9. Soil moisture (0-10cm)

11. Operational LM-prediction May 30, 2004 Lindenberg

12. Mellor&Yamada(3tls)Mellor&Yamada(3tls) May 30, 2004 Sensitivity experiment Reference run Op. scheme (3tls)

15. Recent accuracy checks indicate that the LM-module TERRA satisfactorily simulates the soil moisture in the annual cycle when it is exclusively driven by measurements. Therefore, this module is used at present to simulate the needed external soil moisture fields in the whole LMK area. The sole improvement of soil moisture already yields to a more realistic specific humidity (at 35m). Sensitivity experiments likewise support that the use of external fields of soil moisture and radiation leads to a more realistic atmospheric forcing from the surface. This will advance the reliability of our validation studies. The intended LMK-simulations tentatively should be based on the revised soil types in the Brandenburg region in order to quantitatively estimate the need to extend this revision on the whole integration area. Conclusions