Treatment of S mall S cale Land S urface Heterogeneity for A tmospheric M odelling (SSSAM) Günther Heinemann (1) and Michael Kerschgens (2) ches Institut der Universität Bonn, Auf dem Hügel 20, 53121 Bonn Geophysik und Meteorologie der Universität zu Köln, Kerperner Str. Regional Evaporation at Grid / Pixel Scale over Heterogeneous Land Surfaces
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Treatment of S mall S cale Land S urface Heterogeneity for A tmospheric M odelling (SSSAM)
Treatment of S mall S cale Land S urface Heterogeneity for A tmospheric M odelling (SSSAM). Günther Heinemann (1) and Michael Kerschgens (2). 1 Meteorologisches Institut der Universität Bonn, Auf dem Hügel 20, 53121 Bonn - PowerPoint PPT Presentation
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Treatment of Small Scale Land Surface Heterogeneity for Atmospheric Modelling
(SSSAM)
Günther Heinemann (1) and Michael Kerschgens (2)
1 Meteorologisches Institut der Universität Bonn, Auf dem Hügel 20, 53121 Bonn2 Institut für Geophysik und Meteorologie der Universität zu Köln, Kerperner Str. 13, 50923 Köln
Regional Evaporation at Grid / Pixel Scale over Heterogeneous Land Surfaces
Effects of land surface heterogeneity on atmospheric transports
Realistic simulations LITFASS area 17 June 1998, nesting LM7
Average 9-17 UTC
250 m, LITFASS, vg(LM)≈14 m/s, W = W(LM)
0 4 8 12
A veraging scale km
100
150
200
250
300
H0
,E0
in W
/m²
H0
H0,LS
H0,LS,w*
H0,mos
E0
E0,LS
E0,LS,w*
E0,mos
250m_vg2_nes1km
Idealized simulations LITFASS area
Average 9-17 UTC
250 m, LITFASS, Vg = 2 m/s, W = 60%
H in W/m² H in W/m²
Idealized simulations LITFASS area
250 m, Fx = 2 km, vg=2 m/s250 m, Fx = 250 m, vg=2 m/s
250 m, Fx = 2 km, vg=2 m/s250 m, Fx = 2 km, vg=2 m/s
H0-H0,mosa in W/m²E0-E0,mosa in W/m²
Variance ff(30m) in m²/s²Variance T(0m) in K²
Summary
Method: FOOT3DK simulations (resolution down to 250m)idealized and realistic surfaces and synoptic forcings (LITFASS98)
Assessment of the dynamic effect for averaging methods (mosaic and aggregation) for scales of 10-20 km- dependence on the scale/structure of the heterogeneity- mosaic method yields good results for wind speeds exceeding 4 m/s
Scale dependence of area-averaged surface fluxes caused by non-linear effects- sub-grid TKE (SKE)- radiation and clouds- surface temperature and soil moisture