1. O. Yevteev, M. Shatunova, V. Perov, L.Dmitrieva-Arrago, Hydrometeorological Center of Russia, 2010

2. 2 T s – surface temperature T so – soil temperature T s = T so,k=1 H sfc  sensible heat flux F q sfc  latent heat flux Q rad,net  surface radiation budget, Q rad,net = Q S +Q LW Heat conductivity equation and surface heat budget   soil density, с  soil heat capacity, z – model’s levels inside soil layer z1z2z1z2 T so

3. 3 Sr – solar radiation absorbed by surface Lr – surface effective radiation (thermal)  – emissivity coefficient Q sw – solar radiative flux A – surface albedo  T so 4 – surface longwave flux E atm – long wave radiation of the atmosphere Surface radiation budget

4. 4 Comparison of the surface heat budget components (W/m2) WinterSummer SrLrHFGBudgetSrLrHFGBudget Cloudless case 232  118  56 88 353845  194  418  55 149327 Cloudy case 39 33 22 22 5527 43 55 99  19 446 Sr – solar radiation absorbed by surface Lr – surface effective radiation (thermal) H – turbulent sensible heat flux F – latent heat flux G – soil flux Results for the particular point (mid-latitude) could help to evaluate needed accuracy of the fluxes calculation

5. 5 HMC Spectral model temperature forecast evaluation advance time BIASRMSABSOTNON Model version 24 -0,343,342,620,82523T85L31 -3,24,223,581,12523T169L31 36 -0,084,053,180,55522T85L31 -5,736,745,901,02522T169L31 48 -0,384,633,650,78523T85L31 -2,794,313,570,76523T169L31 60 -0,434,193,190,50522T85L31 -5,736,815,810,90522T169L31 72 -0,395,294,220,77522T85L31 -2,484,633,680,67522T169L31 Central Federal District, March, 2010

6. Cloud optical thickness, Δh – cloud thickness Cloud single scattering albedo δ - cloud water content, ρ – particle density, - mean radius 6 Cloud particles size distribution function Cloud extinction and absorption coefficients (Khvorostianov, 1980)

7. CharacteristicsCloudless LWC, g/m 3 0,050,100,150,200,25 Surface budget, W/m 2 48215797705444 Total atmospheric absorption, W/m 2 152174182186188190 Cloud albedo0,030,640,750,790,820,83 Absorption by cloud, W/m 2 163744474950 Cloud heating, K/day1,43,44,14,44,54,6 TOA budget634331279256242234 System albedo0,070,520,590,630,650,66 7 Radiation characteristics of the cloudy atmosphere and the underlying surface in dependence on the Liquid Water Content (Mid latitude summer atmosphere, one layer cloud, mean droplet radius 6 mkm, Solar zenith angle 60  )

8. 8 CharacteristicsCloudless Mean droplet radius, mkm 369 Surface budget, W/m 2 4825597129 Total atmospheric absorption, W/m 2 152183182181 Cloud albedo 0,030,830,750,68 Absorption by cloud, W/m 2 16424445 Cloud heating, K/day1,43,94,1 TOA budget 634237279310 System albedo0,070,650,590,55 Radiation characteristics of the atmosphere and the underlying surface in dependence on the Mean Droplet Radius (Mid latitude summer atmosphere, one layer cloud, LWC 0.1 g/m 3, Solar zenith angle 60  )

9. 9 Cooling rates (К/day) for the low level cloud in dependence on the mean droplet radius and LWC Mean droplets radius LWC, g/m3 0,030,060,10,20,3 3 mkm  7,3  8,2  8,4 6 mkm  6,7  7,9  8,3  8,4 9 mkm  6,1  7,5  8,1  8,4 Mean droplets radius LWC, g/m3 0,030,060,10,20,3 3 mkm  6,3  7,8  8,5  8,7 6 mkm  5,5  7,3  8,3  8,7 9 mkm  4,9  6,6  7,8  8,6  8,7 Cooling rates (К/day) for the middle level cloud in dependence on the mean droplet radius and LWC

10. 10 1.Background simulation 2.“FLUX” experiment – values of the solar radiation absorbed by surface were increased on 30 W/m 2 in the cloudy grid points 3.“CWC” experiment – values of the integral CWC were increased on 25% The investigation of the surface temperature sensibility to the variations of the radiation fluxes and Cloud Water Content Following pictures represent the mentioned experiments results obtained after 9h of the model’s simulation from 17.07.10, 0:00 Greenwich time : - Low level cloud cover; - Difference of the surface temperature “Ts (experiment) – Ts (background)”

11. 11 Low level cloud cover Surface temperature difference “FLUX” experiment (+ “FLUX” experiment (+ 30 W/m 2 )

12. 12 Low level cloud cover Surface temperature difference “CWC” experiment (+) “CWC” experiment (+ 25% )

13. 13 Conclusions 1.Surface temperature proves to be sensitive to the variation of the incoming solar flux and cloud microphysical properties (CWC) 2.The increasing of absorbed solar radiation by surface at 30 W/m 2 brings to changes of the surface temperature at 1-2 grad, with maximum values up to 3 grad. 3.The increasing of the integral CWC at 25% brings to change of the surface temperature at 1 grad, mainly, with maximum values up to 3 grad. 4.All results are obtained without control of the cloud cover variations during the experiments. 5.The presented results show that physical processes in the atmosphere should be described with the most possible accuracy.

14. Thank you for attention!