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

2

sfc

mm

ksokso

k

so GzzTT

zctT

1,2,

12

11

)()(1

netrad,sfcqsfcsfc QFHG

Ts – surface temperatureTso – soil temperatureTs = Tso,k=1

Hsfc sensible heat fluxFq sfc latent heat fluxQrad,net surface radiation budget, Qrad,net = QS+QLW

Heat conductivity equation and surface heat budgetHeat conductivity equation and surface heat budget

soil density, с soil heat capacity, z – model’s levels inside soil layer

z1

z2

Tso

3

Sr – solar radiation absorbed by surface Lr – surface effective radiation (thermal)

– emissivity coefficient

Qsw – solar radiative flux A – surface albedoTso

4 – surface longwave flux Eatm – long wave radiation of the atmosphere

LrSrETAQQ atmSWnetrad, 41

Surface radiation budgetSurface radiation budget

4

Comparison of the surface heat budget components Comparison of the surface heat budget components (W/m2)(W/m2)

Winter Summer

Sr Lr H F G BudgBudgetet Sr Lr H F G BudgBudg

etetCloudless caseCloudless case Cloudless caseCloudless case

232 118 56 8 3 5353 845 194 418 55 149 327327

Cloudy case Cloudy case39 3 2 2 5 2727 43 5 9 19 4 66

Sr – solar radiation absorbed by surface Lr – surface effective radiation (thermal) H – turbulent sensible heat fluxF – latent heat fluxG – soil flux

Results for the particular point (mid-latitude) could help to evaluate needed accuracy of the fluxes calculation

5

HMC Spectral model temperature HMC Spectral model temperature forecast evaluationforecast evaluation

advance time BIAS RMS ABS OTNO N Model

version

24-0,34 3,34 2,62 0,82 523 T85L31

-3,2 4,22 3,58 1,12 523 T169L31

36-0,08 4,05 3,18 0,55 522 T85L31

-5,73 6,74 5,90 1,02 522 T169L31

48-0,38 4,63 3,65 0,78 523 T85L31

-2,79 4,31 3,57 0,76 523 T169L31

60-0,43 4,19 3,19 0,50 522 T85L31

-5,73 6,81 5,81 0,90 522 T169L31

72-0,39 5,29 4,22 0,77 522 T85L31

-2,48 4,63 3,68 0,67 522 T169L31

Central Federal District , March, 2010

Cloud optical thickness , Δh – cloud thickness

Cloud single scattering albedo

δ - cloud water content, ρ – particle density, - mean radius

β

rexprβ1αΓ

Nrn α1α

0

6

Cloud particles size distribution function

Cloud extinction and absorption coefficients (Khvorostianov, 1980)

3)(α

abs 1)λ(αkr8π11

3α1α

ρr23δσ

222

222

22

2

extk1)(nk1)(n

3)2)(α(α1)(α

r8π

λ3α1α

ρr23δσ

Δhστ extcld

extscattcld σσω

r

Characteristics CloudlessLWC, g/m3

0,05 0,10 0,15 0,20 0,25Surface budget, W/m2 482 157 97 70 54 44

Total atmospheric absorption, W/m2 152 174 182 186 188 190

Cloud albedo 0,03 0,64 0,75 0,79 0,82 0,83Absorption by cloud,

W/m2 16 37 44 47 49 50

Cloud heating, K/day 1,4 3,4 4,1 4,4 4,5 4,6TOA budget 634 331 279 256 242 234

System albedo 0,07 0,52 0,59 0,63 0,65 0,66

7

Radiation characteristics of the cloudy atmosphere Radiation characteristics of the cloudy atmosphere and the underlying surface in dependence on the and the underlying surface in dependence on the

Liquid Water ContentLiquid Water Content (Mid latitude summer atmosphere, one layer cloud, mean droplet

radius 6 mkm, Solar zenith angle 60)

8

Characteristics CloudlessMean droplet radius,

mkm3 6 9

Surface budget, W/m2 482 55 97 129Total atmospheric absorption,

W/m2 152 183 182 181

Cloud albedo 0,03 0,83 0,75 0,68

Absorption by cloud, W/m2 16 42 44 45Cloud heating, K/day 1,4 3,9 4,1 4,1

TOA budget 634 237 279 310

System albedo 0,07 0,65 0,59 0,55

Radiation characteristics of the atmosphere and Radiation characteristics of the atmosphere and the underlying surface in dependence on the Mean the underlying surface in dependence on the Mean

Droplet Radius Droplet Radius (Mid latitude summer atmosphere, one layer cloud, LWC 0.1 g/m3,

Solar zenith angle 60)

9

Cooling rates (К/day) for the low level cloud in dependence on the mean droplet

radius and LWCMean

droplets radius

LWC, g/m30,03 0,06 0,1 0,2 0,3

3 mkm 7,3 8,2 8,4 8,4 8,46 mkm 6,7 7,9 8,3 8,4 8,49 mkm 6,1 7,5 8,1 8,4 8,4

Mean droplets radius

LWC, g/m30,03 0,06 0,1 0,2 0,3

3 mkm 6,3 7,8 8,5 8,7 8,76 mkm 5,5 7,3 8,3 8,7 8,79 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

1. Background simulation

2. “FLUX” experiment – values of the solar radiation absorbed by surface were increased on 30 W/m2 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 investigation of the surface temperature sensibility to the variations of the radiation fluxes and Cloud Water the variations of the radiation fluxes and Cloud Water

ContentContent

Following pictures represent the mentioned experiments results Following pictures represent the mentioned experiments results obtained after 9h of the model’s simulation from 17.07.10, 0:00 obtained after 9h of the model’s simulation from 17.07.10, 0:00 Greenwich time :Greenwich time :

- Low level cloud cover;Low level cloud cover;

- Difference of the surface temperature “Ts (experiment) – Ts Difference of the surface temperature “Ts (experiment) – Ts (background)”(background)”

11

Low level cloud coverLow level cloud cover Surface temperature Surface temperature differencedifference

““FLUX” experiment FLUX” experiment (+(+30 W/m2 )

12

Low level cloud coverLow level cloud cover Surface temperature Surface temperature differencedifference

““CWC” experiment CWC” experiment (+(+25%))

13

ConclusionsConclusions

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/m2 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.

Thank you for attention!Thank you for attention!