o. yevteev, m. shatunova, v. perov, l.dmitrieva-arrago ,
DESCRIPTION
The surface temperature variations due to the changes in solar flux and cloud water content (CWC) ( COSMO-RU simulation results). O. Yevteev, M. Shatunova, V. Perov, L.Dmitrieva-Arrago , Hydrometeorological Center of Russia, 2010. Heat conductivity equation and surface heat budget. - PowerPoint PPT PresentationTRANSCRIPT
O. Yevteev, M. Shatunova, V. Perov, L.Dmitrieva-Arrago , Hydrometeorological Center of Russia, 2010
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sfc
mm
ksokso
k
so Gzz
TT
zct
T
1,2,
12
11
)()(1
netrad,sfcqsfcsfc QFHG
Ts – surface temperature
Tso – soil temperature
Ts = Tso,k=1
Hsfc sensible heat flux
Fq sfc latent heat flux
Qrad,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
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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 BudgBudgetet
Cloudless caseCloudless case Cloudless caseCloudless case
23211
856 8 3 5353 845 194 418 55 149 327327
Cloudy case Cloudy case
39 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
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HMC Spectral model temperature HMC Spectral model temperature forecast evaluationforecast evaluation
advance time
BIAS RMS ABS OTNO NModel 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
rexpr
β1αΓ
Nrn α
1α0
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Cloud particles size distribution function
Cloud extinction and absorption coefficients (Khvorostianov, 1980)
3)(α
abs 1)λ(α
kr8π11
3α
1α
ρr2
3δσ
222
222
22
2
extk1)(n
k1)(n
3)2)(α(α
1)(α
r8π
λ
3α
1α
ρr2
3δσ
Δhστ extcld
extscattcld σσω
r
Characteristics CloudlessLWC, g/m3
0,05 0,10 0,15 0,20 0,25
Surface 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 0,83
Absorption by cloud, W/m2 16 37 44 47 49 50
Cloud heating, K/day 1,4 3,4 4,1 4,4 4,5 4,6
TOA budget 634 331 279 256 242 234
System albedo 0,07 0,52 0,59 0,63 0,65 0,66
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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)
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Characteristics CloudlessMean droplet radius,
mkm
3 6 9
Surface budget, W/m2 482 55 97 129
Total atmospheric absorption, W/m2 152 183 182 181
Cloud albedo0,03 0,83 0,75
0,68
Absorption by cloud, W/m2 16 42 44 45
Cloud heating, K/day 1,4 3,9 4,1 4,1
TOA budget634 237 279 310
System albedo 0,07 0,65 0,590,55
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)
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Cooling rates (К/day) for the low level cloud in dependence on the mean droplet
radius and LWCMean
droplets radius
LWC, g/m3
0,03 0,06 0,1 0,2 0,3
3 mkm 7,3 8,2 8,4 8,4 8,4
6 mkm 6,7 7,9 8,3 8,4 8,4
9 mkm 6,1 7,5 8,1 8,4 8,4
Mean droplets radius
LWC, g/m3
0,03 0,06 0,1 0,2 0,3
3 mkm 6,3 7,8 8,5 8,7 8,7
6 mkm 5,5 7,3 8,3 8,7 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
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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)”
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Low level cloud coverLow level cloud cover Surface temperature Surface temperature differencedifference
““FLUX” experiment FLUX” experiment (+(+30 W/m2 )
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Low level cloud coverLow level cloud cover Surface temperature Surface temperature differencedifference
““CWC” experiment CWC” experiment (+(+25%))
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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!