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A progress with PT MireAlla Yurova
Hydrometcentre of Russia
Priority task: mire parameterization
Ground water
Modified TERRA MMWH modelRg, Rs
Latent heat flux (LHF)parameterizationWater content (WC)
LHFThermal conductivitydependency on WC
Surface fluxes and soil temperatureverification SCLM
External parameter database:mire distribution. Example of St Petersburg region
COSMO, soil_type=8 TERRA satellite image processing (Bartalev et al)
00.10.20.30.40.50.60.70.80.9
0.25 0.5 0.75 1
normalizad water content
ther
mal
con
duct
ivity
, W
m-1
K-1 model meas
00.10.20.30.4
0.50.60.70.80.9
0.25 0.5 0.75 1
normalized water content
ther
mal
con
duct
ivity
, W
m-1
K-1
model meas
Peat thermal conductivity as a function of normalized water content: a) as in original TERRA parameterization, b) according to new parameterization and observed.
Peat thermal conductivity
Johansen equation from TERRA used. Peat-specific parameters from Lawrence and Slater(2007), reverse problem solved to obtain Kersten number as a function of water content
Formulation for the shallow WT
W=Fleff-q,GW=- W(sat-)q=lq·i·K_h(zcat-zwt),
W, -water content, Fleff- gravitational water flux from the layer above minus capillary rise, q-runoff, sat-porosity,i-slope of the water table,·K_h-transmissivity coefficient, lq-lumped parameter
WTWeighted average between saturated and unsaturated water content in the layer Zk goesTo Richards’ equation
Zk
Results: water content in soil . March 2011
2
3
4
5
6
7
8
9
0 1 2
WC
lay
er
t=1
t=2
t=3
t=4
t=5
2
3
4
5
6
7
8
9
0 1 2
WC
laye
r
t=1
t=2
t=3
t=4
t=5
Ground water parameterizationGWstart=1.5 m
Standard run
,,1
,)()()(, 33
2210
Lwt
LwtLwtLwtLwt
zzif
zzifzzszzszzssmmPETET
25,617.0
6525,53.0
65,427.0
wt
wt
wt
zifPETET
zifPETET
zifPETET1
2
ET-evapotranspirationРЕТ-potential ET
y = -0.1671x2 + 8.2973x - 27.163R2 = 0.9863
0102030405060708090
20 25 30 35 40
WTD, cm
mea
n E
T,
WT
/m2 Measurements at Degero
Stormyr mire, summer 2008
Evapotranspiration parameterization
Results: surface fluxes at Degero Stormyr mire, July 2008, SCLM simulations
020406080
100120140
H LE
mea
n f
lux,
W/m
2
meas mod
Results: Bowen ratio Degero Stormyr mire, July 2008, SCLM simulations
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
01
.07
.08
0:0
0
01
.07
.08
13
:00
02
.07
.08
2:0
0
02
.07
.08
15
:00
03
.07
.08
4:0
0
03
.07
.08
17
:00
04
.07
.08
6:0
0
04
.07
.08
19
:00
05
.07
.08
8:0
0
05
.07
.08
21
:00
06
.07
.08
10
:00
06
.07
.08
23
:00
07
.07
.08
12
:00
08
.07
.08
1:0
0
08
.07
.08
14
:00
09
.07
.08
3:0
0
09
.07
.08
16
:00
10
.07
.08
5:0
0
10
.07
.08
18
:00
11
.07
.08
7:0
0
11
.07
.08
20
:00
12
.07
.08
9:0
0
12
.07
.08
22
:00
13
.07
.08
11
:00
14
.07
.08
0:0
0
14
.07
.08
13
:00
15
.07
.08
2:0
0
15
.07
.08
15
:00
16
.07
.08
4:0
0
measmodel
Results: soil temperature at 2 cm Degero Stormyr mire, July 2008, SCLM simulations.
Effect of initialization
Results: soil temperature at 2 cm Degero Stormyr mire, July 2008, SCLM simulations.
Effect of hydraulic diffusivity in the upper peat layer
2m temperature difference between the modified (with the mire parameterization) and the standard COSMO model. 36h forecast, starting at 00 UTC, 10 August 2011, COSMO-RU domain
Results of the tests with the mire parameterization in the 3D COSMO model
Conclusions
• In many areas in Russia mires are more numerous then indicated by soil_type=8
• The parameterization of soil water is very sensitive to initial conditions
• More advanced parameterization is needed for the vertical structure of hydraulic conductivity and diffusivity
Additional ideas arisen from the PT
• Varying depth lower boundary conditions could be use for the whole hydrophobic-dry soil gradient
• …but initialization scheme should be use to assimilate ground water depth data
• Draining and rewetting mires changes the regional climate
• Rice paddies are significant modifiers of the temperature regime in Asia
Thanks for cooperation and your attention!