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!