COSMO Priority Task

Mire parameterization

Alla Yurova (Hydrometcentre of Russia)Gerd Vogel (DWD)

Task aim:

• to incorporate a mire parameterization into the TERRA land surface scheme

• to investigate the influence of mire parameterization on the components of the heat and water balance simulated by TERRA and compare them with available observations

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 preliminary tests with the mire parameterization in the COSMO model

Modifications: mire evapotranspiration as a function of PET for a climatic average position of the mire water table depth

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, Western Siberia

2m temperature difference between the modified (with the mire parameterization) and the standard COSMO model. 72h forecast, starting at 00 UTC, 10 August 2011, single point in Western Siberia (70o E, 62o N)

Difference in the surface latent heat flux (W/m2) between the modified (with the mire parameterization) and the standard COSMO model. 36h forecast, starting at 00 UTC, 10 August 2011, COSMO-RU domain , Western Siberia

More latent heat is released from the mires into the atmosphere

…As a result a cloud cover (low level) is increased

black-with mire parameterization

green- standard

The cloud cover (low level) simulated by the modified (with the mire parameterization) and the standard COSMO model. 72h forecast, starting at 00 UTC, 10 August 2011, single point in Western Siberia (70o E, 62o N)

…Due to intensified convection

CAPE (J/kg) simulated by the modified (with the mire parameterization) and the standard COSMO model. 72h forecast, starting at 00 UTC, 10 August 2011, single point in Western Siberia (70o E, 62o N)

black-with mire parameterization

green- standard

Also modified are:

• Solar and thermal net radiation at the surface

• Boundary layer depth

• Precipitation

• Surface wind field (slightly)

• ...

Conclusion: COSMO model is sensitive to the

additional moisture source introduced by

the mire parameterization

Planned sub-tasks:

1. Compilation of a database of the mire distribution on a 1km grid in TERRA-compatible format based on satellite vegetation classification (GEM, Bartalev ) and national peat surveys (Vompersky et al. )

Consistency check with TERRA soiltype 8(peat) from FAO

Planned sub-tasks:

2. Prescription of peat thermal properties in TERRA with dependencies of thermal conductivity on soil water (ice) content using the organic soil thermal conductivity database

Planned sub-tasks:

3a. MMWH model programmed as subroutine ready to use in TERRA and documented.

WT_max

WT_current

Saturated zone

z,cm

Capillary zone

0.0 0.3 0.6 0.9

The Mixed Mire Water and Heat model MMWH (Granberg et al., 1999)

W=P-E-q,q=lq·i·K_h(zcat-zwt),

W-water content, P-precipitation, E-evapotranspiration, q-runoff, i-slope of the water table,·K_h-transmissivity coefficient, lq-lumped parameter

zcat

zwt

Planned sub-tasks:

3b. TERRA standard soil water transfer code based on Richards equation with an exchange with groundwater at the lower boundary applied and tested for the mire sites.

Planned sub-tasks:

4. Quantitative estimates of the mire parameterization performance in stand-alone TERRA tests for selected mire sites

Degero Stormyr, Nothern Sweden Lammin Suo, North European Russia

Vasyugan bog, Siberia? Abisko, N. Sweden? Finnish mires? (Euroflux network)

Planned sub-tasks:

5a. Integration of the mire parameterization in a fully coupled COSMO model for the COSMO-RU domain .

5b. Investigation of the fully coupled COSMO model performance with the mire parameterization for various seasons.