Global one-meter soil moisture fields for the calibration of GRACE measurements derived from surface observations and satellite passive microwaves

Global one-meter soil moisture fields

for the calibration of GRACE measurements derived from surface observations

and satellite passive microwaves

C. Simmer, R. Lindau, A. Battaglia, F. Ament, H. Wilker University of Bonn

M.Drusch

European Centre for Medium-Range Weather Forecast

ANOVA of Soil Moisture measurements

Variance in mm

Number

of bins Error of the total

mean

Seeming external variance

Error of external

means

Internal

variance True external variance

Relative external variance

Annual Cycle 36 2 388 51 10343 338 3.16%

Interstation 48 2 9133 10 1558 9123 85.40%

Interannual 8 2 39 12 10654 26 0.25%

Total variance External variance Internal variance

= Variance between + Mean variance

the means of the within the

subsamples subsamples

Local longtime means

single cumulative

Climatolog. rain 58.6 58.6

Soil texture 0.5 69.0

Vegetation 37.7 72.8

Terrain slope 2.8 73.0

73% of the soil moisture variance

is explained by four parameters :

Two-step Retrieval

Climatological mean derived from:

• Longterm precipitation

• Soil texture

• Vegetation density

• Terrain slope

Temporal anomalies from:

• Brightness temperatures at 10 GHz

• Anomalies of rain and air temperature

+

Application: DEKLIM

BALTIMOS within DEKLIM (Deutsches

Klimaforschungsprogramm):

Validation of a 10-years climate run of the regional model REMO using SMMR.

Example: Oder catchment

R. Lindau and C. Simmer: Derivation of a root zone soil moisture algorithm and its

application to validate model data. Nordic

Hydrology, accepted for publ.

Application: AMSR

GEOLAND within GMES (Global Monitoring for Environment and Security):

Derivation of global soil moisture fields from AMSR

M. Leroy, R. Lacaze, R. Lindau, F. Oleson, L.

Pessanha, I. Piccard, A. Rosema, J-L.

Roujean, F. Rubel, W. Wagner, M. Weiss, 2004: Towards a European Service Center for Monitoring land surfaces at global and regional Scales: The GEOLAND/ CSP Project

International Archives of Photogrammetry and Remote Sensing, XXth ISPRS Congress, Istanbul, 35 (B4), 783-790.

Lo ng te rm m ea n T em po ra l a no m al y

Comparison with ECMWF‘s Global Soil Moisture Analysis

• Every 6 hours, ECMWF performs a global soil moisture analysis for its operational weather prediction model (Integrated Forecast

System IFS).

• The soil moisture analysis is based on the soil moisture values modelled in the IFS and corrected by analysed fields of proxy

information (i.e. 2m temperature and relative humidity observations;

additional use of satellite passive microwave brightness temperature currently tested by MIUB and ECMWF).

• Depth of analysed soil moisture: 1 m.

• Spatial resolution: currently 0.5° lat/lon (0.25° scheduled for next