Uni Bonn contributions to SMOS Validation
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SMOS Workshop – Hamburg, 9.-10. November 2006 SMOS Uni Bonn contributions to SMOS Validation Ralf Lindau Bonn University
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Uni Bonn contributions to SMOS Validation. Ralf Lindau Bonn University. Bonn contributions. Detection of Radio Frequency Interference Found in SMMR, AMSR etc. Expected also in SMOS Comparison of SMOS soil moisture with existing data Direct measurements from GSMDB AMSR-derived SM - PowerPoint PPT Presentation
Transcript of Uni Bonn contributions to SMOS Validation
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
Uni Bonn contributions to SMOS Validation
Ralf LindauBonn University
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
Bonn contributions Detection of Radio Frequency Interference
- Found in SMMR, AMSR etc.- Expected also in SMOS
Comparison of SMOS soil moisture with existing data- Direct measurements from GSMDB - AMSR-derived SM
Pixel-intern variance- Necessary to interprete the intended validations with point
measurements properly.- build and operate a transportable polarized L-Band radiometer
Investigate signal noise due to rain and vegetation
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOSRadio Frequency
Interference
Time series of 6 GHz brightness temperature from SMMR in France
Until 1981 the normal annual cycle is found.
After 1981 the 6 Ghz signal is completely unusable due to noise.
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
SMMR RFI in 6 GHz
The scatter is low in Sibiria, increases westward and reaches maximum values near St. Petersburg
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
ASMR RFI
In Europe the 10 GHz channel is completely noisy in England and Italy.
In the USA the 6 GHz measurements are corrupted over New York, Boulder etc.
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
AMSR 10 GHz RFI
• RFI is detectable by
• high monthly averages
• high monthly stddev.
250 K
300 K
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
Simple RFI Scheme
• TB > 260 K
• Stddev > 5 K
• TB > 20 K
compared to a 10° x 30°
surrounding
SMOS Workshop – Hamburg, 9.-10. November 2006
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Soil Moisture from AMSR
Longtime mean + 10-day anomalies
SMOS Workshop – Hamburg, 9.-10. November 2006
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2-Step Retrieval
SMOS Workshop – Hamburg, 9.-10. November 2006
SMOS
Pixel-intern VarianceBelarussian soil moisture data
21 stations, 10 daily during about 10 years
Average spatially and compare the reduced variance to the total variance
40% are left for 400-km-Pixels59% are left for SMMR-Pixels
The left external variance is equal to the maximum correlation between point measurements and area averages
