1. SMOS soil moisture validation: status at the Upper
Danube cal/val site eight months after launch
SMOS cal/val proposal: AO ID 3236
Johanna Dall‘Amico1, Alexander Löw2, Florian Schlenz1, Wolfram Mauser1
1University of Munich, Department of Geography, Munich, Germany
2Max-Planck-Institute for Meteorology, KlimaCampus, Hamburg, Germany
Funded by German Aerospace
Center (50EE0731)

2.  Cal/val approach
 The Upper Danube Catchment cal/val site
 Overview campaigns and data
 Preliminary SMOS data analysis
 Conclusions and outlook
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

3. Objectives
SMOS cal/val objectives
 Validate SMOS products
 Soil moisture (L2)
 Brightness temperatures (L1c)
 ... over
 a large area (entire Upper Danube)
 a smaller, but well instrumented area (Vils)
 ... using
 Field measurements
 Large scale land surface modelling
 Ancillary remote sensing data
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

4. Approach
2 1km
1
validation
Land surface Soil moisture SMOS
Soil moisture station Model (PROMET) L2 SM product
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

5. Approach
„L1c Brightness
temperature“ SMOS
3 L-MEB
validation Radiative comparison
Transfer
model
L2
Processor
Radiometer
2 1km
1
validation
API
Land surface Soil moisture SMOS
Soil moisture station model PROMET L2 SM product
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

6. Approach
• Two airborne campaigns
•Comparison with ancillary remote sensing
data: soil moisture product from ENVISAT
„L1c Brightness
ASAR (VISTA GmbH) SMOS
temperature“
3 L-MEB
validation Radiative comparison
Transfer
model
L2
Processor
Radiometer
2 1km
1
validation
API
Land surface Soil moisture SMOS
Soil moisture station model PROMET L2 SM product
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

7. Upper Danube Catchment Vils test site
Radiometer
Size: 77000 km²
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

8. Instrumentation Vils test site
Soil moisture
• Profile (5 probes per station:
2x5,10,25,40cm )
– TDR Probes (IMKO
GmbH)
– ECHO probes
(Decagon)
• Automatic data transmission
• Start: 2007 (one station since
2002)
Meteorological data
• Precipitation
• Longwave radiation
• Temperature (2m)
• Wind speed
• Solar radiation
50 km
• Relative humidity
• Temperature @ 5,40 cm
1
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

9. Land surface modelling
2
Meteorological data from a PROMET land surface model
dense network of in situ stations
(NRT availability; subset shown)
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

10. Model validation
PROMET model has been extensively validated and is still
being validated regularly using in-situ data
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

11. ELBARA 2 radiometer
3
Meteorological
data Rape Grassland
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

12. ELBARA 2 radiometer
Data of ELBARA available through a web client
(full access to instrument ancillary data)
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

13. SMOS airborne campaigns
Rehearsal campaign 2008
SMOS validation campaign 2010

14. SMOS cal/val campaigns
EMIRAD
(Technical University of Denmark)
Thermal camera
(Max-Planck-Institute
for Meteorology, Hamburg)
HUT-2D radiometer
(Aalto University, Helsinki)

15. Radiometer data comparison 2008
EMIRAD minus HUT-2D after temperature correction
30
20
10 Lochheim
first stokes parameter [K]
0 Engersdorf
-10 South
Engersdorf
-20 North
Steinbeissen
-30 South
-40 Steinbeissen
North
-50
-60
08/04/2008 15/04/2008
flight days during rehearsal campaign 2008
Two complementary radiometers during SMOS airborne campaigns
provide added value:
- HUT-2D: imaging system, good spatial resolution
- EMIRAD: better radiometric calibration
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

16. SMOS cal/val campaign 2010
 Five flights: 17, 22, 25 May,
12, 17 June 2010
 Most overflights covered 10
ground stations and the
ELBARA radiometer (white)
and 5 focus areas (red)
 Intensified ground campaign
compared to 2008
 Basic objective
• Representative coverage of
parts of one SMOS pixel
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

17. SMOS cal/val campaign 2010
First data SMOS campaign 2010
EMIRAD data on lake Chiemsee HUT-2D data example (black areas: forest)
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

18. SMOS cal/val campaign 2010
Vils test site
TIR brightness temperatures (raw data)
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

19. Field measurements 2010
Soil moisture
 60 points covering whole focus area (spacing ~ 500m)
 90 points covering smaller sub-area (spacing ~ 100 m)
 =>~ 3000 SM measurements per day in the whole Vils
Soil temperature
Vegetation parameters
 Height, phenology, biomass
Land cover mapping
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

20. Conditions during campaign
 Different soil moisture conditions between saturated and medium dry
 Vegetation growth phase  optical depth
 Air temperature between
10 and 30°C Meteo data Neusling (014)
30
Flights 10
9
25
8
precipitation [mm]
temperature [°C] 20
7
6
precipitation
15 5
air temperature
4
10
3
2
5
1
0 0
15.05.2010 00:00
16.05.2010 05:00
17.05.2010 10:00
18.05.2010 17:00
19.05.2010 22:00
21.05.2010 03:00
22.05.2010 08:00
23.05.2010 13:00
24.05.2010 18:00
25.05.2010 23:00
27.05.2010 04:00
28.05.2010 09:00
29.05.2010 14:00
30.05.2010 19:00
01.06.2010 00:00
02.06.2010 05:00
03.06.2010 10:00
04.06.2010 15:00
05.06.2010 20:00
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

21. Dynamics of ground measurements
soil moisture ground measurements (coarse resolution grid)
45
40
soil moisture vol. %]
35
Lochheim
30 Engersdorf
25 Steinbeissen
20 Neusling
Frieding
15
10
17.05. 22.05. 25.05. 28.05. 12.06. 14.06. 17.06. soil moisture ground measurements (high resolution grid)
time
45
40
soil moisture vol. %
35 Engersdorf
30 Steinbeissen
25 Neusling
20 Frieding
15
10
17.05. 22.05. 25.05. 28.05. 12.06. 14.06. 17.06.
date
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

22. Stations vs. spatial mean
SM station
Ground station measurements
(lines) and mean values of all
measurements at red points (dots
with standard deviation bars)
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

23. Brightness temperatures
L-MEB
Radiative
transfer
model
290
Brightness temperature (TBh) [K]
280
270
260
250
EMIRAD
240
PROMET+LMEB
230
220
PROMET 210
soil moisture 200
17.5.10 27.5.10 6.6.10 16.6.10
Mean values and standard deviations of all values
falling into the central ISEA grid point in the Vils area
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

24. SMOS comparison

25. SMOS data UDC (Vils testsite)
Morning overpasses

26. SMOS data UDC (Vils testsite)

27. L1c comparison
Comparison of SMOS L1c Brightness temperatures with
simulated brightness temperatures (coupled
PROMET+LMEB)
Actual SMOS L1c data processing: L-MEB
• TB Filtering (Flags and additional) Radiative
Transfer
• Combining polarized observations model
• Rotation (Faraday and Geometric)
• Analysis per incidence angle
PROMET
soil moisture
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

28. SMOS L1c vs. PROMET-LMEB
Only morning overpasses (40°)
Brightness temperature (TBh) [K]
17 April 2010 17 June 2010
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

29. Project status
„L1c Brightness
temperature“ SMOS
 
L-MEB
validation Radiative comparison

Transfer

model
L2
Processor
Radiometer
1km
validation



Soil moisture station

Surface state 
Soil moisture
API
SMOS
L2 SM product

30. Conclusions and outlook
 UDC cal/val activities on their way
 More detailed analysis of campaign data in the next months
 More SMOS data analysis as soon as reprocessed L1c data
and L2 data available
IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

31. Thanks!
Funded by German Aerospace
Center (50EE0731)