FR1.L10.5: SMOS SOIL MOISTURE VALIDATION: STATUS AT THE UPPER DANUBE CAL/VAL SITE EIGHT MONTHS AFTER LAUNCH

SMOS soil moisture validation: status at the UpperDanube 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, Germany2Max-Planck-Institute for Meteorology, KlimaCampus, Hamburg, Germany

Funded by German Aerospace Center (50EE0731)

IEEE International Symposium on Geoscience and Remote Sensing - IGARSS 2010 in Honolulu

Cal/val approach

The Upper Danube Catchment cal/val site

Overview campaigns and data

Preliminary SMOS data analysis

Conclusions and outlook


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

Approach

validation

Land surfaceModel (PROMET)

1km

SMOSL2 SM product

Soil moistureSoil moisture station

1


2


Approach

validation

Land surfacemodel PROMET

1km

SMOSL2 SM product

API


L2 Processor

SMOS„L1c Brightness temperature“

Radiative Transfer model

comparisonvalidation

Radiometer

L-MEB

12

3

Approach

validation

Land surfacemodel PROMET

1km

SMOSL2 SM product

API


L2 Processor




Radiometer

L-MEB

• Two airborne campaigns•Comparison with ancillary remote sensingdata: soil moisture product from ENVISAT ASAR (VISTA GmbH)

12

3



Upper Danube Catchment Vils test site

Radiometer

Size: 77000 km²


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

• Relative humidity

• Temperature @ 5,40 cm

50 km

1


Land surface modelling

Meteorological data from a dense network of in situ stations (NRT availability; subset shown)

2

PROMET land surface model


Model validation

PROMET model has been extensively validated and is still being validated regularly using in-situ data

ELBARA 2 radiometer

GrasslandRape

Meteorologicaldata

3


ELBARA 2 radiometer

Data of ELBARA available through a web client

(full access to instrument ancillary data)


SMOS airborne campaigns

Rehearsal campaign 2008

SMOS validation campaign 2010

SMOS cal/val campaigns

HUT-2D radiometer(Aalto University, Helsinki)

EMIRAD(Technical University of Denmark)

Thermal camera(Max-Planck-Institutefor Meteorology, Hamburg)


Radiometer data comparison 2008

Two complementary radiometers during SMOS airborne campaignsprovide added value:

- HUT-2D: imaging system, good spatial resolution

- EMIRAD: better radiometric calibration

-60

-50

-40

-30

-20

-10

0

10

20

30

08/04/2008 15/04/2008

firs

t s

toke

s p

ara

me

ter

[K]

flight days during rehearsal campaign 2008

EMIRAD minus HUT-2D after temperature correction

Lochheim

Engersdorf SouthEngersdorf NorthSteinbeissen SouthSteinbeissen North


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


First data SMOS campaign 2010

EMIRAD data on lake Chiemsee HUT-2D data example (black areas: forest)



Vils test site

TIR brightness temperatures (raw data)



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

Meteo data Neusling (014)

0

5

10

15

20

25

30

15

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.20

10

00

:00

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27

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20

:00

tem

pe

ratu

re [

°C]

0

1

2

3

4

5

6

7

8

9

10

pre

cip

ita

tio

n [

mm

]

precipitation

air temperature

Flights

Conditions during campaign

Different soil moisture conditions between saturated and medium dry Vegetation growth phase optical depth Air temperature between

10 and 30°C


Dynamics of ground measurements


10

15

20

25

30

35

40

45

17.05. 22.05. 25.05. 28.05. 12.06. 14.06. 17.06.

so

il m

ois

ture

vo

l. %

]

time

soil moisture ground measurements (coarse resolution grid)

Lochheim

Engersdorf

Steinbeissen

Neusling

Frieding

10

15

20

25

30

35

40

45

17.05. 22.05. 25.05. 28.05. 12.06. 14.06. 17.06.

so

il m

ois

ture

vo

l. %

date

soil moisture ground measurements (high resolution grid)

Engersdorf

Steinbeissen

Neusling

Frieding

Stations vs. spatial mean

SM station

Ground station measurements(lines) and mean values of all measurements at red points (dotswith standard deviation bars)



Brightness temperatures

200

210

220

230

240

250

260

270

280

290

17.5.10 27.5.10 6.6.10 16.6.10

EMIRAD

PROMET+LMEB

Bri

gh

tness

tem

pera

ture

(TB

h)

[K]

Mean values and standard deviations of all valuesfalling into the central ISEA grid point in the Vils area

L-MEB

Radiativetransfermodel

PROMETsoil moisture

SMOS comparison

SMOS data UDC (Vils testsite)

Morning overpasses

SMOS data UDC (Vils testsite)

L1c comparison

Comparison of SMOS L1c Brightness temperatures withsimulated brightness temperatures (coupledPROMET+LMEB)

Actual SMOS L1c data processing:

• TB Filtering (Flags and additional)

• Combining polarized observations

• Rotation (Faraday and Geometric)

• Analysis per incidence angle

L-MEB

RadiativeTransfer model


PROMETsoil moisture

SMOS L1c vs. PROMET-LMEB

Only morning overpasses (40°)


17 April 2010 17 June 2010

Bri

gh

tness

tem

pera

ture

(TB

h)

[K]

Project status

validation

Surface state

1km

SMOSL2 SM product

API





Radiometer

L2 Processor

L-MEB


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 dataand L2 data available

Thanks!

Funded by German Aerospace Center (50EE0731)

Documents

FR1.L10.5: SMOS SOIL MOISTURE VALIDATION: STATUS AT THE UPPER DANUBE CAL/VAL SITE EIGHT MONTHS AFTER LAUNCH