I N T E R N A T I O N A L I N S T I T U T E F O R G E O - I N F O R M A T I O N S C I E N C E A N D E A R T H O B S E R V A T I O N

20 soil moisture &soil temperature stations

80 km

45 km

80 km

45 km

20 soil moisture &soil temperature stations

For more information:

Maqu and Twente site for validation of SMOS soil moisture products

Introduction

The validation of soil moisture products retrieved from coarse resolution sensors is a critical issue due to a large scale gap between in-situ measurements and satellite estimates at 30-50km spatial resolution and due to the typically high spatial variability of soil moisture. For this reason and in view of the soil moisture dataset which will be provided by SMOS-MIRAS, two extensive soil moisture monitoring networks have been installed in China (Maqu site) and in The Netherlands (Twente site), with the main objectives: to evaluate upscaling methods of soil moisture ground data to satellite sensor resolution cell, to validate a new retrieval algorithm based on the synergistic use of active and passive microwave data, to validate SMOS and other existing soil moisture products. These two test sites were selected because they are located in different climatic regions and they are characterized by different topography, land cover/use and soil hy-drological properties. This will lead to a more accurate validation for different surface conditions and soil moisture ranges. The soil moisture measured at Maqu stations has been preliminary analyzed and compared with VUA-NASA AMSR-E products, showing the capability of the network to monitor the parameter in the area and a good agreement with satellite products.

MAQU SITE

Location: South of Maqu city (Gansu province, China)Coordinates: 33°30’ – 34°15’N, 101°38’ – 102°45’EElevation: 3430 – 3750 mDate of installation: June 2008Climate (Koeppen Clas. Syst.): Cold (Dw, winter dry season)

TWENTE SITE

Location: Twente region, The NetherlandsCoordinates: 52°05’ – 52°27’N, 6°05’ – 7°00’EElevation: -3 – 50 mDate of installation: November 2008 – presentClimate (Koeppen Clas. Syst.): Temperate (Cf)

Station description:

- 2/3 soil moisture & temperature probes - 5, 10 & 20 cm deep (few profiles deep 80 cm) - 1 datalogger - completely buried

L. Dente, Z. Vekerdy, Z. SuHengelosestraat 99

7500AA Enschede, The NetherlandsEmail: dente@itc.nl

Jun WenCAREERI, Chinese Academy of Sciences

260 Donggang West RoadLanzhou 730000, Gansu, P.R.China

The fieldwork in China has been (partially) supported by the European Commission (Call FP7-ENV-2007-1 Grant nr. 212921) as part of the CEOP-AEGIS project (http://www.ceop-aegis.org/)

and has been carried out in collaboration with Cold and Arid Regions Environmental and Engineering Research Institute of

Chinese Academy of Sciences.

Acknowledgment

25 soil moisture &soil temperature stations

75 km

50 km

75 km

50 km

5 cm ->10 cm ->

20 cm ->

40 cm ->& 80 cm

5 cm ->10 cm ->

20 cm ->

40 cm ->& 80 cm

HILLS

FLAT GRASSLAND

RIVER WETLAND

DRY AREA

HILLS

FLAT GRASSLAND

RIVER WETLAND

DRY AREA

Average in-situ smVUA-NASA AMSR-E sm

Organic soils

Sand loam soil

Average in-situ smVUA-NASA AMSR-E sm

Organic soils

Sand loam soil

Soil texture:

silt loam & sand loam & organic soils

Variable topography

Soil texture:

sand & loam sand& organic soils

Variable land cover

Preliminary results

Acknowledgement:

CAS climate station

25 soil moisture &soil temperature stations