Remote sensing data

ATSR-1 observations on 19 August 1991 were collected for HEIFE area, and ATSR-2 on 14 June 1998 for IMGRASS area. Dual view angle data (approximately 0° and 53° at surface) are acquired in four channels by ATSR-1 and seven channels by ATSR-2. The two thermal channels (TIR) in ATSR1 and 2 (the central wavelengths are 11 and 12|j,m) are employed in our study. The TIR sensors are saturated at about 311 K. The standard ATSR-1/2 gridded brightness temperature image (512x512 km2) was produced from nadir and forward view instrument pixels which are collocated and gridded into a 1 km grid resolution (see the World Wide Web site at http://www.atsr.rl.ac.uk/software.html for details).

The satellite overpass time is around llh at local solar time for HEIFE and IMGRASS respectively. Subsets of 20 x 20 km2 for HEIFE and 40 x 40 km2 for IMGRASS were extracted from the ATSR-1 and - 2 images. The standard meteorological radiosounding station in HEIFE is located in the subset. The one for IMGRASS is about 40 km away from the central point of the subset where the Baiyinsumu site is located.

Table 2. Data used in the study at the field sites in HEIFE and IMGRASS

Measurements

Measurements Height

Date

HEIFE

Flux (eddy correlation system)

2.9m

19/08/1991

Tower profile

0.5-20m

08/1991

Tethered balloon sounding

0-1000m

19/08/1991

Low-level sounding

1000-2000m

19/08/1991

Standard meteorological Radiosounding

2000-16000m

19/08/199)

Surface temperature

t.5m

19/08/1991

ATSR-1

780km

19/08/1991

IMGRASS

Directional radiometric surface temperature

1.5m

26-31/07/1998

Flux (eddy correlation system)

4.9m

26-31/07/1998

Tower profile

0.5-8m

14/06, 07/1998

Standard meteorological Radiosounding

Surface-16000m

14/06/1998

Surface temperature

1.5m

14/06/1998

ATSR-2

780km

14/06/1998

0 0

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