A STUDY ON THE SEASONAL CHANGE OF DIFFERENCE OF BRIGHTNESS TEMPERATURES OBTAINED FROM LANDSAT-7/ETM+ AND TERRA/MODIS

摘要

The brightness temperatures (BTs) around Hotien Oasis of the southwestern part of Taklimakan Desert in Xinjiang, China retrieved from the data of Landsat-7/ETM+ band 6 and Terra/MODIS bands 31 and 32, for higher sun elevation observed on June in 2002, indicates following features. (1) Good linear relationship between the BTs of ETM+ and that of MODIS. (2) The observation time adjusted BT of ETM+ is almost equal to that of MODIS. (3) The BT of Terra/MODIS band 31 is slightly higher than that of band 32 over a reservoir while opposite feature is recognized over desert area. (4) The statistical analysis of 225 sample data of ETM+ in one pixel of MODIS for different landcovers indicates that the standard deviation and range of BT of ETM+ corresponding to one pixel of MODIS are 0.45 °C, 2.25 °C for the flat area of desert, while respective values of the oasis farmland and shading side of rocky hill amount to 2.88 °C, 14.04 °C, and 2.80 °C, 16.04 °C. On the other hand, in the seasonal changes of difference of BTs retrieved from ETM and MODIS acquired in 2000 to 2003, it is found that the parabola opens upward in the flat area of desert and the oasis reservoir although the parabola opens downward in the oasis farmland. Furthermore, in the difference of ground surface temperature of a black rubber sheet on the roof at Hiroshima, Japan that had been measured in referring, the parabola opens upward and temperature differences on January and June are approximately 2.7 °C and 0.6 °C .