Preliminary accuracy assessment of MODIS land surface temperature products at a semi-desert site

Ground-based measurements of land surface temperature as measured by Platinum resistance thermometer partly buried in the soil, surface radiation temperature measured by infrared thermometer, and near surface air temperature measurements at Gaize (32.30 degrees N, 84.06 degrees E, 4420 m) on the western Tibetan Plateau from January 2001 to December 2003 were compared with Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products (Version 4) produced by the generalized split-window (MOD11A1) and the day/night LST algorithm (MOD11B1). A comparison of LSTs shows that the LSTs produced by the day/night LST algorithm agree quite well with ground-based surface temperature and surface radiation temperature measurements, with a mean difference of zero and root mean square errors being less than 1 K. MODIS LST retrieved by the day/night LST algorithm is found to be 2.2 K less than the air temperature at 0.5 m above the surface. Compared to that produced by the day/night LST algorithm, the LST produced by the generalized spit-window LST algorithm is underestimated by 1.9 K.