Inter-annual variation of the surface temperature of tropical forests from SSM/I observations

Friday, 19 December 2014
Huilin Gao, Texas A&M University, College Station, TX, United States, Rong Fu, Jackson School of Geosciences, Austin, TX, United States, Wenhong Li, Duke Univ-Nicholas School, Durham, NC, United States, Shuai Zhang, Texas A & M University, Zachry Department of Civil Engineering, College Station, TX, United States and Robert E Dickinson, University of Texas at Austin, Austin, TX, United States
Land surface temperatures (LST) within tropical rain forests contribute to climate variation, but observational data are very limited in these regions. In this study, all weather canopy sky temperatures were retrieved using the passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager/Sounder (SSMIS) over the Amazon and Congo rainforests. The remote sensing data used were collected from 1996 to 2012 using two separate satellites—F13 (1996-2009) and F17 (2007-2012). An inter-sensor calibration between the brightness temperatures collected by the two satellites was conducted in order to ensure consistency amongst the instruments. The interannual changes of LST associated with the dry and wet anomalies were investigated in both regions. The dominant spatial and temporal patterns for inter-seasonal variations of the LST over the tropical rainforest were analyzed, and the impacts of droughts and El Niños (on LST) were also investigated. The remote sensing results suggest that the morning LST is mainly controlled by atmospheric humidity (which controls longwave radiation) whereas the late afternoon LST is controlled by solar radiation.