Analyzing the coupling between air and surface temperature

Investigator: 
TC Chakraborty
Advisor: 
Xuhui Lee
Start Date: 
January, 2017
Description: 

Standard meteorological stations measure the temperature of the air at a height of 1.5-2 m above the ground (Tair). On the other hand, satellite retrievals of surface temperature are based on measurements of thermal radiance emitted from the land surface (Tskin).  While Tair and Tskin are coupled, they represent two different parameters, and are affected differently by the surface energy budget, land use/land cover, and anthropogenic influences [Jin and Dickinson, 2010]. Previously, two studies have looked at the comparison between Tair and Tskin. The first study [Jin and Dickinson, 2010] compared the monthly MODIS TERRA 0.05 degree T¬skin to monthly Global Historical Climatology Network 5 degree by 5 degree Tair [Lawrimore, et al, 2011]. The second study [Zhao and Running, 2011] compared the maximum Tskin from MODIS AQUA 0.05 degree product to the WMO weather station data.

Previously, for my project for the course, ‘Observing Earth from Space’, I analyzed this relationship over North America using high resolution data for each climate zone [Rubel, et al, 2017]. This analysis showed that there are differences in the association between Tair and Tskin for different climate zones. In general, the nighttime coupling is stronger, but no consistent relation was found with the vegetation density, for which Enhanced Vegetation Index (EVI) was used as a proxy.

The previous analysis was probably simplistic since there are many factors other than EVI that can influence this coupling. Moreover, the same EVI value in different land use types can represent different vegetation species, different canopy structure, and different potential evapotranspiration rate, which plays a strong role in this coupling. I want to expand my previous work by looking at this association for each individual MODIS-derived land use within each climate zone.