Evaluation of Differences among Near-surface Air Temperature, Land Surface Temperature and Soil Temperature Using Remote Sensing and Ground-Based Observations

Determining reliable estimation of near-surface air temperature, land surface temperature, and soil temperature are crucial for the global climate system, global energy budget, study of land surface processes, numerical modeling of weather and climate, and land surface model data assimilation. Earlier studies have shown that the difference between soil temperature and surface air temperature is critical for high-latitude freeze and thaw states detection, which play vital role for the global climate system, surface energy budget, hydrological activities, vegetation dynamics, terrestrial carbon budgets, and land-atmosphere trace gas exchange. In the previous study of this research, the analysis of surface air temperature and soil temperature for a three-year period (2013-2015) from ground observations showed a notable difference. Moreover, seasonal effects are seen in differences between air temperature and surface temperature with maximum differences when the transition from freezing to thawing occurs in cold regions. The purpose of this study is to assess the differences among the surface air temperature, land surface temperature and soil temperature over high-latitude regions using satellite- and ground-based observations. The difference between surface air temperature and land surface temperature were assessed during precipitation and non-precipitation condition using Atmospheric Infrared Sounder (AIRS) data aboard the Aqua satellite and ground observations for a longer period. Additionally, both the temperatures from AIRS are then evaluated against the ground-based observations. The differences are characterized based on different land-cover and vegetation types. Furthermore, diurnal, monthly and seasonal variations are also studied from both types of observations. Results of this study will be beneficial for the development of more accurate freeze/thaw states detection algorithm and for the study the global energy budget.