Estimating midday near-surface air temperature by weighted consideration of surface and atmospheric moisture conditions using COMS and SPOT satellite data

Abstract

The measurement of near-surface air temperature (T_a) is critically important for understanding the Earth’s energy and water circulation system and for diverse modelling applications. T_a data obtained from meteological ground stations are basically available but not suitable for large-scale areas, because of their spatial limitation. Remote-sensing techniques can provide a spatially well-distributed T_a map. However, the current remote-sensing methodology for T_a mapping has accuracy inferior to common expectations in terms of the region of various terrestrial ecosystems and climatic conditions. Our aim was to develop a midday T_a retrieval algorithm with reasonable accuracy over Northeast Asia during one seasonal year. In consideration of the various environmental conditions in our study area, T_a was calculated using land surface temperature and the normalized difference vegetation index in the nine cases derived from the combination of surface and atmospheric moisture conditions, and a weighting factor was applied to reduce the bias error among T_a results from nine cases. The reasonable pixel window size was established as 13 × 13. The validation process yielded a coefficient of determination (R²), root mean square error, and bias values of 0.9401, 2.8865 K, and 0.4920 K, respectively. Although the study area includes diverse land-cover and climatic conditions, our satellite-derived T_a data provided better results compared with a previous study of only four cases with no weighting function in the Korean peninsula. Our suggested methodology will be useful in estimating T_a using satellite data, particularly over complex land surfaces.

Acknowledgements

The authors would like to thank the anonymous reviewers whose comments and suggestions greatly improved this article. We greatly appreciate the National Institude of Meteorological Research (NIMR) and the National Meterological Satellite Center (NMSC) of the Korean Meteorological Administration for placing at their disposal the COMS and meteorological station data.

Additional information

Funding

This work was supported by ‘Research for the Metorological and Earthquake Observation Technonology and Its Application [NIMR-2012-B-3]’ of the National Institute of Meteological Research (NIMR) of Korean Meteorological Administration.