Field validation of the GLASS land surface broadband emissivity database using pseudo-invariant sand dune sites in northern China

Abstract

The land surface broadband emissivity (LSBE) is a key parameter for estimating surface radiation, and there have been many studies of the LSBE at global or local scales. However, few studies have validated the surface emissivity database with multi-point field measurement data using infrared radiometry, especially in China. In this study, we focus on the validation of the emissivity product of the global land surface satellite (GLASS) LSBE database for northern China for the period from 2006 to 2011. Specifically, we have employed an eight-day averaged, gridded emissivity product in the 8–13.5 µm spectral range produced at a spatial resolution of 1000 m from the Moderate Resolution Imaging Spectrometer albedo product using a new algorithm. The GLASS LSBE database was validated over bare surfaces with field measurement data from sand samples collected at many pseudo-invariant sand dune sites located in western and northwestern China. By comparing measured emissivity for different land surface types at different sites and different times, it was shown that the results were consistent and that the accuracy of the field measurements was reliable. The results of the validation of GLASS LSBE with these field emissivity data showed very good agreement.

Keywords:

• validation
• broadband emissivity
• field measurement emissivity
• GLASS
• northern China

Acknowledgements

The research was carried out with the support of China's Research and Development Special Fund for Public Welfare Industry [Meteorology GYHY201206002, GYHY200906022-1, and GYHY201306077]; a key project in the national science & technology pillar program during the Eleventh Five-Year Plan of China titled “Improved integrated observations of experiments to support quantitative sandstorm remote sensing and model prediction (2008BAC40B05)”; and a key project of the National High Technology Research and Development Program (863 Program) titled “Generation and applications of global products of essential land variables [2009AA122103-01].” We kindly thank our experiment team including Dr Zhang Y. et al. for assisting us with fieldwork in the western region of Inner Mongolia and also Dr Cheng J. from Beijing Normal University for providing the GLASS LSBE database from 2006 to 2011.