当前位置： 首页»科研成果» 2013 Empirical Algorithms to Map Global Broadband Emissivities Over Vegetated Surfaces 梁顺林、程洁

Emissivities Over Vegetated Surfaces

 

Huazhong Ren, Shunlin Liang, Senior Member, IEEE, Guangjian Yan, and Jie Cheng

 

State Key Laboratory of Remote Sensing Science, School of Geography, Beijing Normal University, Beijing 100875, China;

Laboratoire des Sciences de l’Image, de l’Informatique et de la Télédétection, Université de Strasbourg, 67412 Illkirch, France;

College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China;

Department of Geographical Sciences, University of Maryland, College Park, MD 20742 USA.

 

Abstract

This paper describes two new methods that were used to generate 26 years (1985–2010) of broadband emissivity (BBE) products with spatiotemporal continuity at the global scale from satellite data recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Very High Resolution Radiometer (AVHRR). On the basis of emissivity libraries, the study began with establishing relationships for converting channel emissivities of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and MODIS to BBEs for the 8–13.5-$muhbox{m}$ spectral window and then developed two new algorithms from simultaneous ASTER emissivity products to estimate BBEs over vegetated surfaces using the MODIS and AVHRR data. The MODIS-data-based algorithm (MDBA) uses linear equations with MODIS normalized difference vegetation index (NDVI) and seven channels' albedo; the AVHRR-data-based algorithm uses nonlinear equations with AVHRR red and near-infrared reflectances. The proposed algorithms were first validated with ASTER emissivity products. Results indicated that the root-mean-square errors of both the proposed algorithms were less than 0.015 and their biases were less than 0.003. Comparison with MODIS emissivity products from the day/night algorithm showed that the estimated BBEs using the MDBA were generally smaller than the MODIS products. Cross-comparisons were also made between the proposed algorithms and the NDVI threshold method. Finally, strategies for mapping global BBE products from the MODIS and AVHRR data are presented, and some examples are discussed. The global BBE products are planned to be released throughout the network in the near future.

 

KEY WORDS: Advanced Very High Resolution Radiometer (AVHRR), broadband emissivity (BBE), global products, Moderate Resolution Imaging Spectroradiometer (MODIS), vegetated surfaces

 

PUBLISHED BY: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, 2013, 51 (5): 2619-2631.

 

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