摘要
根据地表热辐射传导方程,提出了一个简单可行且精度较高的专门用于从TM6数据中演算地表温度的方法———单窗算法。这一算法把大气和地表状态对地表热传导的影响直接包括在演算公式中。该方法需要两个大气参数进行地表温度的演算,即大气平均作用温度和大气透射率。本文论述这两个大气参数的估计方法:根据大气水分含量或地表附近空气湿度来估计大气透射率;通过分析标准大气剖面资料,尤其是大气水分和气温随高程的变化规律,根据地表温度推算大气平均作用温度。
The thermal band data of Landsat TM (TM6) is highly suitable for analyzing the spatial patterns of the Earth's heat flux variation and surface temperature. Based on the thermal radiance transfer equation and several approximations to its terms, the authors developed a mono-window algorithm for retrieving land surface temperature (LST) from TM6 data. Unlike the conventional atmospheric correction which requires the in situ atmospheric profile data to estimate the atmospheric thermal radiance and absorption, the proposed mono-window algorithm directly involves the impacts of both atmosphere and the emitted ground into its computation, hence avoids the consequence of inaccurate atmospheric radiance estimate. The proposed algorithm requires two essential atmospheric parameters for LST retrieval: transmittance and atmospheric average temperature. This paper discusses the estimation of the essential atmospheric parameters. Atmospheric effective mean temperature can be estimated using the ground meteorological observation data. Equations also have been constructed for estimation of atmospheric transmittance using the atmospheric water vapor content in the profile. Moderate errors in estimating the two essential atmospheric parameters may cause a bias of about 1.2℃ to the LST retrieval, which is within the acceptable accuracy of 1.5℃ for most applications.
出处
《国土资源遥感》
CSCD
2003年第2期37-43,共7页
Remote Sensing for Land & Resources
基金
国家973项目(2001CB309404)支持。
