非均匀地表蒸散遥感研究综述
Remote sensing research of evapotranspiration over heterogeneous surfaces: A review
- 2016年20卷第2期 页码:257-277
纸质出版日期: 2016
DOI: 10.11834/jrs.20165030
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纸质出版日期: 2016 ,
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[1]周倜,彭志晴,辛晓洲,李福根.非均匀地表蒸散遥感研究综述[J].遥感学报,2016,20(02):257-277.
ZHOU Ti, PENG Zhiqing, XIN Xiaozhou, et al. Remote sensing research of evapotranspiration over heterogeneous surfaces: A review[J]. Journal of Remote Sensing, 2016,20(2):257-277.
本文评述了目前常用的遥感估算地表蒸散方法
包括地表能量平衡模型、Penman-Monteith类模型、温度—植被指数特征空间方法、Priestley-Taylor类模型和其他方法。然而使用这些方法估算地表蒸散时会面临严重的尺度效应
而产生尺度效应的根本原因之一是地表异质性
在分析了非均匀下垫面对水热通量遥感反演造成的影响后
介绍了面积加权、校正因子补偿与温度降尺度3种尺度误差纠正方法;并从地面观测实验的角度简述了非均匀下垫面水热通量真实性检验的研究;最后探讨了将来建立更具时空代表性的非均匀下垫面地表蒸散遥感估算模型可能会面临的一些挑战。
This review surveys the most currently used evapotranspiration estimation methods based on remote sensing. The methods are divided into different categories
including surface energy balance models
Penman–Monteith models
land surface temperature–vegetation index space methods
Priestley–Taylor models
empirical statistical methods
complementary methods
and land process assimilation models. These methods are mainly focused on two problems. The first problem is how to deal with aerodynamic surface temperature used in gradient diffusion equation. One-source models have two major solutions. One is to use remotely sensed radiative temperature as a direct substitution for aerodynamic surface temperature or use semi-empirical relations to obtain the surface–atmospheric differential temperature.In two-source models
the heat fluxes are decomposed by component temperature. The second problem is how to calculate surface resistance that influences heat flux exchange from the soil surface and canopy layers. This process is complicated to calculate at the local scale.Basing from the two problems
scientists combined the features and superiority of remote sensing
such as the relationship between various vegetation indices and surface parameters with the fundamental theory of these methods
and developed these methods from saturated surface toward unsaturated surface to calculate evapotranspiration.However
severe scale effects emerge when these methods are used in heterogeneous surfaces. Surface heterogeneity influences the driving force of evapotranspiration estimation. Thus
three methods to correct scale error over heterogeneous surfaces are shown in detail: area weighting method
correction factor method
and land surface temperature downscaling(or thermal spatial sharpening) method. The core concepts of these methods are to couple high and low spatial resolution satellite data and statistically quantify the inhomogeneity in mixed pixels to correct the scale error in evapotranspiration estimation. In meteorological science
land process models using mosaic(or areaweighted method) and statistical dynamic methods are developed for heterogeneous surfaces. In the statistical dynamic method
one single or two mutually independent surface parameters or atmospheric forces are regarded as random variables. Consequently
their spatial distributions are expressed as probability density function to be melted into evapotranspiration retrieval models. These ideas are worthy to be adopted in remotely sensed evapotranspiration estimation. As another important part of evapotranspiration estimation
the progress of turbulent heat flux validation research over heterogeneous surfaces is introduced at length from the angle of observation experiments. The measured heat fluxes possibly originate from source areas instead of in situ pixels. Thus
the traditional validation method that compares the retrieved pixel value with the observation value to evaluate result accuracy may cause uncertainty. Some schemes are developed using footprint models to determine the scope and weight of source area pixels and decrease the uncertainty in validation. Moreover
we provide a brief introduction of the basic principles of the footprint models that are mostly used in remote sensing in the present case. These models include Eulerian analytic flux footprint models and Lagrangian stochastic trajectory approach. Finally
we discuss the challenges that researchers may encounter in the future to develop representative models of remotely sensed evapotranspiration retrieval over heterogeneous surfaces.
遥感蒸散模型尺度效应非均匀下垫面地面实验
remote sensingevapotranspirationModelscale effectheterogeneous surfacesurface observation experiment
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