Calculation method of time-continuous surface evapotranspiration data

A calculation method and time-continuous technology, applied in the calculation field of surface evapotranspiration data, can solve the problems of not considering the observation error of remote sensing observation, and achieve the effect of reducing observation error

Active Publication Date: 2018-08-31
BEIJING NORMAL UNIVERSITY
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Problems solved by technology

[0005] At present, the research on the time scale extension method from day to month / year includes mathematical method, surface impedance method and reference crop evaporation ratio method, etc. However, these methods do not consider the observation error of remote sensing observation itself, so they have certain limitations

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  • Calculation method of time-continuous surface evapotranspiration data
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Embodiment 1

[0054] Data assimilation refers to the method of fusing new observation data during the operation of the numerical model on the basis of considering the temporal and spatial distribution of data and the errors of observation field and background field. This algorithm is dedicated to solving the problem of time scale expansion in remote sensing estimation of surface evapotranspiration, combining the assimilation method and the Penman-Monteith formula to expand the time scale of daily evapotranspiration from day to month / year to generate a time-continuous area with a resolution of 1km The evapotranspiration data set promotes the wide application of remote sensing estimation ET products in fields related to hydrological cycle and land surface energy.

[0055] The embodiment of the present invention constructs a complete assimilation system for evapotranspiration data assimilation of the surface by remote sensing, mainly including: model operator, observation operator, assimilation...

Embodiment 2

[0153] Beijing is the capital of China, and also the political, economic and cultural center of the country. However, with the deepening contradictions in urban water use, water resources have become a bottleneck restricting the prosperity and development of cities. This algorithm extends the sunny daily evapotranspiration retrieved by the Liu-2007 model to the monthly through the SCE_UA method, and obtains the spatial distribution of annual evapotranspiration. from figure 2 The assimilation method estimation results in (ET_SCEUA) shows that the annual evapotranspiration in the eight urban districts of Beijing is significantly lower than that of the surrounding suburban districts and counties. Small. Among surrounding districts and counties, Huairou and Miyun in the north had higher evapotranspiration than Daxing and Fangshan in the south. This distribution feature of surface evapotranspiration is related to the urban planning of Beijing. There are many real estate projects...

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Abstract

An embodiment of the invention provides a method for calculating time-continuous surface evapotranspiration data. The method mainly comprises: on a non-sunny day, calculating an adjustment factor alpha of an energy distribution item and an adjustment factor beta of a vegetation canopy impedance item by utilizing a cost function through an SCE_UA algorithm; and optimizing a method for calculating a surface evapotranspiration simulation value on the non-sunny day according to the adjustment factor alpha of the energy distribution item and the adjustment factor beta of the vegetation canopy impedance item, and calculating the surface evapotranspiration simulation value on the non-sunny day with the optimized calculation method. The method is committed to solving the problem of time scale expansion in remote sensing estimation of surface evapotranspiration, daily evapotranspiration is subjected to time scale expansion from day to month / year in combination with an assimilation method and a Penman-Monteith formula, and high-precision time-continuous region evapotranspiration data sets capable of being used in multiple fields are produced, so that observation errors caused by data observation on the non-sunny day are reduced, and wide application of ET (evapotranspiration) remote sensing estimation products to related fields of hydrologic cycle and land surface energy is facilitated.

Description

technical field [0001] The invention relates to the technical field of surface water, in particular to a method for calculating time-continuous surface evapotranspiration data. Background technique [0002] Evapotranspiration (ET) is an important component of surface water balance, and its energy form, latent heat flux (LE), is an important component of surface energy balance. The latent heat flux transfers the heat stored on the underlying surface to the gas layer near the underlying surface in the atmospheric boundary layer through turbulent exchange, and is an important energy and material exchange process in the Earth system. The heat required for the phase transition of liquid water is latent heat, which is the single largest heat source of atmospheric heat. Therefore, the study of latent heat flux plays an important role in weather and climate dynamics. The exchange process of momentum, moisture and heat between the earth and the atmosphere, especially the quantificat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/15
Inventor 徐同仁许蕗刘绍民徐自为孟杨繁宇
Owner BEIJING NORMAL UNIVERSITY
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