Method for calculating 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

Active Publication Date: 2016-02-03
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

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  • Method for calculating time-continuous surface evapotranspiration data
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  • Method for calculating time-continuous surface evapotranspiration data

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Example Embodiment

[0053] Example one

[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 spatial and temporal distribution of data and the errors of observation and background fields. This algorithm is dedicated to solving the problem of time scale expansion in the estimation of surface evapotranspiration from remote sensing. Combining the assimilation method and Penman-Monteith formula, the time scale of daily evapotranspiration is expanded from day to month / year to generate a time continuous area with 1km resolution. The evapotranspiration data set promotes the wide application of remote sensing estimation of ET products in the hydrological cycle and land surface energy related fields.

[0055] The embodiment of the present invention constructs a complete remote sensing estimation of evapotranspiration data assimilation system, which mainly includes: model operator, observation operator, assimila...

Example Embodiment

[0152] Embodiment two:

[0153] Beijing is the capital of China and the political, economic, and cultural center of the country. However, as the urban water use contradiction is deepening, water resources have become a bottleneck restricting the prosperity and development of the city. This algorithm uses the SCE_UA method to extend the sunny day evapotranspiration retrieved by the Liu-2007 model to the month to obtain the spatial distribution of the annual evapotranspiration. From figure 2 The estimation result of the assimilation method (ET_SCEUA) in Beijing Municipality shows that the annual evapotranspiration of the eight districts of Beijing is significantly lower than that of the surrounding suburban counties. This is mainly because the underlying surface of the city is mostly artificial surfaces such as cement, and the annual evapotranspiration is relatively high. small. In the surrounding districts and counties, the annual evapotranspiration in Huairou and Miyun in the n...

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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 calculation method for time-continuous surface evapotranspiration data. Background technique [0002] Evapotranspiration (Evapotransspiration, 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. Latent heat flux transfers the heat stored on the underlying surface to the air layer near the underlying surface in the atmospheric boundary layer through turbulent exchange, which 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 largest single 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, especiall...

Claims

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Application Information

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IPC IPC(8): G06F19/00
Inventor 徐同仁许蕗刘绍民徐自为孟杨繁宇
Owner BEIJING NORMAL UNIVERSITY
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