A Method of Evapotranspiration Data Assimilation Based on Distributed Time-varying Gain Hydrological Model

A time-varying gain and hydrological model technology, applied in the field of evapotranspiration estimation, can solve the problems of underestimation of evapotranspiration, accumulation of precision errors, and low precision, and achieve the effects of easy operation, reduced uncertainty, and optimized model simulation

CN104765981BInactive Publication Date: 2019-05-10INST OF GEOGRAPHICAL SCI & NATURAL RESOURCE RES CAS
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2019-05-10
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses an evapotranspiration data assimilation method based on a distributed time varying gain hydrological model. The method includes the following steps that first, data preparation is conducted, and daily evapotranspiration is obtained based on a remote sensing model and flux observation data to be used for 'observation'; second, an initial ambient field is generated and model simulation is driven; third, when 'observation' data occur, an observation field and a prediction field are obtained; fourth, an analysis field is acquired in an assimilation mode through an ensemble Kalman filtering algorithm; fifth, the ambient field is updated. According to the method, through the data assimilation technology, an evapotranspiration result with high precision is used as observation information, the hydrological model is adjusted to operate, error accumulation is reduced, and an evapotranspiration sequence with high precision and continuous time is simulated. Compared with the prior art, the evapotranspiration can be assimilated directly through the method, the model nondeterminacy can be lowered, operating is easy, a water cycle physical mechanism is realized, and the method can be widely applied to accurately estimating and continuously acquiring region evapotranspiration.
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Description

technical field

[0001] The invention relates to the field of evapotranspiration estimation, in particular to an evapotranspiration data assimilation method based on a distributed time-varying gain hydrological model. Background technique

[0002] The key link of the water cycle in the evapotranspiration (ET) basin determines the interaction and feedback of "geosphere-biosphere-atmosphere" in the earth system. Accurate estimation of evapotranspiration is crucial for studying global or regional water and energy balance, and the relationship between to climate change, water resource management, crop yield estimation, and environmental protection. Therefore, the research on evapotranspiration estimation methods has always been an important topic of common concern in the fields of agronomy, meteorology, hydrology, and geography.

[0003] At present, the main ways to estimate regional evapotranspiration are: empirical formula method, hydrological model and remote sensing ET model...

Examples

Embodiment Construction

[0029]The technical solution of the present invention will be further specifically described below through specific implementation examples and in conjunction with the accompanying drawings.

[0030] as attached figure 1 with 2 As shown, a method for assimilating evapotranspiration data based on a distributed time-varying gain hydrological model includes the following steps:

[0031] Step 1, data preparation:

[0032] The daily evapotranspiration of the watershed is obtained as the "observation" of the assimilation system through the inversion of the remote sensing model of evapotranspiration (flux observation data). By calibrating the parameters of the distributed time-varying gain hydrological model, the parameters are optimized to obtain a model with simulation stability. Hydrological model as a model operator;

[0033] Step 2, generate the initial background field:

[0034] On the basis of calibrating the parameters of the distributed time-varying gain hydrological mod...