Combined prediction method of reference crop evapotranspiration

A combination of forecasting and evacuation technology, applied in forecasting, instrumentation, data processing applications, etc., can solve problems such as difficult wide-scale promotion, relatively strict requirements on the completeness and quality of meteorological data, and difficulty in meeting forecasted meteorological data. To achieve the effect of reliable prediction results and reduced impact

Active Publication Date: 2017-01-25
HOHAI UNIV
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Problems solved by technology

[0003] So far, various computational ET 0 Among the methods, the Penman (PM) formula recommended by FAO has a strong theoretical basis and high accuracy, but the method has relatively strict requirements on the completeness and quality of meteorological data, and it is difficult to meet the forecast meteorological data in practice. Therefore, This method is difficult to generalize on a large scale

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  • Combined prediction method of reference crop evapotranspiration
  • Combined prediction method of reference crop evapotranspiration
  • Combined prediction method of reference crop evapotranspiration

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Embodiment Construction

[0015] like figure 1 As shown, the combined prediction method of reference crop evapotranspiration based on weather forecast data provided in this embodiment includes two parts: model construction (①-④) and model application (⑤):

[0016] ①Calculation of ET by PM method based on historical meteorological data 0 , and as ET 0 standard value;

[0017] ② ET calculated by PM method 0 The standard value is the target, according to the principle of least squares, the ET calculated by the respective methods 0 value and ET 0 The minimum sum of squared errors between the standard values ​​is the goal, and the parameters in each method in the Hargreaves model, Fourier model, multiple regression model, and symbolic regression model formula are determined respectively, as follows:

[0018] 1) Hargreaves model: Considering the influence of two main meteorological factors, temperature and radiation, the formula is as follows:

[0019] ET 0 =0.408×a×(17.8+T mean )×TR c × R a

[00...

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Abstract

The invention discloses a combined prediction method of reference crop evapotranspiration; an Hargreaves model subjected to regional correction, a Fourier series model based on time series, a multiple regression model based on multi-year average correction method and an ET<0> estimating model based on symbolic regression (SR) algorithm are utilized, calculating is performed by using standard method Penman formula based on historical data, calculation results of each model and a residual sum of squares between standard methods under different weather conditions are acquired based on the calibration and evaluation of the four models, weight of each model in combined prediction is determined based on the respective residual sum of squares, and ET<0> combined prediction value based on the four models is acquired by using weather forecast data as an input. Therefore, uncertainty of single-method prediction is decreased, and reliability of ET<0> prediction is improved.

Description

technical field [0001] The invention relates to the field of agricultural irrigation forecasting, in particular to a combined forecasting method for reference crop evapotranspiration. Background technique [0002] Agriculture is inseparable from water, and the rationality of the irrigation system directly affects the growth of crops. Affected by geographical conditions in my country, the temporal and spatial distribution of natural precipitation is extremely uneven. Even in the humid southern regions, natural precipitation alone cannot meet the water demand of crops in each growth period. Therefore, a reasonable irrigation system is to ensure effective and timely water supply for crops and save water. resource key. Evaporation of reference crops reflects the evaporation capacity of the atmosphere, and is the basic data for estimating the water demand of different crops. To study the evaporation of reference crops (ET 0 ) is an important data for agricultural water use plann...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06Q10/04G06Q50/02
CPCG06Q10/04G06Q50/02
Inventor 徐俊增王海渝刘文豪刘博弈卫琦杨士红
Owner HOHAI UNIV
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