Watershed ecological drought evaluation and prediction method

Abstract

The invention discloses a watershed ecological drought evaluation and prediction method. Currently, ecological drought is not strictly defined, and a drought index framework which is generally applicable and takes ecological health of rivers is not formed yet. A monthly flow process simulated by a vertical mixed production flow model of a watershed grid unit, a P-III distribution function is adopted for fitting theoretical probability distribution, and the skewed distribution is converted into standard normal distribution to obtain ecological drought index value of the watershed. The ecological water demand quantity of a river channel is calculated according to the Tennant method, the ecological runoff quantity values required by different levels are standardized, and the drought level dividing standard of the ecological drought indexes of the watershed is determined. The evaluation range of the current drought index is expanded, and an ecological technical support can be provided forcomprehensive building of a watershed drought early-warning and monitoring system and watershed health. Forecast and prediction can be carried out on further changes of the ecological drought by combining the meteorological and hydrological information.

Description

technical field [0001] The invention belongs to the technical field of drought forecasting and early warning, and in particular relates to a watershed ecological drought assessment and forecasting method. Background technique [0002] Drought disasters are one of the most important natural disasters in my country. Since the 1990s, drought disasters have shown the characteristics of increasing frequency, expanding spatial pattern, prolonging duration, expanding affected areas and increasing disaster losses. According to statistics, the average annual reduction in industrial output value due to drought is more than 230 billion yuan, and the reduction in grain production accounts for more than 60% of the total grain production caused by various natural disasters. The frequency of major droughts in my country also increased from 1950 to 1990. 26.8% increased significantly to 47.6% from 1991 to 2011. Drought disasters have also expanded and intensified from the northern and north...

AI Technical Summary

Problems solved by technology

The construction of the drought index provides a better method reference for the development of the ecological drought index. However, the evaluation of the index does not take into account the impact of drought on the entire ecosystem of the habitat in the study area, and at the same time, it cannot be used for other months except July-September. Accurate Assessment of Ecological Drought Situation

In addition, the drought classification of the index is only applicable to its own research area and cannot be promoted or directly applied in other areas

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