A Method for Assessment and Forecasting of Watershed Ecological Drought

Abstract

The invention discloses a watershed ecological drought assessment and forecast method. At present, there is no strict definition of ecological drought and a set of drought index framework with high degree of universality considering the ecological health of rivers has not been formed. The invention is based on the watershed grid The monthly flow process simulated by the vertical mixed runoff model of the grid unit is used to fit the theoretical probability distribution with the P‑III distribution function, and the skewed distribution is transformed into a standard normal distribution to obtain the ecological drought index value of the watershed, which is calculated according to the Tennant method The ecological water demand of the river course is standardized, and the required ecological runoff values ​​of different grades are standardized to determine the drought grade division standard of the ecological drought index of the river basin. The invention expands the evaluation range of the current drought index, can provide ecological technical support for the overall construction of the watershed drought warning and monitoring system and the health of the watershed, and can forecast and predict further changes in ecological drought in combination with 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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