Based On Grade Adjustment Of Z-index Temporal And Spatial Analysis On Drought Events In Northwest Liaoning

Drought is one of the worst natural disasters, and it impact on people’s production andlife. In recent years, with economic development, population growth and global warming,inclement weather frequently occur, especially localized drought has further aggravated.Drought frequently occurs in Northwest Liaoning. The drought index selection is critical fordrought. Domestic and foreign scholars achieved a lot in this regard. Compared with otherdrought index, Z-index can be more objective reflects the degree of drought. However, thepremise of its application is based on the assumptions. This article is based on the gradeadjustment of Z-Index, and analysis temporal and spatial characteristics of droughts inNorthwest Liaoning. The major research contents and results includ:（1）Using40rainfall stations’ rainfall data from1971to2010and historical droughtinformation in Northwest Liaoning, and based on Z-Index, according to National Droughtgrade standards to assessment drought. It compared with the different levels droughtfrequency of calculated and the theoretical frequency, and adjusted critical value of thedifferent levels drought. The evaluated frequency of drought match to the theoreticalfrequency, and obtained Z-Index drought grade standards of Northwest Liaoning.（2）Based on the grade adjustment of Z-Index to assess drought in northwest Liaoning.It compare with results of the evaluation and data about the historical drought. The gradeadjustment of Z-Index match to actual drought in Northwest Liaoning.（3）Based on the grade adjustment of Z-Index, and combined with GIS software,wavelet analysis, kriging spatial interpolation method and empirical orthogonal function(EOF) to draw drought spatial and temporal distribution, and to analysis temporal and spatialcharacteristics of droughts in Northwest Liaoning. In time, the drought trend, the variousgrades drought frequency, as well as drought cycle were analyzed. In space, the annua, spring,summer, and autumn droughts were analyzed by Kriging. At the same time, making theanalysis by EOF, the results show that drought has three spatial distribution pattern inNorthwest Liaoning. （4）According to the results, this article explored drought the measures in NorthwestLiaoning, and proposed targeted suggestions. It will provide a reference to the relevantdepartments about drought in Northwest Liaoning.