Study On The Impact Effect Of Water Resources Emergency Management In Liaoning Province Based On Drought And Flood Indicators

In view of the frequent occurrence of drought and flood disasters in Liaoning Province and the imperfect water resources and emergency management system,based on historical disaster data and meteorological data,this study analyzed the spatial and temporal distribution law and influencing factors of standardized precipitation evapotranspiration index(SPEI),and then revealed the formation background and risk formation mechanism of drought and flood disasters in the study area.At the same time,the long-period drought-flood abrupt alternation index(LDFAI)and short-period drought-flood abrupt alternation index(SDFAI)were used to analyze the spatial and temporal distribution characteristics of drought-flood abrupt alternation in Liaoning Province.Through the analysis of the distribution of droughts and floods in Liaoning Province and the characteristics of droughts and floods in Liaoning Province,according to the relativity,dynamics,regionality and controllability of water resources emergency management,a natural-social evaluation system of water resources emergency management in Liaoning Province based on SPEI and LDFAI is established.The entropy weight method is used to measure the degree of influence of the index,to achieve the goal of objective selection of indicators and differential evaluation.The index system and neural network model are used to analyze the time law of water resources emergency management in Liaoning Province,to explore the characteristics and mechanism of drought and flood stress,and to explore the sensitivity of SPEI and LDFAI emergency management indicators in Liaoning Province based on deep learning.In order to provide control measures and suggestions for emergency management of water resources in Liaoning Province.The conclusions are as follows :(1)From 1970 to 2020,SPEI in Liaoning Province had obvious periodic changes on the three scales of month,season and year.Drought and flood events occurred alternately,and the overall trend was wetting.The spatial distribution of SPEI is obvious.The frequency of drought in western Liaoning,southern Liaoning and northern Liaoning is higher,and the frequency of drought in the central region is the smallest.Most of Liaoning Province has light drought throughout the year,while the extreme drought only occurs in Qingyuan and Zhangwu areas.The strongest correlation between SPEI and annual and seasonal scales is precipitation,followed by potential evapotranspiration.ENSO cold and warm events have a certain impact on drought and flood in Liaoning Province,and the impact of warm events is more obvious.It shows different resonance periods,and its correlation strength also has spatial differences.(2)From the perspective of time,LDFAI and SDFAI in Liaoning Province showed a fluctuating trend from 1970 to 2020,and the overall upward trend of LDFAI and SDFAI indicated that the risk of drought to flood in Liaoning Province would increase in the future.Both LDFAI and SDFAI show that the spatial difference of the occurrence probability of drought-flood abrupt alternation events in Liaoning Province is closely related to the uneven distribution of precipitation in Liaoning Province.Spatially,the probability of drought-flood abrupt alternation events represented by SDFAI is much higher than that of LDFAI.There is a certain similarity in the spatial development trend of the two types of drought-flood abrupt alternation indexes.From the perspective of center of gravity migration,the change range of LDFAI center of gravity is significantly greater than that of SDFAI.At the same time,LDFAI and SDFAI have the same migration direction from July to August and from August to September.(3)Research on the effect of water resources emergency management based on drought and flood indicators,the diagnosis and analysis of water resources emergency management system in Liaoning Province,the overall state of water resources emergency system in Liaoning Province showed a significant improvement in fluctuations,the construction of water resources emergency management evaluation index system in Liaoning Province and the analysis of influencing factors show that different subsystems have different effects on SPEI and LDFA.In the model based on SPEI,socio-economic conditions have the greatest impact,followed by water resources management capacity and water resources ecological security,and water resources conditions have the least impact.In the model based on LDFAI,water resources ecological security has the greatest impact,followed by socio-economic conditions and water resources conditions,and water resources management capacity has the least impact.In terms of time,the change of the overall index of water resources emergency management in Liaoning Province from 2001 to 2021 shows a fluctuating upward trend.In terms of space,there are obvious differences in the classification of different prefecture-level cities under different hydrological conditions.In the normal year,the whole province is in a normal state.In the wet year,the eastern part of Liaoning Province is in an emergency state,and in the dry year,the northwest of Liaoning Province is in an emergency state.In the sensitivity analysis,the output results of the SPEI-based model are more sensitive to the changes of irrigation area and population.The output results of the LDFAI-based model are the most obvious for the changes of NDVI and farmland water use rate.