Research On The Characteristics Of Regional Flood Disaster Resilience And Its Constraining Effect On Planting Structure From The Perspective Of Complexity

As a natural disaster with sudden,multiple,uncertain and high hazard,flood disasters have become the hotspot of disaster prevention and mitigation research to accurately identify the temporal and spatial evolution characteristics of resilience,key driving factors and their impact mechanisms.In view of the lack of a relatively objective and comprehensive evaluation index system for flood disaster resilience,the lack of reliability comparison in the selection and application of evaluation methods,the lack of comprehensive identification of key influencing factors and the analysis of driving effects.This paper takes the Jiansanjiang Branch of Beidahuang Agricultural Reclamation Group Co.,Ltd.and 15 farms under its jurisdiction as the research area,and explores the characteristics of regional precipitation complexity.The spatiotemporal variation law and driving mechanism of the flood disaster resilience of Jiansanjiang Branch were deeply analyzed.In addition,the evolution trend of resilience under different scenarios was analyzed,and the optimization scheme of planting structure under the constraint of resilience was explored.The main research results are as follows:(1)Precipitation is affected by multiple factors,which makes it show a remarkable complexity.In order to comprehensively,accurately and reasonably reflect the complexity of precipitation in different regions,the monthly precipitation complexity of Jiansanjiang Branch was analyzed by Modified fine composite multi-scale dispersion entropy based on projection pursuit model refined by the selfish herd optimizer with elite opposition-based learning(EOSHO-PP-RCMDE).The results showed that the monthly precipitation complexity of Jiansanjiang Branch showed the spatial distribution characteristics of high in the east and low in the west,and the precipitation complexity indices in the east and west were 0.6240 and0.6109,respectively.In the model performance analysis,the discrimination value,rationality coefficient and stability coefficient of EOSHO-PP-RCMDE reached 1.1946,0.9611 and 0.9769,respectively.Compared with the projection pursuit model based on the selfish herd algorithm to optimize the fine composite multi-scale scatter entropy Modified fine composite multi-scale dispersion entropy based on projection pursuit model refined by the selfish herd optimizer(SHO-PP-RCMDE)and the projection pursuit model based on the empire competition algorithm to optimize the fine composite multi-scale scatter entropy Modified fine composite multi-scale dispersion entropy based on projection pursuit model refined by the Imperialist Competitive Algorithm(ICA-PP-RCMDE),it has higher reliability,rationality and efficiency.stability,as a new method to explore the complexity of regional precipitation.(2)Starting from the connotation of flood disaster resilience,combined with the measurement results of the complexity of precipitation,in the four systems of natural ecology,human society,economic society,and infrastructure equipment,a preliminary selection set of indicators for flood disaster resilience was constructed.Cumulative Information Contribution Rate-Pearson Correlation Coefficient(CICR-PCC)was used to optimize the initial selection of indicators,and the evaluation index system of flood disaster resilience was constructed,which provided a scientific data basis for the reasonable evaluation of flood disaster resilience.Using Support vector regression model refined by the selfish herd optimizer with elite opposition-based learning(EO-SHO-SVM)to analyze the spatiotemporal evolution characteristics of the flood disaster resilience of Jiansanjiang Branch from 1996 to 2019.The results show that: in terms of time,the average resilien ce index of the 15 farms of Jiansanjiang Branch increased from 1.887 to 3.521 in 1996-2019;in terms of space,after a period of development,each farm reached a higher resilience level.From 2016 to 2019,the level of resilience showed an obvious regional pattern.As a whole,it was higher in the central and eastern regions,and lower in the western regions.There was a trend of unbalanced development within the farm,and this trend was increasing.In the model performance test,Support Vector Machine(SVM),Imperialist Competitive Algorithm-Support Vector Machine(ICA-SVM)and Selfish Herd OptimizerSupport Vector Machine(SHO-SVM)are introduced for comparative analysis.The results show that the EO-SHO-SVM model has prominent advantages in terms of fitti ng performance,reliability,rationality and stability.It fully shows that the EO-SHO-SVM model is highly advanced and practical in the measurement of flood disaster resilience.It can provide a more accurate evaluation model for regional flood disaster r esilience evaluation.(3)Comprehensively consider the results obtained by covariance-analytic hierarchy process(Cov-AHP),entropy weight method,built-in weight coefficient method of EO-SHOSVM model,and combine the theory of serial number summation.It was found that the weights of the natural ecosystem,socioeconomic system,humanistic social system,and infrastructure equipment system reached 0.333,0.408,0.149,and 0.110,respectively.Among the various indicators,Precipitation Complexity,paddy field coverage,Land-average flood prevention investment,GDP per capita,agricultural commodity output value per unit area,Water conservancy project investment as a percentage of GDP,and Rainfall have a high impact effect,which can be regarded as the key to flood disaster resilience.driving factor.On this basis,combined with the national policy requirements and the relevant planning of the local government,using the scenario analysis method,Scenarios I,II and III are set up according to the three modes of economic development: high,medium and low.On this basis,climate change conditions were introduced,and scenarios IV,V and VI were set up to analyze and predict the resilience level under different scenarios.It was found that good economic conditions can promote the rapid development of regional resilience,even in the face of adverse climatic conditions,the resilience can still be maintained at a high level,while poor socioeconomic conditions often lead to poor functioning of resilience.(4)The crop planting structure of Jiansanjiang Branch is developing towards a single development,of which the proportion of rice planting area is as high as 90%.In order to avoid social and ecological problems caused by a single planting structure,increase the diversity of planting structures of Jiansanjiang Branch,while ensuring the healthy development of flood disaster resilience.Taking flood disaster resilience as a constraint condition for the optimization of agricultural planting structure,considering regional economic,social,ecological and water resources and other factors.Using the NSGA-III multi-objective optimization algorithm combined with specific scenarios,the optimal planting structure scheme under the constraints of flood disaster resilience was solved.The results showed that:in 2025,the rice planting proportions of scenarios I-VI were reduced by 30.44%,29.30%,19.30%,37.79%,36.74% and 18.76%,respectively,compared with those before the optimization.In 2030,the proportion of rice planting in scenarios I-VI decreased by 38.04%,36.11%,21.30%,38.75%,38.57%,and 20.63%,respectively,compared with the unoptimized ones.In 2035,the proportion of rice planting in scenarios I-III will be reduced by 38.28%,38.28% and 20.41%,respectively,compared with before the optimization.The results showed that the proportion of rice planting area was greatly reduced by optimizing the planting structure,and the diversified development of planting structure was promoted.In 2035,in scenarios IV-VI,due to heavy rain,the rice planting area will be increased to 100%,so as to reduce the impact of flood disasters.By analyzing the optimization scheme of planting structure with or without resilience constraints,it was found that the proportion of rice planting under the constraints of resilience was higher.Since the increase in the proportion of rice area helps to enhance the level of resilience to flood disasters,the adjustment of the planting structure under the constraint of resilience will increase the proportion of paddy field.Through the adjustment of planting structure considering the constraints of flood disaster resilience,while maintaining the healthy development of resilience.It also avoids the ecological problems caused by the single planting structure,and ensures the maximum benefits in terms of economy,society,ecology and water resources,thereby promoting the sustainable development of society.