Assessment of Flood Catastrophe Risk for Grain Production at the Provincial Scale in China Based on the BMM Method

Flood catastrophe risk assessment is imperative for the steady development of agriculture under the context of global climate change,and meanwhile,it is an urgent scientific issue need to be solved in agricultural risk assessment discipline.This paper developed the methodology of flood catastrophe risk assessment,which can be shown as the standard process of crop loss calculation,Monte Carlo simulation,the generalized extreme value distribution（GEV） fitting,and risk evaluation.Data on crop loss were collected based on hectares covered by natural disasters,hectares affected by natural disasters,and hectares destroyed by natural disasters using the standard equation.Monte Carlo simulation based on appropriate distribution was used to expand sample size to overcome the insufficiency of crop loss data.Block maxima model（BMM） approach based on the extreme value theory was for modeling the generalized extreme value distribution（GEV） of flood catastrophe loss,and then flood catastrophe risk at the provincial scale in China was calculated.The Type III Extreme distribution（Weibull） has a weighted advantage of modeling flood catastrophe risk for grain production.The impact of flood catastrophe to grain production in China was significantly serious,and high or very high risk of flood catastrophe mainly concentrates on the central and eastern regions of China.Given the scenario of suffering once-in-a-century flood disaster,for majority of the major-producing provinces,the probability of 10% reduction of grain output is more than 90%.Especially,the probabilities of more than 15% decline in grain production reach up to 99.99,99.86,99.69,and 91.60% respectively in Anhui,Jilin,Liaoning,and Heilongjiang.Flood catastrophe assessment can provide multifaceted information about flood catastrophe risk that can help to guide management of flood catastrophe.

Research on the suitability of population distribution at the provincial scale in China

The relationship between population distribution and resources, environment and social-economic development has a significant influence on the human development. This paper set up a set of index system and model methods for the assessment of the coordination between population and resources, environment and social-economic development, and it quantitatively evaluated this coordination at the provincial scale in 2000 and 2010 respectively Based on this set of index system, the suitability degree and the spatial-temporal pattern of population distribution at the provincial scale were carefully characterized. The restriction of population distribution at the provincial scale was graded and classified, and the coordinated development strategy of population, resources, environment and social economy was finally put forward. The results showed that： （1） The environmental suitability of population distribu- tion at the provincial scale was generally high in China, which tended to be stable from 2000 to 2010. （2） The restriction of water and land resources at the provincial scale was generally strong in China, but it tended to be weak from 2000 to 2010. （3） The coordination degree between the social-economic development and population distribution at the provincial scale was mostly at a middle level, which was in the positive upward path from 2000 to 2010. （4） The suitability of population distribution at the provincial scale was mostly at a middle level, all of which was rising from 2000 to 2010. （5） The coordination degree between population dis- tribution and resources, environment and social-economic development at the provincial scale was divided into four grades, including basic coordination, relative coordination, awaited coordination and urgent-needed coordination. （6） The basic ways to promote the coordinated development of population, resources and environment in different regions in China can be summarized as： implementing the strategy of population agglomeration and evacuation, guiding the orderly flow of population, optimizing the spatial distribution of popu- lation and drawing up the spatial planning of population development.