| Mountain torrents are one of the most widespread and serious disasters among China's natural disasters.China has a vast territory,complex and diverse landform types,and obvious spatial differences in climate types,making the spatial and temporal distribution of precipitation extremely uneven.Heavy rains are concentrated in some areas and highintensity storms occur frequently,which often leads to mountain torrents.The torrential floods and other secondary disasters induced by them have caused huge losses to people's lives and property.Due to the complex natural conditions in China,the characteristics and regular pattern of mountain torrents that occur under the interactions of precipitation,topography and land use are different,which affects the spatial distribution of mountain torrents.Through literature review,it is found that domestic and foreign research focused on the temporal and spatial distribution characteristics and risk assessment of regional torrents.Most of them are based on the spatial distribution and risk zoning of torrents in a certain region,and the spatial distribution pattern of torrents at large scale has not been properly revealed.As a major cause of torrents,rainstorms have not been paid enough attentions,and their connections have not been fully explored.Besides,existing studies on driving forces of torrents are mostly qualitative analysis.Quantitative studies are necessary so that the contributions of driving forces can be exactly and precisely revealed.Therefore,the historical torrential hazard data,topographic data,precipitation data and other multi-source data are analyzed to study the temporal and spatial distribution characteristics of torrents in China using GIS techniques.This study tries to grasp the temporal and spatial variation law of mountain torrents,study the explanatory power of storm and underlying surface factors on mountain torrent events,and further transform it into relevant weight factors,so as to draw the distribution map of mountain torrent risk in China,and clarify the spatial differentiation law of mountain torrent risk grade in China from the perspective of driving factors and combining with the characteristics of China's natural geography and climate.The research results are of great significance for the early warning and prevention of mountain torrents in China,and can provide a basis for relevant departments to formulate accurate disaster response measures.The main work include:(1)By means of spatial analysis and geographic statistics of GIS,the spatial and temporal evolution characteristics of mountain torrent disasters in China are studied based on historical data of mountain torrent disasters.Generally speaking,the spatial distribution of mountain torrent disasters in China shows a decreasing trend from southeast to northwest,and the frequency of mountain torrent disasters is higher in Southeast and Southwest China.Based on the spatial statistics and analysis of mountain torrent disaster points with the landform,geomorphology and geo-climatic conditions and underlying surface,it is found that the mountain torrent occurrence is obviously different due to underlying surface.It is found that the mountain torrent occurrence is obviously high in the subtropical monsoon region and the hilly region with medium and low fluctuations.(2)By developing a rainstorm identification tool to extract rainstorm events from long time series TRMM satellite rainfall data,the spatial and temporal distribution characteristics of rainstorm occurrence in the whole country are studied.It is found that there are significant spatial differences in the total amount of rainstorm in different regions,and the spatial distribution of rainstorm also shows a decreasing trend from southeast to northwest.Moreover,with the increase of rainstorm amount,frequency and average intensity of rainstorm,the number of mountain torrent disaster points is also increasing,which indicates that the occurrence of mountain torrent disaster is closely related to rainstorm events.(3)In order to quantitatively analyze the driving forces of rainstorms and underlying surface factors,the explanatory power of each driving factor in the interpretation of torrential disasters was studied using geographic detectors.It was found that the explanatory powers of soil type and rainstorm factor were the highest,indicating that these two factors were the main driving forces affecting the occurrence of torrential disasters.The explanatory power of each driving factor is transformed into weight,and the risk assessment of mountain torrent disasters in China is carried out based on the model of mountain torrent risk assessment.The results show that the southern and eastern coastal areas are the high risk areas of mountain torrent disasters in China.These areas should be the key areas for mountain torrent disaster prevention and control. |
PDF Full Text Request