基于不同数据的新疆山洪淹没模拟及致灾阈值分析

利用实测淹没深度、数字高程(DEM)、土地利用类型、小时降水、定量降水估测(Quantitative Precipitation Estimation,QPE)等数据,通过FloodArea模型对新疆博尔博松流域3次(2013年8月25日、2015年6月28日、2016年6月17日)洪水过程进行再现模拟,对模拟结果的分布特征进行分析,以实测数据进行精度检验,并建立了面雨量-淹没深度关系,在此基础上确定了研究区四个淹没等级对应的致灾临界雨量。运用不同数据模拟得出淹没分布特征为随着时间的变化淹没深度具有上升的趋势,淹没过程可分为蓄积期、稳定增长期和波动上升期3个阶段;通过精度验证得出:FloodArea模型运用自动站降水数据模拟的淹没深度与实测数据相比偏高,而QPE、R-QPE(订正后QPE)数据模拟的则偏低,这三种数据的模拟结果与博尔博松村和塔尔村两个考察点的绝对误差分别为0.46 m、0.78 m、0.35 m和1.35 m、1.44 m、0.65 m,R-QPE数据模拟出的淹没深度效果最好,更能精确地反映出该流域洪水淹没情况;通过相关性分析可知,模拟洪水淹没深度与7 h累计时效的面雨量的相关性最好,相关系数达到了0.989,在此基础上建立了面雨量-淹没深度的关系;按照面雨量-淹没深度的关系和山洪灾害等级划分标准得出,预警点累计时效7 h面雨量对应四个等级的致灾临界雨量阈值分别为:四级6.25 mm、三级23.61 mm、二级49.64 mm、一级75.67 mm。

Comparative Analysis of Xinjiang Mountain Flooding Simulation and Threshold based on Different Data

In this paper,the flooding events in boerbosong basin is studied using observed flood depth data,digital elevation map(DEM) data,land use type data,hourly precipitation data,quantitative precipitation estimation(QPE) data,et al.FloodArea model was utilized to simulate the flood process of the study area on 25 August2013,28 June 2015 and 17 June 2016.The spatial and temporal distribution characteristics are analyzed based on the precision test of the measured data.Then the relationship between surface rainfall and submerged depth was established,and the critical rainfall corresponding to the four flood levels in the study area was determined.It is also found that the submerged depth is increasing,which can be divided into three stages:accumulation period,stable growth period and fluctuation uplift period.Through precision verification,the flooded depth derived by FloodArea model is higher than observation,while QPE and R-QPE(revised quantitative precipitation estimates data) data are lower than that observed.The above three data simulation results absolute error of the investigation points(borborzon and Tal village) is 0.46 m,0.78 m,0.35 m and 1.35 m,1.44 m and 0.65 m respectively.RQPE data can simulate the flood depth with the best accuracy and can reflect the flood situation of the basin.Through correlation analysis,the correlation between the surface rainfall of the cumulative aging for 7 h and the simulated flood depth is the best,with the correlation coefficient reaching 0.989.On this basis,the relationship between surface rainfall and submerged depth is established.The relationship between surface rainfall and flood depth was obtained according to mountain flood disaster grade,the cumulative aging of 7 h surface rainfall at the early-warning point can obtain the threshold values of four levels of critical rainfall causing disasters:level 4 is6.25 mm,level 3 is 23.61 mm,level 2 is 49.64 mm and level 1 is 75.67 mm respectively.