中国夏季极端气温同前期土壤湿度的联系

发布时间：2018-04-09 03:04

本文选题：土壤湿度　切入点：资料对比　出处：《南京信息工程大学》2017年硕士论文

【摘要】：中国是世界上遭受气象灾害影响最为严重的国家之一,开展各类极端气候的研究和极端气候预测具有重要意义,夏季极端气温是我国常见的气象灾害,国内对夏季气温预测主要考虑的因子为海表面温度和环流因子,利用土壤湿度建立我国夏季极端气温预测模型的研究还较少,土壤湿度能否提高中国夏季极端气温的预测准确率还需进一步研究。首先,本文基于1992～2010年全国778个农业气象站土壤湿度观测资料、ERA_interim、JRA55、NCEP-DOER2和20CR土壤湿度再分析资料,通过平均差值、相关系数、差值标准差、标准差比四个参数,利用Brunke排名方法和EOF分析,对四套土壤湿度再分析资料在中国西北东部—华北—江淮区域的适用性进行了分析;其次,利用中国587站日最高、最低气温观测资料、月平均的ERA_interim 土壤湿度再分析资料及扩展重建的海表面温度(ERSST)资料,对极端气温指数进行了定义,利用变形的典型相关分析(BP-CCA)和集合典型相关分析方法(ECC),分析了 1979～2009年我国夏季极端气温与前期(春、前冬)土壤湿度、海表面温度间的线性联系,建立了中国夏季极端气温预测模型,并对独立样本检验的效果进行了评估;最后合成分析和相关性分析,对春季土壤湿度异常对中国东北、江淮地区夏季极端高温的影响的可能机制进行了初步分析,得到以下结论:(1)不同季节的平均偏差空间分布上,JRA55资料同观测数据的平均偏差在±0.08m3.m-3之间,春、夏季西北东部JRA55 土壤湿度偏小,ERA_interim、NCEP-DOE R2、20CR资料较观测数据偏湿,华北南部、江淮地区平均偏差小于西北东部、华北北部。在年际变化上,各个季节ERA_interim资料同观测资料最为接近,能稳定地再现西北东部、华北、江淮地区土壤湿度干湿变化趋势,反映出重要的旱涝年。整体而言,四套再分析资料中ERA_interim资料同观测资料接近,JRA55、NCEP-DOER2资料次之,20CR资料最差。(2)同中国夏季极端气温联系密切的前期海表面温度异常的空间分布为类PDO型,以及前期华南、东北、西北地区土壤湿度异常;交叉检验结果表明基于前冬预测因子的极端气温预测模型技巧高于春季,基于土壤湿度的极端气温预测模型技巧高于海表面温度;独立样本检验表明基于前期土壤湿度、海表面温度的ECC模型对中国东部夏季极端气温有一定的预测能力,可以在夏季极端气温的预测业务中考虑前期土壤湿度及海表面温度的影响。(3)合成分析结果显示江淮、缅甸附近、中国东北、印度北部区域春季SM异常与中国东北、江淮地区的500hPa位势高度、200hPa纬向风异常存在联系。东北地区夏季极端高温影响因子为500hPa位势高度异常、华北至贝湖附近200hPa纬向风异常;江淮地区夏季极端高温的影响因子除500hPa位势高度异常外,200hPa纬向风异常也是重要影响因子。
[Abstract]:China is one of the countries most seriously affected by meteorological disasters in the world. It is of great significance to carry out research on various kinds of extreme climate and forecast extreme climate. The extreme temperature in summer is a common meteorological disaster in China.The main factors of summer temperature prediction in China are sea surface temperature and circulation factor.Whether soil moisture can improve the prediction accuracy of summer extreme temperature in China needs further study.Firstly, based on the soil moisture observation data of 778 agricultural meteorological stations in China from 1992 to 2010, the paper analyzes the soil moisture reanalysis data of ERAIP JRA55, NCEP-DOER2 and 20CR, through four parameters: average difference, correlation coefficient, standard deviation of difference and ratio of standard deviation.Using Brunke ranking method and EOF analysis, the applicability of four sets of soil moisture reanalysis data in the east of northwest China-North China-Jianghuai region was analyzed. Secondly, the daily maximum and lowest temperature data of 587 stations in China were used.The monthly average ERA_interim soil moisture reanalysis data and the extended reconstructed sea surface temperature data are used to define the extreme temperature index.By using the canonical correlation analysis of deformation (BP-CCAA) and the method of collective canonical correlation analysis, the linear relationship between the extreme temperature in summer from 1979 to 2009 and the soil moisture and sea surface temperature in China from 1979 to 2009 was analyzed.The prediction model of extreme temperature in summer in China was established, and the effect of independent sample test was evaluated. Finally, the effects of soil moisture anomaly in spring on Northeast China were analyzed by synthetic analysis and correlation analysis.The possible mechanism of the effect of extreme high temperature in summer in Jianghuai area is analyzed. The following conclusions are drawn: 1) the average deviation between JRA55 data and observational data in different seasons is 卤0.08m3.m-3 in spring.In summer, the JRA55 soil moisture in the eastern part of Northwest China is smaller than that of the observed data. The average deviation in the southern part of North China and the Jianghuai area is less than that in the east part of northwest China and the northern part of North China.In terms of interannual variation, the ERA_interim data in each season are most close to the observed data, and can steadily reproduce the soil moisture and dry change trend in the eastern part of the northwest, North China and Jianghuai areas, reflecting the important drought and flood years.As a whole, the spatial distribution of the early sea surface temperature anomalies in the four sets of reanalysis data, which are close to JRA55 / NCEP-DOER2 data, followed by JRA55 / NCEP-DOER2 data and China's summer extreme temperatures, is similar to that of PDO type, as well as that of South China and Northeast China.The results of cross test showed that the forecasting skill of extreme temperature model based on pre-winter forecast factor was higher than that of spring, and that of extreme temperature model based on soil moisture was higher than that of sea surface temperature.Independent sample tests show that the ECC model based on soil moisture and sea surface temperature has a certain ability to predict extreme summer temperatures in eastern China.The synthetic analysis results show that the SM anomaly in spring and Northeast China in the area near Myanmar, northeast China and northern India can be taken into account in summer extreme temperature prediction.The 500hPa geopotential height of 200 HPA zonal wind anomaly exists in the Jianghuai area.The influence factors of extreme high temperature in summer in Northeast China are 500hPa geopotential height anomaly and 200hPa zonal wind anomaly in the area from North China to Beihu Lake, and the influence factor of extreme high temperature in summer in Jianghuai area is not only 500hPa geopotential height anomaly but also 200hPa zonal wind anomaly.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152.71

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