华南前汛期降水的气候特征研究

Study on Climatic Features of Pre-Summer Flood Period Precipitation in South China

利用1968-2007年华南94站逐日降水资料,通过EOF、REOF分析表明,EOF分析得到的前4个典型场可以很好地反映华南前汛期降水空间分布的异常结构,分别为整体一致的空间结构、东西相反的空间结构、南北相反的空间结构、中间与周围地区相反变化的空间结构,且通过分析NCEP/NCAR资料场发现不同的环流形势是引起模态不同的原因。REOF旋转后的前5个空间模态可较好地为华南前汛期降水进行气候区划,分为华南东南部、华南中部、华南东北部、华南西南部和华南西北部这5个区域,具体分析了与EOF第4模态类似的REOF第2模态的环流成因,并发现此模态与2月南方涛动指数和1月Nino3.4指数存在正相关性。

The rainfall data of 94 stations in south China from 1968-2007 are analyzed by the way of EOF and REOF. According to the analysis results,the former four typical fields from the EOF analysis can successfully reflect the anomalous spatial distribution of rainfall in South China,to be specific,consistent as a whole,disparate in the south and the north,disparate in the east and the west,disparate in the central and the peripheral areas. Through the analysis of the NCEP / NCAR data,it can be found that different modals are caused by different circulation situation. The former five by the REOF rotated spatial patterns can make climate zoning in pre-summer flood period precipitation of south China： divided into southeast,central,northeast,southwest and southnorth. And the circulation situation of the second mode which is similar from the forth mode of EOF was analyzed. This mode has a positive correlation with soi index in February and Nino3. 4 index in January.