海南省汛期旱涝特征

CHARACTERISTICS OF DROUGHT AND FLOOD IN HAINAN PROVINCE RAINY SEASON

通过Z指数和经验正交函数(EOF)对海南省汛期(5～10月)降水作旱涝等级划分、型态分布和旱涝时空分布特征研究,发现海南省各地汛期降水具有一致性, 1960年代中期以来, 汛期旱涝具有由偏旱转为偏涝的趋势,西、北部的部分地区为全省的旱涝多发区。进一步研究表明,汛期严重旱涝年的前期和同期环流的差异场均存在显著差异区,汛期旱涝等级与前期逐月环流场之间都有高相关区,且存在明显的隔季相关。由普查出的前期各月环流场的高相关因子经相关稳定性检验后作逐步回归,结果表明以位势高度场为因子的预报方程具有较好的拟合和预报能力。

The grades of drought and flood, the distribution characteristics of precipitation and the temporal and spatial distribution characteristics of drought and flood in the rainy seasons (from May to October) of Hainan province were studied with the methods of Zindex and empirical orthogonal function (EOF). The results indicate that the precipitation of rainy season in Hainan province is consistent, and after mid-1960s, the change tendency of flood season is from drought to flood. The drought and flood frequently take place in some regions of the west and the north of the province. Further research indicates that there are distinctly contrast areas in the discrepancy fields of previous and same-period circulation. Drought and flood grades in rainy seasons and the previous monthly mean circulation fields exist higher correlation areas, moreover the correlation of the every other season is marked. The stepwise regression equations were obtained with the higher stability correlation factors of the previous monthly circulation fields which were testing. The results show that the prognostic equation using the factor of geopotential height have better fitting and forecast capabilities.