1951—2013年周口地区降水时空变化特征研究

Temporal and Spatial Distribution of Precipitation in Zhoukou Area from 1951 to 2013

为了研究区域降水的时空演变规律,根据周口地区28个雨量站1951—2013年的月降水量实测资料,利用经验正交函数(EOF)分析法、Mann-Kendall检验法及Morlet小波分析法,分析了周口地区63年来降水的空间分布、时间系数变化特征和时间序列的趋势性、突变性及周期性。结果表明,周口地区降水的空间分布有3种模式:全市丰(枯)一致型、南丰(枯)北枯(丰)型和东丰(枯)西枯(丰)型,其中全市丰(枯)一致型为周口地区降水的主要分布模式,其中1966年的全市降水偏枯和2003年的全市降水偏丰最为典型;周口地区降水量由东南向西北逐渐减小,各站点降水趋势变化不一,西南部呈下降趋势,中北部呈上升趋势,降水总体呈下降趋势;区域整体降水在1997年发生了突变,整体降水周期性变化明显,存在时间尺度为21 a的变化周期。研究结果可为周口地区的农业生产以及旱涝预警和减灾防灾提供理论支撑。

In order to study the temporal and spatial evolution process of regional precipitation, based on the monthly precipitation data of 28 stations from 1951 to 2013, by using the method of empirical orthogonal function analysis, Morlet wavelet analysis and Mann- Kendall text, the precipitation in recent 63 years of Zhoukou area was analyzed at the sides of time series trends, periodicity, mutation and spatial distribution. The results show that：the spatial distribution of precipitation had three typical modes, they are the citywide consistent wet（dry）type, the southern wet（dry） and northern dry（wet） type and the eastern wet（dry） and western dry （wet） type, the citywide consistent wet（dry） type is the main precipitation distribution pattern in Zhoukou area, the most typical characterstics are the drier citywide precipitation in 1966 and the wetter citywide precipitation in 2003 ; The precipitation in Zhoukou area is diminishing from southeast to northwest; The mutation point of the annual precipitation variation occurred around the year of 1997, and the precipi- tation had a periodical features of 21 years. The results provide a theoretical basis for the agricultural production, drought and flood warning and disaster prevention and reduction.