青岛市气象和水文干旱变化特征分析

Characteristics of Meteorological and Hydrological Drought Change in Qingdao City

利用青岛市气象和天然径流资料,借助极端降水指数、气象和水文干旱指数,采用回归分析、相关分析和ARCGIS空间分析等方法对该市气象和水文干旱的变化特征进行分析。主要结论为:(1)青岛市无雨日数明显增多,降水量则呈减少的趋势;最大连续无雨日数(pxcdd)和平均干旱期长度(pdsav)的上升在西部地区大于东部地区,而降水量(prcptot)的下降在东部地区大于西部地区。(2)气象干旱指数SPI和水文干旱指数SSI均表明青岛市干旱呈加剧特征;SSI所反映的旱涝发生频次少于SPI,但持续时间大于SPI,尤以1个月和3个月尺度更明显。(3)干旱指数与历史旱灾面积的相关性较好,其中水文干旱指数与成灾面积的相关性更强,而气象干旱指数与受灾面积的相关性更强。此外,由于干旱的累积效应,在降水并不十分稀缺的年份,造成的局部旱情亦十分严重。

Based on the daily precipitation data,the monthly natural runoff data,the extreme precipitation index and the meteorological and hydrological drought indexes,this paper analyzed the change characteristics of the meteorological and hydrological drought in Qingdao City by applying the regression analysis,correlation analysis and ARCGIS spatial analysis methods.The results indicate that(1) The rainless days in Qingdao City have increased significantly,and the rainfall has a decreasing trend;The maximum consecutive drought days(pxcdd) and the mean length of drought period(pdsav) increase faster in the west than that in the east,while the total precipitation(prcptot) decrease faster in the east than that in the west.(2) The meteorological drought index(SPI) and the hydrological drought index(SSI) both indicate that the drought is intensifying;The occurrence frequency of flood and drought reflected by SSI was less than SPI,but the duration was longer than SPI,especially at the scale of 1 and 3 months.(3) The drought index has a good correlation with the historical drought area,among which the hydrological drought index has a stronger correlation with the drought-stricken area,while the meteorological drought index has a stronger correlation with the drought disaster area.In addition,due to the cumulative effects of drought,the drought situation can also be very severe when precipitation is not so scarce.