河套及邻近地区530年旱涝基本气候特征与演变

Basic Climate Characteristic and Evolution of Drought and Flood in the Hetao and Its Vicinity Area for Recent 530 Years

选用1470—2005年河套及其邻近地区21个气象站的旱涝等级,分析了该地区536年旱涝演变特征与变化趋势。结果表明:河套及其邻近地区530年平均旱涝等级均>3,整体偏旱,且西部为稳定的干旱,东部为旱涝相间。该地区旱涝异常在空间上可划分为4种典型结构,即全区一致旱(涝)型、东南旱(涝)—西北涝(旱)型、西南旱(涝)—东北涝(旱)型和中部旱(涝)与东西涝(旱)反向型。自15世纪70年代的53个年代中有19个年代的平均旱涝等级距平空间结构与上述4种类型相似。线性趋势分析表明,该地区近536年时间尺度上没有表现出明显的干旱化趋势,但近50年干旱程度明显加重,如银川、西安的旱涝等级半个世纪上升了近1个等级。旱涝等级总体存在准23年、准26年,准73年和准100年的显著周期。

Based on the drought and flood grades of 21 meteorology stations in the Hetao and its vicinity area from 1470 to 2005, recent 536-year drought and flood evolution characteristics and tendencies were analyzed. Results show that average drought and flood grades to be bigger than 3, the whole is dry, west for the stable drought and eastern alternates with for the drought and flood in the Hetao and its vicinity area in recent 530 years. The drought and flood of this area may be divided 4 typical kinds of structures in the spatial anomaly： The entire area consistent is drought （flood） ; Southeast drought （flood）- northwest flood （drought）; Southwest drought （flood）-northeast flood （drought） and middle drought （flood） and east-west flood （drought） are reverse. The average drought and flood grades of 19 ages anomalous spatial structures in 53 ages and the above 4 kinds of types are similar from in 1570＇s . The linear trend analysis indicated that, this area has not displayed the obvious drought tendency in recent 536-year time scales, but arid degree obviously aggravates in 50 years, like drought and flood grades Yinchuan, Xi＇an in half century raise the nearly 1 grade. The drought and flood grades overall have significant periods of quasi 23 years, quasi 26 years, quasi 73 years and quasi 100 years.