宁夏春、夏、秋季干旱与降水集中期及集中度的关系  

Relationship of Drought with Precipitation-Concentration Period and Precipitation-Concentration Degree in Ningxia in Spring,Summer and Fall

作　　者：纳丽[1,2] 郑广芬[1] 任少云[1] 许建秋[1,2] 

机构地区：[1]宁夏气象防灾减灾重点实验室,宁夏银川750002 [2]银川市气象局,宁夏银川750002

出　　处：《冰川冻土》2013年第4期1015-1021,共7页Journal of Glaciology and Geocryology

基　　金：公益性行业专项(GYHY201006023);中国气象局气候变化专项(CCSF2011-26);宁夏科技攻关项目"银川市城市规划大气环境影响评估研究"(KGX-12-09-02);宁夏自然科学基金项目(NZ10212)资助

摘　　要：应用宁夏气象台站1961-2010年逐候降水量序列资料,计算了春、夏、秋季3个季降水的集中期、集中度和干旱Z指数,运用趋势分析、相关分析、合成分析讨论了3季的集中期、集中度与旱涝程度的时空变化特征及其相互关系.结果表明:50a来宁夏春夏秋干旱等级均呈加剧趋势,秋季加剧更明显,3季中中部干旱带加剧最严重,南部山区次之,北部最小.春季集中期无明显变化趋势,但集中度有上升趋势,夏季集中期、集中度缓慢下降,秋季集中期、集中度变化不明显;近10a来3季集中度明显增大,春夏两季集中期推迟.春季降水集中度对干旱没有显著影响,但首场透雨出现早晚对干旱影响显著,透雨出现偏早,干旱等级低,反之亦然;夏季集中期对干旱影响不显著,但集中度显著影响干旱,集中度高,雨涝发生概率越大,集中度低,干旱发生概率大;秋季集中期、集中度对干旱都有影响,集中度高,集中期早,雨涝发生概率大,反之干旱出现概率大.Based on the precipitation data from meteorological stations in Ningxia from 1961 to 2010, the spring, summer and fall precipitation-concentration period （PCP）, precipitation-concentration degree （PCD） and the Z-index are calculated, and their spatio-temporal variations are further studied by using trend analysis, correlation analysis and synthesis analysis. It is found that during the 50 years, the drought grade was increasing in spring, summer and fall, especially in fall. The drought in the central arid area was most serious, followed by the southern mountainous area, and was lightest in the northern area. There was no significant change in PCP during spring and fall, but a slight decrease in summer. The PCD went up and down, respectively, in spring and summer, without obvious change in fall. During the last 10 years, the PCD had grown significantly in all the three seasons, while the PCP had been postponed in spring and summer. However, the drought grade was distinctly affected by the time of first soaking rainfall instead of PCD in spring. Early soaking rainfall often led to low drought grade, and vice versa. In summer, the PCD had a greater influence on the drought grade than on PCP. The highly concentrated rainfall will increase the possibility of flood, while the drought will appear more often when PCD is low. The drought grade is affected by both PCP and PCD in fall. High PCD and early PCP imply more floods, otherwise more drought.

关 键 词：宁夏 干旱 降水集中期 降水集中度 关系 

分 类 号：P426[天文地球—大气科学及气象学]