摘要
以晋陕蒙地区60个气象站点1960—2013年逐日降水观测资料为基础,分析了晋陕蒙地区近54年来年均降水量和极端降水量的时空变化。研究发现,近54年来,晋陕蒙3个省（区）：（1）年均降水量都在波动中呈缓慢的减少趋势,减少趋势均不显著,晋陕蒙三省（区）减少趋势分别为14.014、10.706 mm·10a-1和0.76 mm·10a-1;空间上内蒙古年均降水量呈现出明显的东西差异,由东部400~500 mm向西减少到200 mm以下,山西年均降水量由东南向西北递减,晋东南在500~800 mm,而晋西北在400~500 mm,陕西年均降水量表现为南多北少的特点,陕南地区大于800 mm,陕北下降到400~500 mm。（2）从变化趋势上来看,从东南向西北,降水出现由减少到增多的变化趋势,原来降水多的地区趋于减少,降水少的区域趋于增多,晋陕蒙地区内部降水量差异趋于减小。内蒙古东部减幅为0~1 mm·a-1,而西部增幅为0~1 mm·a-1。山西省南部最大减幅1~3 mm·a-1,而在晋东北减幅在3 mm·a-1以上。陕北和陕南地区减幅较小为0~1 mm·a-1,陕西中部大部分地区减幅较大为1~3 mm·a-1。（3）200 mm和400 mm降水等值线呈明显年代际波动,1970年代和1990年代偏西偏北,1980年代和2000年代偏东偏南。近年来夏季风影响范围缩小,内蒙古降水趋于减少,晋陕南部略有增加。（4）年均极端降水量呈不显著增加趋势,变化幅度大部分在0~1 mm·a-1,此时段内极端降水量未发生突变,极端降水量的增加,使本地区降水处于不稳定状态;极端降水强度方面,山西和陕西的极端降水强度明显大于内蒙古,山西和陕西极端降水强度由南向北依次递减,陕西南部大于50 mm·a-1,而北部降低到30~40 mm·a-1,山西省大部分地区在40~50mm·a-1,只有在北部为30~40 mm·a-1,内蒙古极端降水强度由东向西逐步减少,东部为30~40 mm·a-1,西部在20 mm·a-1以下,极端降水强度的变化趋势内部差异不大;极端降水日数呈弱增长,增长水平不显著,此时段内极端降水日数没有出现剧烈变化。
Based on the daily measured precipitation data during 1960 to 2013 from 60 meteorological stations in Shanxi,Shaanxi and Inner Mongolia,analyzed the spatial-temporal variation of average annual precipitation and the extreme precipitation in recent 54 years of these provinces. The results showed that：（ 1） The average annual precipitation was presentted a slow decrease trend in the fluctuation,but the decrease was not noteble. The decrease trend in Shanxi,Shaanxi and Inner Mongolia was 14. 014 mm·10a- 1,10. 706 mm·10a- 1and 0. 76 mm·10a- 1,respectively. In space the precipitation of Inner Mongolia presented the obvious differences between East and West and from 400 to 500 mm in East reduced to less than 200 mm in West. The yearly average precipitation in Shanxi was decreased from Southeast to Northwest. It was 500 to 800 mm in Southeast and 400 to 500 mm in Northwest. The yearly average precipitation in Shaanxi was presentted the characteristics more in South and less in North. It was more than 800 mm in Southern Shaanxi and 400 to 500 mm in Northern Shaanxi.（ 2） From Southeast to Northwest,the precipitation appeared the change trend from decrease to increase. The precipitation in former rich area was tended to reduce and less area was tended to increase. The difference of internal precipitation inShanxi,Shaanxi and Inner Mongolia was tended to decrease. The decrease was 0 to 1 mm·a- 1in Eastern Inner Mongolia and the increase was 0 to 1 mm·a- 1in Westen Inner Mongolia. The maximal decrease was 1 to 3 mm·a- 1in South Shanxi and was decreased above 3 mm·a- 1in Northeast Shanxi. The decrease was total less than 0 to1 mm·a- 1in North and South Shaanxi.（ 3） The precipitation isoclines of 200 mm and 400 mm were obviously presented the decade fluctuation,in 1970 s and 1990 s were inclined to North and West,in 1980 s and 2000 s were inclined to East and South. In recent years,the impact range of summer monsoon was reduced,so the precipitation was tended to reduce in Inner Mongolia and slightly increase in southern Shanxi and Shaanxi.（ 4） The yearly average extreme precipitation was showed no significant increasing trend,most of the changes were 0 to 1 mm·a- 1. In these periods,the extreme precipitation did not occur the mutations. The increase of the extreme precipitation,let the precipitation in these regions were presentted unstable situation. In the intensity of extreme precipitation,the intensity of Shanxi and Shaanxi was higher than in Inner Mongolia. The intensity of Shanxi and Shaanxi was decreased from south to north. In South Shaanxi was large than 50 mm·a- 1,but in North Shaanxi was decreased to30 to 40 mm·a- 1. It was 40 to 50 mm·a- 1in most areas of Shanxi,only in north was 30 to 40 mm·a- 1. The intensity of extreme precipitation in Inner Mongolia was gradually reduced from East to West,in East was 30 to 40mm·a- 1and in West was less than 20 mm·a- 1. The change trend of the intensity of extreme precipitation was not big for internal differences. The days for extreme precipitation were weakly increased,but the increasing level was not notable. The extreme precipitation days was not occurred the drastic change in this period.
出处
《干旱地区农业研究》
CSCD
北大核心
2016年第3期213-220,260,共9页
Agricultural Research in the Arid Areas
基金
国家自然科学基金项目(41471071)
中央高校基本科研业务费创新团队项目(GK201301003)
关键词
年降水
极端降水
时空变化
晋陕蒙地区
annual precipitation
extreme precipitation
spatial-temporal variation
Shanxi
Shaanxi and Inner Mongolia
