干旱区生态环境知识资源中心(Arid): 我国西北干燥区降水变化规律①

Arid

	我国西北干燥区降水变化规律①
其他题名	Changes in Precipitation over Northwest China
	任国玉 1; 袁玉江 2; 柳艳菊 1; 任玉玉 1; 王涛1 ; 任霄玉 1
来源期刊	干旱区研究
ISSN	1001-4675
出版年	2016
卷号	33 期号:1 页码:1-19
中文摘要	利用多种资料并参考已有研究,综合分析、讨论了我国西北干燥区现代降水变化的特征和可能原因,获得如下认识: ① 在最近半个多世纪,实测记录揭示出西北地区降水量存在较明显的上升趋势,其中西部上升更加显著。进入21世纪以来,全区降水量比20世纪90年代有进一步上升,其前10a平均降水量比1961年以来任何年代都高,2010年秋季和年总降水量达到有记录以来的最高值。② 新疆北部和天山地区树轮气候重建表明,20世纪80年代初期的大气降水增加现象很可能是近200a未曾发生,但并非史无前例,现代降水量的增加没有明显超过历史时期的最湿润阶段,这样就不排除其仍为多年代到世纪尺度上气候自然振动节律表现的可能性。③ 根据再分析资料,1979年以来,整层积分的净水汽通量出现较明显增加趋势,但这种增加并非是由西、南和北边界的输入通量增加造成的,主要是东边界输出通量显著减少的结果,同时大气可降水量增加并不显著。因此,实测降水量增加似乎与全球大气水汽含量增加及区域外水汽输入通量变化关系不大,可能是对区域内气候变化与变异响应的表现形式。④ 已有研究显示,相比华北地区,在过去和未来大气温室气体浓度持续上升条件下,全球和区域气候模式更为一致地模拟出了西北地区降水量显著增加的趋势,暗示西北降水量增加可能是对全球气候变暖的响应,但与近几十年水汽通量趋势变化分析和多数古气候重建结论不完全一致。⑤ 区域和局地灌溉面积扩大以及城市发展等绿洲化过程,可能显著增加了陆面的实际蒸发量,成为西北地区气象观测站附近降水量增多的重要驱动因子。气候变暖与气溶胶排放引起的山地冰川融化及其河湖水位上升,可能加强了这种局地人为气候效应。⑥ 在全球、区域和局地不同尺度的人类活动综合影响下,预计西北干燥区绿洲及其城市和附近局部区域未来20~30a降水量总体上仍将增多,但这种长期变化趋势很可能与年代到多年代尺度的自然降水变异节律相互叠加,而在新疆北部和天山等地,自然气候演变预示可能进入一个多年代降水偏枯时期,致使未来特定区域和时段的合成降水量变化情景趋于复杂化。
英文摘要	This paper synthesizes and updates the analyses on precipitation change in Northwest China previously reported by Chinese researchers,and discusses about the possible causes for the observed trends in precipitation. Annual precipitation in the region has been found to increase over the past half a century,with the increase in western part of the region more significant. The last decade witnesses a further rise in annual precipitation compared to 1990s. Analyses using tree-ring data from a few sites show that the increase of precipitation since the beginning of 1980s might have been unprecedented in terms of the last 2 centuries; however,more reconstructions using tree-ring data from across the region indicate that the present precipitation might not have been so abnormal for the past centuries because lager than present precipitation ever appeared in a few of decades in history. Considering the observed and proxy data in combination, it is not unlikely that the evident increase in annual or seasonal precipitation over the last decades might have been the consequence of natural climate variability on decadal to multi-decadal time scales. Updated analysis of the net moisture budget and precipitable water using NCEP and ERA reanalysis data shows that no significant increase in moisture transport into the region across the western, southern and northern boundaries,and the significant increase in net moisture flux are mainly due to the large decline of moisture transport out of the region across the eastern boundary,during the time period 1979 - 2012. This implies that the observed increase in precipitation in the region might not have been explained as a response to global warming, in spite of the fact that almost all climate models driven by the increased CO_2 concentration in atmosphere for both past and future have produced the upward precipitation trends consistent with observations, indicating that the probability that the increased precipitation in the region is a response to anthropogenic global warming is larger as compared to the other regions of the country including North China. On the other hand,evidences are accumulating that the expanded irrigation areas in Oasis and cities in Northwest China have caused the increase in actual evaporation, resulting in the increase in atmospheric moisture and precipitation observed at the meteorological stations. Accelerated melting of the mountainous glacial due to regional climate warming and the black carbon deposition on ice and snow surface,and theresulting rise of lake water levels might have provided extra moisture into local atmosphere. The paper also makes a first-order projection of precipitation in 2 - 3 decades to come. It is estimated that annual and summer precipitation in Oasis and cities of Northwest China will be likely to increase assuming the enhanced human activities and urbanization. This will not rule out the possibility that natural climate variability on multi-decadal scales will dominate the precipitation trends for the coming 2 - 3 decades,and will make the locally anthropogenic increase of precipitation less evident for certain places and time periods.
中文关键词	气候变化 ; 降水量 ; 树轮 ; 水汽通量 ; 人类活动 ; 自然变异 ; 未来趋势 ; 干燥区 ; 西北地区
英文关键词	climate change precipitation tree-ring moisture flux human activity natural variability projection arid region Northwest China
语种	中文
国家	中国
收录类别	CSCD
WOS类目	METEOROLOGY ATMOSPHERIC SCIENCES
WOS研究方向	Meteorology & Atmospheric Sciences
CSCD记录号	CSCD:5623646
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/234277
作者单位	1.国家气候中心, 中国气象局气候研究开放实验室, 北京 100081, 中国; 2.中国气象局沙漠气象研究所, 乌鲁木齐, 新疆 830002, 中国
推荐引用方式 GB/T 7714	任国玉,袁玉江,柳艳菊,等. 我国西北干燥区降水变化规律①[J],2016,33(1):1-19.
APA	任国玉,袁玉江,柳艳菊,任玉玉,王涛,&任霄玉.(2016).我国西北干燥区降水变化规律①.干旱区研究,33(1),1-19.
MLA	任国玉,et al."我国西北干燥区降水变化规律①".干旱区研究 33.1(2016):1-19.