The Missing Mountain Water: Slower Westerlies Decrease Orographic Enhancement in the Pacific Northwest USA

被引：141

作者：

Luce, C. H. ^{[1
]}

Abatzoglou, J. T. ^{[2
]}

Holden, Z. A. ^{[3
]}

机构：

[1] US Forest Serv Res & Dev, Boise, ID 83702 USA

[2] Univ Idaho, Dept Geog, Moscow, ID 83844 USA

[3] US Forest Serv Reg 1, Missoula, MT 59807 USA

来源：

SCIENCE | 2013年 / 342卷 / 6164期

基金：

美国国家科学基金会;

关键词：

CLIMATE-CHANGE; PRECIPITATION; VARIABILITY; STREAMFLOW; SNOWPACK; FLOW; SENSITIVITY; PATTERNS; SHIFTS; TRENDS;

D O I：

10.1126/science.1242335

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Trends in streamflow timing and volume in the Pacific Northwest United States have been attributed to increased temperatures, because trends in precipitation at lower-elevation stations were negligible. We demonstrate that observed streamflow declines are probably associated with declines in mountain precipitation, revealing previously unexplored differential trends. Lower-troposphere winter (November to March) westerlies are strongly correlated with high-elevation precipitation but weakly correlated with low-elevation precipitation. Decreases in lower-tropospheric winter westerlies across the region from 1950 to 2012 are hypothesized to have reduced orographic precipitation enhancement, yielding differential trends in precipitation across elevations and contributing to the decline in annual streamflow. Climate projections show weakened lower-troposphere zonal flow across the region under enhanced greenhouse forcing, highlighting an additional stressor that is relevant for climate change impacts on hydrology.

引用

页码：1360 / 1364

页数：5

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