Mountain snowpack response to different levels of warming
Mountain snowpack response to different levels of warming
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DOI：
10.1073/pnas.1805953115
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发表时间：
2018-10-23
影响因子：
11.1
通讯作者：
AghaKouchak, Amir
中科院分区：
文献类型：
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作者：
Huning, Laurie S.;AghaKouchak, Amir
温度变化影响着山区积雪的分布和持续性，而山区积雪为世界各地的大量人口提供了重要的融雪水资源。温度升高会减少山地雪水当量（SWE）的数量，迫使其质量中心向更高的海拔移动。我们使用一个独特的多变量概率框架来量化的响应4月1日SWE量和它的质心在整个内华达州（美国）的冬季气温增加1.0至2.0摄氏度。每升高1.0摄氏度，超过长期（1985-2016年）平均范围SWE体积（15.7 km（3））的概率降低20.7%。相应地，质心高于其长期平均值（2，540米）的可能性增加了60.6%。我们进一步表明，冬季温度升高1.5 ℃和2.0 ℃，分别使超过长期平均SWE体积的概率降低了31.0%和41.1%，而对于这些温度变化，质心高于2,540 m的可能性增加了79.3%和89.8%。我们还描述了整个内华达州山脉的区域变异性，并表明该山脉的西北部和东南部地区分别为30.3%和14.0%，不太可能有1 4月SWE量超过其长期平均值为1.0摄氏度的增加，他们各自的平均冬季温度。总体而言，在北方内华达州内华达州的西南偏东表现出更高的水文脆弱性比在南部地区的变暖。鉴于预期的山区温度上升，预计未来观测到的西南偏东变化率将加剧。
Temperature variability impacts the distribution and persistence of the mountain snowpack, which critically provides snowmelt-derived water resources to large populations worldwide. Warmer temperatures decrease the amount of montane snow water equivalent (SWE), forcing its center of mass to higher elevations. We use a unique multivariate probabilistic framework to quantify the response of the 1 April SWE volume and its centroid to a 1.0 to 2.0 degrees C increase in winter air temperature across the Sierra Nevada (United States). A 1.0 degrees C increase reduces the probability of exceeding the long-term (1985-2016) average rangewide SWE volume (15.7 km(3)) by 20.7%. It correspondingly is 60.6% more likely for the centroid to be higher than its long-term average (2,540 m). We further show that a 1.5 and 2.0 degrees C increase in the winter temperature reduces the probability of exceeding the long-term average SWE volume by 31.0% and 41.1%, respectively, whereas it becomes 79.3% and 89.8% more likely that the centroid will be higher than 2,540 m for those respective temperature changes. We also characterize regional variability across the Sierra Nevada and show that the northwestern and southeastern regions of the mountain range are 30.3% and 14.0% less likely to have 1 April SWE volumes exceed their long-term average for a 1.0 degrees C increase about their respective average winter temperatures. Overall, the SWE in the northern Sierra Nevada exhibits higher hydrologic vulnerability to warming than in the southern region. Given the expected increases in mountain temperatures, the observed rates of change in SWE are expected to intensify in the future.