Environmental Studies Program, University of Montana, Missoula, Montana, United States of America.
PLoS One. 2021 Apr 13;16(4):e0248736. doi: 10.1371/journal.pone.0248736. eCollection 2021.
Water availability in western Canada and the United States is dependent on the accumulation of snowpack in the montane regions and threatened by increased winter temperature and more precipitation as rain linked to climate change. In order to make reasoned decisions to adapt to climate change managers require knowledge of the role of temperature and precipitation in SWE development and data to distinguish the relative retention response of snowpack regions to expected temperature and precipitation regime shifts at the watershed scale. Using the Daymet interpolated 1 km2 dataset, effects of elevation, temperature (Tmax, Tmin and Tavg) and precipitation on April 1 SWE in the Crown of the Continent were tested by linear regression and Kendall correlation. Changes in Daymet estimated snow water equivalent (SWE) in response to increased temperatures and changes in precipitation were estimated in two ways: 1) comparing April 1SWE in the 11 warmest (mean Tmax February) and driest (mean precipitation January to March) years with the 22 cooler/wetter years 1981-2013 and 2) SWE retention from April 1 to June 1 over the period 1980 to 2013 across 120 watersheds in a major continental headwater region, the Crown of the Continent of North America. Historical analysis of period warm year April 1 SWE was assumed to indicate the recent impact of warmer winter temperatures. Changes in snowpack April 1 to June 1 reflected likely effects on peak runoff and were, therefore, also relevant for future climate change adaptation considerations. Winter (JFM) precipitation proved more influential than temperature in shaping April 1 SWE response at the regional scale. Of the three factors, elevation was most positively associated with April 1 SWE at the watershed scale. Temperature and precipitation influenced SWE accumulation and persistence at the watershed scale, but higher precipitation was more closely associated with higher April 1 SWE retention. Ranking of watershed snowpack retention in warm and dry years, combined with spring snowpack retention offers data to assist identification of watersheds with greatest snowpack persistence in the face of anticipated climate change effects.
加拿大西部和美国的水资源供应依赖于山区积雪的积累，而积雪则受到冬季温度升高和更多降水的威胁，这些降水与气候变化有关。为了做出合理的决策来适应气候变化，管理人员需要了解温度和降水在 SWE 发展中的作用，并获得数据来区分流域尺度上积雪区对预期温度和降水格局变化的相对保留响应。使用 Daymet 插值的 1km²数据集，通过线性回归和 Kendall 相关分析，测试了海拔、温度（Tmax、Tmin 和 Tavg）和降水对科罗娜大陆 4 月 1 日 SWE 的影响。通过两种方式估计 Daymet 估计的雪水当量（SWE）对温度升高和降水变化的响应变化：1）将 11 个最温暖（2 月平均 Tmax）和最干燥（1 月至 3 月平均降水）年与 22 个较冷/较湿润年（1981-2013 年）的 4 月 1 日 SWE 进行比较，2）在 1980 年至 2013 年期间，在北美洲科罗娜大陆主要源头地区的 120 个流域内，从 4 月 1 日到 6 月 1 日的 SWE 保留量。假设对温暖年份 4 月 1 日 SWE 的历史分析表明了最近冬季温度升高的影响。4 月 1 日至 6 月 1 日的积雪变化反映了对峰值径流的可能影响，因此对于未来的气候变化适应考虑也很重要。冬季（JFM）降水在塑造区域尺度上 4 月 1 日 SWE 响应方面比温度更具影响力。在这三个因素中，海拔与流域尺度上的 4 月 1 日 SWE 最正相关。温度和降水影响流域尺度上的 SWE 积累和持久性，但较高的降水与较高的 4 月 1 日 SWE 保留量更密切相关。在温暖和干燥年份对流域积雪保留量进行排名，结合春季积雪保留量，可以提供数据来帮助识别在预期气候变化影响下具有最大积雪持久性的流域。
