ABSTRACT In situ observations of snow water equivalent (SWE) from manual snow surveys and automated sensors are made at approximately 1000 sites across Canada in support of water resource planning for flood control and hydroelectricity production. These data represent an important source of information for research (e.g., validation of hydrological and climate models), for applied studies (e.g., ground snow loads), and for climate monitoring. This note describes the process to update a Canadian historical snow survey dataset to 2016 and the production of a 0.1° gridded version for research applications. Analysis of trends in SWE, snow depth (SD), and density over the 50-year period from 1967 to 2016 revealed large spatial variability in trend sign and strength, with a relatively small percentage of points showing statistically significant trends. Where SWE and SD trends were significant, they tended to be negative, which is consistent with previous investigations of snow cover changes in Canada. The results show evidence of a latitudinal dependence in SWE trends, with the largest negative trends occurring over lower latitudes, and a tendency for mainly positive trends in Arctic SWE, which is consistent with observations from Russia and climate model projections of the response of Arctic snow cover to climate warming. Arctic sites also showed evidence of an increasing trend in 1 April snowpack density of 6.6 kg m−3 per decade but little corresponding change in SD. This has potentially important consequences for the soil thermal regime because it provides a cooling influence from an increase in the snowpack effective thermal conductivity. The snow survey dataset is available from the Government of Canada Open Data portal.

中文翻译：

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加拿大历史雪调查数据更新和雪水当量趋势分析，1967-2016

摘要 在加拿大大约 1000 个地点通过人工雪调查和自动传感器对雪水当量 (SWE) 进行了原位观测，以支持洪水控制和水电生产的水资源规划。这些数据是研究（例如验证水文和气候模型）、应用研究（例如地面雪荷载）和气候监测的重要信息来源。本说明描述了将加拿大历史积雪调查数据集更新到 2016 年的过程，以及为研究应用生成 0.1° 网格版本的过程。对 1967 年至 2016 年 50 年间 SWE、积雪深度 (SD) 和密度趋势的分析显示，趋势符号和强度的空间变异性很大，只有相对较小百分比的点显示出具有统计意义的趋势。在 SWE 和 SD 趋势显着的地方，它们往往是负面的，这与之前对加拿大积雪变化的调查一致。结果显示 SWE 趋势存在纬度依赖性的证据，最大的负趋势发生在低纬度地区，并且北极 SWE 主要呈正趋势，这与俄罗斯的观测结果和北极雪响应的气候模型预测一致覆盖气候变暖。北极站点还显示出 4 月 1 日积雪密度增加趋势的证据，每十年 6.6 kg m-3，但 SD 几乎没有相应变化。这对土壤热状况具有潜在的重要影响，因为它通过积雪有效热导率的增加提供冷却影响。