ABSTRACT We investigated the influence of post-collection changes and snow gauge undercatch on the stable isotopic compositions of winter precipitation. Post-collection changes by evaporation or sublimation can be severe, and may be minimized, but not eliminated, by emptying collection gauges immediately after snowfall. Snow gauge undercatch caused two main effects: a small direct effect caused by preferential separation of snow particles during snowfall, and a much larger effect on the measured stable isotopic compositions of average annual precipitation as a result of under representation of winter precipitation. Despite these effects, however, we found little change to calculated local meteoric water lines (LMWL) for Saskatoon, SK, Canada. A comprehensive 27-year LMWL for Saskatoon which incorporates these effects can be described by δ2H = 7.69 ± 0.096 × δ18O – 2.22 ± 1.72 (r2 = 0.97, n = 208).

中文翻译：

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雪规欠捕量及其对降水氢氧稳定同位素组成的影响

摘要 我们研究了收集后变化和雪规欠捕量对冬季降水稳定同位素组成的影响。蒸发或升华造成的收集后变化可能会很严重，在降雪后立即清空收集仪表可以将其最小化，但不能消除。雪规欠捕量造成两个主要影响：由降雪期间雪粒子的优先分离引起的小的直接影响，以及由于冬季降水的代表性不足而对年平均降水量的测量稳定同位素组成产生更大的影响。然而，尽管有这些影响，我们发现加拿大 SK 萨斯卡通计算的当地大气水线 (LMWL) 几乎没有变化。包含这些影响的萨斯卡通 27 年综合 LMWL 可以用 δ2H = 7 来描述。