While snowpack is the main influence on Rio Grande water year streamflow, spring hydroclimate can play a role in moderating this influence in a subset of years. Through an investigation of the relationship between winter snowpack and spring hydroclimate conditions and Rio Grande streamflow, we find low snowpack years with relatively cool, wet springs coincide with slightly above median streamflow in 18% of the years in the instrumental record (1936–2018), while the opposite conditions occur during 24% of years. Over this period, an increase in years with low snowpack/cool wet springs is evident, likely due to a significant decreasing trend in snowpack. We analyze two 15-century tree-ring reconstructions to provide long-term context for the variable relationship between snowpack and spring hydroclimate. Results suggests irregular but quasi-multidecadal periods when spring conditions may have moderated the effect of a relatively dry winter or reduced the effect of a relatively wet winter. The reconstructions also provide context for the observed trend in the increasing importance of spring conditions over the instrumental period, which appears to be related to both natural climate variability and climate change. In the Rio Grande basin, as mountain snowpack declines due to warming temperatures, spring conditions may be playing an increasingly important role for water resources, at least in the near term.

中文翻译：

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春季气候对格兰德河源头的调节影响：古视角


虽然积雪是格兰德河水年径流的主要影响因素，但春季水文气候可以在部分年份中起到缓和这种影响的作用。通过对冬季积雪和春季水文气候条件以及格兰德河水流之间关系的调查，我们发现在仪器记录（1936-2018）中，18%的年份中，春季相对凉爽湿润的低积雪年份与略高于中值的水流一致。 ，而相反的情况发生在 24% 的年份里。在此期间，低积雪/凉爽湿润泉水的年份明显增加，这可能是由于积雪显着减少的趋势。我们分析了两个 15 世纪的树木年轮重建，为积雪和春季水文气候之间的变量关系提供长期背景。结果表明，在不规则但准数十年的时期内，春季条件可能减轻了相对干燥的冬季的影响或减少了相对潮湿的冬季的影响。重建还为所观察到的春季条件在工具时期重要性日益增加的趋势提供了背景，这似乎与自然气候变率和气候变化有关。在里奥格兰德盆地，随着气温升高导致山地积雪减少，春季条件可能对水资源发挥着越来越重要的作用，至少在短期内如此。