资源环境科技发展态势分析平台

This study examines the changing characteristics of snow water equivalent (SWE) in western United States and their teleconnections with large-scale variability of the Pacific and Atlantic Oceans. This study evaluated the relationship among sea surface temperatures (SST), 500-mbar geopotential height (Z(500)), 500-mbar east-west wind (U-500), and western United States SWE (1 March, 1 April, and 1 May). The averages of SST, Z(500), and U-500 were computed to create a lead time of 2-10 months. Three different 6-month series were computed - January-June, April-September, and July-December - and were correlated with SWE stations in the western United States. The study utilized singular-value decomposition (SVD) for a period of 1961-2016 to correlate the SWE and climate indices. SVD was applied between the standardized SST and SWE to obtain their correlation and to evaluate connection with Z(500) and U-500 within the same SVD relationship. Specifically, SVD was not applied independently on each variable prior to this study. The correlations were observed to increase as the lead time decreased. First mode SVD showed a pronounced non-El Nino-Southern Oscillation short-wave train for the July-December climate in the Z(500) data; this terminated over the Great Lakes region, and was strongly correlated with the warming of the SST near the east coast of Japan, resulting in decreased SWE in the study area. Second mode SVD showed a negative correlation between SWE stations in Colorado and Utah and SST near the Asian and Australian continents. The associations between climate indices and SWE that were identified during this study could be used to improve long-term forecasts, resulting in better management of water resources in the region.