资源环境科技发展态势分析平台

Variability in October daily snow water equivalent (SWE) change using self-organizing maps (SOMs) was explored in this study. In addition, connections between October Eurasian daily snow water equivalent change (Delta SWE) and the leading mode of atmospheric intra-seasonal variability, the Madden-Julian Oscillation (MJO), were considered. Through this analysis, dipole and tripole patterns of daily Delta SWE over Eurasia were identified and were moderately negatively correlated to mid-tropospheric geopotential height anomalies. Additionally, SOM nodes capturing over 91% of October days were found moderately correlated with at least one MJO phase. The majority of correlation coefficients with magnitude above 0.30 were found for MJO phases 4-7, indicating that tropical convective anomalies over the Indian Ocean and Maritime Continent have the most impact on October circulation and snow variability. Furthermore, MJO phases with above-normal frequency were most often found in SOM nodes with positive correlations between their respective 500-hPa height anomalies, while MJO phases with below-normal frequency were most often found in SOM nodes with negative correlations between their respective 500-hPa height anomalies. These correlation patterns provide additional evidence linking the MJO to Eurasian snow variability. These results highlight a new application of SOMs in identifying snow variability throughout Eurasia during the month of October, in addition to providing evidence for tropical modulation of the extratropics on the intra-seasonal timescale.