Impact of Spring Sea Ice Variability in the Barents-Kara Region on the Indian Summer Monsoon Rainfall

The rapidly changing Arctic climate has far-reaching implications for global weather systems, particularly through teleconnections that link high-latitude processes to tropical regions. This study unravels the impact of Barents-Kara (B-K) region sea ice anomalies during the spring season (March-May) on the Indian Summer Monsoon Rainfall (ISMR) patterns from 1959 to 2021. By analyzing low- and high-sea-ice years, the study reveals contrasting atmospheric circulation patterns that drive monsoonal variability over India. During low-sea-ice years, weakened ice cover over the Arctic induces negative sea level pressure anomalies in summer over the Arctic region. This triggers cyclonic activity, which initiates southward-propagating Rossby wave trains. The wave train exhibits a distinct ridge-trough-ridge-trough pattern as it propagates from Europe to the Far East and towards the North Pacific. This atmospheric configuration shifts the subtropical westerly jet southward, enhancing subsidence and suppressing monsoonal convection over the Indo-Gangetic Plain, ultimately reducing the ISMR. Conversely, high-sea-ice years exhibit a reversed pattern, with negative geopotential height anomalies over the Arctic and a ridge over central Asia. This promotes upper-level divergence, enhancing convection and strengthening monsoonal rainfall over the Indo-Gangetic Plain. These findings reveal the critical role of springtime B-K sea ice in shaping summer atmospheric circulation and monsoonal rainfall patterns over India, highlighting the far-reaching impact of Arctic Sea ice variability on tropical weather systems.