Response of North Pacific storm tracks to multiscale SST anomalies in a stable state of the Kuroshio extension system during the cold season

Abstract

In the present study, the response of North Pacific storm tracks to spatial multiscale (large-scale and mesoscale) sea surface temperature anomalies (SSTAs) in stable state of Kuroshio Extension (KE-related SSTAs) system are investigated. The results show that storm tracks are significantly strengthened with local enhanced rainfall in the central North Pacific and near the west coast of the North American continent in response to KE-related large-scale SSTAs, while they shift to the north and are significantly strengthened in the central-eastern North Pacific and Gulf of Alaska with remote impact on precipitation along west coast of North America continent in response to KE-related mesoscale SSTAs. The anomalous storm tracks influenced by KE-related SSTAs at different spatial scales are closely related to the locations of low-level baroclinicity. The response of horizontal advection of temperature to different scales of KE-related SSTAs in the lower atmosphere plays an important role in resulting baroclinicity anomalies.

The Northern Hemisphere Wintertime Storm Track Simulated in the High‐Resolution Community Earth System Model

“…The storm track shows significant positive anomalies in the northern flanks of the long-term mean maximum and weak negative anomalies in the southern flanks when the oceanic front is intensified in the Kuroshio Extension (Figures 7a and 7b). It suggests that the poleward shift of the storm track shows a close association with strengthened oceanic fronts, which is consistent with the findings of previous work (e.g., Chen et al, 2022;Foussard et al, 2019;Graff & LaCasce, 2012). Compared to LR, the positive anomaly regions in HR seem to be further north (about 5°), indicating a stronger SST gradient (up to 1-2°C/100 km) along the Kuroshio Extension (Figure 7c) due to the better resolved mesoscale SST (C. Zhang et al, 2020a).…”

“…Besides EGR, BCEC also exerts a significant impact on modulating energy absorption efficiency by synoptic transient eddies (Cai et al., 2007; Nakamura & Sampe, 2002), which is expected to influence storm tracks (e.g., Chen et al., 2022; Ma & Zhang, 2018; C. Zhang et al., 2020a). Therefore, we examine the simulated BCEC processes in the lower troposphere which involve two parts.…”