Strengthened Connections Between Arctic Sea Ice and Thermal Conditions Over the Tibetan Plateau in May After the 2000s

The thermal conditions of the Tibetan Plateau (TP) during spring are significantly related to climate changes on regional and hemispheric scales. The surface skin temperature over the TP in May exhibits an increasing trend over the northern and central-western regions since the 2000s. This heterogeneous distribution has a strengthened relationship with changes in Arctic sea-ice concentration (SIC) over the Barents-Kara Seas after 2001, showing a significant negative correlation. Along with the dramatic SIC variations after 2001, there is a mid-latitude wave train akin to the Circumglobal Teleconnection (CGT), accompanied by an anomalous anticyclone around the TP. On the one hand, the high-latitude energy associated with the SIC changes spreads through the Barents-Kara Seas toward the southeast, causing intensified westerly winds over the West Siberian Plain. The anomalies imply a poleward subtropical jet, which affects the anticyclonic anomaly over the TP, situated south of the jet axis, through dynamic processes. On the other hand, the cyclonic anomalies at high latitudes, linked with reduced SIC, inhibit snow melting and bring lower soil moisture content. Consequently, increased meridional temperature gradients and background baroclinicity cover the West Siberian Plain and regions encompassing the Black Sea and the Mediterranean, demonstrating the impacts of SIC variations on mid-latitude Rossby waves. Responses to the anomalous anticyclone over the TP, heightened downward motions favor enhanced adiabatic heating and result in reduced cloud cover, further causing decreased snow depth. Influenced by snow-albedo and cloud-radiation feedback, the net downward short-wave radiation increases and leads to the TP warming after 2001.