Tropical Indian Ocean warming contributions to China winter climate trends since 1960

Abstract

This study investigates observed and modeled contributions of global sea surface temperature (SST) to China winter climate trends in 1960-2014, including increased precipitation, warming through about 1997, and cooling since then. Observations and Atmospheric Model Intercomparison Project (AMIP) simulations with prescribed historical SST and sea ice show that tropical Indian Ocean (TIO) warming and increasing rainfall causes diabatic heating that generates a tropospheric wave train with anticyclonic 500-hPa height anomaly centers in the TIO or equatorial western Pacific (TIWP) and northeastern Eurasia (EA) and a cyclonic anomaly over China, referred to as the TIWP-EA wave train. The cyclonic anomaly causes Indochina moisture convergence and southwesterly moist flow that enhances South China precipitation, while the northern anticyclone enhances cold surges, sometimes causing severe ice storms. AMIP simulations show a 1960-1997 China cooling trend by simulating increasing instead of decreasing Arctic 500-hPa heights that move the northern anticyclone into Siberia, but enlarge the cyclonic anomaly so it still simulates realistic China precipitation trend patterns. A separate idealized TIO SST warming simulation simulates the TIWP-EA feature more realistically with correct precipitation patterns and supports the TIWP-EA teleconnection as the primary mechanism for long-term increasing precipitation in South China since 1960. Coupled Model Intercomparison Project (CMIP) experiments simulate a reduced TIO SST warming trend and weak precipitation trends, so the TIWP-EA feature is absent and strong drying is simulated in South China for 1960-1997. These simulations highlight the need for accurately modeled SST to correctly attribute regional climate trends.

Robust Solar Signature in Late Winter Precipitation Over Southern China

“…Wintertime precipitation over southern China is known to be strongly affected by tropical sea surface temperature (SST) anomalies. Numerous studies have noted that the El Niño–Southern Oscillation (ENSO; Chen et al, ; Wang et al, ; Wu et al, ; Zhou, ), as well as positive SST anomalies in the tropical Indian Ocean (Li et al, ; Li & Zhou, ; Wu et al, ), can increase southern China winter precipitation. Apart from tropical SSTs, extratropical atmospheric dynamical processes, particularly teleconnections originating from the North Atlantic/European (NAE) region, also affect precipitation anomalies in China.…”

Skilful two‐month‐leading hybrid climate prediction for winter temperature over China

“…Moreover, the EAWM is also modulated by Pacific Decadal Oscillation, North Pacific Oscillation, AO, Antarctic Oscillation (AAO), and quasistationary planetary wave activity on decadal and interdecadal timescales (Fan andWang, 2004, 2006;Zhou et al, 2007;Wang et al, 2008b;Wang et al, 2009b;He and Wang, 2012;Huang et al, 2012;Sun et al, 2016). Consequently, winter SAT in China is affected by the Siberian high, East Asian trough (EAT), East Asian jet stream, and related factors like sea surface temperature (SST), AO, North Atlantic Oscillation (NAO), and so on (Jiang et al, 2014;Li et al, 2013;Liang et al, 2014;Song and Wu, 2017;Wang et al, 2008a;Wu et al, 2018;You et al, 2013).…”