hide
Free keywords:
-
Abstract:
The influence of the Pacific Anticyclone on the summer climate and heatwave in the adjacent regions has been increasing in the past few decades. Our analysis identified the enhancing trends in the center and periphery of the Pacific Anticyclone, suggesting an enhancement and expansion of the Pacific anticyclone in the past four decades. The expansion of the anticyclone was well coupled with the positive upper-level geopotential height trends in the extratropics. The enhancing trends in the anticyclonic circulation in the troposphere coincided with the increasing and enhancing trends of heatwaves in northeast Asia, west China, Siberia, and western North America. Further analysis revealed the close association of the enhancing anticyclone and heatwave with the SST trend pattern, which exhibited a dramatic trend since 1980s, after removing the ENSO signals. AGCM simulations forced by prescribed SST changes suggested the influences of SST trends on the enhancement and expansion of the Pacific anticyclone in boreal summer.
