Global climate change has strongly increased the worldwide frequency of extreme heat in recent decades.
Global climate change has strongly increased the worldwide frequency of extreme heat in recent decades. South Korea and southern-central Japan are also frequently affected by extreme heat, and the extreme heat in these two regions tend to occur simultaneously. A scientific collaboration of climatologists examined the large-scale circulation leading to the concurrent extreme heat over South Korea and Southern-Central Japan. Their findings have been published in Journal of Climate recently.
"The concurrent extreme heat result from a deep anomalous anticyclone over East Asia, which induces anomalous subsidence and consequent higher surface temperature," said Ke XU, the first author on the paper, who is a postdoc working with Prof. Riyu LU and Prof. Jiangyu MAO in the Institute of Atmospheric Physics, Chinese Academy of Sciences.
XU also noted that the anomalous anticyclone is initiated by wave trains originating from upstream regions, which propagate eastward along the Asian westerly jet in the upper troposphere. "These wave trains can be categorized into two types that are characterized by the precursor anticyclonic and cyclonic anomalies, respectively, over central Asia," XU said. "The two types of wave pattern are indicative to the occurrence of EH over South Korea and southern–central Japan."
Image: Concurrent extreme heat over South Korea and southern-central Japan. (Credit: Ruidan Chen)