Taiwan to face extreme weather as PSH pressure system shifts west

Taipei, Sept. 24 (CNA) Taiwan will face more frequent extreme weather because the Pacific subtropical high (PSH) pressure system has gradually expanded west over the past 70 years and now covers the country, Taiwan's Central Weather Administration (CWA) said Tuesday.

The CWA said in a Facebook post that its analysis of PSH intensity over the past 70 years revealed a significant shift.

From 1951 to 1980, the westernmost average range of the PSH was around the 135th meridian east. However, between 1981 and 2010, this range expanded significantly to approximately the 120th meridian east, meaning it covered Taiwan, the weather agency said.

The CWA pointed out that in the most recent decade studied (2011-2020), the average range of the PSH extended even further to cover southern China.

The PSH has expanded due to global warming and particularly influences summer weather due to the subsidence -- descending air typically associated with high-pressure weather systems -- bringing stable conditions which lead to warm and dry air, the CWA said.

The expansion of the area the PSH covers suggests that average summer temperatures in Taiwan will continue to rise, the CWA said, adding that the country would face more frequent risks brought by extreme temperatures and more droughts in the future.

Furthermore, Taiwan could face more severe climate crises as high temperatures increase the likelihood of droughts, while droughts cause temperatures to be even more extreme, according to the CWA.