Tibetan Plateau heat source strengthens water vapor transport leading to excessive rainfall in northeastern China
by Matteo Cavallito
The Tibetan Plateau has always acted as a regulator of summer rainfall in southern China. However, this effect, scientists now observe, would also occur in the northeastern part of the country on the push of a decisive factor: soil moisture. This is supported by recent research published in the journal Advances in Atmospheric Sciences.
The study, notes Han Yizhe, researcher and lead author in a statement released by the researchers, unveils the mechanisms behind rainfall during the warmer months. And it helps improve the scientific prediction of rainfall in the region.
The Atmospheric Heat Source
The work, by researchers at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, focuses on the so-called Atmospheric Heat Source (AHS). And it examines data collected from 1961 to 2020.
In spring, the research explains, “the strong Tibetan Plateau AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the Yellow River Valley–North China region (YRVNC). Thus, soil moisture increases, which regulates local thermal conditions by decreasing local surface skin temperature and sensible heat.”
The memory effect of soil moisture
Moreover, “Owing to the memory of soil moisture, the lower spring sensible heat over the YRVNC can last until mid-summer.”
This phenomenon “decrease the land–sea thermal contrast, and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western Pacific.” Finally, by altering the atmospheric circulation over the East Asia-Pacific region, the same phenomenon “leads to a cyclonic anomaly and excessive summer precipitation over Northeast China.”
The Tibetan Plateau is at the center of several phenomena
The Tibetan Plateau has long been considered a key player in the complex phenomena that regulate the Planet’s climate. Some time ago research by a group of scientists from Beijing Normal University published in the journal Nature Climate Change highlighted the importance of the complex network of interactions between the atmosphere, oceans, land, ice and biosphere. These elements affect different areas of the world.
When occurring in a certain region of the Planet, the researchers pointed out, it is possible for certain critical phenomena to trigger certain effects in another connected area.
By analyzing a huge number of hourly air temperature measurements at more than 65,000 locations and operating simulations to predict future climate changes, the authors had described these relationships in mathematical terms. The numbers in particular had shown that there was a clear connection between the unusual temperatures recorded in the Amazon and Tibet over the past 40 years.