The Soil Temperatures on the Tibetan Plateau Impact Global and Regional Climate

Predicting the weather is difficult. Even with the most advanced technology, natural systems are too complex for meteorologists to accurately predict beyond 10 days.

So predicting the months and seasons in the future is a challenge; However, this is the focus of the growing field of climatology that began in earnest in the 1980s. I began by discovering how weather patterns are affected by El Niño, a natural phenomenon that causes surface water temperatures in the eastern Pacific Ocean to rise for up to a year.

El Niño increases the likelihood of some global weather conditions: North and South America get more precipitation, Australia gets less precipitation, and Japan is less likely to experience an active typhoon season. Similarly, other ocean temperature conditions in the Atlantic and Pacific make regional and remote weather outcomes more likely, including precipitation in the tropics and the strength of major storms. Each new factor discovered improves researchers’ ability to predict the weather by months and seasons.

For the past 20 years, UCLA professor Yong Kang Xu has been learning how the Earth’s temperature and humidity affect climate patterns. His most recent papers published in Bulletin of the American Meteorological Society Co-authored by a global group of elite scientists, they found that changes in soil temperature in the Tibetan Plateau affect key climate patterns, such as the East Asian monsoon – a monsoon that helps produce food, generate energy and maintain ecosystems in the lands it inhabits. out of a billion people.

Soil temperatures on the Tibetan plateau alter the temperature gradient from the peaks of the Himalayas all the way to the Bay of Bengal, the source of monsoon moisture. This, in turn, affects the pattern of high- and low-pressure systems and the jet stream—a flow of air high in the atmosphere that has a strong effect on where storms dump their precipitation. The study found that a cooler Tibetan Plateau increases the likelihood of a weak monsoon, while warmer conditions increase the likelihood of strong winds, with a greater propensity for flooding in the Asian monsoon region.

The effect mirrors one found by Xue’s research in North America. When the Rocky Mountains are cooler in the spring, the Southern Plains are more likely to experience dry weather or drought conditions in the summer. Conversely, a warmer spring increases the chance of wetter conditions — including severe flooding, such as the disastrous 2015 Houston Memorial Day flood.

This latest study also found that the temperature fluctuations of these two mountain systems are linked through the Tibetan Plateau – the Rocky Mountain Wave Train – a pattern of high and low pressure systems that extends across the Pacific Ocean. Where the Tibetan Plateau is warm, the Rocky Mountains are cold and vice versa.

“The temperature effect of the Tibetan Plateau is not limited to the eastern part of the lowland plains of China, and the Rocky Mountains affect precipitation in the southern plains — it is global,” Xue said.

He says that even changes of a degree or two in surface temperatures can make a big difference. This is because of the vastness of geological features such as the Tibetan Plateau, which is about a million square miles of land with an average elevation of nearly 15,000 feet above sea level. In some locations, temperature changes account for up to 40% of precipitation anomalies.

To arrive at their findings, the researchers combined satellite and ground-based temperature and precipitation observations with global climate models. The models simulate climate outcomes based on data measurements, with and without the influence of soil temperature changes in the Tibetan Plateau.

This study is the first to explore the relationship between soil temperatures in the Tibetan Plateau and global climate and weather phenomena. Xue stressed that more research is needed to clarify the details.

The aim of the research is to improve the ability to predict weather conditions for the coming months and seasons of the year. Doing this more effectively could save billions or even trillions of dollars by giving industries like agriculture better guidance. Having knowledge in advance of the light monsoon season, for example, could direct farmers to plant more drought-tolerant crops. Better forecasts could also help protect human lives in severe weather and floods.

Understanding the influence of the Tibetan Plateau on climate improves the ability of meteorologists and climatologists to predict seasonal and sub-seasonal weather conditions. And while the forecast is far from certain, knowing there is a higher likelihood of a strong monsoon or drought occurring is valuable, said David Nehlen, UCLA professor of atmospheric and ocean sciences and one of the paper’s authors.

“If you’re a farmer who decides how much crop insurance you want to buy and you can use that forecast across several years, you’ll be ahead in the long run,” Neelen said. “It’s the same with El Niño. It doesn’t guarantee, but it helps.”