New study reveals snow-ground thermal coupling on Qinghai-Tibet Plateau

LANZHOU -- A new study by Chinese scientists has shed light on the coupling effects of snow cover and ground thermal on the Qinghai-Tibet Plateau, according to the Northwest Institute of Eco-Environment and Resources (NIEER) under the Chinese Academy of Sciences.

The study incorporates snow cover processes into land surface and climate models for cold regions, which is significant to improving the accuracy of permafrost evolution and the assessment of extreme event risks, the NIEER said.

Conducted by a joint team of researchers from the NIEER and the Nanjing University of Information Science and Technology (NUIST), the study was published in the journal Agricultural and Forest Meteorology.

The Qinghai-Tibet Plateau is home to the world's largest high-altitude permafrost zone. Given the context of global warming, the warming rate and related factors of this plateau have raised concerns.

"Compared to the snow in Arctic regions, snow on the Qinghai-Tibet Plateau is typically thin and short-lived. Snow cover critically influences ground thermal regimes and surface energy fluxes in alpine permafrost regions," said Hu Guojie, a researcher with the NIEER.

Snow-ground coupling on the Qinghai-Tibet Plateau is dominated by shallow-snow processes and strong surface-atmosphere interactions, according to Hu.

The team of researchers carried out years of continuous in-situ observations to uncover the in-depth coupling effects between snow cover and ground thermal on the Qinghai-Tibet Plateau.

Scientists conducted observations and studies at two alpine permafrost sites, situated at altitudes of 5,100 meters and 4,538 meters above sea level, respectively.

They analyzed snow cover characteristics, ground surface temperature (GST) responses and energy flux dynamics at both sites.

Furthermore, the research team proposed a "four-interval mechanism framework" to describe the evolutionary path of the various coupling stages between snow cover and ground thermal conditions.

According to Hu, this framework provided operational criteria and parametric ideas for the snow-ground coupling in the shallow snow-dominated areas on the Qinghai-Tibet Plateau.

"Our study quantified the nonlinear thermal effects of shallow snow cover on alpine permafrost," said Zhao Lin, professor at the NUIST in East China's Jiangsu province.

"The results provide observational evidence and conceptual benchmarks to support the development of threshold-sensitive snow-ground coupling schemes in land surface and permafrost models for the Qinghai-Tibet Plateau under a changing climate," Zhao added.