LANZHOU, Aug. 21 (Xinhua) -- Chinese researchers have systematically unveiled the patterns and underlying mechanisms of the dry-wet evolution patterns of the arid regions in northwest China, shedding light on the regional ecological security, according to Lanzhou University.

The study was carried out by a research team at the College of Earth and Environmental Sciences of Lanzhou University. The results of the study have been recently published in the journal Science Bulletin, said the university.

Given the background of climate change, the evolution of water resources in the arid regions of northwest China shows significant regional differences since the 1960s. The west has shown gradual warming and humidification, while the upper reaches of the Yellow River in the east have shown a continuous "aridification," according to Li Yu, leader of the study team and a professor at Lanzhou University.

"Our new study revealed the core mechanisms of dry-wet evolution differentiations between the east and west parts of arid regions in northwest China, especially clarifying the key role of the El Ni?o-Southern Oscillation (ENSO), a recurring climate pattern affecting the tropics and extratropics," said Li.

Researchers of the team have been dedicated to the study of the Qilian Mountains, a key ecological shield in western China which straddles the border between northwestern Gansu and Qinghai provinces.

The Qilian Mountains lie at the transition zone between the Qinghai-Tibet Plateau, the arid region of Central Asia and the East Asian monsoon region, making them an ideal location for investigating the wet and dry evolution of the East Asian Monsoon Marginal Zone (EAMMZ).

To better understand Holocene dry-wet variations and their driving mechanisms in this zone, the study team conducted an integrated study combining modern climatological processes, sedimentary records, and paleoclimate simulations.

Researchers established a network on the evolution of lakes in the mountain range and their surrounding inland areas. Based on the analysis of continuous lake and aeolian sedimentary profiles, they accurately characterized the wet and dry evolution of the Holocene in this region.

The study results indicate that Holocene climate changes in this region were primarily influenced by tropical air-sea interactions in the Pacific Ocean, rather than by monsoon intensity controlled by low-latitude solar radiation.

In recent years, northwest China has witnessed a trend of warm and humid climate, and the future amplitude of ENSO may increase significantly. It will lead to changes in the hydrological evolution pattern of the basin and an increased risk of extreme drought events in the region, according to the study results.

Systematically clarifying the key meteorological drivers behind dry-wet anomalies in the monsoon marginal zone is not only an important frontier scientific issue, but also essential for informed decision-making and the development of effective countermeasures to ensure the ecological security of the northwest China region, according to Li.

"Our findings provide a crucial scientific basis for understanding the evolution of water resources in northwest China, given the background of global warming and for predicting its future trends," Li added. ■