Progress has been made in the study of the feedback effect of vegetation change on climate in high Asia

Remote sensing evidence based on multiple data sources and indicators shows that global warming has greatly enhanced vegetation activities, the vegetation index has shown a significant upward trend, and the growing season has been significantly extended
.
The enhancement of vegetation activity and the extension of the growing season may bring about cooling effect by enhancing evapotranspiration, or may cause warming by reducing the surface albedo, which has a strong feedback effect
on climate change 。 Most studies have shown that vegetation ecosystems in alpine areas of Asia are extremely sensitive to climate change, and vegetation activities regulate the material and energy exchange between terrestrial ecosystems and the atmosphere by changing the biophysical characteristics and processes of the surface, and ultimately change the surface energy balance, but due to the obvious regional differences in the physical, chemical and biological characteristics of the earth's surface, the feedback effect of vegetation on climate factors may also vary from region to region
.
The study of the interaction between vegetation and climate change is a hot spot
of great concern of scholars at home and abroad.

In response to the above problems, based on the GLDAS assimilation dataset, the team of researcher Chen Yaning of the State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, quantitatively evaluated the sensitivity of key land surface flux parameters to high Asian vegetation activities using the biophysical mechanism of attribution method - Biophysical Model (IBM), and quantified the feedback effect
of vegetation activities on high Asian climate change on this basis.

The results showed that the high Asian vegetation index showed an overall upward trend in the past 20 years, with a rate of 0.
505 × 10-3 W m-2 μm-1 sr-1 yr-1 yr-1 (SIF) and ^1.
7 × ^10-3(NDVI), and the overall vegetation activity in the growing season continued to increase.
However, vegetation browning occurred in the central Tianshan Mountains and southeast Tibet
.
The cells of 64.
22% (SIF) and 53.
68% (NDVI) of vegetation cover showed negative sensitivity of surface temperature to vegetation activity, mainly in the two parameters
of bovembenbi and aerodynamic drag.
The enhancement of vegetation activity changes the original equilibrium state of latent heat and sensible heat flux, and increases the turbulent heat transfer between land and atmosphere, especially the latent heat flux
.
With the greening of vegetation, the bauvenbi, albedo and sensible heat flux showed a downward trend, and the increase rate of surface temperature and air temperature also slowed down
.
The climate mitigation effect of vegetation activity in high Asia is gradually increasing, especially in the Tibetan Plateau and the northeast of high Asia, the maximum cooling effect can reach -1.
337 K
.
The results are of great significance for understanding the feedback effect of alpine vegetation dynamics on climate change, and provide a scientific basis
for ecosystem solutions to cope with global change.

The results were published in Agricultural and Forest Meteorology under the title "Biophysical impacts of vegetation dynamics largely contribute to climate mitigation in High Mountain Asia", and the first author of the paper is Dr.
Liu Yongchang of Xinjiang Birthplace.

The research was supported
by the National Key Research and Development Program of China and the National Natural Science Foundation of China.

Article link: https://authors.
elsevier.
com/a/1g0jqcFXJcsJm

Figure 1.
Zonal statistics of vegetation dynamics and temperature changes in high Asia and its subregions ((A) and (B)).

(C) and (D) are the spatial distribution plots
of temperature changes induced by different vegetation indices.
(E) and (F) are the feedback effects
of land surface temperature caused by the background climate.