Ecosystem-dependent responses of vegetation coverage on the Tibetan
Plateau to climate factors and their lag periods
- shuohao cai,
- Xiaoning Song,
- Ronghai Hu,
- Da Guo
Xiaoning Song
University of the Chinese Academy of Sciences
Author ProfileAbstract
The spatial-temporal variation character-istics of vegetation activity
and its cli-mate response patterns are of great sig-nificance in
deepening our understand-ing of regional vegetation degradation and
climate change trends. The response of vegetation to climate factors
varies spatially due to its heterogeneity. More-over, there may be lag
periods before climate factors affect vegetation. In this paper, we
studied the responses of vege-tation to climate factors at an
ecosystem-dependent scale. GIMMS NDVI3g data were collected to indicate
vegetation activity. Pure pixels with a single vegeta-tion type were
extracted to reduce the influence of the raw NDVI data. Then, a stepwise
regression method was adopted to calculate the regression equation for
NDVI and meteorological data with the consideration of effect lag times.
In the results, the vegetation activity showed an overall increasing
trend over the last 31 years, but there was strong spatial
heter-ogeneity. The response of vegetation activity to most climate
factors showed a lag, especially the response to precipita-tion.
Generally, there was no correlation between vegetation coverage and
precip-itation at the start of the growing season. Moreover, for most
vegetation, the cor-relation between vegetation activity and
precipitation increased to a peak and then decreased during the growing
sea-son. In addition, there was no obvious lag period for the effect of
the sunshine percentage on vegetation. The lag period of temperature
varied on different vege-tation type and growth stage. These find-ings
could contribute to a better under-standing of the drivers and
mechanisms of vegetation degradation on the Tibetan Plateau.