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 characteristics of vegetation activity
and its climate response patterns are of great significance in deepening
our understanding of regional vegetation degradation and climate change
trends. The re-sponse of vegetation to climate factors varies spatially
due to its heterogeneity. Moreover, there may be lag periods before
climate factors affect vegetation. In this paper, we studied the
responses of vegetation to climate factors at an ecosystem-dependent
scale. GIMMS NDVI3g data were collected to indicate vegetation activity.
Pure pixels with a single vegetation type were extracted to reduce the
influence of the raw NDVI data. Then, a stepwise regression meth-od 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 heterogeneity. The response of
vegetation activity to most climate factors showed a lag, especially the
response to precipitation. Generally, there was no correlation between
vegetation coverage and precipitation at the start of the growing
season. Moreover, for most vegetation, the correlation between
vegetation activity and precipita-tion increased to a peak and then
decreased during the growing season. 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 vegetation type and growth
stage. These findings could contribute to a better understanding of the
drivers and mechanisms of vegeta-tion degradation on the Tibetan
Plateau.