Trend Changes of the Vegetation Activity in Northeastern East Asia and the Connections with Extreme Climate Indices

Abstract

In the context of global warming, vegetation activity in northeastern East Asia (40–45°N, 105–130°E) (NEA) shows a significant growth trend on a multidecadal scale, but how vegetation changes on a decadal scale is unclear. In this study, we find a significant trend of vegetation greening in northeastern East Asia during 1982–1998 and a slowdown in the greening trend during 1998–2014. Trend analysis of the extreme climate indices reveals that the trends of precipitation-related extreme climate indices are similar to those of vegetation change, and further correlation analysis reveals that precipitation-related extreme climate indices have a strong positive correlation with the NDVI. The results indicate that the vegetation in northeastern East Asia is more sensitive to precipitation changes, especially extreme precipitation, compared with the temperature and related extreme indices. Furthermore, the analysis of large-scale atmospheric circulation changes suggests a role of Northwest Pacific subtropical high (NPSH) in the trend changes of precipitation-related extreme indices. The strengthening of NPSH before 1998 enhances the moisture transport to the NEA, providing abundant water vapor favorable for extreme precipitation events, while after 1998, the NPSH trend is much weakened, corresponding to a decrease in the moisture transport trend.

Long-Term Effects of Altered Precipitation Patterns on Alpine Vegetation Species Composition on the Qinghai-Tibet Plateau

“…Environmental adaptation determined the vegetation species composition in alpine grasslands under climate change. In recent decades, climate change increased the frequency of extreme events [29][30][31]. As the main factor to determine the distribution of biological communities, accelerated climate variations had changed the adaptability and competitiveness of different species in the ecosystem [43].…”

“…Numerous previous research concluded that temperature was more important as a driving factor in vegetation growth on the QTP [22,[24][25][26][27][28]. However, since the 21st century, global warming slowdown and frequent precipitation extremes caused by atmospheric circulation made the impacts of precipitation on vegetation more concerned [29][30][31]. According to recent studies, changing precipitation patterns showed more significant effects on vegetation than annual and seasonal precipitation [32][33][34][35][36][37].…”

Impacts of Extreme-High-Temperature Events on Vegetation in North China

“…In contrast, the northeastern region contains coniferous and broad-leaved forests with abundant water resources [13], where the conservative water use of forests helps mitigate the impacts of extreme heat events. The increase in the maximum temperature in high-latitude forest areas extends the growing season of plants and enhances photosynthesis, resulting in the promotion of vegetation growth [27,81].…”