17:15 〜 18:45
[ACG35-P04] Exploring the impact of climate change on vegetation dynamic in Siberia from 2000 to 2022
キーワード：葉面積指数、シベリア、植生のダイナミクス、気候変動
The Northern Hemisphere is experiencing amplified warming and greening. A large and growing body of research suggests that the magnitude of warming due to anthropogenic climate change in the Arctic is four times the global average. Vegetation is a crucial component of terrestrial ecosystems, as it plays a key role in the energy, water and carbon exchanges between the land surface and atmosphere. Therefore, understanding and quantifying vegetation dynamics in Siberia, a hotspot in the Northern Hemisphere, is critical to improve our understanding and monitoring of terrestrial ecosystems. In this study, we utilized newly developed sensor-independent (SI) moderate resolution imaging spectroradiometer (MODIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS) leaf area index (LAI) as the proxy of vegetation and explored the impact of climate change (e.g. air temperate, precipitation and radiation) on vegetation dynamics in Siberia during 2000-2022. Overall, the average, 0.5 and 0.8 quantile, maximum annual LAI showed similar increase trends, which means Siberia is experiencing a greening trend. Specifically, average annual LAI showed an increase trend in 80.77% of the regions, most of the regions with declining LAI are in central, northeast and southwest Siberia. We also used MODIS v061 LAI data, results showed similar trend and spatial-temporal pattern with SI LAI. The regions with declining LAI consisted of evergreen needleleaf forests, mixed forest, woody savannas, and savannas. However, each of these four vegetation types has shown an overall increasing trend on average, indicating the declined LAI in Siberian is independent of land cover. Finally, by analyzing the meteorological data of ERA5, we found that LAI decrease in central, northeast and southwest Siberia mainly is caused by water and heat stress, and LAI decrease in north and south Siberia is caused by energy lacking. Our results suggest that Siberia is going is experiencing a greening trend, while there are some regions, under water and heat stress, experiencing a browning trend.