Biophysical impacts of vegetation dynamics largely contribute to climate mitigation in High Mountain Asia
Biophysical impacts of vegetation dynamics largely contribute to climate mitigation in High Mountain Asia
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DOI：
10.1016/j.agrformet.2022.109233
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发表时间：
2022-12
影响因子：
6.2
通讯作者：
Yongchang Liu;Zhi Li;Yaning Chen;Patient Mindje Kayumba;Xuanxuan Wang;Chuanxi Liu;Yunxia Long
中科院分区：
文献类型：
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作者：
Yongchang Liu;Zhi Li;Yaning Chen;Patient Mindje Kayumba;Xuanxuan Wang;Chuanxi Liu;Yunxia Long
卫星和现场观测数据表明，全球变暖极大地增强了植被活动(绿化)，植被指数(VIS)呈广泛上升趋势。然而，植被对陆地表面温度的生物物理影响(T S)是广泛未知的，特别是在亚洲高山地区。研究结果表明，在研究期间，植被以0.505×10−3W m−2μm−1 sr−1yr−1(太阳诱导叶绿素荧光：SIF)和1.7×10−3yr−1(归一化植被指数：nDVI)的速率被绿化，分别占总像素数的52.75%和47.24%。然而，天山中部和西藏东南部等地区也出现了植被褐变。同时，64.22%的植被面积(SIF)和53.68%的植被面积(NDVI)表现出T-S对植被活动的负敏感性，特别是在西藏和昆仑东部的草本和灌丛植被。此外，牛比和空气动力阻力(Ra)对植被活动表现出负敏感性。最重要的是，植被活动引起的温度变化分别为-0.278 K(ΔT N D V I C I B M)、-0.538 K(ΔT S I F C I B M)、0.028 K(ΔT N D V I S I B M)和0.024 K(ΔT S I F S I B M)。此外，在敏感度方法(ΔT V e g NDVI I B M)中，超过一半的像素点检测到植被降温，SIF的植被降温更为明显，占64.22%，而NDVI为53.68%。植被活动的增强改变了潜热通量和感热通量(Le，H)的原始平衡，增加了陆地和大气之间的湍流热传递，特别是L等。我们的研究结果对于理解干旱高寒地区植被动力学对气候变化的响应和反馈具有重要意义。
Satellite-driven and site observational data show that global warming has greatly enhanced vegetation activity (greening), with a broad upward trend in vegetation indices (VIs). However, the biophysical impact of vegetation on land surface temperature (T s) is widely unknown, particularly in High Mountain Asia (HMA). In this study, we assessed vegetation dynamics in HMA from 2000 to 2020 and used intrinsic biophysical mechanism (IBM) models to quantify the biophysical feedback effects of vegetation on T s. The results illustrate that, during the study period, HMA has undergone greening at a rate of 0.505× 10− 3 W m− 2 μm− 1 sr− 1 yr− 1 (solar-induced chlorophyll fluorescence: SIF) and 1.7× 10− 3 yr− 1 (normalized vegetation index: NDVI), accounting for 52.75% and 47.24% of the total number of pixels, respectively. However, vegetation browning has occurred in areas such as the central Tien Shan and southeastern Tibet. Meanwhile, 64.22%(SIF) and 53.68%(NDVI) of the vegetation area in HMA showed a negative sensitivity of T s to vegetation activity, particularly herbaceous and scrub vegetation in Inner Tibet and eastern Kun Lun. Additionally, the Bovine ratio and aerodynamic drag (r a) exhibited a negative sensitivity to vegetation activity. Most importantly, the vegetation activity-induced temperature changes were-0.278 K (Δ T N D V I C I B M),-0.538 K (Δ T S I F C I B M), 0.028 K (Δ T N D V I S I B M), and 0.024 K (Δ T S I F S I B M). Moreover, in the sensitivity method (Δ T V e g S I B M), vegetation cooling was detected in more than half of the pixels in HMA and was even more pronounced with SIF, accounting for 64.22% compared to 53.68% with NDVI. Enhanced vegetation activity alters the original balance of latent and sensible heat fluxes (Le, H) and increases the turbulent heat transfer between land and atmosphere, particularly L e. Our findings have important implications for understanding the response and feedback of vegetation dynamics to climate change in arid alpine regions.