Zhong Run, Yan Kai, Gao Si, Yang Kai, Zhao Shuang, Ma Xuanlong, Zhu Peng, Fan Lei, Yin Gaofei
Innovation Research Center of Satellite Application (IRCSA), Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; School of Land Science and Techniques, China University of Geosciences, Beijing 100083, China.
Innovation Research Center of Satellite Application (IRCSA), Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; School of Land Science and Techniques, China University of Geosciences, Beijing 100083, China.
Sci Total Environ. 2024 Jan 20;909:168488. doi: 10.1016/j.scitotenv.2023.168488. Epub 2023 Nov 14.
Extreme Climatic Events (ECEs) are increasing in intensity, frequency, and duration as the earth warms, which greatly affects the vegetation phenology. However, the response of vegetation phenology to different types of ECEs (e.g., extreme hot, extreme cold, extreme drought, and extreme wet) has not been extensively studied. To fill this knowledge gap, we investigated the relationship between the length of growing season (LOS) of grassland and ECEs on the Qinghai-Tibetan Plateau (QTP). First, we analyzed the spatial distribution and interannual trends of phenology based on the MODIS Normalized Difference Vegetation Index (NDVI). Second, we used Coincidence Rate (CR) analysis to quantify the relationship between LOS anomalies and ECEs. Finally, we analyzed the sensitivity of LOS to the intensity of ECEs. The results indicated that the spatial distribution of LOS was closely related to local hydrothermal conditions, with longer LOS in places with more precipitation or higher temperatures during the growing season, and LOS extended by 0.28 days/year from 2000 to 2022. Moreover, we found that the CR of negative LOS anomalies to ECEs notably exhibited variations along climatic gradients, with higher CR to extreme hot generally occurring in warmer areas. Meanwhile, the CR of extreme wet increased while the CR of extreme drought decreased with increasing precipitation. We also found that the sensitivity of LOS to ECEs changed more markedly, along the climatic gradients, in alpine ecoregions compared to temperate ecoregions. Overall, the sensitivities of LOS ranked in descending order of absolute sensitivity to extreme drought, extreme wet, extreme hot, and extreme cold. This study furthers our understanding of the grassland response to ECEs under different hydrothermal conditions, which can provide valuable reference for the management and conservation of grassland ecosystems in QTP under future climate change scenarios.
随着地球变暖，极端气候事件（ECEs）的强度、频率和持续时间都在增加，这对植被物候产生了极大影响。然而，植被物候对不同类型的极端气候事件（如极端高温、极端低温、极端干旱和极端湿润）的响应尚未得到广泛研究。为了填补这一知识空白，我们研究了青藏高原（QTP）草地生长季长度（LOS）与极端气候事件之间的关系。首先，我们基于MODIS归一化植被指数（NDVI）分析了物候的空间分布和年际变化趋势。其次，我们使用符合率（CR）分析来量化生长季长度异常与极端气候事件之间的关系。最后，我们分析了生长季长度对极端气候事件强度的敏感性。结果表明，生长季长度的空间分布与当地水热条件密切相关，生长季降水较多或温度较高的地区生长季长度较长，2000年至2022年生长季长度每年延长0.28天。此外，我们发现生长季长度负异常对极端气候事件的符合率沿气候梯度显著变化，极端高温的符合率通常在较温暖地区较高。同时，随着降水量增加，极端湿润的符合率增加，而极端干旱的符合率降低。我们还发现，与温带生态区相比，高山生态区生长季长度对极端气候事件的敏感性沿气候梯度变化更为明显。总体而言，生长季长度对极端气候事件的敏感性按绝对敏感性从高到低排序为极端干旱、极端湿润、极端高温和极端低温。本研究进一步加深了我们对不同水热条件下草地对极端气候事件响应的理解，可为未来气候变化情景下青藏高原草地生态系统的管理和保护提供有价值的参考。
