Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, 100084, China.
Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100094, China.
Sci Rep. 2024 Aug 2;14(1):17905. doi: 10.1038/s41598-024-68066-7.
Northwest China has undergone notable alterations in climate and vegetation growth in recent decades. Nevertheless, uncertainties persist concerning the response of different vegetation types to climate change and the underlying mechanisms. This study utilized the Normalized Difference Vegetation Index (NDVI) and three sets of meteorological data to investigate the interannual variations in the association between vegetation and climate (specifically precipitation and temperature) from 1982 to 2015. Several conclusions were drawn. (1) R (relationship between Growing Season NDVI and precipitation) decreased significantly across all vegetation, while R (relationship between Growing Season NDVI and temperature) showed an insignificant increase. (2) Trends of R and R exhibited great variations across various types of vegetation, with forests displaying notable downward trends in both indices. The grassland exhibited a declining trend in R but an insignificant increase in R, while no significant temporal changes in R or R were observed in the barren land. (3) The fluctuations in R and R closely aligned with variations in drought conditions. Specifically, in regions characterized by VPD (vapor pressure deficit) trends less than 0.02 hpa/yr, which are predominantly grasslands, a rise in SWV (soil water volume) tended to cause a reduction in R but an increase in R However, a more negative trend in SWV was associated with a more negative trend in both R and R when the VPD trend exceeded 0.02 hPa/yr, primarily in forests. Our results underscore the variability in the relationship between climate change and vegetation across different vegetation types, as well as the role of drought in modulating these associations.
中国西北地区近几十年来气候和植被生长发生了显著变化。然而，不同植被类型对气候变化的响应及其潜在机制仍存在不确定性。本研究利用归一化差异植被指数（NDVI）和三套气象数据，从 1982 年到 2015 年调查了植被与气候（特别是降水和温度）之间年际变化的关系。得出了以下结论。（1）所有植被的生长季 NDVI 与降水的关系（R）显著降低，而生长季 NDVI 与温度的关系（R）呈不显著增加趋势。（2）R 和 R 的趋势在各种植被类型之间存在很大差异，森林这两个指数都呈现明显的下降趋势。草原 R 呈下降趋势，R 不显著增加，而荒漠区 R 和 R 没有明显的时间变化。（3）R 和 R 的波动与干旱条件的变化密切相关。具体来说，在 VPD（蒸气压亏缺）趋势小于 0.02 hpa/yr 的地区，主要是草原，SWV（土壤水体积）的增加往往导致 R 的降低，但 R 的增加。然而，当 VPD 趋势超过 0.02 hPa/yr 时，SWV 的更负趋势与 R 和 R 的更负趋势有关，主要是在森林地区。我们的研究结果强调了不同植被类型之间气候变化与植被关系的可变性，以及干旱在调节这些关系中的作用。
