摘要
蒙古高原是中国北方重要的生态安全屏障，为厘清蒙古高原干旱时空动态及对植被物候的影响，利用 SPEIbase 2.9数据集和基于累积NDVI的Logistic曲线曲率极值法反演的植被物候数据集，分析1982—2022年蒙古高原干旱时空特征及干旱对植被返青期和枯黄期的累积影响。结果表明：(1)不同尺度SPEI均呈显著下降趋势，随着时间尺度的增加干旱化趋势加剧、干旱化面积明显增大，中部和西部地区干旱化尤为严重。(2)植被返青期提前和推迟的面积占比分别为50.03%和49.97%，枯黄期推迟和提前的面积占比分别为67.85%和32.15%；荒漠草原返青期和枯黄期主要表现为推迟趋势，针叶林和森林草原北部返青期显著提前、枯黄期呈推迟趋势。(3)蒙古高原(荒漠除外)79.62%的区域植被返青期与1~12个月尺度SPEI呈最大正相关，干旱尺度主要为中期尺度，尤其7~9个月尺度的干旱对植被返青期影响明显；54.15%的区域植被枯黄期与SPEI呈最大负相关，干旱尺度主要为1~3个月尺度。其结果对防御蒙古高原干旱及对植被物候和生产力的影响具有重要意义。
Abstract
The Mongolian Plateau is a crucial ecological zone in northern China. The SPEIbase 2.9 dataset and the logistic curvature extremum method based on cumulative NDVI data were used to elucidate the spatiotemporal dynamics of drought and its impact on vegetation phenology in the Mongolian Plateau. The vegetation phenology dataset was inverted to explore the cumulative impact of drought on the start and end of the growing season (SOS and EOS, respectively) in the Mongolian Plateau from 1982 through 2022. Different time scales of Standardized Precipitation Evapotranspiration Index (SPEI) showed significant decreasing trends. With larger timescales, the drought degree intensified, and the area of drought increased significantly. The droughts were particularly severe in the central and western regions. Earlier and later SOS were observed in 50.03% and 49.97% of regions, respectively, and later and earlier EOS were observed in 67.85% and 32.15% of regions, respectively. Overall, SOS and EOS were delayed in the desert steppe. In contrast, the SOS occurred earlier in the coniferous forest and later in the northern part of the forest steppe. Correlation values for SPEI and SOS were maximal during a 1-12 months timescales for 79.62% of the region in the Mongolian Plateau (excluding deserts); over an intermediate-term timescale, a drought duration of 7-9 months had a significant impact on the SOS. Negative correlations between SPEI and EOS over a 1~12 months timescales were highest for 54.15% of the study area, primarily over a 1-3 months timescales. Our findings can help elucidate the factors critical for drought prevention and predict its impact on vegetation phenology and productivity in the Mongolian Plateau.关键词
干旱/植被物候/返青期/枯黄期/蒙古高原Key words
drought/vegetation phenology/start of the growing season (SOS)/end of the growing season (EOS)/Mongolian Plateau引用本文复制引用
张巧凤,于红博,黄方.蒙古高原干旱时空特征及对植被物候的累积影响[EB/OL].(2024-11-12)[2026-04-02].https://chinaxiv.org/abs/202411.00149.学科分类
自然地理学/灾害、灾害防治/环境科学理论
评论