2000—2019大别山地区植被活动特征及其对异常降水的响应

The reginal vegetation activity in Ta-Pieh Mountains from 2000 to 2019 and its response to abnormal precipitation

大别山区作为生态过渡地带是淮河流域生态系统及其敏感区之一,研究区域尺度异常降水及植被活动的时空变化趋势,定量辨识区域植被活动对异常降水的响应,对于区域水土保持、生态安全和可持续发展具有重要意义。基于2000—2019年密集时序MODIS 13Q1遥感影像,通过像元二分模型定量反演区域植被活动时序变化特征,并结合国家气象科学数据中心日降水资料,利用趋势分析、Mann-Kendall突变检验和空间分析等方法,深入探究了2000—2019大别山地区植被活动时空变化趋势特征以及对异常降水的影响。研究结果显示:(1)2000—2019年大别山区植被覆盖度总体呈现为分段性上升的趋势,整体增速为0.01/10a(P<0.05,双尾),2011年前后到达区域峰值,然后进入高位震荡;(2)2000—2019年大别山区异常降水频次总体呈现下降的趋势,东部及南部异常降水频次显著高于其他地区;(3)2000—2019年大别山区植被活动与异常降水显著相关且空间分异明显突出,随着海拔的升高正相关区域明显增加。平原低海拔地区(<200 m)正相关的区域占比仅为25.30%,到高海拔地区(>1000 m)正相关区域占比可达54.91%。表明区域异常降水对大别山区不同生态系统植被活动的影响截然不同,高海拔丘陵森林生态系统对异常降水表现出更强的韧性,而低海拔平原农田生态系统对异常降水则表现出更为脆弱。

Ta-Pieh Mountain area is one of the ecologically sensitive area in the Huai River Basin.Studying the temporal and spatial variation trend of regional scale abnormal precipitation and vegetation activities,and quantitatively identifying the response of regional vegetation activities to abnormal precipitation is of great significance for regional soil and water conservation,ecological security and sustainable development.Based on the dense time series MODIS 13Q1 remote sensing images from 2000 to 2019,firstly,the temporal change characteristics of regional vegetation activity were quantitatively retrieved by pixel dichotomy model.And then,combined with the daily precipitation data of the National Meteorological Science Data Center,using the methods of trend analysis,Mann Kendall mutation test and spatial analysis,the temporal and spatial variation trend characteristics of vegetation activities and their impact on abnormal precipitation in Ta-Pieh Mountain Area from 2000 to 2019 were explored.The results showed that:(1)From 2000 to 2019,the vegetation coverage in Ta-Pieh Mountain area generally showed a piecewise upward trend,with an overall growth rate of 0.01/10a(P<0.05,double tailed).Reginal vegetation coverage reaching the regional peak around 2011,and then entering the high-level oscillation.(2)From 2000 to 2019,the frequency of abnormal precipitation in the Ta-Pieh Mountains showed a slight downward trend;and the frequency of abnormal precipitation in the East and South was significantly higher than that in other areas.(3)From 2000 to 2019,there was a significant correlation between vegetation activity and abnormal precipitation in Ta-Pieh Mountain area,but the spatial differentiation was obvious.With the rise of altitude,the positive correlation area increased significantly.The proportion of positively correlated areas in low altitude areas(<200 m)in plains was only 25.30%,and the proportion of positively correlated areas in high altitude areas(>1000 m)could reach 54.90%.It implies that the effects of regional abnormal precipitation on the vegetation activities of different ecosystems in the Ta-Pieh Mountains are quite different.High altitude hilly forest ecosystem shows stronger resilience to abnormal precipitation,while low altitude Plain Farmland ecosystem shows more vulnerability to abnormal precipitation.