黄河流域植被时空变化及其对气候要素的响应

在气候变化和人类活动的双重作用下，黄河流域生态环境不断发生变化。探讨植被生长动态对于实施生态保护政策至关重要。利用Advanced Very High Resolution Radiometer(AVHRR) Leaf Area Index(LAI)遥感资料，结合气候要素数据，分析1981—2017年黄河流域植被覆盖的时空分布特征，探讨气候要素对其变化的影响及贡献率。研究结果表明：(1)时序上，黄河流域植被覆盖呈显著增长趋势，夏季植被覆盖的增长幅度和年际波动最大，冬季植被覆盖呈缓慢平稳增长，波动最小。(2)空间上，植被覆盖显著提高的区域占整个区域的52.1%,主要分布在中东部平原；显著降低的区域占4%,主要分布在北部和西部高原山地；生态脆弱的区域植被覆盖率大多有不同程度的提高，但生态环境良好的部分区域植被覆盖率降低。(3)时序上，黄河流域植被覆盖与气温具有显著的正相关关系。春夏冬三季的植被覆盖与气温呈显著正相关，与降水呈不显著关系；秋季的植被覆盖与气温和降水量均呈显著正相关；春秋冬三季的植被覆盖与太阳辐射呈不显著负相关，夏季的植被覆盖与太阳辐射呈不显著正相关。春夏秋冬四季的气温对植被覆...

Spatio-temporal variation in vegetation coverage and its response to climate factors in the Yellow River Basin, China

Under the dual effects of climate change and human activities, the ecological environment of the Yellow River Basin is constantly changing. It is very important to explore the dynamics of vegetation growth for the implementation of ecological protection policy. Based on Advanced Very High Resolution Radiometer (AVHRR) Leaf Area Index (LAI) remote sensing data and climate factors data, we analyzed the spatio-temporal characteristics of vegetation cover in the Yellow River Basin from 1981 to 2017, and discussed the impacts and contribution rate of climate change on vegetation. The results showed that:(1) in the study period, the vegetation cover in the Yellow River Basin showed a significant growth trend. The maximum growth range and annual fluctuation of vegetation cover occurred in summer, the smallest fluctuation, slow and steady growth occurred in winter. (2) Spatially, the areas with significantly improved vegetation cover accounted for 52.1% of the whole region, mainly distributed in the central and eastern plain. The decreased area accounted for 4%, mainly distributed in the northern and western plateau mountains. Most of the ecologically fragile regions had different degrees of vegetation restoration, but vegetation cover reduced in some regions with good ecological environment. (3) There was a significantly positive correlation between vegetation cover and air temperature in the Yellow River Basin. The vegetation covers in spring, summer and winter had a significantly positive correlation with their air temperature, but had no obvious correlation with precipitation. While the vegetation cover in autumn had a significantly positive correlation with air temperature and precipitation. There was no significantly negative correlation between vegetation covers and solar radiation in spring, autumn and winter, but no significantly positive correlation in summer. The contribution rate of air temperature to vegetation covers in spring, summer, autumn and winter was greater than that of precipitation and solar radiation. The contribution rate of air temperature to vegetation covers in spring and autumn was greater than that in summer and winter. The contribution rate of precipitation to vegetation cover in autumn was larger than that in spring, summer and winter. Of the four seasons, the contribution rate of solar radiation to vegetation cover in spring was the largest. (4) Spatially, the vegetation cover in 77.0% of the Yellow River Basin had a maximum negative correlation with air temperature, when vegetation lagged the air temperature by 7 months. The vegetation cover in 96.1% of the Basin had a positive correlation with precipitation, and changes in vegetation cover was coincided with precipitation or lagged by one month. The vegetation cover in more than 72.2% of the Basin had a negative correlation with solar radiation when vegetation lagged the solar radiation by 8 months.