ISSN 1000-3665 CN 11-2202/P

    基于时间序列植被指数资料的承德市植被覆盖时空演变分析

    Temporal and spatial evolution of vegetation cover in Chengde based ontime series NDVI data

    • 摘要: 承德是京津冀地区重要的水源涵养区和防风固沙区,是京津冀生态环境支撑区的重要组成部分,其植被状况将直接影响着区域生态环境质量的改善。基于MOD13Q1时间序列NDVI资料,利用线性回归分析法、像元二分法、稳定性分析法等测度承德市全域2000—2018年植被覆盖时空演变特征,并分析气候、地形等因素对植被覆盖的影响。结果表明:(1)承德市全域植被状况年际变化总体发生了改善,植被生长季夏季的NDVI值最高,月度变化中7月份NDVI值最大,多年均值达到0.775 2。(2)植被年际变化趋势显著性存在空间差异,植被指数极显著增加区域面积最大,占比59.08%,而极显著减少和显著减少的区域面积较小,分别占全域的0.76%和0.58%,主要分布在承德市中部、南部等地区。(3)承德市各区县植被覆盖状况均以较高覆盖度为主,面积达到45 585.69 km2。在多年植被覆盖度稳定性格局中,西北部波动较大,其余大部分地区稳定性好,波动较低。(4)承德市NDVI受5—7月份降水量和月均温的影响较大,植被的长势可能受到了前期气象条件的滞后效应影响。地形特征对承德全域植被覆盖状况也有一定的影响,总体来看承德市地势低平地区的NDVI值相对较低。研究结果可为承德市加强重要区域生态保护、优化国土空间开发格局和科学制定生态修复措施提供参考。

       

      Abstract: Chengde is a very important water conservation area and sand prevention area in Beijing-Tianjin-Hebei region. It is also an important part of the ecological environment support area. Its vegetation status will directly affect the improvement of regional ecological environment quality. Based on the NDVI data of MOD13Q1, linear regression analysis, pixel dichotomy and stability analysis were used to measure the spatiotemporal evolution characteristics of vegetation cover in Chengde from 2000 to 2018, and analyzed the impact of climate, terrain and other factors on vegetation coverage. The results showed that:(1) the interannual change of vegetation in Chengde has been improved. The NDVI value in summer is the highest in vegetation growing season, and the NDVI value in July is the largest in monthly change, and the annual average value is 0.775 2. (2) The results showed that there were spatial differences in the annual variation trend of vegetation. The area with extremely significant increase in vegetation index was the largest, accounting for 59.08%, while the area with extremely significant decrease and significant decrease accounted for 0.76% and 0.58% of the whole area, respectively. They mainly distribute in the central and southern areas in Chengde. (3) The vegetation coverage of each district and county in Chengde is mainly high coverage, with an area of 45 585.69 km2. In the pattern of vegetation coverage stability, the northwest fluctuates greatly, and the rest areas have good stability and low fluctuation. (4) The NDVI of Chengde is greatly affected by the precipitation and monthly average temperature from May to July, and the growth of vegetation may be affected by the lag effect of the previous meteorological conditions. In general, the NDVI value of low-lying areas in Chengde is relatively low. The research results can provide reference for Chengde to strengthen the ecological protection of critical regions, optimize the spatial development pattern of land and scientifically formulate ecological restoration measures.

       

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