基于遥感生态指数的雄安新区生态质量评估

城镇化建设的持续推进给生态环境带来的压力日益增加,多方位、客观、准确、快速测算区域生态环境质量是生态学研究的一个重点.本研究从绿度、湿度、热度、干度4方面分别提取了归一化植被指数(NDVI)、湿度指数(WET)、地表温度(LST)、归一化建筑-土壤指数(NDBSI)4个分量指标,采用基于ENVI平台的主成分分析技术集成所选指标,基于新型遥感生态指数(RSEI)对1995—2015年雄安新区生态质量进行评估.结果表明: 1995、2004和2015年,雄安新区的RSEI均值分别为0.724、0.710、0.682,生态质量总体呈下降趋势;1995—2015年间,研究区RSEI主要由4、5级向1、2、3级转变,生态质量改善和恶化的面积分别占总面积的8.9%和20.9%,生态改善区域主要位于雄县东部和南部,主要原因在于该区域大面积的林地和园地受到当地政府的高度重视和严格保护,生态质量恶化区域主要位于城镇外围以及白洋淀周边,原因在于白洋淀水域面积的锐减和城市化的不断推进;RSEI与各分量指标的平均相关系数为0.804,均高于各分量指标间的平均相关系数,表明RSEI能较好地综合各分量指标信息,全面准确反映研究区生态质量状况.

Ecological quality assessment of Xiongan New Area based on remote sensing ecological index

The continuous urbanization leads to increasing pressure on the ecological environment. It is a key point to measure regional ecological environment quality objectively, accurately and quickly from multiple directions in ecological research. In this study, the normalized vegetation index (NDVI), wet index (WET), land surface temperature (LST), and normalized difference building-soil index (NDBSI) were extracted from the aspects of greenness, humidity, heat and dryness. The ecological quality of Xiongan New Area between 1995 and 2015 was evaluated by integrating selected indicators to measure the remote sensing ecological index (RSEI) with principal component analysis technology based on ENVI platform. The results showed that the average RSEI of Xiongan New Area was 0.724, 0.710, and 0.682 in 1995, 2004 and 2015, respectively, showing a downward trend. RSEI mainly changed from 4, 5 to 1, 2 and 3 in the study area from 1995 to 2015. Ecological quality improved and deteriorated area accounted for 8.9% and 20.9% of the total area respectively. The ecological quality improved area was mainly located in the east and south of Xiongxian County, because a large area of forests and gardens was highly valued and strictly protected by the local government. The ecological quality deteriorated area was in the periphery of the town and the surrounding area of Baiyangdian due to the sharp decline of the water area of Baiyangdian and the continuous urbanization. The three-year average correlation coefficient between RSEI and each component index was 0.804, which was higher than that between other component indices. Our results showed that RSEI could efficiently integrate the information of each component index and comprehensively and accurately reflect the ecological quality of the study area.