基于线性混合像元分解的沈阳市三环内城市植被盖度变化

Urban vegetation coverage change inside the Third-Ring Road of Shenyang City,China: A study with linear spectral unmixing technique

基于2001和2006年Landsat TM影像,通过线性混合像元分解（linear spectral unmix-ing,LSU）方法提取沈阳市三环内的植被盖度信息,结合目视解译2006年QuickBird影像得到的研究区土地利用类型图,分析了2001—2006年研究区植被盖度的动态.结果表明：2001—2006年,研究区植被盖度变化剧烈,绿化建设和由城市扩张导致的农田占用现象并存,且前者的植被增加超过后者的植被损失;研究区道路、居住区、公共设施用地、公共绿地及广场的植被盖度均有不同程度的增加（5%~9%）,工业用地几乎没有变化;研究区绿化建设格局比较合理,城区内外植被盖度的两极分化现象虽依然存在,但已得到缓解;研究期间,该区主要地类植被盖度随距市中心距离而递增的顺序为公共绿地及广场（0.8%.km-1）〈居住区（1.5%.km-1）〈工业用地（1.7%.km-1）〈公共设施用地（2.4%.km-1）〈道路（2.9%.km-1）;公共设施用地和道路植被盖度两极分化现象依然较严重,需加强绿化建设并严格管理.

Based on the Landsat TM images of 2001 and 2006, and by using linear spectral unmixing （LSU） technique, the information of urban vegetation coverage inside the Third-Ring Road of Shenyang City was extracted, and the dynamic change of the vegetation coverage in 2001-2006 was analyzed, in combining with a land use map derived from the visual interpretation of a QuickBird image of 2006. The results showed that in 2001-2006, the urban vegetation coverage in study area changed drastically. Urban greening and the cropland encroachment caused by urban sprawl coexisted, and the vegetation gain from urban greening was larger than the vegetation loss from cropland encroachment. The vegetation coverage of road, residence, public facilities, and park and square increased with varying degrees （5%-9%）, while industrial land changed little. The spatial distribution of urban greening was relatively reasonable. Though the polarization of vegetation coverage between central city and suburban still existed, this polarization had been mitigated to some extent. With the increase of the distance from city center, the vegetation coverage increased in sequence of park and square （0. 8% · km^-1 ） 〈 residence （1.5%· km^-1） 〈 industrial land （ 1.7% · km^-1） 〈public facilities （2. 4%· km^-1） 〈 road （2.9%· km^-1）. The polarization of vegetation coverage in public facilities and road were still serious, suggesting that more greening programs and strict conservation efforts were needed.