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

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% x km(-1)) < residence (1.5% x km(-1)) < industrial land (1.7% x km(-1)) < public facilities (2.4% x km(-1)) < road (2.9% x 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.