Abstract. Islands are an important part of the marine ecosystem. Increasing impervious surfaces in the Zhoushan Islands due to new development and increased population have an ecological impact on the runoff and water quality. Based on time-series classification and the complement of vegetation fraction in urban regions, Landsat thematic mapper and other high-resolution satellite images were applied to monitor the dynamics of impervious surface area (ISA) in the Zhoushan Islands from 1986 to 2011. Landsat-derived ISA results were validated by the high-resolution Worldview-2 and aerial photographs. The validation shows that mean relative errors of these ISA maps are < 15 %. The results reveal that the ISA in the Zhoushan Islands increased from 19.2 km 2 in 1986 to 86.5 km 2 in 2011, and the period from 2006 to 2011 had the fastest expansion rate of 5.59 km 2 per year. The major land conversions to high densities of ISA were from the tidal zone and arable lands. The expansions of ISA were unevenly distributed and most of them were located along the periphery of these islands. Time-series maps revealed that ISA expansions happened continuously over the last 25 years. Our analysis indicated that the policy and the topography were the dominant factors controlling the spatial patterns of ISA and its expansions in the Zhoushan Islands. With continuous urbanization processes, the rapid ISA expansions may not be stopped in the near feature.

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As an effective survey tool for oil spill detection, the airborne hyper-spectral sensor affords the potentiality for retrieving the quantitative information of oil slick which is useful for the cleanup of spilled oil. But many airborne hyper-spectral images are affected by sun glitter which distorts radiance values and spectral ratios used for oil slick detection. In 2005, there's an oil spill event leaking at oil drilling platform in The South China Sea, and an AISA+ airborne hyper-spectral image recorded this event will be selected for studying in this paper, which is affected by sun glitter terribly. Through a spectrum analysis of the oil and water samples, two features --"spectral rotation" and "a pair of fixed points" can be found in spectral curves between crude oil film and water. Base on these features, an oil film information retrieval method which can overcome the influence of sun glitter is presented. Firstly, the radiance of the image is converted to normal apparent reflectance (NormAR). Then, based on the features of "spectral rotation" (used for distinguishing oil film and water) and "a pair of fixed points" (used for overcoming the effect of sun glitter), NormAR 894 /NormAR 516 is selected as an indicator of oil film. Finally, by using a threshold combined with the technologies of image filter and mathematic morphology, the distribution and relative thickness of oil film are retrieved. INTRODUCEAs the development of economy, oil resources are more and more important for human. Followed, the oil spills in ocean from ships and oil platforms are increasing which have a serious influence to the marine environment. With remote sensing technology, several oil spill information such as distribution, thickness and type can be retrieved to help human clean oil film under scientific decisions.In oil spill remote sensing, thermal infrared camera, ultraviolet camera, microwave radiometer, multi-spectral scanners, synthetic aperture radar, laser fluorescence sensors have been used, but each of them has its own limitations [1] . With the widely use of the hyper-spectral technology, using hyper-spectral sensor to detect oil spills are constant attended by scholars. The hyper-spectral technology has great potential on the quantitative monitoring of oil distribution, type and quantity of spilled oil which effectively compensates the deficiencies of other sensors. *

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Sensitivity analysis about small watershed is an important way to objectively understand the development characteristics of debris flow ditches. With the support of Remote Sensing and Geographic Information System technologies, Dongchuan County with frequent debris flow development in Kunming, Yunnan Province, southwest China was selected as the research object, the Landsat image and Digital Elevation Model were used to interpret the small watersheds on both sides of the Xiaojiang River. By selecting four indicators of fault zone, slope, gully density and land use as the impact factors, the sensitivity coefficients were quantitatively calculated. The following research results were obtained: The distribution feature of debris flow small watersheds was that, the Dongchuan fault zone was the axis which small watersheds were symmetrically distributed on; the sensitivity of the Dongchuan fault zone was the highest in the buffer distance of 5-10 km, which was prone to debris flow disasters; the debris flow was most sensitive in the slope range of 40°-50°; the debris flow was most sensitive to the gully density of 0.6-0.9 km/km2 with broken surface; three types of land use such as bare land, water and construction land had high sensitivity coefficient and were easy to cause mountain disasters. According to the sensitivity coefficients of the above impact factors, the stacking method superposition analysis was carried out to obtain the sensitivity distribution of debris flow disasters in Dongchuan County. The medium sensitive area accounted for 53.84% of the total area, and the high sensitive area accounted for 27.02% of the total area. The medium sensitive area and the high sensitive area were the main areas where debris flow occurred. This study has certain reference significance for disaster prevention, soil and water conservation by quantitative calculation and comparison of debris flow disaster sensitivity.