The Wenchuan Earthquake of magnitude 8.0 struck Sichuan Province in south-west China on 12 May 2008. This paper presents an overview of the use of multi-source satellite images in investigating the influence of this earthquake around the epicentral area. The results show the capability of remote sensing technique for damage detection in quake-hit areas. Optical satellite images (FORMOSAT-2 and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)) provide useful information, although rain and cloud limit the availability of satellite data. However, the Synthetic Aperture Radar (SAR) sensor provides information in all weather conditions. Combined optical satellite and SAR data have been used to assess the damage of earthquakes, including landslides, barrier lakes and collapsed buildings. From the interferogram of two phased array type L-band SAR (PALSAR)/Advanced Land Observing Satellite (ALOS) images, more than 100 cm of ground displacement was found in Beichuan County, one of the worst-affected earthquake areas. These examples show the use of satellite images in post-disaster damage assessment and planning during the rescue operation soon after a major event such as the 12 May 2008 earthquake.

Multi-source remote-sensing data were used to study the aftermath of the 2006 Lebanon oil spill: Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m data and advanced synthetic aperture radar (SAR) images were used to delineate the extent of the oil spill; QuikScat data were used to derive the wind field; and MODIS Ocean Colour data were used to demonstrate the variability of chlorophyll-a concentration (Chl-a) and sea surface temperature (SST). No significant changes were found in marine phytoplankton in the first few months after the oil spill. However, a big phytoplankton bloom was observed after 10 months, when Chl-a increased from 0.1 to 1.0 mg m^–3. After considering the time-series variability of Chl-a and SST and the spatial variability of Chl-a and bathymetry, we concluded that this phytoplankton bloom was probably related to the Lebanon oil spill.

Quantification of vegetation cover can facilitate an improved understanding of ecosystem function and crop yield. Current methods of cover measurement can be divided into field surveys and remote sensing, with their associated advantages and disadvantages. Digital camera images provide high temporal and spatial resolution at low cost than satellite images. A method to accurately and conveniently estimate crop cover from digital camera images is presented. The digital camera images were converted from red-green-blue to hue-saturation-intensity color space. Hue segmentation technique enhanced the characteristics of plant tissues, and identified green tissues easily. Vegetation and non-vegetation binary pseudo-color images were produced and crop cover was calculated for each plot. By comparing leaf area index and wheat yield with time series cover data from the 2005 growing season, two results were obtained: (1) there were high correlations between cover and leaf area index at four stages (r2 = 0.88, 0.96, 0.97, and 0.92); (2) crop cover at 80 - 90 days after sowing can be used to predict the wheat yield with good results. Our results suggest this method is an accurate and efficient means of measuring vegetation cover in cropland.

Temporal variations of chlorophyll a (Chl a) concentration before and after the Montara oil spill in August 2009 in the Timor Sea were analysed using MODIS-derived Chl a data. Time series data suggested a decrease in Chl a concentration following the oil spill, but an increase occurring in May 2010. A 4000 km² patchy phytoplankton bloom with a high concentration of 13.8 mg m⁻³ occurred southeast of the platform, which coincided with the location the residual oil spill finally moved to. The Chl a was usually high in that area in May, but reached a peak in May 2010: the monthly Chl a for May 2010 was one and a half times higher than that of the average value for May between 2003 and 2009. The present study also analysed as many as 15 cases of major marine oil spills in the world and discussed their impacts on phytoplankton. The results suggested that the increase of Chl a may have relations with the oil spill incident. Natural seasonal variability is also an important factor for the formation of the phytoplankton bloom.