Coast zone, the primary area of oceanic resources and the ‘golden area’ in marine social-economic developments, plays an important role in regional and national economics of near coast countries and regions. Recent natural disasters around the world including the flood in New York from super storm Sandy and severe Typhoon Vicente that hit Hong Kong should have drawn global attention to coastal area disasters. The coastal area can be defined as the band of dry land and adjacent ocean space (water and submerged land) in which terrestrial processes and land uses directly affect oceanic processes and uses, and vice versa [1]. Actually, because of the interaction between land and ocean, a highly complex ecological system inhabits at this area. They are sensitive to multiple inner or outer factors that could bring great change to the whole system, as well as influencing urban infrastructures, marine resources and human health. This results in coastal zone studies to be highly complicated and interdisciplinary. The problem is that this complexity is still increasing with evolution in exploitation technology, marine logistics and human lifestyle.

Coastal zone is always an area affected by varies hazards, natural and human-induced. Beside the most notorious natural disasters typically like earthquake, tropical cyclones and tsunamis, the human-induced oil spill, red tide and water pollution are also of great environmental concern now. Considering the high density of large cities and main economical centers located within coastal area, if we do not take actions regarding the coastal environmental protection and sustainable development, the consequences can be disastrous.

Among all, one primary coastal environmental issue is water quality, which is related to coastal and estuarial water pollution, coastal erosion, red tide and other environmental issues. The reason of water quality decline can be multiple. In coastal regions, discharges from the treatment of urban wastewater, industry and fishing farms are the main point-pollution sources, which contribute pollution in the form of toxic chemicals and heavy metals, oxygen-depleting nutrients and pathogens. On the other hand, non-point sources are more difficult to tracking. They mainly come from scattered pollution sources brought by rainfall or melting snow or other media. Among them, agriculture is a key source, but urban land, forestry, atmospheric deposition and rural dwellings can also make contributions. The long and multistep pollution generation and diffusion process makes it harder to detect and forecast this procedure. Unfortunately, its impact is not less. Complexity makes analysis and tracking on pollution resources difficult.

Direct water pollution is one primary aspect of coastal environmental problems, red tide, oil spills and sea level changes are also important issues. It is positive to see that people started to realize the importance of coastal studies, especially focused on environmental hazard detection and prevention, many of which related to coastal water quality monitoring. Among many approaches, remote sensing technology is one of the most effective tool in detecting coastal environmental hazards and pollutions. In recent years, it has been wildly applied in red tide and oil spill monitoring, land-use land-change detection, coral mapping, and water component analysis regarding water quality. For example, using remotely sensed data, concentrations of chlorophyll a(Chl a), coloured dissolved organic matter (CDOM), and total suspended solid (TSS) in water bodies can be monitored for water quality assessment. MODIS and Lands at products or other optical sensors data have been proved reliable in land-use land-cover classification, which contributes to coastal land management’s and pollution source analysis and control. Remote sensing technology is especially a strong tool regarding to hazards like oil spills which are impossible to detect by conventional field trips or frequent visits for samples. In satellite Synthetic Aperture Radar (SAR) images, the oil spills appears as dark spots. Their shape, form, location and diffusion situation can be clearly determined, which makes forecasts of its moving direction and assessment of impacts on coastal environment possible.

Opportunities come with challenges. One is that coastal water components are much too complex for simple analysis. Because of detrital material due to coast erosion or brought from the wind or from rivers, correlations between compounds fall down. Therefore to completely describe coastal waters, more complex algorithms such as physically based algorithms should be used, which often relate to the radioactive transfer theory or backscattering theory. For instance, speaking of oil spills, not every case study is successful in its identification. It still puzzles the scientists that how to distinguish between real oil spills and natural oil generated by marine organism, as they looks similar or very close to each other in satellite SAR images. Moreover, the depth of oil cover is hard to detect or estimate. It brings great difficulties in providing oil spill alerts before it is found, which is highly valuable practically. Many more challenges lies in pollution diffusion pattern analysis and simulation, sea level change studies and red tide forecast and preventions.

Nevertheless, remote sensing provides the opportunity and foundation of frequent high-resolution multi-spectral monitoring on all kinds of environmental information at on package, which is especially applicable for coastal zone studies. Modern research trends of more interdisciplinary cooperation and better international communication also brings a positive prospect. For the future of coastal zone studies, more efforts and cooperation are still needed. Coastal zone study has now entered the era of pursuing high-resolution mapping, in-time monitoring and cost-effective output product, and that is why open access of data and research findings are highly preferred. It is our sincere hope that the Open Access trend which the OMICS promotes can be a real worldwide trend and can encourage and facilitate more high quality coastal studies especially in developing countries.