On the basis of mixture theory of concentration of Helland-Hansen (Maoet al,1964; Helland-Hansen.1916).this paper takes salinity as a conservative factor is the process of dilution and mixture and selects by relative analysis the hydrological and chemical factors which are closely related to salinity.Then making use of the Q type mufti-dimensions cluster analysis,we get the results that the water masses in the western Taiwan Strait include the follwing,the coastal water along Fupan,Zhejiag and Guangdong Provinces,the diluted fresh water of Minjisag.Jiulong sad Hanpang Rivers,the nuxing water in the Taiwea Strait,upwelling cold/warm water to the northwest of the Taiwan Shoal end the upwelling water to the east of Guangdong.The mixing water in the Taiwan Strait during spring and summer is composed of a Kurashio branch,the surface water of the South China Sea.coastal water along Fujian,Zhejiang and Guaogdoog Provinces.While in autumn and winter,it is mixed up from Kuroshio branch,the shelf water is the Fast China Sea,and the coastal water along Fujian,Zhejiang and Guattgdong. There is an obvious seasonal change of growth and decline in these water masses.
The ocean color satellite is mainly applied to measure the water constituents such as chlorophyll, suspended material and yellow substance. The leaving water radiance is very small part of the total radiance arrival at the sensor about 3%-15%,and depends on the properties of the orbit and sensor. Before the satellite is launched on the orbit, it needs to simulate the radiation imagery in order to evaluate the quality and availability of the satellite data. If the parameters of satellite orbit, the properties of sensor as well as the characteristics of the atmosphere and water have been known, the radiation scattered by air molecule and aerosol, reflected solar radiation, water leaving and total radiation arriving at the sensor can be simulated by the models of radiation transfer in the atmosphere, air/water and subsurface water. In this paper, the mechanism, models and procedures of the radiation simulation are first discussed and employed to simulate a series of imageries for the Chinese satellites FY-lA, FY-1B, and ROCSAT-1 (Taiwan, China), and American satellite Ses STAR. Their results show that the solar irradiance arrived at water surface and the sun glitter mainly affect the quality and availability of satellite data, which depend on the orbit properties. Finally, some suggestions are proposed to improve the quality and availability of a:ean color satellite data.
Hy-1 is a first China's ocean color satellite which will be launched as a piggyback satellite on FY-1 satellite using Long March rocket. On the satellite there are two sensors:one is the China's ocean color and temperature scanner (COCTS), the other is CCD coastal zone imager (CZI).The COCTS is considered to be a main sensor to play a key role. In order to understand the characteristics of future ocean color images observed, a simulation and evaluation study on the quality and availability of the COCTS image has been done. First, the simulation models are introduced briefly, and typical simulated cases of radiance images at visible bands are introduced, in which the radiance distribution is based on geographic location, the satellite orbital parameters and sensor properties, the simulated method to evaluate the image quality and availability is developed by using the characteristics of image called the complex signal noise ratio (CSNR). Meanwhile, a series of the CSNR images are generated from the simulated radiance components for different cases, which can be used to evaluate the quality and availability of the COCTS images before the HY-1 is placed in orbit. Finally, the quality and availability of the COCTS images are quantitatively analyzed with the simulated CSNR data. The results will be beneficial to all scientists who are in charge of the COCTS mission and to those who plan to use the data from the COCTS.
Coastal water environment is essentially enhanced by ocean color which is basically decided by substances concentration in water such as chlorophyll, suspended material and yellow substance.It is very difficult, even not possible, to detect water color by expensive ship routing, because of its temporal and spatial variety of feature and scales in the very complicated dynamical system of coastal water.With the development of satellite technique in the last 20 a, space sensors can be applied to detect ocean color by measuring the spectra of water-leaving radiance.It is proven that ocean color remote sensing is a powerful tool for understanding the process of oceanic biology and physics. Since the 1980s, great attention has been paid to the advanced remote sensing technique in China, especially to development of satellite programs for the coastal water environment.On 7 September 1988, China launched her first polar orbit satellite FY-1A for meteorological and oceanographic application (water color and temperature) and the second satellite FY-1B two years later.In May 1999, China launched her second generation environment satellite FY-1C with higher sensitivies, more channels and stable operation.The special ocean color satellite HY-1 is planned to be in the orbit in 2001, whose main purpose is to detect the coastal water environment of China seas.China is also developing a very advantageous sensor termed as Chinese moderate imaging spectra radiometer (CMODIS) with 91 channels, which will be a good candidate of the third generation satellite FY-3 in 2003. The technical system of ocean color rermote sensing was developed by the Second Institute of Oceanography (SIO), State Oceanic Administration (SOA) in 1997.The system included data receiving, processing, distribution, calibration, validation and application units.The Hangzhou Station of SIO, SOA has the capability to receive FY-1 and AVHRR data since 1989.It was also a SeaWiFS scientific research station authorized by NASA, USA to free receive SeaWiFS data from 16 September 1997. In the recent years, the local algorithms of atmospheric correction and inversion of ocean color have been developed for FY-1C and SeaWiFS, to improve the accuracy of the measurement from satellites efficiently.The satellite data are being applied to monitor coastal water environment, such as the spatial distribution of chlorophyll, suspended material and yellow substance, red tide detection and coastal current study.The results sbow that the ocean color remote sensing has latent capacity in the detection of coastal water environment.In consideration of the update technique progress of ocean color remote sensing and its more important role in the detection of coastal water in the 2000s, some suggestions are set forth, which would be beneficial to the design of a cheaper but practical coastal water detection system for marine environment preservation.