*********** 102194B.SAT *********** Contributory Categories: BIO, GEO, MET, PHY Country: China From: Foreign Broadcast Information Service CD-rom disk # 4 JPRS-CST-94-004 JPRS Science & Technology China 1 April 1994 Aerospace KEYWORDS: China; Oceanography, Remote Sensing +++++ Part II/II Part I: INTRODUCTION, OBJECTIVES AND REQUIREMENTS OF SATELLITE REMOTE SENSING IN OCEANOGRAPHY: 1. Monitoring the Dynamic Ocean Environment; 2. Observation of Ocean Color; 3. Mapping of the Coastal Belt and Offshore Islands. [IN PREVIOUS MESSAGE B] Part II: CHINA'S ACCOMPLISHMENTS AND TECHNOLOGICAL GAP IN SATELLITE REMOTE SENSING IN OCEANOGRAPHY: 1. Application of Remote-Sensing Data From Meteorology Satellite in Oceanography; 2. Application of Remote-Sensing Data From the Landsat Satellite in Oceanography; 3. Deficiencies of the NOAA and Landsat Satellites in Oceanography Applications; 4. China's Technology Gap in Satellite Remote Sensing for Marine Applications; CHINA'S GOALS FOR THE DEVELOPMENT OF SATELLITE REMOTE SENSING FOR MARINE APPLICATIONS IN THIS CENTURY: 1. Establishing Ground Systems for Receiving and Processing Satellite Remote-Sensing Data; 2. Establishment of Ground Systems for Receiving and Processing Data From Ocean Color Monitoring Satellites; 3. Promoting Basic Research of Marine Satellite Technologies [IN THIS MESSAGE B] +++++ PROSPECTS FOR SATELLITE REMOTE SENSING IN OCEANOGRAPHY OUTLINED (Cont. from Part I) III. CHINA'S ACCOMPLISHMENTS AND TECHNOLOGICAL GAP IN SATELLITE REMOTE SENSING IN OCEANOGRAPHY During the past 10 years, significant advances have been made in satellite remote-sensing technology. In this country, progress has been slow mainly because of inadequate remote-sensing data. But even under these limited conditions a great deal has been accomplished, and some useful results have been produced. These results are derived from data collected by the meteorology satellites and earth resource satellites. 1. Application of Remote-Sensing Data From Meteorology Satellite in Oceanography Since the early 1980s, when China began receiving data from the U.S. polar-orbit NOAA satellites and the Japanese geostationary GMS satellites, the following results have been produced: (1) The data from NOAA AVHRR infrared channels 3, 4, 5 have been processed to derive surface temperatures of the ocean; the accuracy of the derived temperatures is +/- 1ëC on average and +/- 0.5ëC over a localized area; the geopositioning accuracy is 1-3 km. The data have been used in the following applications: 1) Issuing timely reports of ocean conditions to the fishing industry. By using the data of surface temperatures to determine the front of cold and warm currents, it is possible to issue timely reports of ocean conditions to the fishing fleet; these data have proved to be quite reliable from tests conducted over the past few years. 2) The Black Tide is a current that travels along the western boundary of the Pacific Ocean; it starts from Taiwan, moves northward past Okinawa, then turns east toward the coast of Japan, and terminates at 160ëE. It is a warm current system which has a direct effect on the climate of regions along its path. By analyzing the surface temperature data, preliminary results of the distribution of surface currents in the East China Sea during winter and spring have been obtained. (2) Data from AVHRR infrared channels 3, 4, 5 of the NOAA satellite are used to monitor ice conditions in the northern part of Bo Hai and the Yellow Sea. Ice maps of this region have been constructed using sophisticated data processing techniques including projection transformation, position correction, and image enhancement; these maps show detailed diagrams of ice coverage and thickness distribution of ice. The maps are broadcast and distributed to the user every winter. (3) Data from channel 1 (visible-light channels) of the NOAA satellite and channels 1, 3, 4 of the NIMBUS-1 satellite are used in a remote-sensing test to measure water color at selected points along the river and at the mouths of rivers; preliminary results of chlorophyll concentrations at the mouth of the Yantze River and in Hangzhou Bay and Bo Hai Bay have been obtained. (4) Real-time cloud maps from the GMS satellite and its derived products are used to determine wind speed and direction, which in turn are used to predict the intensity, the location of the eye, and the path of a typhoon. 2. Application of Remote-Sensing Data From the Landsat Satellite in Oceanography In the mid-1980s, China constructed a ground station to receive remote-sensing data from the U.S. Landsat. The data have been used in the following applications in oceanography: (1) The MSS and TM data from Landsat are used to derive preliminary results of suspended mud and sand concentrations at the mouths of the Yellow River, the Yangtze River, Hangzhou Bay, the Pearl River, the Min River and the Yalu River. The results obtained for the Yellow River are found to be correlated with the movement of mud and sand in the offshore region, the erosion of the shoreline, the characteristics of the flow system and with the formation of the river delta. Therefore they provide a valuable data base for establishing future development plan for the Yellow River Delta, for performing maintenance and repair, and for developing oil fields and harbors in this region. (2) The MSS and TM data from Landsat are also used to survey the northwest region of Hainan Island and to construct 1:200,000 and 1:500,000 scale maps that describe the vegetation cover, the terrain, the geology and land use of that region. 3. Deficiencies of the NOAA and Landsat Satellites in Oceanography Applications (1) The accuracy of the AVHRR detector of the NOAA satellite in measuring ocean surface temperature is rather poor; also, the detector is subject to cloud cover limitations and therefore cannot make continuous temperature measurements. In monitoring ice conditions, the surface resolution and geopositioning accuracy of the detector are poor; therefore it is difficult to obtain information on ice movement. In measuring ocean color, the spectral resolution and sensitivity of the detector are both quite low, hence it is difficult to obtain quantitative measures of chlorophyll concentration. (2) The TM (ETM) data from Landsat have poor spectral resolution and low sensitivity so it is difficult to obtain quantitative measures of suspended mud and sand in the ocean; in monitoring ice conditions, its repetition period is too long to be useful in providing information on ice movement; in mapping the coastal belt, the detector does not have sufficient dynamic range to accommodate the large difference in reflectivity between water and land. (3) Many of the important marine environmental elements cannot be effectively measured by the remote sensors of the NOAA satellite or the Landsat; e.g., measurement of key dynamic parameters of the ocean; quantitative determination of the ocean color; quantitative measure of the pollution level in the ocean; and measurement of the depth of the ocean floor. 4. China's Technology Gap in Satellite Remote Sensing for Marine Applications The development of marine remote-sensing techniques in the United States began in the mid-1960s; the data used were collected by the TIROS/NOAA satellites and the GOES family of weather satellites. In the early 1980s, China began receiving data from the TIROS/NOAA satellites and the GMS satellites, and in the mid-1980s, the data were first used in marine applications. Therefore, China is 20 years behind the United States and Western Europe in terms of receiving and applying data from weather satellites. Nevertheless, significant progress had been made within the past 10 years and China's current technology has reached a level comparable to that of advanced nations. But in the area of global weather monitoring and ocean monitoring, little progress can be made until China launches its own satellites. China's first experimental weather satellite, the Feng Yun-1A, was launched in September 1988, again 20 years behind the first TIROS/NOAA satellites; further effort is required to improve its operating life and storage capacity. In July 1972, the United States launched the first land-monitoring satellite, the Landsat-1. In 1986, China began receiving remote-sensing data from Landsat-4 (launched on 16 July 1982), and has continued to receive data for the past six years. Data from Landsat have generated excellent results in the survey of land resources, but they have not contributed a great deal to the important aspect of oceanography -- mapping of the coastal belt and offshore islands. In February 1992, Japan launched its own Landsat which is equipped with an L-band synthetic aperture radar in addition to a multi-band scanning radiometer; it has a ground resolution of 18 m x 18 m and has large onboard storage capacity. Therefore, the Japanese Landsat is a satellite with full-duration, all-weather global monitoring capability. The first Chinese Landsat is currently under development; it probably will not be launched until after 1994. Its detectors are similar to those used on the U.S. Landsat-5; in other words, the technology used on the Chinese Landsat is also 20 years behind. In June 1978, the United States launched the world's first integrated marine observation satellite, the SEASAT-A. It is equipped with five detectors, four of which are microwave detectors, and one is a visible-light-infrared radiometer. This satellite operated continuously for over 100 days, during which time it collected various data on ocean wave fields, wind fields, current fields, internal waves, boundaries between land and water, terrains of shallow sea, ice distribution, oil pollution, and terrains of the ocean surface. Analysis of the data by scientists in the international community shows that the detectors onboard the SEASAT-A are primarily used to monitor the ocean's dynamic phenomena. Improved versions of the SEASAT-A detectors have been implemented on the ERS-1 satellite, which was launched by the European Space Agency (ESA) in July 1991; they are designed to monitor ice conditions in the ocean. China currently does not have the technological maturity to launch its own marine satellites. The microwave detectors required for marine applications are still in the experimental stage; also, there is a lack of comprehensive research effort to develop microwave remote sensors for marine applications. In October 1978, the United States launched the world's first ocean-color monitoring satellite, the NIMBUS-7; it was equipped with a multi-channel microwave radiometer and a coastal zone color scanner (CZCS). During 10 years of operation (1978-1988), particularly the first five years, it had collected one-third of the global data on ocean color, ocean surface temperature, and wind velocity. In addition, the United States is planning to launch another ocean-color monitoring satellite, the SEASTAR. Its onboard SEAWIFS detectors with eight visible-light bands are expected to provide better performance than the CZCS. In China, there are no immediate plans for launching ocean-color monitoring satellites. IV. CHINA'S GOALS FOR THE DEVELOPMENT OF SATELLITE REMOTE SENSING FOR MARINE APPLICATIONS IN THIS CENTURY Satellite remote-sensing technology for marine application in China today is approximately 20-25 years behind the state-of-the-art. In order to accelerate the pace of development and to narrow the technology gap, we should concentrate our efforts on the development of integrated techniques for applying remote-sensing data in oceanography. We should also emphasize the systematic development of various technologies associated with satellite remote sensing, particularly detector technology, in order to build a good technical foundation in preparation for the launch of China's own marine satellites early next century. 1. Establishing Ground Systems for Receiving and Processing Satellite Remote-Sensing Data The plan is to extend the capabilities of existing ground stations to receive data from the ERS-1 satellite, the JERS-1 satellite (launched by Japan in February 1992), the ERS-2 satellite (a follow-on satellite to ERS-1, scheduled to be launched at the end of 1994), the RADARSAT (to be launched by Canada in 1994), and three other polar-orbit satellites (the United States, Western Europe and Japan each plan to launch one satellite after 1997). During the 1990s, when China's own satellite remote-sensing technology is still in the early stage of development, the most cost-effective approach would be to make use of the remote-sensing data collected by foreign satellites. Such data will be used to meet the growing domestic needs in ocean petroleum development, marine products, marine engineering, ocean transportation, disaster prevention, ocean exploration, ocean management and military applications; this will also provide an opportunity to accumulate a knowledge base in applying microwave remote-sensing data, and to build a solid technical foundation for launching our own marine satellites. The establishment of such systems will enhance China's position in the international community of remote sensing for marine applications. 2. Establishment of Ground Systems for Receiving and Processing Data From Ocean Color Monitoring Satellites By upgrading existing ground stations of the weather satellites operated by the National Bureau of Oceanography, we will be able to receive data from foreign ocean-color monitoring satellites (e.g., the SEASTAR and the ADEOS). In view of the fact that China will not have its own ocean-color satellite during the 1990s, sharing data from other countries appears to be a viable approach. The SEASTAR and the ADEOS satellites are expected to continue operating until the end of this century. They will be able to provide data on chlorophyll concentration in the ocean, suspended mud and sand content, and partial assessment of water quality; such data are important for the development and maintenance of fishing and cultivation zones, the construction of harbors and shipping lanes, and the development and utilization of beach-front areas. 3. Promoting Basic Research of Marine Satellite Technologies The topics of basic research should include various types of microwave detectors (such as synthetic aperture radar, radar altimeter, microwave scattering meter, microwave radiometer, water-color detector and laser fluorescent detector), precision orbit determination techniques and precision measurement techniques. +++++ END Part II/II CMR Disclaimer================================================== This document contains information all or part of which is or may be copyrighted in a number of countries. Therefore, commercial copying and/or further dissemination of this text is expressly prohibited without obtaining the permission of the copyright owner(s) except in the United States and other countries for certain personal and educational uses as prescribed by the "fair copy" provisions of that countries Copyright Statues. ================================================================= ************** END Msg. 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