An international remote sensing system: A possibility

There have been growing national capabilities in the observation of Earth from space and a corresponding increase in the global awareness of environmental problems. In response, within the past decade consensus has been reached with respect to the recommendations of Unispace-82, the Principles of Remote Sensing and Agenda 21 of the June 1992 United Nations Conference on Environment and Development (UNCED); the latter was convened ‘to lay the foundation for a global partnership between developing and more industrialized countries, based on mutual needs and common interests, to ensure the future of the planet’. Similarly, the framework for international cooperation in such programmes as the US-led Earth Observing system (EOS) and the International Geosphere-Biosphere Programme (IGBP) have been established. An international remote sensing system that is user-driven may be the next logical step.     

The IRS-P3 remote sensing mission

ISRO has developed the PSLV rocket (Polar Spacecraft Launch Vehicle) for polar orbiting satellites up to 1000 kg and is conducting a series of test missions. One of this is the IRS-P3, an remote sensing satellite with German participation. The payload consists of 3 scientific instruments: The wide field sensor WiFS for vegetation monitoring (ISRO), the imaging spectrometer MOS (DLR/Germany) for coastal zone and ocean studies an the X-ray astronomy payload (ISRO). The paper gives technical details and parameters on the launch vehicle, the satellite, the instruments and scientific goals and data utilization.     

The benefits of remote sensing for energy policy

A strong remote sensing regime is a necessary component of any contemporary national or international energy policy. Energy is essential to the functioning of modern industrial society, and as such it is the responsibility of governments to produce sound national energy policies in order to ensure stable economic growth, ecologically responsible use of energy resources and the health and safety of citizens. Comprehensive, accurate and timely remote sensing data can aid decision making on energy matters in several areas. This paper looks at the benefits that can be realized in resource exploration, weather forecasting and environmental monitoring. Improvements in the technology of remote sensing platforms would be of great value to buyers of energy, sellers of energy and the environment. Furthermore, the utility of such information could be enhanced by efforts of government agencies to communicate it more effectively to the end-user. National energy policies should thus include investments not only in satellite system hardware to collect data, but also in the services required to interpret and distribute the data.     

Multispectral remote sensing of aerosols

Aerosols are common atmospheric constituents that occur both naturally (clouds, sea spray, dust, smoke, and volcanic emissions) and artificially (smog, smoke, certain hazes, detonation products, and industrial emissions). Some, like the great dust bowl storms in the U.S. in the 1930s, are a combination of natural and manmade agents. Most aerosols are difficult to model because they are composed of small, non-spherical particles whose optical constants and particle sizes are poorly known. Spectroscopic observations of aerosols in the thermal infrared atmospheric window between 8 and 13.5 μm offer the opportunity to detect aerosols both day and night down to very low column densities. Such observations can also identify the gross chemical composition of the particles and, in some cases, the actual sizes and shapes. In this paper, we discuss thermal i.r. observations of three types of aerosols: satellite measurements of volcanic dust, ground-based observations of airborne desert soil and both ground- and space-based measurements of cirrus clouds.     

The activities of ocean colour remote sensing in China

This article reviews the development of ocean colour remote sensing over the past decade in China. China launched its first remote sensing satellite FY-1A on 7 September 1988 and its second, FY-1B on 3 September 1990. Both of them had a Very High Resolution Scanning Radiometer (VHRSR) which involved two channels (0.48–0.53 and 0.53–0.58 u) for measuring ocean colour. A new polar orbiting satellite FY-1-02 was scheduled to be in orbit by 1998 with an improved VHRSR which has more (10) channels and is more sensitive for ocean colour remote sensing. The special programme of the ocean colour satellite HY-1 has been approved by the Chinese government, as has the planning of another new generation polar orbiting remote sensing satellite, FY-3. A type of sensor has been developed known as the Chinese Moderate Imaging spectroradiometer (CMODIS). Following its review, the article will describe the future activities of ocean colour remote sensing in China and explain their scientific goal.     

A US dilemma — satellite remote sensing privatization

NASA's and EOSAT's efforts to keep the USA in the technological forefront of remote sensing have been hampered by budgetary constraints and bickering. This article is a plea for a continued and explicit commitment by the US government to the promotion of the necessary technology and cooperative programmes. Unless the issues are tackled with a sense of urgency, the author argues, the French or Japanese may take over the lead.     

The modular optelectronic multispectral scanner system for spaceborne remote sensing

A multispectral scanner system for spaceborne remote sensing of land and coastal/ocean features is under development for the German Ministry for Research and Technology. The system is based on the use of multilinear detector arrays for visible and infrared spectral bands.The electronically scanning image system MOMS (Modular Optoelectronical Multispectral Scanner) consists of individual spectral channel modules which can be grouped to dedicated mission tasks. Those dedicated tasks are land surface thematic mapping, sea or vegetation monitoring and in a stereo mode conventional photo interpretation and mapping.The basic performance data would allow up to 10,000 pixels per scan line, corresponding to about 20 m resolution at 200 km swath width out of observation satellite altitudes with narrower spectral bands than used on the current systems. High spectral resolution (up to 20 nm) is feasible at medium spatial resolution (～ 60 m).An experimental airborne scanner has been successfully flown in spring 1978. High-resolution modules development in the visible/NIR is under way and will be flight tested in early 1981.     

The use of remote sensing satellites for verification in international law

This paper examines the use of remote sensing satellites for verification in public international law. Verification always depends on the specific agreement or mission to be verified. There are no general framework rules: the means of verification and the verifying authorities vary from agreement to agreement and from mission to mission. Rapid technological development and the intensifying international cooperation have led to an increasing number of international verification missions. Whereas, in the past, verification was at the heart of intelligence and national services, the commercialization of the remote sensing industry and the information revolution have supported the creation of joint initiatives in this field. Traditionally, verification is associated with disarmament and arms control treaties, but the paper will underline that this is only one field of application for verification missions. It is important to note that there is no binding international regime specifically addressing such activity. The lack of legal certainty in this field also applies to the use of remotely sensed data as evidence in legal proceedings.     

Orbital remote sensing: Space technology applications in South-east Asia

The changing context of space remote sensing applications is described in terms of evolving needs and capabilities in South-east Asia and in terms of recent policy decisions in spacefaring nations. Emphasis is placed on the need for a technology which allows the monitoring of, eg the exploitation and degradation of natural resources, crop development, climatic effects and the like. The implications of policy adjustments in the US LANDSAT programme, including its proposed commercialization, are discussed, and the potential role of other existing and future satellites is reviewed.     

A strategy to study regional hydrology and terrestrial ecosystem processes using satellite remote sensing, ground-based data and computer modeling

This paper describes a multidisciplinary research project which seeks to characterize the terrestrial water cycle and use this characterization to derive simulations of carbon dioxide and methane flux. The water cycle work links interpolated climate fields, macrohydrologic models and Scanning Multichannel Microwave Radiometer datasets. The aim of the analysis is to use output from calibrated water balance models to develop relationships with SMMR datasets. SMMR estimates of surface hydrology can then be evaluated. Both modeled and SMMR datasets will be tested as inputs to regional biogeochemical models. All determinations will be made under climatically-averaged conditions and for 1979–1985, the years for which SMMR data is available.     

Satellite remote sensing in aid of development: the Tunis Declaration

A policy statement of the Centre Régional de Télédétection des Etats de l’Afrique du Nord (CRTEAN) (North African Centre for Remote Sensing) was prepared in the wake of a conference, held in Tunis, on the use of remote sensing to aid development. This report briefly describes the areas covered by the seminar, provides information on the structure and activities of the CRTEAN and reproduces the policy document, known as the Tunis Declaration.     

The analysis of investments in demonstrative small satellite projects for remote sensing

The demonstrative small satellite projects (DSSP) for appreciation of the small satellites (SS) effective use in the perspective national space systems of remote sensing environment, as well as the ozone layer and the near Earth space are considered. The national potential for development, building, launch and missions of SS is discussed. The pecularities of the Russian market of remote sensing informative products and servicies are analysed to specify and stress the significance and perspectives of this market. In view of budget constraints in transitive period from centralized to market economics in Russia the different sources of DSSP financial support are considered.     

Developing countries and remote sensing: how intergovernmental factors impede progress

Developing countries lag significantly behind more advanced nations in the local adoption and application of satellite remote sensing technology. Narrowing this gap through appropriate international cooperation is, however, often constrained by national interests and priorities. The paper presents an overview of several of these inter-governmental constraints using as its main basis the outcomes of recent regional and international conferences hosted by the United Nations. Future enhancement of international cooperation in remote sensing will occur best within settings where both developing and technologically advanced countries are sensitive and responsive to each other's concerns.     

The promise and problems of the land remote sensing policy act of 1992

After nearly a decade of attempting to guide the complex process of land remote sensing in the US, the 1984 Land Remote Sensing Commercialization Act was repealed. In its place, Congress passed the Land Remote Sensing Policy Act of 1992. This action was prompted by what many observers consider a failed attempt at commercialization and the inability of the old law's provisions to meet the compelling needs of scientific research. The new law attempts to address these failures and, in many respects, is successful. Nonetheless it still embodies some of the problems associated with the earlier law. This article compares the provisions of the two laws and provides an analysis of the new law's strengths and weaknesses.     

Some consequences of the commercialization of satellite remote sensing

Remote-sensing technology developments will influence the flow and requirements of remote-sensing data until the end of this century. Sensing-upon-request modes of operation are becoming regular practice and, in combination with commercial sales, are leading to contracts in which copyright clauses and other conditions influence the distribution of remote-sensing data. Moreover, the introduction of programmable and directable sensor systems is making it easier to gather more data over certain areas at the cost of less or none over others, leading to potential indirect censorship. The development of a media market for remote-sensing products also brings a threat of actual censorship on the release and use of imagery. The effects of the technology developments and commercialization policies require a careful consideration of whether or not the present international remote-sensing regime, as governed by the UN principles relating to remote sensing of the Earth from space, can continue unmodified in future.     

Parameterization of surface temperature retrieval for remote sensing experiments

A simple parameterization has been developed for determining the actual surface temperature from the effective brightness temperature measured radiometrically in the 11 μm window region. This algorithm allows the computation of atmospheric correction without performing detailed radiative transfer calculations. Correction due to atmospheric water vapor is represented in terms of the integrated water vapor burden. Correction due to variation of surface emittance is represented in terms of its deviation from unity. Parameteric representation has also been developed for simultaneous variation of both parameters. The parameterization is based on model calculations performed with a line-by-line radiative transfer program. Sensitivity of the retrieved surface temperature to uncertainties of water vapor burden and surface emittance have also been examined.     

中国公务飞行市场发展展望

公务飞行市场是中国民航业中一个新兴的细分市场,该细分市场目前正方兴未艾,虽然现在刚刚起步,但随着中国经济的不断发展其发展潜力不可小觑。可以预测,民航未来发展最快的就将是公务飞行市场。     

Remote sensing of precipitation by a satellite-borne microwave remote sensor

The problem of remote sensing of precipitation by a satellite-borne microwave rain scatterometer is discussed. A downward-looking scanning pencil-beam antenna system is used. The combination of the range-gate method and low side lobe level is used to separate echoes from precipitation layers in the main lobe from ground clutter in the side lobes. Various parameters of the satellite-borne microwave rain scatterometer are calculated and characteristics of systems at 10 and 34.45 GHz are considered. The transmitter peak power needed to observe precipitation with sufficient signal-to noise ratio is calculated by means of the radar equation. The signal (i.e. the received power from the resolution volume of the precipitation) and the received power due to the ground clutter are calculated and the signal-to-clutter ratio is obtained by applying the radar equation. An airborne microwave rain scatterometer is proposed for preliminary experiments.     

Comparison of remote sensing experiments from airborne and space platforms

Recent technological advances in the development of instruments and platforms like aircraft, balloons, satellites, the space station and, very recently, Zeppelin dirigibles, have opened up many new applications for remote sensing. This paper is an attempt to summarise and compare advantages and disadvantages as well as limitations, restrictions and perspectives of passive remote sensing instruments used on the different platforms and it should help to select the best platform for a special application for Earth observation.     

国内外遥感标准现状分析

简介国内外现有遥感标准的状况,并在梳理与分析的基础上,结合我国遥感技术的发展,对我国遥感标准化工作的规划提出发展建议.