Alternative Energy Sources The issues involved in determining alternative energy sources for Antarctica are integrally related to the energy needs. During the Antarctic summer the population is the highest and the power needs are the greatest. During the six months of winter the power needs are at their lowest. Thus the alternatives to be considered at these two different times may also be different. Alternative energy sources usually include not only solar, but also biomass, water, geothermal and wind. Ground-based solar energy using photovoltaic technologies is under current consideration for the summer months [Wills, 1988], but during the winters, solar cells are not feasible so other renewable sources should be considered. Water and biomass can be eliminated quickly as ice is the primary characteristic of Antarctica; biomass not only has a low energy density but would also have to be shipped in at a cost and disposed of. [Broman, 1991] suggests that the McMurdo sound area could use geothermal energy but only during the winter. This is expensive to realize with drilling and machinery to deal with the high ionization of resulting water. Wind may be the most viable option as velocities can reach up to 320 km per hour [Dalby, 1992] and this option will probably be explored in the next few years. The current concern with wind power is the durability of the equipment, especially in the extreme conditions of Antarctica. If it proves to be a cost-efficient environmental alternative it may overtake solar power as the preferred option. Though currently, solar power seems to have the most potential for the summer months. Effects of Beamed Power (Scientific Measurement) In our study we are interested in the transmission from a space platform to the Earth's surface. Problems dealt with in this demonstration allow the correlation between the microwave beam and the atmospheric gases which govern the radiation exchanges in the terrestrial atmosphere (mainly CO2, CH4, etc.,) with important consequences in determining any change in the greenhouse effect. Therefore it is essential to monitor the following parameters in the presence and the in absence of the microwave beam: Column content and vertical profile of ozone, temperature, vertical profiles of CIO and H2O, profiles and vertical distribution of aerosols and NO2, column contents of NO2 and HC1, vertical profiles of CH4, N2O, HNO3, CIO, NO2, OH, and the electron density in the ionosphere. These measurements are being done on a continuing basis by a number of satellites, and good baseline figures are now available. One example is the Upper Atmosphere Research Satellite (UARS) which was launched on the September 12, 1991. Its main objectives are to perform simultaneous, comprehensive measurements of the Earth's stratosphere, mesosphere and lower thermosphere, for investigations of energetic, chemical composition and dynamics. In Table 10.3.1 is a list of the detectors that are onboard the UARS and their main functions. From a scientific standpoint, Antarctica is an appropriate place for a space to Earth microwave beam since there are similar ground-based measurements already in place. Another reason is based on a sun-synchronous orbit for the spacecraft which would enable measurements about every two hours over Antarctica. Finally, the fact that there is darkness six months of the year over Antarctica makes the measurements during this time period a more reliable estimate of beam effects on the atmosphere as sunlight would be absent. Table 10.3.1 Detectors on UARS and their main function [Kendall, 1992], INSTRUMENT DESCRIPTION MEASUREMENT OBJECTIVES CLAES: Cryogenic Limb Array Etalon Spectrometer Scanning spectrometer sensing atmospheric infrared emissions in the spectral range 3.5-12.7 microns Concentrations of members of the N and Cl families, O3, H2O, CH4, and CO2 at altitudes of 10-60 km: atmospheric temperature profiles for indirect wind measurements ISLAMS: Improved Stratospheric and Mesospheric Sounder Radiometer sensing atmospheric infrared emissions in the spectral range 4.6-16.6 microns Atmospheric temperature structure and variability: minor constituent distributions including the N family, water, methane carbon monoxide, and ozone
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