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John E. Pearson, Donald H. Rimbey, and Gary E. Jones

Abstract

The transfer of various gases through the soil-atmosphere interface is of interest to agronomists, meteorologists, biologists and many others. Such gases include carbon dioxide, water vapor and radon. A system applicable to measurements of the emanation of gases has been developed and used to investigate the emanation of radon-222. The instrumentation was designed so that the variation of soil gas emanation with time, wind speed, soil moisture, soil type, and geographical location could be studied. The system has measured a net transport through the earth-atmosphere interface of 1.1±0.6 atoms of radon-222 per square centimeter per second (mean of 27 means, eight samples each, ± standard deviation of 27 means). For a set of eight samples collected on a given site, the coefficient of variation was 0.3 to 0.4. The analysis of a single sample provided the amount of radon-222 collected with an error of about 5 per cent.

The system is completely portable, including the power supply, and can be carried from a vehicle by two men. It was designed to minimize disturbance of the site at all times, providing air flow and pressure within the collecting apparatus comparable to those in nature during sampling. Sampling sites can be chosen as desired, and all equipment can be removed from the site when sampling is completed. During a sampling trip to the Rocky Mountains, the equipment was transported 3000 miles without any breakage. Throughout an experiment on the diurnal variation of radon emanation, two duplicate systems were operated 12 hours each without difficulty.

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Roland J. Viger, Lauren E. Hay, Steven L. Markstrom, John W. Jones, and Gary R. Buell

Abstract

The potential effects of long-term urbanization and climate change on the freshwater resources of the Flint River basin were examined by using the Precipitation-Runoff Modeling System (PRMS). PRMS is a deterministic, distributed-parameter watershed model developed to evaluate the effects of various combinations of precipitation, temperature, and land cover on streamflow and multiple intermediate hydrologic states. Precipitation and temperature output from five general circulation models (GCMs) using one current and three future climate-change scenarios were statistically downscaled for input into PRMS. Projections of urbanization through 2050 derived for the Flint River basin by the Forecasting Scenarios of Future Land-Cover (FORE-SCE) land-cover change model were also used as input to PRMS. Comparison of the central tendency of streamflow simulated based on the three climate-change scenarios showed a slight decrease in overall streamflow relative to simulations under current conditions, mostly caused by decreases in the surface-runoff and groundwater components. The addition of information about forecasted urbanization of land surfaces to the hydrologic simulation mitigated the decreases in streamflow, mainly by increasing surface runoff.

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NPOESS

Next-Generation Operational Global Earth Observations

Thomas F. Lee, Craig S. Nelson, Patrick Dills, Lars Peter Riishojgaard, Andy Jones, Li Li, Steven Miller, Lawrence E. Flynn, Gary Jedlovec, William McCarty, Carl Hoffman, and Gary McWilliams

The United States is merging its two polar-orbiting operational environmental satellite programs operated by the Department of Commerce and the Department of Defense into a single system, which is called the National Polar-orbiting Operational Environmental Satellite System (NPOESS). During the next decade, NPOESS will provide global operational data to meet many of the needs of weather forecasters, climate researchers, and global decision makers for remotely sensed Earth science data and global environmental monitoring. The NPOESS Preparatory Project (NPP) will be launched in 2011 as a precursor to NPOESS to reduce final development risks for NPOESS and to provide continuity of global imaging and atmospheric sounding data from the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) missions. Beginning in 2014, NPOESS spacecraft will be launched into an afternoon orbit and in 2016 into an early-morning orbit to provide significantly improved operational capabilities and benefits to satisfy critical civil and national security requirements for space-based, remotely sensed environmental data. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Meteorological Operation (MetOp) spacecraft will complement NPOESS in a midmorning orbit. The joint constellation will provide global coverage with a data refresh rate of approximately four hours. NPOESS will observe more phenomena simultaneously from space and deliver a data volume significantly greater than its operational predecessors with substantially improved data delivery to users. Higher-resolution (spatial and spectral) and more accurate imaging and atmospheric sounding data will enable improvements in short- to medium-range weather forecasts. Multispectral and hyperspectral instruments on NPOESS will provide global imagery and sounding products useful to the forecaster that are complementary to those available from geostationary satellites. NPOESS will support the operational needs of meteorological, oceanographic, environmental, climatic, and space environmental remote sensing programs and provide continuity of data for climate researchers. This article that describes NPOESS was completed and accepted for publication prior to the White House decision in February 2010 ordering a major restructuring of the NPOESS program. The Department of Commerce will now assume primary responsibility for the afternoon polar-orbiting operational environmental satellite orbit and the Department of Defense will take primary responsibility for the early morning orbit. However, NPP, as described in this article, is still scheduled to be launched in 2011. Several of the instruments and program elements described in this article are also likely to be carried forward into future U.S. polar-orbiting operational environmental satellite missions.

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