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doi: 10.1175/1520-0477(1999)080<0805:AROCSE>2.0.CO;2pmid: N/A
Water is one of the most basic commodities on earth sustaining human life. In many regions of the world, traditional sources and supplies of ground water, rivers and reservoirs, are either inadequate or under threat from ever-increasing demands on water from changes in land use and growing populations. This has prompted scientists and engineers to explore the possibility of augmenting water supplies by means of cloud seeding.This paper provides an overview of the current scientific status of weather modification activities to enhance precipitation for both glaciogenic and hygroscopic seeding experiments. It is important to emphasize that although funding for scientific studies has decreased substantially during the past decade, operational programs have actually increased.During the last 10 years there has been a thorough scrutiny of past experiments involving experiments using glaciogenic seeding. Although there still exist indications that seeding can increase precipitation, a number of recent studies have questioned many of the positive results, weakening the scientific credibility. As a result, considerable skepticism exists as to whether these methods provides a cost-effective means for increasing precipitation for water resources.Recent results from hygroscopic seeding experiments provided for some renewed optimism in the field of precipitation enhancement. Although promising results have been obtained to date, some fundamental questions remain that need to be answered in order to provide a sound scientific basis for this technology.
Changnon, Stanley A.; Kunkel, Kenneth E.
doi: 10.1175/1520-0477(1999)080<0821:REUOCD>2.0.CO;2pmid: N/A
During the last 20 years the use of climate data and information in agriculture and water resources has increased dramatically. This has resulted from vastly improved access to comprehensive datasets and climate information made available by wide use of personal computers, as well as ease of access due to Internet connections to computer systems containing specially developed climate databases and information packages. Furthermore, the recent development of better, more sophisticated information about how climate conditions affect various physical conditions and economic outcomes has enabled more informed decisions by managers, who, in turn, developed a greater awareness of how to utilize climate information. The demand for information has grown as a result of increasing economic pressures and because certain agricultural and water management activities and their infrastructure have become more sensitive to certain climate aberrations. These factors have led to the development of new suppliers of data and information, including regional climate centers to handle the quick assembly of updated databases, and the expansion of the private sector into the provision of specialized climate information needed by a wide variety of users. Key new uses relate to near-real-time access to constantly updated interpreted data and to availability of sophisticated information products relating current and future climate conditions to specific outcomes. In sum, these advances represent major improvements in the service of atmospheric sciences to the nation, helping to improve the economy and environmental management.
doi: 10.1175/1520-0477(1999)080<0831:TGEBA>2.0.CO;2pmid: N/A
The energy fluxes at the earth's surface determine, to a great extent, the thermal conditions and the circulation of the atmosphere. Accurate energy flux measurements, therefore, are essential for understanding (i) the formation of the present climate and (ii) the climatic changes of the past and the future.The Global Energy Balance Archive (GEBA) database currently stores 220 000 energy flux monthly means that have been measured at 1500 stations at the earth's surface. The station histories (i.e., records of known changes in instrumentation, data evaluation procedures, and data publication standards) are also stored in the GEBA database. Quality control procedures are applied to the energy flux data and energy flux data suspected of being afflicted with error are flagged. The GEBA database enables the efficient production of datasets for use in climate research.GEBA datasets have been successfully used for the reevaluation of the energy balance at the earth's surface, validation of remote sensing algorithms, validation of surface energy fluxes simulated by general circulation models, investigation of the absorption of solar radiation by clouds, and evaluation of the impact of aerosols stemming from biomass burning in equatorial regions.The GEBA database has been redesigned since 1994. This redesign included removal of contradictions in the station history data, updating of the global radiation data, and enhancement of the quality control of global radiation data. The GEBA data were made available on the Internet in October 1997.
Dirmeyer, Paul A.; Dolman, A. J.; Sato, Nobuo
doi: 10.1175/1520-0477(1999)080<0851:TPPOTG>2.0.CO;2pmid: N/A
The Global Soil Wetness Project (GSWP) is an ongoing land surface modeling activity of the International Satellite Land-Surface Climatology Project (ISLSCP), a part of the Global Energy and Water Cycle Experiment. The pilot phase of GSWP deals with the production of a two-year global dataset of soil moisture, temperature, runoff, and surface fluxes by integrating uncoupled land surface schemes (LSSs) using externally specified surface forcings from observations and standardized soil and vegetation distributions. Approximately one dozen participating LSS groups in five nations have taken the common ISLSCP forcing data to drive their state-of-the-art models over the 198788 period to generate global datasets. Many of the LSS groups have performed specific sensitivity studies, which are intended to evaluate the impact of uncertainties in model parameters and forcing fields on simulation of the surface water and energy balances. A validation effort exists to compare the global products to other forms of estimation and measurement, either directly (by comparison to field studies or soil moisture measuring networks) or indirectly (e.g., use of modeled runoff to drive river routing schemes for comparison to streamflow data). The soil wetness data produced are also being tested within general circulation models to evaluate their quality and their impact on seasonal to interannual climate simulations. An Inter-Comparison Center has also been established for evaluating and comparing data from the different LSSs. Comparison among the model results is used to assess the uncertainty in estimates of surface components of the moisture and energy balances at large scales and as a quality check on the model products themselves.
doi: 10.1175/1520-0477-80.5.879pmid: N/A
The National Science Foundation Young Scholar Program The Excitement of Meteorology successfully brought the atmospheric and related sciences to high school students in Mississippi. The four-week summer program was administered through the Jackson State University Meteorology Program in the Department of Physics, Atmospheric Sciences, and General Science and was supported by the Mississippi Science Partnership program office. This commuter program provided an opportunity to learn, study, and research the field of meteorology. Through instructional sessions, laboratories, field trips, and peer contact participants were exposed to the concepts of atmospheric motion, the development of storms, and the practical application of meteorology during a one-month period. The program was intended to help students make their own career decisions and to foster their interest in the sciences and meteorology. The goals and objectives of the program were to develop basic science skills; make participants aware of the interdisciplinary nature of meteorology; provide participants with the opportunity to see and hear the meteorologist as a researcher, teacher, and communicator; provide the information and incentive necessary for participants to choose a career in meteorology or the sciences; make participants aware of the various employment opportunities in the field; and show the moral and ethical responsibilities and importance of atmospheric science to society. Thirty sophomore and junior high school student participants (22 females and 8 males, nearly all of whom were AfricanAmerican) completed the program. All were tested on their meteorological knowledge and skills gained during the program and questioned about their field and lecture experiences. They also graded the effectiveness of all speakers, presentations, videotapes, and laboratory sessions. Through surveys it was found that the participants' desire to pursue a science career and to go to college were increased by the program. They also indicated that the program objectives had been met and that the program had met their expectations. They were particularly pleased with the opportunity to work in a college setting and with professional scientists.
Schmetz, Johannes; Hinsman, Donald; Menzel, W. Paul
doi: 10.1175/1520-0477-80.5.893pmid: N/A
The Fourth International Winds Workshop (IWW4) was held in Saanenmoeser, Switzerland, from 20 to 23 October 1998. The workshop was organized by the European Organisation for the Exploitation of Meteorological Satellites, and the World Meteorological Organization was the local host. IWW4 followed previous meetings convened in Washington, D.C., in September 1991; Tokyo, Japan, in December 1993; and Ascona, Switzerland, in June 1996. The International Winds Workshop convenes the International Winds Working Group, which communicates with the Coordination Group for Meteorological Satellites on issues of importance regarding wind derivation from satellites. It provides a forum for data producers and users to share information on the characteristics of satellite-tracked winds and to optimize their use in several applications, especially numerical weather prediction. This report describes the proceedings of the Fourth International Winds Workshop and includes recommendations.
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