Analytical search for the stochastic-dominating process in the drift- deposition problem

The random processes in the drift-deposition problem are examined separately to see if any one of them dominates the statistical properties of the outcome. The three prime candidates are assumed to be the drop size distribution, the distribution of break-away points, and turbulent diffusion. It is seen that the drop size distribution probably has dominant infiuence on the deposition of the large-size (drift or carry-over) drops. Turbulence has a comparable iniluence on the deposition of the small drops for downwind distances of the order of 10 tower heights and then dominates for large downwind distances, provided the atmosphere is not stable. Uncertainties in details of how the drops break free from the plume's updraft preclude an accurate evaluation of this effect and seriously limit the accuracy of any drift-deposition prediction. To remedy this, more field data is needed. (auth

Atmospheric sciences transfer between research advances and energy-policy assessments (ASTRAEA). Final report, 1 April 1996--31 December 1997

Consistent with the prime goal of the ASTRAEA project, as given in its peer-reviewed proposal, this final report is an informal report to DOE managers about a perceived DOE management problem, specifically, lack of vision in DOE`s Atmospheric Chemistry Program (ACP). After presenting a review of relevant, current literature, the author suggests a framework for conceiving new visions for ACP, namely, multidisciplinary research for energy policy, tackling tough (e.g., nonlinear) problems as a team, ahead of political curves. Two example visions for ACP are then described, called herein the CITIES Project (the Comprehensive Inventory of Trace Inhalants from Energy Sources Project) and the OCEAN Project (the Ocean-Circulation Energy-Aerosol Nonlinearities Project). Finally, the author suggests methods for DOE to provide ACP with needed vision

Relationships between removal processes and residence times for atmospheric pollutants

This report is concerned with improving estimates for the residence times of atmospheric trace constituents in various atmospheric reservoirs. Residence times are defined only for steady-state conditions; i.e., when the net growth rate vanishes. The most useful case of vanishing net growth rate is when the total growth rate is equal to the decay rate. It is demonstrated that the most important advance towards improving estimates of pollutant residence times is through proper choices of reservoirs. Chosen reservoirs should possess the following features: steady-state conditions, uniform mixing ratio throughout or throughout specified subreservoirs, and subreservoirs chosen in which removal rates can be treated as approximate constants. An example of a poorly mixed reservoir, the stratosphere, is discussed. In another example, it is suggested that commonly used reservoirs for atmospheric CO/sub 2/ have been chosen poorly and that a substantial portion of the anthropogenic CO/sub 2/ released during the past 50 years may still be mixing into the stratosphere. In another example, it is suggested that determination of the dry deposition velocity for accumulation-mode aerosol particles may not be so important as previously thought. To improve estimates for the atmospheric residence times of these particles, it is important to increase knowledge of what is called the ascension velocity

Buoyant plume model for pedestrians

Equations for the steady-state rise of a buoyant plume are derived directiy from the conservation laws for mass, momentam and energy. Top-hat profiles are used and it is assumed that there is no horizontal pressure gradient across the plume's boundary. In the resulting equations there are four unspecified quantities: the drag and heat transfer coefficients, the entrainment velocity and heat production. Results are shown for the (isentropic) case when all these quantities are zero as well as for cases with various combination of these quantities different from zero and using simple relaxation models. In this way some insight is gained into their separate eftects on the plume's propenties. Results of a simple model to account for a mean wind are also demonstrated. The need for more field data is obvious. (auth

Scavenging ratios based on inflow air concentrations

Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data