Mass-based Approach Research Articles

A determination of character and frequency changes in air masses using a spatial synoptic classification

Of the numerous climate change studies which have been performed, few of these have analyzed recent trends using an air mass-based approach. The air mass approach is superior to simple trend analysis, as it can identify patterns which may be too subtle to influence the entire climate record. The recently-developed ‘spatial synoptic classification’ (SSC) is thus used to identify trends over the contiguous United States for summer and winter seasons from 1948 to 1993. Both trends in air mass frequency and character have been assessed. The most noteworthy trend in frequency is a decline in air mass transitional days (TR) during both seasons. In winter, decreases of up to 1% per decade are noted in parts of the central U.S. Other notable trends include a decrease in moist tropical (MT) air in winter, and an increase in MT in summer over the southeastern states. Numerous national and local air mass character changes have been uncovered. A large overall upward trend in cloudiness is noted in summer. All air masses feature an overnight increase, yet afternoon cloudiness increases are generally limited to the three ‘dry air masses’. Also in summer, a significant warming and increase in dew point of MT air has occurred at many locales. The most profound winter trend is a large decrease in dew point (up to 1.5°C per decade) in the dry polar (DP) air mass over much of the eastern states. © 1998 Royal Meteorological Society

An air mass-based approach to regional GCM validation

An air mass-based approach to regional GCM validation

Detecting Structural Climate Change: An Air Mass-Based Approach in the North Central United States, 1958–1992

Abstract Empirical climate change studies are more beneficial when they go beyond simply reporting fluctuations in average temperature. Ideally, dynamic causes of the change should also be addressed. This strategy allows conceptual models of the associated physical-change mechanisms to be developed. The analysis of air masses can play a central role in this approach. Changes in their distribution and characteristics point to modifications in the mid-latitude general circulation. The integrated method air-mass classification scheme was applied to this problem in the north central United States (NCUS) over the 1958–1992 period. Monthly averages for relative frequency, 850-hPa temperature, and 850-hPa dewpoint temperature were calculated for every air mass in each season. There were major changes over the study period during spring and summer and minor changes in the other two seasons. In winter, northern stations showed a slight warming of continental (equivalent to continental polar) air. During spring, tr...

Hazardous Waste Reduction — Measurement of Progress

Measuring progress on a national basis for the reduction in hazardous waste generated has been carefully examined. A successful measurement must follow the decision-making basis by which industry adopt such changes in order to adequately reflect the pace of waste reduction. Mass-based approaches are useful in some evaluations of priorities, but are inadequate and produce major anomalies in reporting. Thus a measurement approach was developed to focus on the potential for cost-effective waste reduction and then the rate of accomplishment of that potential by industry. The economic-based concept was found to correct the substantial anomalies inherent in a mass-based approach. The new methodology is suitable for use by individual industry and can maintain a certain level of proprietary control.