Quantitative analysis of summer air masses in the eastern United States and an application to human mortality

Abstract

A recently developed continental-scale air mass-based classification is used to identify the spatial occurrences of 6 air masses (dry polar, dry temperate, dry tropical, moist polar, moist temperate, and moist tropical) in the eastern United States for summer from 1961 to 1990. This procedure, the spatial synoptic classification (SSC), is based on 'seed' day identification of synoptic events and discriminant analysis to group days together which are within the same air mass type. Thus, the evaluation of the frequency and modification of air masses across a large region is possible. Using the SSC, maps of air mass frequencies and afternoon temperatures and dew points are developed. Rates of modification are determined as each air mass traverses the region. As an example of the environmental applicability of the SSC, the impact of climate upon human mortality is analyzed at 3 climatically different locations (New Orleans, LA; Memphis, TN; and Chicago, IL). Results show how the day-to-day mortality fluctuations are sensitive to air mass type. A particular air mass which is associated with distinctly high mortality is identified for Memphis and Chicago; no such air mass is apparent for New Orleans, where the weather/mortality signal is very weak.

Extreme summer temperatures in Iberia: health impacts and associated synoptic conditions

“…In recent years, one of the most promising methodologies has focused on the establishment of robust links between different air-mass types or atmospheric weather situations, and the associated effects on human health at a local or regional scale. Most applications were developed for sites located in the USA (Kalkstein, 1991;Kalkstein and Smoyer, 1993;Greene and Kalkstein, 1996), including a warning system for the Philadelphia area . Similar approaches have now been adapted to other regions, such as England (McGregor et al, 1999) and Australia (Guest et al, 1999).…”

An Evaluation of Climate/Mortality Relationships in Large U.S. Cities and the Possible Impacts of a Climate Change

“…Thus, this new procedure will permit an interregional comparison of high risk air masses, something that has never been attempted before. It (24).…”

“…Initial estimates of these criteria are specified for each air mass at each location after careful evaluation of surface meteorological data and maps, and days that satisfy the criteria are selected to represent seed days for the air mass. These seed days are used to classify all other days, and a number of seed days for each air mass is used to develop a robust sample of the typical character of each air mass at each location (23,24).…”

“…Because the goal is to classify each day into one of the pre-existing air masses described above and to use the seed day means as input into the classification, discriminant function analysis was selected as the appropriate classification tool (25,26 At many locations in summer, MT air accounts for over 50% of the total daily occurrences (24); thus, the MT airmass was subdivided using the procedures described above into three subcategories designated MT1, MT2, and MT3. The (21).…”

Climate change, climate justice and the application of probabilistic event attribution to summer heat extremes in the California Central Valley

“…Variables examined include the total number of days in a month with maximum temperatures exceeding 40.6°C (Luber and McGeehin 2008), heat stress due to high relative humidity (Knowlton et al 2009) and nighttime temperatures Greene and Kalkstein 1996). Heat stress has been found to be especially important in terms of societal impact in recent studies (Mastrangelo et al 2006) and has been applied within the context of PEA (Sippel and Otto 2014).…”