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This paper examines year-to-year variations in the large-scale summertime hydrologic cycle over the southwestern United States using a suite of regional model simulations and surface- and upper-air-based observations. In agreement with previous results, it is found that observed interannual precipitation variations in this region can be subdivided into two spatiotemporal regimes—one associated with rainfall variability over the southwestern portion of the domain centered on Arizona and the other associated with variations over the southeastern portion centered on western Texas and eastern New Mexico. Because of the limited duration of the model simulation data, it is possible to only investigate one positive rainfall season over the Arizona region and one negative rainfall season over the New Mexico region. From these investigations it appears that for the positive rainfall anomalies over Arizona excess seasonal precipitation is balanced by both enhanced evaporation and vertically integrated large-scale moisture flux convergence. Vertical profiles of these terms indicate that the anomalous large-scale moisture flux convergence is actually related to a decrease in the mean large-scale moisture flux divergence aloft; below 800 mb there is a decrease in the mean moisture flux convergence typically found at these levels, which in turn produces anomalous moisture divergence from the region. For the negative rainfall anomalies over New Mexico similar results, but of opposite sign, are found; one exception is that at the lowest levels there is an additional (negative) contribution to the vertically integrated moisture flux convergence anomaly related to a weakening of the mean low-level moisture flux convergence during the low-rainfall year. Further studies using two different model simulations with the same large-scale dynamic forcing but differing initial soil moisture values indicate that similar balances are also found for rainfall anomalies related to surface soil moisture changes within the domain, suggesting that the changes in large-scale moisture flux convergence described above can be attributed to both year-to-year variations in the regional land–atmosphere interactions as well as variations in the large-scale circulation patterns. [ABSTRACT FROM AUTHOR]

Abstract: Saccharide compositions were measured in ambient particulate matter (PM) samples collected at four sites in Eastern Texas and Central Arizona in an effort to assess the contribution from biomass burning, atmospheric entrainment of soil, and primary biological aerosol particles (PBAPs) in regions with different climate patterns and ecosystems. In spite of the concentration difference, samples from the four study sites showed similar saccharide composition and seasonal variation, with the only exception being trehalose, likely resulting from the influence of local climatic conditions. Comparison of samples at the Arizona site showed different saccharide enrichment patterns between PM2.5 and PM10, which is consistent with their proposed sources as determined by a correlation analysis between observations. A positive matrix factorization (PMF) model was used to resolve three saccharide-related source factors and their relative source contributions to ambient PM using saccharides as tracers. Both the correlation and PMF model results indicate a stronger influence from local biogenic sources on aerosol saccharides at the rural sites than the urban site in Texas, and a greater impact from the PBAP and other biologically derived sources for PM collected in the Arizona location. This paper will provide the first analysis of saccharides in both fine and coarse PM in two US regions with dramatically different climates and ecosystem and provide a characterization of the ambient aerosol sources. [Copyright &y& Elsevier]

The article offers information related to the growth of freestanding emergency departments (ED) in the U.S. It mentions that growth has been spurred by a variety of factors including overcrowded hospital-based EDs, expanding demands for emergency care, a desire by health care systems to create satellite locations to attract patients, health care entrepreneurship, and evolving state rules that have made it easier in some localities to open them.