Changing Temperature Inversion Characteristics in the U.S. Southwest and Relationships to Large-Scale Atmospheric Circulation
نویسندگان
چکیده
Continental temperature inversions significantly influence air quality, yet little is known about their variability in frequency and intensity with time or sensitivity to dynamical changes with climate. Inversion statistics for six upper-air stations in the American Southwest are derived for the period 1994–2008 from radiosonde data reported by the Global Telecommunication System (GTS) and National Climatic Data Center (NCDC), which use different significant level standards. GTS data indicate that low-level elevated inversions have increased in frequency at four of six sites, consistent with enhanced regional stagnation projected by models. NCDC data, in contrast, show remarkable declines in weak, near-surface inversions through 2001, indicating local surface conditions may counteract atmospheric dynamics in regulating inversion activity and air quality. To further test the sensitivity of inversion activity to climate, associations between wintertime inversion frequency and largescale circulation are quantified using the self-organizing map technique. Twenty-four representative circulation patterns are derived from North American Regional Reanalysis (NARR) 500-hPa geopotential height fields, and these patterns are correlated with inversion frequency at each site. Inversion activity in Salt Lake City, Utah, and Albuquerque and Santa Teresa, New Mexico, is found to correspond well with large-scale anticyclonic ridging; however, sensitivities to large-scale circulation in Denver, Colorado, and Flagstaff and Tucson, Arizona, are weak. Denver stands out in exhibiting a higher percentage of near-surface inversions in winter than the other southwestern sites. These findings indicate that dynamical changes with climate will not uniformly influence inversions and hence urban air quality conditions in the American Southwest.
منابع مشابه
Study of the models of large-scale atmospheric circulation system model on intesify rainfall in Ardebil plain
Atmospheric circulation is important to determine the surface climate and environment, and affect regional climate and surface features. In this study, to quantify its effect, the classification system, developed by Lamb is applied to obtain circulation information for Ardabil, North West Province in Iran, on a daily basis, and is a method to classify synoptic weather for study area. For that p...
متن کاملبررسی نقش گـردش منطقهای جو بر روی خـاورمیانه در وقـوع تـوفانهای
1- Introduction In middle and lower troposphere, the main control factor of weather and climate over the Middle East is a local to regional scale thermal forcing including forcing from high mountains. In this regard, regional scale atmospheric circulation associated with surface forcing has an important role in the occurrence of summer dust storms over the area. Southwest of Iran experiences a...
متن کاملبررسی همدیدی روزهای بسیار آلوده درشهرمشهد مورد مطالعه: 13و14نوامبر2007
For a synoptic analysis of high polluted days in 13 and 14 November 2007, a combinatorial synoptic analysis was used. From methodology prospect, the present study has utilized the "circular environment" synoptic approach and with respect to the restrictions on very high-polluted days in Mashhad city, the subjective synoptic analysis used for data processing and analyzing the prevailin...
متن کاملLarge-scale atmospheric circulation patterns associated with the occurrence of severe storms Zab basin
متن کامل
Winter Nighttime Temperature Inversions and Their Relationship with the Synoptic-scale Atmospheric Circulation
The present work aims at examining the association of nighttime temperature inversions and synoptic-scale circulation in the Athens basin. Temperature inversions have a direct impact in the diffusion and transport of pollutants, a fact that highlights the importance of investigating their cause effect relationship. For this purpose, randiosonde measurements from the upper-air station in Hellini...
متن کامل