The synoptic scale features over the eastern Mediterranean (EM) for July–August are examined using National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis data. The region is subjected to two primary factors: mid–upper level subsidence and lower level cool advection, associated with the Etesian winds. The interdiurnal variations of these factors were found to be correlated with each other, with a maximum of r = 0.76, found between the 700 hPa subsidence and the 925 hPa wind speed. The impact of these factors on the temperature regime was examined through their contributions in the temperature tendency equation at 32.5 °N, 35 °E. A significant correlation was found between them at the 850 hPa level, indicating that they tend to balance each other. This explains the low interdiurnal temperature variations there in summer. Zonal-vertical and isentropic cross-sections indicate the existence of a closed circulation connecting the EM with the Asian monsoon, and a meridional-vertical cross-section indicates a signature of the Hadley cell across eastern North Africa. Air back-trajectories demonstrate that the EM is connected at the lower troposphere with Europe, at the midtroposphere with eastern North Africa and at the higher troposphere with the Asian monsoon. Significant correlation was found between the interdiurnal variations in the upward motion over the Asian monsoon and the subsidence over the Levant, with a 1 day lag, implying that the Asian monsoon controls the interdiurnal variations over the Levant. A detailed analysis shows that the correlation between the two dynamic factors governing the EM results from a linkage existing between each one of them and the Asian monsoon. An intensification of the Asian monsoon enhances both the subsidence over the Levant, via the circulation connecting them, and the Etesian winds, due to the enhanced pressure gradient between the two regions. Copyright  2004 Royal Meteorological Society.

https://www.tau.ac.il/~pinhas/papers/2004/Ziv_et_al_IJC_2004.pdf

The factors governing the summer regime of the eastern mediterranean

This chapter considers a set of issues related to the synoptic climatology of the Mediterranean region (MR). The main Northern Hemisphere teleconnections affecting the MR and their role on temperature, precipitation, and atmospheric cyclones are described. The characteristics of the cyclones in the MR are presented. The role of teleconnections and atmospheric regimes on temperature and precipitation is discussed. The content includes extremes of temperature, precipitation, wind, and storminess (considering also marine aspects such as waves and storm surges).

Climate of the Mediterranean: Synoptic Patterns, Temperature, Precipitation, Winds, and Their Extremes

Mineralogical and chemical characterization of suspended atmospheric particles over the east Mediterranean based on synoptic-scale circulation patterns

[1] “High-ozone days,” defined as days featuring ozone concentrations in excess of 80 ppbv for at least 2 hours over broad geographical regions, were identified for the years 1997 to 2000. The 103 days so obtained were classified into key synoptic-scale types prevailing over the eastern Mediterranean. Analyses of the temporal behavior of ozone mixing ratios during the high-ozone days show that the peak values are more frequent during the transitional (spring and autumn) seasons (65% of 103 days) than during the summer season (35%). These transition season episodes are associated with hot and dry air masses originating east of Israel, where ozone precursor emissions are negligible, indicating that high ozone levels are more dependent on air mass characteristics than on upwind precursor emissions. A comparison of the spatial distribution of background concentrations (defined as those measured at 0600 LST) for “high-ozone days” and for unstable winter days revealed little spatial variation for the winter cases, whereas a significant and consistent spatial variation existed for the high-ozone cases regardless of circulation type. This finding suggests that ozone background concentrations are more affected by seasonal variation than by spatial variation. In addition, distinctive patterns of diurnal variations were found to be related to synoptic-scale circulation type and geographical region.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002JD002147

Relationship between synoptic‐scale atmospheric circulation and ozone concentrations over Israel

A 3-yr dataset (February 2000–November 2002) of 30-min averages for particulates, visibility, and meteorological data were analyzed to examine the dependence of particulate matter of less than 10 μm in diameter (PM10) mass concentrations and visibility in Tel Aviv, Israel, on seasonal meteorological conditions, synoptic weather patterns, and airmass history. The persistent nature of the summer synoptic weather pattern in the east Mediterranean (EM) region yielded the highest mean visibility (35 km) and lowest variability in PM10 concentrations, as compared with the higher variance for the other seasons, and spring in particular. The frequent passage of the “Sharav” cyclones during spring causes natural dust outbreaks with extreme values that result in a much higher PM10 annual mean (57 μg m−3) as compared with other larger cities. The history of the air mass dictating the physical and chemical properties of the particulate matter reaching Israel was assessed by back-trajectory analysis from prede...

J. Koch

Papers

A synoptic analysis of the meteorological conditions affecting dispersion of pollutants emitted from tall stacks in the coastal plain of Israel

Atmospheric conditions leading to buildup of benzene concentrations in urban areas in Israel