The present volume reviews several of the currently important questions and presents detailed reports from investigators all over the continent.
As such, it provides insight into the current scientific views about ozone in Europe. Would you like to tell us about a lower price? If you are a seller for this product, would you like to suggest updates through seller support? Read more Read less. From the Back Cover One of the principal concerns in recent years regarding the atmospheric environment has been the formation of ozone and other photo-oxidants over much of Europe in the summer.
Read more. No customer reviews. Share your thoughts with other customers. Write a customer review. Amazon Giveaway allows you to run promotional giveaways in order to create buzz, reward your audience, and attract new followers and customers.
Forschungszentrum Jülich - JSC Staff - Martin Schultz's publications
Learn more about Amazon Giveaway. Set up a giveaway.
- Tropospheric Ozone Research: Tropospheric Ozone in the Regional and Sub - Google Libros;
- Global distribution and trends of tropospheric ozone: An observation-based review.
- Costas Varotsos | National & Kapodistrian University of Athens - quedoormerkfimart.cf;
- Global distribution and trends of tropospheric ozone: An observation-based review;
- Catholic Roots and Democratic Flowers: Political Systems in Spain and Portugal.
Despite the fact that higher average temperatures are associated with higher rates of ozone production, if the large-scale pressure pattern shifted such that the East Coast were preferentially under a trough in the early summer, that region would likely experience reduced concentrations of ozone. Unfortunately, although general circulation models predict a shift in the large-scale ridge-trough pattern associated with global warming, no two models predict the same shift in patterns, and none of the predictions of pattern shifts should be viewed with confidence.
Unfortunately, the preferred pressure ridge-trough pattern is unpredictable for periods beyond about 10 days. As a result, ozone concentrations cannot be predicted for longer periods.
- A Companion to the Ancient Near East.
- Youth, Pornography and the Internet;
- Stress and Distress among the Unemployed: Hard Times and Vulnerable People (Springer Studies in Work and Industry).
- 2. Tropospheric ozone: background information.
- Cloe - Angel With Attitude.
In the eastern United States, high concentrations of ozone in urban, suburban, and rural areas tend to occur concurrently on scales of over kin. This blanket of ozone can persist for several days, and the concentrations can stay high greater than 80 ppb for several hours each day. The major characteristics of episodes of high ozone concentration in the East were identified first during rural field studies sponsored by EPA from to RTI, ; Decker et al. Ozone concentrations above 80 ppb were found for several consecutive days over areas larger than , km 2.
The episodes generally were associated with slow-moving, high-pressure systems, when the weather was particularly favorable for photochemical formation of ozone; there were warm temperatures, clear skies, and light winds. The highest ozone concentrations often were found on the trailing side of the center of the high-pressure system. These early studies showed that average. Subsequent case studies documented the occurrence of high concentrations of ozone in the Midwest, Northeast, South, and on the Gulf Coast Vukovich et al.
High concentrations are found throughout the atmospheric boundary layer when such conditions occur e. Some of the highest concentrations of ozone are found in plumes of pollutants downwind of urban and industrial areas. Studies that use surface and aircraft data have shown that the high concentrations are superimposed on elevated background concentrations during high-ozone episodes. The higher background concentrations are presumably due to enhanced photochemical production of natural and anthropogenic ozone in the warm, cloud-free conditions that characterize such episodes. The plumes may maintain their integrity for 12 hours, and they can cover an area larger than by 50 km; the length of a plume is typically three times its width White et al.
Small cities approximately , population can generate ppb ozone over background concentrations Spicer et al. Concentrations found in plumes from larger cities St. Louis, Boston, Chicago, or Baltimore are more typically elevated by ppb over background White et al. The most extreme cases, where concentrations are ppb higher than background, are found over Connecticut, downwind of the New York-New Jersey industrial and metropolitan area Rubino et al.
Plume studies were reviewed by EPA a and Altshuller Analyses of data from rural sites in the United States have focused on the seasonal and diurnal behavior of ozone and the frequency distributions of its concentration RTI, ; Decker et al. The annual cycle of monthly mean and monthly maximum values of ozone and the diurnal cycle in July are shown in Figure for typical rural sites in the eastern and western United States. Cumulative probability distributions providing percentile rank scores for April 1 to Sept.
Concentrations of ozone are highest in spring and summer, and average values are similar at all sites, about ppb. Monthly maximum concentrations the average of the daily maxima are much higher at the SURE sites in the East, however, than at remote sites in the West, ppb versus ppb. The higher maxima are not reflected in the daily average values because the diurnal variation is much more pronounced at most of the eastern sites, with lower minima compensating for higher maxima.
Values within a few ppb of the daily maximum persist for h, from late morning until well into the evening at some sites. Western sites affected by urban plumes also can show concentrations over 80 ppb Fehsenfeld et al. The highest concentrations are observed at the central and eastern rural sites influenced by major urban and industrial sources of pollution those in northern Indiana, Pennsylvania, Delaware, and Massachusetts in this case ; high concentrations are less common at the more remote central and eastern sites in Wisconsin, Louisiana, and Vermont.
Daily maximum concentrations of ozone for all of are shown in Figure for four rural sites within km of one another in the northeast. The high concentrations usually occur in periods a few days long, and high- and low- ozone days tend to occur concurrently. Ozone concentrations stay elevated for several hours each day during the high periods.
Variations in ozone concentrations were highly correlated over distances of several hundred kilometers, and the highest concentrations tended to occur concurrently, or within days of one another, at widely separated stations. Daily maximum ozone concentrations exceeded 90 ppb at more than half of the sites during these episodes and often were greater than ppb at one or more sites.
An analysis of the weather for each episode shows that high-ozone episodes were most likely in the presence of weak, slow-moving, persistent high-pressure systems as they migrated from west to east, or from northwest to southeast, across the eastern United States. Fast-moving and intense anticyclones highs were much less likely to promote the occurrence of ozone pollution episodes.
The analysis of 2 complete years of data strengthens the conclusions of the case studies discussed earlier. There are no indications that either the weather or the ozone concentrations in and were particularly anomalous, although the concentrations could have been somewhat above average in Logan, The influence of the paths of anticyclones on the spatial pattern of ozone in the eastern two-thirds of the United States was examined by Vukovich and Fishman They showed maps of the mean diurnal maximum values of ozone for July and August of , using rural data where possible, and typical paths of anticyclones for each of these months.
They concluded that if there is a persistent path for migratory high-pressure systems, the regions of high concentrations of ozone are associated with that pathway.
An analysis of the climatology of anticyclones in July for shows that the preferred track is across the northeast rather than across the southeast United States Zishka and Smith, There was a downward trend in the number of anticyclones during this period. The data discussed above show that there is a persistent blanket of high ozone in the eastern United States several times each summer, generally associated with stagnant high-pressure systems. Since rural ozone values commonly exceed 90 ppb on these occasions, an urban area need cause an ozone increment of only 30 ppb over the regional background to cause a violation of the NAAQS in a downwind area.
Such increments have been demonstrated in the plume studies discussed earlier and in systematic studies of three urban areas Kelly et al. Kelly et al. For the upper quartile of ozone days in , the ozone daily maximum was ppb at the plume site, and the concentration at h was 47 ppb at the rural site. On the day with the highest maximum ozone, ppb, ozone concentrations were about 90 ppb at rural sites. Altshuller examined ozone formation in the St. Louis plume using 2 years of surface data from 12 sites. He compared the maximum ozone concentration at the station nearest the plume center and the average of the maximum ozone at upwind stations to obtain the change in ozone concentration D O 3.
Monthly mean values of D O 3 were ppb, with an overall average of 45 ppb; high concentrations were most common in July and August, and the 90th-percentile value of D O 3 was 80 ppb. In another study of the same data, Shreffler and Evans showed that upwind concentrations were ppb and that D O 3 appeared to be independent of the upwind concentrations. Finally, Lindsay and Chameides compared maximum ozone concentrations from stations upwind and downwind of Atlanta and at a rural site km away.
On days when urban ozone concentrations exceeded ppb, the ozone concentration was ppb at the upwind station and ppb at the downwind station, suggesting that the city contributed ppb above the immediate background. On these days, the ozone concentration at the rural site was 65 ppb, 20 ppb higher than average.
A study of the meteorological conditions associated with high-ozone days above 80 ppb in 17 cities demonstrated the regional nature of the problem, at least in the Northeast. Samson and Shi examined the wind flow for all days in when ozone exceeded 80 ppb in these cities, using trajectory calculations integrated backwards to the source region. They found that days with concentrations above ppb were generally associated with low wind speeds, with the exception of Portland, Maine, where high-ozone days were moderately windy, presumably due to long-range transport of ozone from the south and west.
The median distance the air had traveled in the previous 24 hours was about km for the northeastern cities, suggesting long-range transport, but only km for the southern cities. High-ozone days tended to occur over a longer season for the southern cities than for the northeastern cities Figure Linvill et al.source link
Tropospheric Ozone Research
Measurements made between and at Pic du Midi, France, m above sea level, used the same type of paper and techniques as those employed at Montsouris Marenco et al. Accounting for differences in pressure and humidity between Pic du Midi and Montsouris, Marenco et al. From until the end of the record in ozone increased steadily to 14 ppbv, while ozone at Montsouris at this time decreased. Marenco et al. These time series are the only known records that provide reliable quantitative or semi-quantitative insight into the changing photochemical environment over Europe in the early 20 th century.
While the Pic du Midi ozone mixing ratios appear to be more reliable than any other record outside of Montsouris, the results raise the obvious question of why ozone at 3 km above sea level at Pic du Midi, a site heavily influenced by the free troposphere, was no greater than ozone at the low elevation site of Montsouris. This lack of a vertical ozone gradient in the lower troposphere is in direct contrast with ozonesonde observations from around the world that showed a consistent increase in ozone with altitude during the s and s Logan, The latest generation of atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project ACCMIP show a vertical ozone gradient in the northern mid-latitude lower troposphere during the s that is weaker than the period —, but the models overestimate s lower tropospheric ozone by a factor of two compared to Pic du Midi and Montsouris Stevenson et al.
Due to the uncertainty of lower tropospheric ozone predicted by models for the s, there is presently no explanation for the observed lack of an ozone vertical gradient above France in the late s. Those authors concluded that ozone increased by a factor of 5 between the late s and the early s and by a factor of 2 between the s and early s. Similar conclusions were drawn by Staehelin et al. They found that ozone in the alpine valley surrounding Arosa, Switzerland increased by a factor of 2. Analysis of other sites in central Europe showed that ozone increased with similar rates at several elevations between sea level and 3.
These ozone increases coincided with rising European NO x emissions that increased by a factor of 4. Measurements began at Cape Arkona in using a wet chemical method until Warmbt, , after which continuous ozone measurements began at the nearby coastal site of Zingst, 60 km to the southwest. Combining the two sites produces a continuous record with more than 57 years of data Figure 1.
In the late s and early s yearly average ozone values were in the 15—20 ppbv range, which doubled by the end of the 20 th century, in agreement with the high elevation European ozone trends compiled by Marenco et al. Trend lines are fit through the yearly average ozone values using the linear least-square regression method.
Navigation and service
Trend lines in Europe only extend through when the positive trend appears to have ended. This figure is modified from the original that appeared in IPCC Spurred by the goals of the International Geophysical Year IGY to expand geophysical observations globally, exploratory ozone measurements were made at remote sites in Antarctica Wexler, and Mauna Loa, Hawaii in — Junge, Comparison of the — measurements from the sea-level site of Little America on the Ross Ice Shelf based on a month running mean from April until October to the same time period at Arkona on the northern German coast shows that annual average ozone was greater at Little America, 22 ppbv vs.
However, the greater values at Little America were driven by enhanced ozone values during the dark winter months. Comparison of short-term ozone measurements at other coastal Antarctic sites to Arkona in the early and mids yields similar results Oltmans and Komhyr, In the s quantitative ozone measurements became more widespread and efforts were made to routinely monitor the atmosphere at rural and remote locations for the purposes of detecting long-term changes in the global composition of the atmosphere Figure 1 and Table 1. Continuous records in southern Germany began at the rural hilltop site of Hohenpeissenberg in and the mountaintop site of Zugspitze m in Gilge et al.
Ozone measurements at remote sites were established by the U. Routine ozonesonde profiles became available in Germany, the US, Japan and Antarctica in the early s Oltmans et al.