Extreme climate of the global troposphere and stratosphere in 1940-42 related to El Niño.

Although the El Niño/Southern Oscillation phenomenon is the most prominent mode of climate variability and affects weather and climate in large parts of the world, its effects on Europe and the high-latitude stratosphere are controversial. Using historical observations and reconstruction techniques, we analyse the anomalous state of the troposphere and stratosphere in the Northern Hemisphere from 1940 to 1942 that occurred during a strong and long-lasting El Niño event. Exceptionally low surface temperatures in Europe and the north Pacific Ocean coincided with high temperatures in Alaska. In the lower stratosphere, our reconstructions show high temperatures over northern Eurasia and the north Pacific Ocean, and a weak polar vortex. In addition, there is observational evidence for frequent stratospheric warmings and high column ozone at Arctic and mid-latitude sites. We compare our historical data for the period 1940-42 with more recent data and a 650-year climate model simulation. We conclude that the observed anomalies constitute a recurring extreme state of the global troposphere-stratosphere system in northern winter that is related to strong El Niño events.

Measured trends in stratospheric ozone.

Recent findings, based on both ground-based and satellite measurements, have established that there has been an apparent downward trend in the total column amount of ozone over mid-latitude areas of the Northern Hemisphere in all seasons. Measurements of the altitude profile of the change in the ozone concentration have established that decreases are taking place in the lower stratosphere in the region of highest ozone concentration. Analysis of updated ozone records, through March of 1991, including 29 stations in the former Soviet Union, and analysis of independently calibrated satellite data records from the Total Ozone Mapping Spectrometer and Stratospheric Aerosol and Gas Experiment instruments confirm many of the findings originally derived from the Dobson record concerning northern midlatitude changes in ozone. The data from many instruments now provide a fairly consistent picture of the change that has occurred in stratospheric ozone levels.

Spatial variability of different fractions of particulate matter within an urban environment and between urban and rural sites.

The spatial variability of different fractions of particulate matter (PM) was investigated in the city of Basel, Switzerland, based on measurements performed throughout 1997 with a mobile monitoring station at six sites and permanently recorded measurements from a fixed site. Additionally, PM10 measurements from the following year, which were concurrently recorded at two urban and two rural sites, were compared. Generally, the spatial variability of PM4, PM10, and total suspended particulates (TSP) within this Swiss urban environment (area = 36 km2) was rather limited. With the exception of one site in a street canyon next to a traffic light, traffic density had only a weak tendency to increase the levels of PM. Mean PM10 concentration at six sites with different traffic densities was in the range of less than +/- 10% of the mean urban PM10 level. However, comparing the mean PM levels on workdays to that on weekends indicated that the impact of human activities, including traffic, on ambient PM levels may be considerable. Differences in the daily PM10 concentrations between urban and more elevated rural sites were strongly influenced by the stability of the atmosphere. In summer, when no persistent surface inversions exist, differences between urban and rural sites were rather small. It can therefore be concluded that spatial variability of annual mean PM concentration between urban and rural sites in the Basel area may more likely be caused by varying altitude than by distance to the city center.

[The two ozone problems: too much in the troposphere, too little in the stratosphere]. / Die beiden Ozonprobleme: zuviel in der Troposphäre, zuwenig in der Stratosphäre.

Trends analysis based on the long-term Swiss ozone measurements from Arosa and Payerne operationally performed by the Swiss Meteorological Institute are presented. These measurement include stratospheric ozone (approximately 90% of total ozone) and tropospheric ozone. The total ozone measurements from Arosa, the world longest series started at 1926, indicate, that total ozone has declined since about 1970 by approximately 5%. The ozone balloon soundings, operationally performed at Payerne since 1969 (2-3 ascents per week) show, that stratospheric ozone has decreased strongly in the last 20 years, whereas tropospheric ozone, remarkably has increased during this period. The relative change was strongest in the troposphere (more than 10% per decade, 3-4% increase per year during 1982-1988). However, on an absolute scale, changes in the stratosphere were strongest (relative decrease: 6 to 7% per decade at 20-22 km). The present scientific theories of the two ozone problems are reviewed: stratospheric ozone decrease was caused by the anthropogenic emissions of fluorochlorocarbons and other compounds mainly released from the earth surface. Tropospheric ozone has increased due to photochemical production of mainly anthropogenically emitted nitrogen oxides, volatile organic compounds and CO.

Analysis of 23 cases of primary carcinoma of the fallopian tube over 50 years.

The authors report on 23 cases of primary Fallopian tube carcinoma occurring over the past 50 years. In addition, the literature of the past 30 years was reviewed. The 5-year survival rate was 40%, increasing considerably with lower tumor stage or better tumor differentiation. The adjuvant therapies used did not prolong survival. Results were compared to other studies, and diagnostic and therapeutic trends are pointed out. Due to the rareness of the tumor, there are no controlled studies as to the effectiveness of therapeutic regimens. Therapy is purely empiric and usually follows the guidelines for ovarian cancer. There are no established tools for a safe preoperative diagnosis. The tumor is highly aggressive and quickly spreading. Initial tumor stage and differentiation are determinants for the prognosis. Therefore, a radical approach is indicated whenever a tubular malignancy cannot be excluded.

Large-scale nitrogen oxide plumes in the tropopause region and implications for ozone

Continuous measurements of nitrogen oxide and ozone were performed from a commercial airliner during 1 year at cruising altitudes below and above the tropopause. The upper tropospheric nitrogen oxides distribution was found to be strongly influenced by large-scale plumes extending about 100 to 1300 kilometers along the flight track. The plumes were frequently observed downwind of thunderstorms and frontal systems, which most probably caused upward transport of polluted air from the continental boundary layer or nitrogen oxide production in lightning strokes, or both. Particularly in summer, average ozone concentrations in the plumes were enhanced compared to the tropospheric background levels.

Chromatographic analysis of organic compounds in the atmosphere.

Fused silica capillary columns with thick films of cross-linked coatings have been used to separate many of the organic compounds that are present in the volatile fraction of automobile exhaust and in ambient air. Techniques have been developed that allow reversible collection and pre-concentration of organic compounds in ambient air on polymeric sorbents with minimal artifacts. The exhaust samples, which are directly injected without pre-concentration on sorbents, contain many of the same organic compounds that are found in sorbent-collected samples of urban ambient air. Similar anthropogenic organic compounds are not, in general, detected (less than 0.02 ppbV) in air samples from remote, rural areas in Colorado.