Peculiarities in Aitken Nuclei Counts in the Tropical and Subtropical Stratosphere.
MISSOURI UNIV ROLLA GRADUATE CENTER FOR CLOUD PHYSICS RESEARCH
Pagination or Media Count:
The analysis of AN concentrations measured during a series of flights over tropical and subtropical regions performed in the months of November 1974 and February 1975 gave the following conclusions. 1 Vertical profiles of AN concentrations over Panama differ substantially from those over Houston. In winter months over Houston one can usually find strongly expressed layers of very high concentration AN in the troposphere. Often there was an increase of AN counts below the middle-latitude tropopause and below the extension of the tropical tropopause as well. An vertical profiles over Panama have an almost constant AN concentration below the tropopause and a steep decrease of concentrations above it. 2 The mean AN concentration above equatorial regions is very low. At altitudes higher than 18 km it rarely amounts to over 20 AN cu cm. 3 There is strong indication that convection in tropical regions correlates with AN counts when measurement is made below the tropopause. However, above the tropical tropopause there is no indication that AN are transported in a considerable concentration from the troposphere due to convection. 4 A negative correlation between AN and ozone concentration was found over the Gulf of Mexico at altitudes above 17 km. This correlation was not so strongly expressed over equatorial regions or north of 40 deg N latitude at the same flight level 18 km. 5 There was no apparent correlation between AN counts and ozone concentration just above the tropopause which was deduced by several authors for larger particulates.
- Atmospheric Physics