600
KRUGER, HOSLER, AND MILLER
varies considerably from day to day, the ?°Sr concentration should be a
continuous function with height. In areas where temperature inversions
persist at approximately the same height for weeks or months, such as
along the west coast of the United States or in the Tradewind Belt,
Stratification of nuclear debris may be expected. Our first observation
of this effect was noted in the Santa Barbara cyclone study.” From
Figs. 6 and 7 it is deduced that the rain falling from the upper altostratus layer evaporated in the dry air below, producing strong cooling
that led to the removal of the inversion above the surface marine layer.
The sudden infusion of the marine layer into the precipitating system
appears to be responsible for the brief but sharp decrease in the Sr
concentration and the corresponding increase in the rainfall rate. The
dilution of the upper-layer rainwater may be linked to an initial dif-
ference in air concentration below and above the temperature inversion. This effect is currently being studied in greater detail as part of
the orographic rain study underway along the slopes of the Mauna
Loa Volcano on the Island of Hawaii.
REFERENCES
1. P. Kruger, L. P. Salter, and C. L. Hosler, Meteorological Influences on Sr®®
Fallout Concentrations in Precipitation: Part 1, Large-scale Uplift, in Radioactive Fallout from Nuclear Weapons Tests, A. W. Klement, Jr. (Ed.),
USAEC Report TID-7632, pp. 242-255, February 1962.
2. L, P. Salter, P. Kruger, and C. L. Hosler, Sr®° Concentration in Precipita-
tion from Large-Scale Uplift, J. Appl. Meteorol., 1: 357-365 (1962).
3. P. Kruger and C. L. Hosler, Meteorological Evaluation of Radioactive Fallout, USAEC Report NSEC-62, Nuclear Science and Engineering Corp.,
Mar. 31, 1962.
4, P. Squires, Penetrative Downdrafts in Cumuli, Tellus, 10: 381 (1958).
5. H. R. Byers, General Meteorology, 3rd Ed., McGraw-Hill Book Company,
Inc., New York, 1959.
6. E. F. Danielsen, The Laminar Structure of the Atmosphere and its Relation
to the Concept of a Tropopause, Arch. Meteorol. Geophys. Bioklimatol.,
Ser. A, 11(H.3): 293 (1959).
7. D. O. Staley, On the Mechanism of Mass and Radioactivity Transport from
Stratosphere to Troposphere, J. Atmos. Sci., 19: 450 (1962),
8. P. Kruger and C. L. Hosler, Sr®® Concentration in Precipitation from Convective Showers, J. Appl. Meteorol,, 2: 379-389 (1963).
9. S. M. Greenfield, Rain Scavenging of Radioactive Particulate Matter from
the Atmosphere, J. Meteorol., 14: 115 (1957).
10. I. Langmuir, The Production of Rain by Chain-reaction in Cumulus Clouds
at Temperatures above Freezing, J. Meteorol., 5: 175 (1948).
11. L. M. Vaughan and W. A. Perkins, The Washout of Aerosol Particles and
Gases by Rain, Technical Report No. 88, Aerosol Laboratory, Stanford University, 1961.
.
12. H. Landsberg, Atmospheric Condensation Nuclei, Gerlands Beitr. Geophys.
Suppl. Ba, UI, Erg. d Kosm, Phys., 155, (1938).
13. W. G. Durbin and R. J. Murgatroyd, A Series of Measurements from Aircraft of Freezing and Condensation and Salt Nuclei over Southern England,
Nubila, 6(1): 55-73 (1964).