COSMIC-RAY PRODUCED RADIOACTIVE ISOTOPES AS TRACERS FOR STUDYING LARGE- SCALE ATMOSPHERIC CIRCULATION

Journal Article · Thu Jan 01 04:00:00 EST 1959 · J. Atmospheric and Terrest. Phys.

DOI:https://doi.org/10.1016/0021-9169(59)90124-2· OSTI ID:4790787

Peters, B

In the interval between two consecutive condensations of moisture, atmospheric air accumulates radioactive isotopes produced by cosmic particles in collisions with nitrogen, oxygen, and argon. The production rates of these isotopes depends strongly on altitude and latitude; the rate of removal depends, between rains, essentially on the half life of each isotope. These facts can be used to label air masses and to trace their trajectories. The isotopes that seem to be most useful for meteorological investigations are P/sup 32/ (half life 14 days), P/sup 33/ (25 days), Be/sup 7/(53 days), and S/sup 35/ (87 days). Their concentrations are studied in rains in India during l956 and l957, and approximate values are obtained for the annual fall-out. These experimental fallout values are compared with values calculated from the expected isotope production by cosmic radiation in various parts of the atmosphere. The fall-out based on the annual production of Be/sup 7/ agrees well with the measured annual fall-out. The measured fall-out of P3/ is somewhat higher and that of P/sup 33/ and S/sup 35/ between two and five times higher than the calculated values. The discrepancy is probably significant, although the full-out data are not very accurate; it is presumably due to an underestimate of the contribution that neutrons with energy below ~40 Mev make to the number of nuclear disintegrations in argon. The data indicate that condensation of water vapor removes cosmicray induced radioactivity from the air very efficiently. lt can therefore be concluded that different isotopes appear in rain water in the same proportion in which they existed in the air before the moisture was removed. Stratosphere air differs markedly from air that remains in the troposphere throughout the period between successive condensations and precipitations; apart from the fact that its level of activity will in general be higher, it ntains a much larger proportion of long-lived compared to hort-lived isotopes. Air that descends from the stratosphere and moves into lower regions remains clearly distingusibable for very long periods, until it has been strongly diluted or cleansed by condensation. The simultaneous determination of radioactivity due to two or more isotopes in a individual rain leads, therefore, to information on the pa t history of the air mass from which the water was condensed. A detailed analysis of twenty-one rain samples from various parts of India, taken between July and December 1957, shows that none of the air masses has characteristics of air that had descended from the stratosphere. (auth)

• Research Organization: Tata Inst. of Fundamental Research, Bombay
• NSA Number: NSA-16-016587
• OSTI ID: 4790787
• Journal Information: J. Atmospheric and Terrest. Phys., Journal Name: J. Atmospheric and Terrest. Phys. Vol. Vol: 13
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ADSORPTION
AIR
ALUMINUM ALLOYS
ARGON
ATMOSPHERE
BERYLLIUM 7
CHROMIUM ALLOYS
COBALT ALLOYS
CORROSION
COSMIC RADIATION
FALLOUT
GAS FLOW
GEOLOGY, MINERALOGY, AND METEOROLOGY
HASTELLOY
INCOLOY
INTERACTIONS
LIQUEFYING
LOSSES
MOLYBDENUM ALLOYS
MOTION
NICKEL ALLOYS
NITROGEN
OXIDES
OXYGEN
PHOSPHORUS 32
PHOSPHORUS 33
QUANTITATIVE ANALYSIS
QUANTITY RATIO
RAIN
STEAM
STRESSES
SULFUR 35
SUPERHEATING
TITANIUM ALLOYS
TRACER TECHNIQUES
VAPORS
WATER
WEIGHT