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SESSION IIB DISCUSSION
POLAN: Mr. Ferber, does your curve showing the amount of
debris in the troposphere apply only to pure air bursts or does it
apply to contact surface bursts as well?
FERBER: It is for air bursts only. If there is contact with the
surface there will be local fallout and therefore perhaps a different
distribution of debris with height. The few data we have indicate that
there is more activity in the stem for surface bursts than for air
bursts.
SETTER: Dr. Thatcher, please explain what is meant by “the
overwhelming effect of oceanic air” in causing the low concentrations
of tritium in precipitation collected from oceanic stations.
THATCHER: I think this expression is actually used in connection
with continental stations that are annually affected by “overwhelming”
oceanic air masses, TheSe are the stations in the monsoon belt. Here
the stations show the typical pattern of continental tritium fallout in
approximately the first half of the year; i.e., they show relatively high
tritium concentrations and a pronounced spring peak, At the onSet of
the monsoon, at about midyear, the tritium concentrations at these
stations drop dramatically because of the rush of moisture-laden air
from the ocean (principally the Indian Ocean). Surface ocean water
has
a low tritium concentration because of downwind mixing. Re-
evaporated water from the land, on the other hand, has a high tritium
concentration because of very limited mixing with old soil water. In
the first half of the year, much of the limited rain that occurs derives
from reevaporated water.
GENERAL DISCUSSION
REITER: I am faced with the difficult task of trying to condense
into a few words what has taken 1'4 days to explain. Of course I can
only present a very brief outline of some of the questions that were
raised during this session. In presenting a few points here, I am not
choosing them with any particular reference or preference but rather
to stimulate a discussion.
This session covered a very wide range of topics on the atmospheric relations to radioactive fallout. We listened to many speakers,
whose
topics
bridging
ranged
from
meteorology
to
nuclear chemistry. A
of the gaps between the diverging fields discussed would
help to promote understanding, particularly in the usage of rather
Specific terminology. I would not be in the least surprised if some
chemist should ask the question: “What is potential vorticity,
what is it supposed to be good for?”
and
Let uS make an attempt to arrange the topics covered in this
session into four groups: One group dealt with the very large-scale