456
REITER AND MAHLMAN
100
300 MB
300°K
GRB
OKC
Fig. 35—Schematic wind profiles
300°K isentropic surfaces
Shown in Fig. 4.
along the 300-mb isobaric and the
approximately corresponding to conditions
define the boundaries of air traveling in the northern jet branch. The
air contained in this branch moves rather rapidly over areas with an
insufficiently dense radiosonde network. Thus estimates of transport
have been made of the southern jet branches only to avoid the difficulties presented by these phenomena. These are presented in Table l,
which is based on this study and onone undertaken by Mahlman.’
It was assumed that the sinking air showed potential vorticities —
larger than 10 x 107° cm-sec-deg/g (see Fig. 6), that it was dry to the
point of “motorboating” of the humidity sensor (see Figs. 7a and ‘b),
and that strong wind shears outlined its boundaries against the surrounding tropospheric air (see Figs. 3a and 3b). With the horizontal
extent of the sinking air mass thus established, we can compute the
total amount of air involved in the fallout process,
Ap
-
5
dA
§
(6)
where M = mass
Ap = thickness of stable layer
A= area
g = acceleration of gravity
by planimetering the areas dA between isolines of Ap, i.e., the thickness of the stable layer in which the isentropic surface under investigation is contained.
Difficulties were encountered in the estimates made for November
1962 because the stable, upper, contaminated layer, characterized by