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  • Author or Editor: A. D. Belmont x
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A. D. Belmont
,
D. G. Dartt
, and
G. D. Nastrom

Abstract

The observed variability patterns of monthly mean zonal winds over an 11-year period, from 80°N–70°S and from 20–65 km, are explained in terms of component patterns of a long-term mean, quasi-biennial, annual and semi-annual periodic variations. Interannual variations are displayed by monthly mean height-time sections for each of eleven years, and Northern Hemisphere–-Southern Hemisphere differences are seen from 11-year mean, latitude-month sections for each 10 km. An 11-year mean, height-month section at the equator shows the transition of the easterly regime at low levels to a westerly one at highest levels. Summer easterlies extend from equator to pole, from 30 to 50 km, but winter westerlies extend from equator to about 70° only at 60 km. Also, only at 60 km are there westerlies from pole to pole during the equinoxes. The stronger Southern Hemisphere westerly circulation of the troposphere is found to extend to at least 40 km, and possibly to 60 km. Southern summer easterlies are the same as, or stronger than, those in the Northern Hemisphere. Improved latitudinal rocket network coverage is needed in the Southern Hemisphere. Finer time resolution is essential everywhere to obtain diurnal variations.

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A. D. Belmont
,
D. G. Dartt
, and
G. D. Nastrom

Abstract

The mean and individual seasonal reversal progressions are described for each of the 11 years of available rocket observations from 80°N to 80°S, and from 20 to 65 km. Isochrone sections were based on the time sections of the preceding paper and on frequencies of east-west wind data.

In the Northern Hemisphere the mean spring reversal starts in early April at highest altitudes and progresses downward and southward. The mean fall reversal proceeds simultaneously both upward from 20 km and downward from 60 km at high latitudes and then southward and downward. Both the onset and direction of the spring reversal are highly irregular from year to year, but the fall process is very uniform and rapid, starting in August and reaching 20 km in the subtropics in two months.

The Southern Hemisphere spring reversal appears to move from low to high latitudes oppositely to that in the Northern Hemisphere, and downward, taking about three months to reach 60°S at 20 km. The Southern Hemisphere fall proceeds to low latitudes and altitudes from both highest subtropical altitudes and lowest polar altitudes. The local nature of spring reversals for individual years is stressed.

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R. W. Wilcox
,
G. D. Nastrom
, and
A. D. Belmont

Abstract

Amplitudes and phases of the annual, quasi-biennial (QBO) and semiannual oscillations of Northern Hemisphere total ozone (1957–72) and North American ozonesonde (1962–74) data are presented. For total ozone, the annual wave has a maximum amplitude (120 m atm cm) along the east coast of Asia, where it occurs in February. The QBO has its largest amplitude (20 m atm cm) also over extreme eastern Siberia. The maximum amplitude (25 m atm cm) of the semiannual wave occurs at high latitudes and its first maximum tends to occur in late winter over most of the hemisphere. In general, these periodic variations have their maxima where standing waves indicate maxima in northward transport. It appears that these results are not greatly affected by differences in Dobson and M-83 instruments.

Eight years of new ozonesonde data at Resolute improve the estimates of monthly vertical distribution and periodic variability at high latitudes. The vertical distribution of ozone shows a maximum concentration about 10 km above the tropopause, and the largest amplitude of the periodic variations also parallels the tropopause. The amplitude of the annual wave (18 × 1011 cm−3) is near 16 km in the arctic and decreases to 4×1011 cm−3 at 30°N. The annual maximum occurs in February-March throughout the stratosphere north of 40°N. The maximum amplitude of the QBO (5 × 1011 cm−3) is centered in the arctic near 13 km and the level of the maximum rises to 24 km in the tropics, where the amplitude is smaller. The QBO appears to progress both upward and downward from near 20 km at all latitudes, taking 8 months to reach 13 km in the arctic. The semiannual wave's maximum amplitude (4 × 1011 cm−3) occurs in the arctic near 18 km where the first maximum occurs in February-March.

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W. C. Shen
,
G. W. Nicholas
, and
A. D. Belmont

Abstract

TIROS VII 15-μ radiation data were used to study Southern Hemisphere stratospheric warmings during the winter of 1963 over regions which had little conventional data. Three significant warmings could be mapped despite the latitudinal limit of 60S. The first, from 20 July to 13 August, and the second from 26 August to 16 September each reached a maximum in the Australian sector with temperature increases of 10C and 24C near Campbell Island. The warmings moved eastward from Australia and the South Indian Ocean. The third, or final warming, occurred in the western South Pacific from 16 October to 10 November with a temperature increase of 21C. This warming travelled southeastward toward the South Atlantic Ocean. This study demonstrates the validity and usefulness of single-day satellite data. It is strongly suggested that future observations of the same narrow CO2 band be carefully processed to filter out only the random time fluctuations in order that potentially high resolution in time and space of this system can be realized. The 15-μ radiation can indeed provide mid-stratospheric temperature data over the major portion of the globe which now has no upper-air observational network at all. A truly polar orbit such as that of Nimbus, would further provide such data over the central polar regions where this atmospheric layer experiences dramatic changes and is of most interest.

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A. D. Belmont
,
G. W. Nicholas
, and
W. C. Shen

Abstract

Temperatures derived from the 15-μ CO2 channel of the radiometer carried aboard the TIROS VII satellite were compared to the radiosonde temperatures at 100, 70, 50, 30, 20 and 10 mb at 97 stations in the Northern Hemisphere from 20 January to 17 February 1964. The 15-μ temperature is rarely colder than the 30-mb temperature, and it generally falls between the 10- and 30-mb temperatures. The highest correlation between 15-μ and radiosonde temperatures was 0.7 at both 30 and 20 mb, near the level of maximum weight which applies to the 15-μ radiance weighting function profile. The variation of 15-μ temperatures with longitude closely follows the variation of 10-100 mb thickness pattern.

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