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- Author or Editor: A. D. Belmont x
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Abstract
The diurnal component in meridional wind is estimated for each season at twelve rocket stations. Amplitudes and phases are presented as a function of height-latitude or as vertical profiles. Many of the gross features of the tide persist throughout the year, but as they migrate in height and latitude the amplitude or phase at a given location may undergo large changes with season. Longitudinal variations in the diurnal tide are found in the mid-stratosphere, and it is suggested they are coupled with longitudinal variations in the tropospheric temperature structure.
Abstract
The diurnal component in meridional wind is estimated for each season at twelve rocket stations. Amplitudes and phases are presented as a function of height-latitude or as vertical profiles. Many of the gross features of the tide persist throughout the year, but as they migrate in height and latitude the amplitude or phase at a given location may undergo large changes with season. Longitudinal variations in the diurnal tide are found in the mid-stratosphere, and it is suggested they are coupled with longitudinal variations in the tropospheric temperature structure.
Abstract
The 12-year mean temperature and the amplitude and phase of the quasi-biennial oscillation (QBO) and first three harmonies of the annual wave are presented on height-latitude sections, 20 to 65 km, 80°N to 30°S. New features include adjusting the long-term mean temperature for errors due to solar radiation effects and for biasing by the diurnal tide. Due to the longer period of record used here, the extratropical QBO differs from that reported previously in the literature. Amplitudes of the annual wave at 30°S are larger than those at 30°N at all levels; the amplitude ratio is greatest near 50 km. The largest amplitude (7°C) of the semiannual wave in the stratosphere or mesosphere is near 75°N at 32 km. The terannual wave's amplitude near 35 km at 55°N is as large as the amplitude of the semiannual wave there and is larger than the well-known tropical %semiannual wave. These thermal properties of the upper atmosphere require theoretical explanations, stratosphere modelers should be able to reproduce them, and continued observations are needed to describe their hemispheric differences at high latitudes and altitudes.
Abstract
The 12-year mean temperature and the amplitude and phase of the quasi-biennial oscillation (QBO) and first three harmonies of the annual wave are presented on height-latitude sections, 20 to 65 km, 80°N to 30°S. New features include adjusting the long-term mean temperature for errors due to solar radiation effects and for biasing by the diurnal tide. Due to the longer period of record used here, the extratropical QBO differs from that reported previously in the literature. Amplitudes of the annual wave at 30°S are larger than those at 30°N at all levels; the amplitude ratio is greatest near 50 km. The largest amplitude (7°C) of the semiannual wave in the stratosphere or mesosphere is near 75°N at 32 km. The terannual wave's amplitude near 35 km at 55°N is as large as the amplitude of the semiannual wave there and is larger than the well-known tropical %semiannual wave. These thermal properties of the upper atmosphere require theoretical explanations, stratosphere modelers should be able to reproduce them, and continued observations are needed to describe their hemispheric differences at high latitudes and altitudes.
Abstract
Height-time sections of mean monthly observed upper-air zonal winds at stations within 20 degrees of the equator show not only an almost biennial oscillation of the wind in the middle or upper stratosphere but that there is a relative wave, 180 degrees out of phase to the first, which occurs in the lower stratosphere. The two waves are merged near the equator; they are best distinguished from each other about 9N to 15N and, although still noticeable as separate occurrences of westerlies from 15N to 20N, the intensity of the westerlies is much reduced. Both waves occur at progressively higher levels from one biennium to the next. This observed double cycle is caused by the combination of the fundamental annual and biennial waves, and the upward progression appears due to the difference in phase lags with height of these two component waves.
Abstract
Height-time sections of mean monthly observed upper-air zonal winds at stations within 20 degrees of the equator show not only an almost biennial oscillation of the wind in the middle or upper stratosphere but that there is a relative wave, 180 degrees out of phase to the first, which occurs in the lower stratosphere. The two waves are merged near the equator; they are best distinguished from each other about 9N to 15N and, although still noticeable as separate occurrences of westerlies from 15N to 20N, the intensity of the westerlies is much reduced. Both waves occur at progressively higher levels from one biennium to the next. This observed double cycle is caused by the combination of the fundamental annual and biennial waves, and the upward progression appears due to the difference in phase lags with height of these two component waves.
Abstract
Daily data at 16 stations along five latitudes from 13°N. to 33°S. were carefully examined at the 50-, 100-, and 500-mb. levels for evidence of longitudinal phase progression of the quasi-biennial oscillation (QBO). At 50 mb. there is evidence of west to east progression although there are many irregularities and much uncertainty. The phase dates differ by days at low latitudes. At 100 and 500 mb., it appears that the QBO originates in tropical America and progresses both eastward and westward, occurring last in the Indian Ocean. The progression time ranges from 1 to 2 yr. At 500 and 100 mb., however, a cellular phase progression in possible due to the difficulty of identifying corresponding waves with a very meager network.
It appears now that the QBO may not be simultaneous in longitude and that its speed and even direction of propagation, like its other properties, may very from cycle to cycle. The analysis is being expanded to other levels and latitudes to obtain better continuity in following each wave.
Abstract
Daily data at 16 stations along five latitudes from 13°N. to 33°S. were carefully examined at the 50-, 100-, and 500-mb. levels for evidence of longitudinal phase progression of the quasi-biennial oscillation (QBO). At 50 mb. there is evidence of west to east progression although there are many irregularities and much uncertainty. The phase dates differ by days at low latitudes. At 100 and 500 mb., it appears that the QBO originates in tropical America and progresses both eastward and westward, occurring last in the Indian Ocean. The progression time ranges from 1 to 2 yr. At 500 and 100 mb., however, a cellular phase progression in possible due to the difficulty of identifying corresponding waves with a very meager network.
It appears now that the QBO may not be simultaneous in longitude and that its speed and even direction of propagation, like its other properties, may very from cycle to cycle. The analysis is being expanded to other levels and latitudes to obtain better continuity in following each wave.
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.
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.
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.
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.
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.
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.
Abstract
The 10.7-cm solar radio flux is considered to be highly correlated with solar extreme ultraviolet radiation, thermospheric temperatures, sunspots, and the 27-day and 11-year solar cycles. To investigate the possibility of ultraviolet radiation being a cause of the quasi-biennial oscillation in tropical stratospheric winds and temperatures, the daily values of 10.7-cm flux were subjected to a non-linear, curve-fitting analysis to determine the major component sinusoidal frequencies of the time series. No evidence was found for a period near 26 months; hence, to the extent that extended ultraviolet 10-cm flux relationship is valid, ultraviolet insolation does not appear to vary with a quasi-biennial oscillation.
Abstract
The 10.7-cm solar radio flux is considered to be highly correlated with solar extreme ultraviolet radiation, thermospheric temperatures, sunspots, and the 27-day and 11-year solar cycles. To investigate the possibility of ultraviolet radiation being a cause of the quasi-biennial oscillation in tropical stratospheric winds and temperatures, the daily values of 10.7-cm flux were subjected to a non-linear, curve-fitting analysis to determine the major component sinusoidal frequencies of the time series. No evidence was found for a period near 26 months; hence, to the extent that extended ultraviolet 10-cm flux relationship is valid, ultraviolet insolation does not appear to vary with a quasi-biennial oscillation.
Abstract
Abstract
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.
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.
