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1.
Total ozone observations in the international network have been used as a basis for the analysis of the mean monthly ozone distribution over the globe for the period 1957–75. It has been found that during the period 1961–70 the total ozone amount increased in the Northern Hemisphere by about 12 percent and that this increase seems to be significant at all latitudes. Although the data were sparse for the Southern Hemisphere, there did not appear to be any significant ozone changes during the 10 year period. Relatively large geographic variations were found in the ozone trends and it is suggested that these variations are related to large scale changes in the atmospheric circular pattern. 相似文献
2.
Rumen D. Bojkov 《Pure and Applied Geophysics》1969,74(1):165-185
Summary Ozone observations made during 1964 and 1965 at nine Mediterranean, central and southeast European stations (latitudes 38–52°N, longitudes 9–23°E) reveal patterns of seasonal and shorter time-variations in total ozone as well as in vertical ozone distribution. During the winter-spring season, a significant increase (20%) of ozone occurs essentially simultaneously with the spring stratospheric warming, and is noticed at all stations.—Autocorrelation coefficients show that the total ozone on any day is strongly related to the total ozone of the preceding four days in summer or one or two days in winter-spring or autumn. Changes of total ozone in southeast Europe correlate closely with those in Mediterranean Europe, and less closely with those from north central Europe.—Power spectrum analysis detects the dependence of ozone changes on processes with periods longer than 6–8 days, and indicates a significant oscillation with a period of 14–15 days, perhaps a result of the direct influence of lower stratospheric circumhemispheric circulation. — Reliable vertical ozone soundings were not available from all stations. The mean vertical profiles at Arosa, Switzerland (47°N) and Belsk, Poland (51°) are very similar. More than 60% of the variability of the total ozone is contributed by changes in ozone concentration between 10 and 24 km; less than 10% is due to variations above 33 km. Changes in ozone partial pressure at different altitudes, and relationships of those changes to total ozone, indicates that a mean vertical ozone distribution may be described adequately by considering the ozone changes in four layers: a) the troposphere, b) the lower stratosphere up to 24 km, c) a transition layer from 24 km to a variable upper border at 33–37 km, and d) the layer above 33–37 km.Part of this paper was presented at the Ozone Seminar in Potsdam, Germany, 27 September 1966. 相似文献
3.
Coherency spectra derived from time series of stratospheric quantities indicate oscillations in the frequency range below 0.5 d–1 which are correlated on a global scale. Satellite observations of total ozone and stratospheric radiance (BUV and SIRS, Nimbus4, April–November 1970) have been used to derive phase relationships of such oscillations. As an example, an oscillation of total ozone with a period of 7.5 d and zonal wave number zero is analyzed in detail. The basic assumption is made and tested, that the oscillation reflects stratospheric planetary waves as obtained from Laplace's tidal equations. The observed latitudinal phase shifts for the total ozone oscillation are in good agreement with theoretical predictions. It is concluded from the observations of ozone and radiance that mainly divergence effects related to global-scale waves are responsible for the 7.5 d oscillations of total ozone at high and middle latitudes and at the equator whereas in the latitude range 10°S–20°S predominantly temperature effects are important. Meridional wind amplitudes of some 10 cm/s are sufficient to explain the high and mid-latitude ozone oscillations. At low latitudes vertical wind amplitudes of about 0.2 mm/s corresponding to height changes of the ozone layer of roughly ±20 m are obtained. 相似文献
4.
Summary Observations of the ozone distribution indicate that modifications are required to the photochemical theory. These modifications involve ozone destruction by hydrogen and nitrogen products and ozone transport (both vertical and horizontal) due to atmospheric motions in the stratosphere. If the photochemical terms in the ozone continuity equation are omitted, changes due to atmospheric transport alone can be evaluated.Numerical computations were made of the three-dimensional wind structure as derived from the 12-layer (0–36 km) General Circulation Model developed by NCAR. The results showed that ozone is transported from the equatorial stratosphere poleward and downward in both hemispheres. The horizontal transport is primarily by the Hadley Cell in the tropics and by large-scale eddies in mid and high latitudes. The dominant mechanism for ozone transport are found to be similar to those derived for the horizontal heat and momentum transport found in other general circulation studies. 相似文献
5.
Meteorological rocket soundings, launched between 1968–74 at six locations representative of low, middle, and high latitudes in the northern hemisphere, are employed to determine the vertical, meridional and off-diagonal components of the eddy diffusivity in the northern hemispheric statosphere and lower mesosphere.It is shown that the distribution of the vertical and meridional components of the eddy diffusivity are similar in the northern hemisphere, although the magnitude of the former is 107 smaller than that of the latter; the magnitude of the off-diagonal eddy diffusivity is about 103 smaller than that of the meridional eddy diffusivity. In the troposphere, a maximum eddy diffusivity occurs in the mid-latitude at about 7 km above the mean sea level for both the summer and winter seasons. In the stratosphere, a maximum eddy diffusivity occurs in the mid-latitude at about 33 km in the winter, but no maximum in the summer.Paper presented at the World Meterological Organization Technical Conference on Global Observations of Atmospheric Pollution Relative to Climate, Boulder, Colorado, 20–24 August 1979. 相似文献
6.
Seasonal variations of ozone are studied by taking into consideration both photochemical and dynamical processes. Assuming that the seasonal variations of total ozone amounts are linear combinations of photochemical equilibrium variations and those due to atmospheric motions, the observed variations of the total ozone amount seem reasonably to be explained.The concept mentioned above implies that the time scale of ozone might be rather short in the lower stratosphere. The order of the half restoration time was estimated to be 10 to 102 days in the lower stratosphere. Thus the estimated time scale of ozone must be somewhat longer than that of the temperature in the lower stratosphere, of which variation usually shows its maximum in the midwinter in middle latitudes, while that of ozone shows its maximum in the late winter or early spring. As the maximum values of both quantities would appear in the early summer without air motions, the similarity in the phase differences of temperature and ozone suggests the validity of the concept of this paper. 相似文献
7.
An observation by UHF ST radar of a subsidence pattern on the right side of the exit region of a jet streak is reported. The onset of the subsidence pattern occurred at 23:30 UTC on the 29 November 1991, when a downward motion was initiated above 14 km. The injections of stratospheric air in this region seem to have an intermittent nature; they occur during at least three intervals during the lifetime of the subsidence pattern. Comparison of these results with an ECMWF analysis suggests that it is an unfolding case. However, observation of turbulent intensities w’ greater than 60 cm s−1 at the tropopause level also suggests the existence of a turbulent flux between the stratosphere and the troposphere. From the turbulence characteristics measured by the radar and the potential temperature profile obtained by radiosonde data, the eddy diffusivity at the tropopause level has been calculated. An eddy diffusion coefficient ranging between 5 and 7 m2 s−1 is found. From these values, and with the assumption of a climatological gradient of the volume mixing ratio of ozone in the lower stratosphere, it is possible to deduce a rough estimate of the amount of ozone injected from the stratosphere into the troposphere during this event. A rate of transfer of 1.5×1020 molecules of ozone per day and per square meter is found. 相似文献
8.
Diurnal variations in the vertical ozone density distribution have been calculated for the height range 40–150 km by extending our existing computer programs. The steady-state profiles were first calculated for fifteen constituents in the original program and three additional constituents (CH4, CO and CO2); the result was used as the initial condition for the time-dependent solution. The profile of the eddy diffusion coefficient used in this study was determined by comparing the model profile with the observations for CH4, whose density distribution is verysenstive to the eddy diffusion coefficient The effects of hydrogen and nitrogen compounds on the ozone density are discussed somewhat quantitatively; they reduce the ozone density mainly in the mesosphere and stratosphere, respectively. Special attention is given to the large depression of the ozone density at around 70–85 km, which has been obtained in many theoretical models but has neither been explained nor definitely confirmed by observations. Our time-dependent model indicates that the depression develops at night by the effect of hydrogen-oxygen and nitrogen-oxygen reactions and of eddy diffusion transports. The latter effect also produces an increase of the ozone density after midnight at some heights in the depression region. 相似文献
9.
David H. Shonting 《Pure and Applied Geophysics》1970,81(1):202-210
Summary Data are presented concerning Reynolds Stresses in wind waves obtained from time series records of horizontal and vertical velocity components of motion beneath the ocean free surface. The stresses, of the order of 25 dyne cm–2, are generally positive indicating horizontal momentum transfer downward through the dynamic wind wave regime. The magnitude of the observed stress increases with wind speed and sea state. The co-spectra show strong negative peaks which appear at the ambient wave frequencies and indicate that the correlations or eddy stresses of the gross wave motions are responsible for the momentum flux. This is a corroboration of results reported previously by the writer in this journal. 相似文献
10.
The results of 21 rocket flights of Arcas optical ozonesondes have been combined to produce estimates of the mean ozone distribution and its variability which apply to a broad range of latitudes. The flights were launched at sites from near the equator to 58°S and to 64°N in the years from 1965 to 1971. The local-noon mean ozone densities in molecules/cubic centimeter are 7.0×1010 at 50 kw, 6.7×1011 at 40 km, 3.1×1012 at 30 km, and 3.1×1012 at 20 km. The maximum density is 4.5×1012 at 24 km. The range of observed densities is about ±30% of the mean value at 50 km, ±40% at 40 km, ±40% at 30 km and +200%, –66% at 20 km. The variabilities at the higher altitudes in this set of observations are much less than that indicated from previous measurements. 相似文献
11.
The interannual variability of monthly mean January and July precipitation and its possible change due to global warming are assessed using a five-member ensemble of climate for the period 1871–2100, simulated by the CSIRO Mark 2 global coupled atmosphere–ocean model. In the 1961–1990 climate, for much of the middle to high latitudes the standard deviation of precipitation for both months is roughly proportional to the mean, with the coefficient of variation (C) typically 0.3–0.5. The variability there is shown to be largely consistent with that from a first-order Markov chain model of the daily rainfall occurrence, with the distribution of wet-day amounts approximated by a gamma distribution. Global distributions of Mark 2-based parameters of this stochastic model, commonly used in weather generators, are presented. In low latitudes, however, the variability from the coupled model is typically double that anticipated by the stochastic model, as quantified by an ‘overdispersion ratio’. C often exceeds one at subtropical locations, where rain is less frequent, but sometimes relatively heavy.The standard deviation of monthly mean precipitation S generally increases as the global model warms, with the global mean S in 2071–2100 in January (July) being 9.0% (11.5%) larger than in 1961–1990. Decreases in some subtropical locations occur, particularly where mean precipitation decreases. The global pattern of overdispersion is largely unchanged, however, and the changes in S can be related to those in the stochastic model parameters. Much of the increase in S is associated with increases in the scale parameter of the gamma distribution of wet-day amounts. Changes in C, which is unaffected by this parameter, are generally small. Increases in C in several subtropical bands and over northern midlatitude land in July are related to a decreased frequency of precipitation, and (to a lesser degree) changes in the gamma shape parameter. Some potential applications of the results to downscaling are discussed, and illustrated using observed rainfall from southeast Australia. 相似文献
12.
J. K. Angell 《Pure and Applied Geophysics》1980,118(1):378-386
Examined are temperature and ozone variations in the Northern Hemisphere stratosphere during the period 1958–77, as estimated from radiosondes rocketsondes, ozonesondes, and Umkehr measurements. The temperature variation in the low tropical stratosphere is a combination of the variation associated with the quasi-biennial oscillation, and a variation nearly out of phase with the pronounced 3-yearly temperature oscillation (Southern Oscillation) present in the tropical troposphere since 1963. Based on radiosonde and rocketsonde data, the quasibiennial temperature oscillation can be traced as high as the stratopause, the phase varying with both height and latitude. However, the rocketsonde-derived temperature decrease of several degrees Celsius in the 25–55 km layer of the Western Hemisphere between 1969 (sunspot maximum) and 1976 (sunspot minimum) is not apparent in high-level radiosonde data, so that caution is advised with respect to a possible solar-terrestrial relation.There has been a strong quasi-biennial oscillation in ozone in the 8–16 km layer of the north polar region, with ozone minimum near the time of quasi-biennial west wind maximum at a height of 20 km in the tropics. A quasi-biennial oscillation in ozone (of similar phase) is also apparent from both ozonesonde data and Umkehr measurements in 8–16 and 16–24 km layers of north temperate latitudes, but not higher up. Both measurement techniques also suggest a slight overall ozone decrease in the same layers between 1969 and 1976, but no overall ozone change in the 24–32 km layer. Umkehr measurements indicate a significant 6–8% increase in ozone amount in all stratospheric layers between 1964 and 1970, and in 1977 the ozone amount in the 32–46 km layer was still 4% above average despite the predicted depletion due to fluorocarbon emissions. The decrease in ozone in the 32–46 km, layer of mid latitudes following the volcanic eruptions of Agung and Fuego is believed to be mostly fictitious and due to the bias introduced into the Umkehr technique by stratospheric aerosols of volcanic origin. Above-average water vapor amounts in the low stratosphere at Washington, DC, appear closely related to warm tropospheric temperatures in the tropics, presumably reflecting variations in strength of the Hadley circulation. 相似文献
13.
Dr. Hans-Karl Paetzold 《Pure and Applied Geophysics》1953,24(1):83-94
Zusammenfassung Aus den bei Ballonaufstiegen, bei Mondfinsternissen und durch den Umkehreffekt gemessenen Ozonverteilungen werden für verschiedene geographische Breiten gemittelte Ozonverteilungen abgeleitet und mit den theoretisch photochemisch berechneten Verteilungen verglichen, wodurch der Spielraum der letzten erheblich eingeengt wird. — Die Diskrepanz zwischen der berechneten und der gemessenen Ozonverteilung unterhalb des Ozonmaximums in 23 km Höhe lässt auf eine bedeutende Wirkung des Massenaustausches in der Troposphäre und in der unteren Stratosphäre schliessen, der nach den Aequator hin stark zunimmt. — In mittleren und höheren Breiten tritt — vornehmlich im Frühjahr — ein zweites tieferes Ozonmaximum in 16 km Höhe auf, das photochemisch nicht zu erklären ist, sondern advektiv, durch aus polaren Breiten herzugeführtes Ozon bedingt wird.
Summary The mean ozone distribution for various geographical latitudes is derived from ozone distributions measured by means of balloon ascents, eclipses of the moon and the «Umkehreffekt» and compared with the theoretically calculated photochemical distributions, whereby the full scope of the latter is considerably limited. —The discrepancy between the calculated and the measured ozone distribution below the ozone maximum at 23 km altitude is a sign of a considerable effect of mass exchange in the troposphere and lower stratosphere which increases towards the equator. In the mean and higher latitudes we find — especially in spring — a second lower ozone maximum at 16 km altitude which cannot be explained photochemically but is probably due to advection, to ozone transported down from polar latitudes.相似文献
14.
Darrell F. Strobel 《Pure and Applied Geophysics》1989,130(2-3):533-546
A review of the important constraints on gravity wave induced diffusion of chemical tracers, heat, and momentum is given. Ground-based microwave spectroscopy measurements of H2O and CO and rocket-based mass spectrometer measurements of Ar constrain the eddy diffusion coefficient for constituent transport (K
zz
) to be (1–3)×105 cm2s–1 in the upper mesosphere. Atomic oxygen data also limitsK
zz
to a comparable value at the mesopause. From the energy balance of the upper mesosphere the eddy diffusion coefficient for heat transport (D
H
) is, at most 6×105 cm2s–1 at the mesopause and decreasing substantially with decreasing altitude. The available evidence for mean wind deceleration and the corresponding eddy diffusion coefficient for momentum stresses (D
M
) suggests that it is at least 1×106 cm2s–1, in the upper mesosphere. Consequently the eddy Prandtl number for macroscopic scale lengths is >3. 相似文献
15.
Evaluations of radiosonde soundings over North America and Europe, measurements aboard commercial airlines, and permanent ozone registrations at nineteen ground-based stations between Tromsö, Norway, and Hermanus, South Africa, yield three belts of higher ozone intrusion from the stratosphera and maximum values of the annual means at about 30°N, at between 40°–45°N and at about 60°N. A marked decrease of the annual mean values of the tropospheric ozone is detected towards the equator and the pole, respectively.In the northen hemisphere the maximum of the annual cycle of the tropospheric ozone concentration occurs in spring at high latitudes and in summer at mid-latitudes.For the tropical region from 30°S to 30°N a strong asymmetry of the northern and southern hemisphere occurs. This fact is discussed in detail. The higher troposphere of the tropics seems to be a wellmixed reservoir and mainly supplied with ozone from the tropopause gap region in the northern hemisphere. The ozone distribution in the lower troposphere of the whole tropics seems to be controlled by the up and down movements of the Hadley cell. The features of large-scale and seasonal variation of tropospheric ozone are discussed in connection with the ozone circulation in the stratosphere, the dynamic processes near the tropopause and the destruction rate at the earth's surface. 相似文献
16.
Takio Murakami 《Pure and Applied Geophysics》1977,115(5-6):1283-1301
The energy equation was applied to four limited regions to investigate the basic mechanisms through which area-averaged eddy kinetic energy is maintained during the northern winter. The regions selected for this study are as follows: extratropical North Pacific (24.2°N–44.6°N, 130°E–150°W), tropical eastern North Pacific (0°–19.6°N, 170°W–110°W), South China Sea and. Bay of Bengal (0°–19.6°N, 80°E–140°E), and Timor Sea and eastern Indian Ocean (0°–19.6°S, 80°E–140°E). The zonally averaged upper flows over the first region were found to be barotropically stable. In contrast, they were barotropically unstable over the second region; namely, eddy motions over the tropical eastern North Pacific are maintained by receiving energy from zonal flows via barotropic interaction. The third and fourth regions are characterized by the importance of the conversion process between eddy available potential and eddy kinetic energy.Contribution No. 77-5, Department of Meteorology, University of Hawaii, USA. 相似文献
17.
Using over 2200 ozonesonde ascents, published byHering andBorden [1]–[5] and byDütsch
et al. [6], [7], the average vertical distribution of the ozone mixing ratio is found for different latitudes and for different seasons up to a height of 30 km. The method by which the ozone formed at great heights in low latitudes becomes concentrated in the lower stratosphere of high latitudes is discussed, and the meridional circulation theory is strongly suggested.Oxford, May 1972. 相似文献
18.
W. Lawrence Gates 《Pure and Applied Geophysics》1972,96(1):217-227
Summary From numerical solutions of a wind-driven homogeneous ocean model, anegative lateral eddy viscosity of the order 104 cm2 sec–1 is inferred from the large-scale time-dependent currents in the interior of an enclosed shallow basin. The transient Rossby waves in this region produce a systematic convergence of eddy momentum at the latitude of the maximum average eastward current, and thus effect a transfer of zonal momentum from the large-scale eddies to the mean flow. In this sense they are analogous to the Rossby waves in the atmospheric general circulation, and it is speculated that such waves may help to maintain the mean zonal ocean currents. Although this negative viscosity induced by the large-scale transients is relatively small compared with the prescribed lateral viscosity of 108 cm2 sec–1 and should be given a quite different physical interpretation, it is evidently an important viscous effect for the mean flow in the interior of the basin. The prescribed viscosity, on the other hand, is effective in controlling the model's simulated sub-grid scale dissipation, which occurs almost entirely in the nearby steady boundary currents. 相似文献
19.
The influence of the Earth's inertia ellipsoid triaxiality, both on the motion of the Angular Velocity Vector with respect to Tisserand's reference frame (hereinafter – AVV,T), the motion of the same vector in Space (hereinafter – AVV,S) as well as on the motion of Tisserand's Reference Frame in Space (hereinafter – TRF,S) is considered. It is shown that the observable effects are as follows: (1) in all three types of motions (AVV,T), (AVV,S) and (TRF,S) there are significant (observable) semidiurnal components which may be detected by modern GPS- and VLBI-measurements. Additionally, there is a long-periodic perturbation of (TRF,S) motion which is rather small for the Earth, but may be significant for the other planets of the Solar System (if the triaxiality of the inertia ellipsoid is sufficiently large and whenever the orbital and diurnal rotations are synchronous and, at the points of equinoxes, the orientation of the planet's principal equatorial moments of inertia is invariable in space). For the case of the Earth, the results of our calculations are compared with the results of modern GPS-observations. 相似文献
20.
Jan. Vondrák 《Surveys in Geophysics》1999,20(2):169-195
Earth rotation parameters (ERP) in the interval 1899.7–1992.0 are obtained from re-analysis of the observed latitude/universal time variations by optical astrometry. Hipparcos Catalogue is used to define the celestial reference frame, within which the ERP are described, with special care devoted to 'problematic' double and/or multiple stars. The terrestrial reference frame is defined by the adopted latitudes/longitudes of participating instruments and their secular motions as given by the NUVEL-1 NNR model of plate motions, and it is chosen to be very close to the International Terrestrial Reference Frame (ITRF). More than four million observations made with 48 different instruments at 31 observatories, located all over the world, are utilized to determine polar motion, celestial pole offsets and (after 1956) universal time UT1, all at 5-day intervals. Along with these parameters, the combinations of Love and Shida numbers, governing the tidal variations of the local verticals at individual observatories, are also determined. The analysis of the results covering almost a century, namely the long-periodic polar motion and length-of-day changes, is presented. 相似文献