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1.
It could be shown by measurements of the air conductivity and using a mean profile for the ionization rate that experimental and theoretical values of the recombination rate of small ions based on a three body recombination process (Thomson) are in very good agreement up to 20 km altitude. The divergency of the experimental and theoretical curves above 20 km can be interpreted by assuming that there exists in this altitude region a crossover from the three body recombination to a two body recombination process. The value of the recombination coefficient is about 4·10–7 cm3 s–1 in 25 km altitude, compared with 1.4·10–6 cm3 s–1 at ground level. Furtheron it was possible for the first time to get some experimental data of attachment coefficients up to 13 km from simultaneous measurements of the air conductivity and Aitken nuclei concentration. These values are in good agreement with those obtained by theoretical considerations.  相似文献   

2.
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   

3.
Summary Spectrometric experiments performed, in November 1976, within the framework of the Latitude Survey Mission on board the NASA Convair 990 from Ames Research Center are briefly deseribed. The results presented concern odd nitrogen molecules, HCl and water vapor. In terms of vertical column density, HNO3 is predominant over NO+NO2 at all latitudes higher than 40 degrees. A seasonal variation of NO2 abundance is observed, with larger values in the summer hemisphere at high latitude. The mean zenith column density of HCl above 11 km is 1.5×1015 mol.cm–2, with no evidence for any seasonal or climatic variation. Local number densities as high as 1.4×1010 mol.cm–3 for HNO3 and 5.4×1014 mol.cm–3 for water vapor have been measured during the same flight near 11 km.  相似文献   

4.
Warneck  P.  Junge  C. E.  Seiler  W. 《Pure and Applied Geophysics》1973,106(1):1417-1430
The consumption of both methane and carbon monoxide in the lower stratosphere is due predominantly to reaction with OH radicals. The possibility of deriving OH concentration from measurements of the decrease of CH4 and CO mixing ratios above the tropopause is explored. The observations and the basic chemistry are briefly summarized. Simple one-dimensional diffusion models are employed to derive expressions for the decrease of CH4 and CO mixing ratios with altitude above the tropopause, and the influence of important parameters is discussed. Vertical air velocities resulting from large-scale organized mean motion and from synoptic variations are shown to distort the concentration altitude profiles of methane and carbon monoxide, respectively. Suitable averaging of observational data is required to eliminate the effects due to vertical motion. Then a reliable value for the effective OH number density should be obtainable. At present an estimate of 4×106 molecules/cm3 is derived.  相似文献   

5.
Summary Theoretical considerations are put forward for identifying the Dynamic and Static Methods of Diffusion measurements of aerosol particles. On the basic of this equality the Exhaustion Method of Diffusion developed byPollak andMetnieks for the size-frequency resolution of a heterogeneous aerosol by Dynamic Diffusion Methods should be applicable to Static Methods. This hypothesis is tested using a Pollak-Nolan nucleus counter as decay vessel. It is shown that turbulence in the counter is the most serious obstacle against this type of approach to finding the size components of an aerosol. The time involved, the high humidity in the counter and a hypothetical nucleus-free zone are other major difficulties for relatively large Aitken nuclei. It is established, however, that for particles whose diffusion coefficient is of the order of 10–3 cm2 sec–1, the proposed method should be quite workable.  相似文献   

6.
In the light of new measurements of small aerosol particles in the lower stratosphere, some of the old investigations—which were only published in part in scientific journals—are reviewed and compared. The discussion focuses on whether the Aitken nuclei (AN) size distribution up to 20 km can be described by Junge’s or log-normal density functions and under what circumstances one can find a bimodal distribution of these particles. The ion flow in correlated to the stratospheric pollution (intercept with the jet aircraft, volcanic activity) and is, in mean, directly proportional to the aircraft altitude in the undisturbed lower stratosphere. Note: The GCCPR, Univ. Missouri at Rolla, reports quoted in the article can be obtained from the author.  相似文献   

7.
Calculating the global mass exchange between stratosphere and troposphere   总被引：1，自引：0，他引：1  
Large-scale cross-tropopause mass fluxes are diagnosed globally from 1979 to 1989 for Northern Hemisphere winter conditions (December, January, and February). Results of different methods of approaches with regard to the definition of the tropopause and the way to calculate the mass fluxes are compared and discussed. The general pattern of the mass exchange from the tropopause into the stratosphere and vice versa agrees fairly well when using different methods, but the absolute values can differ up to 100%.An inspection of the temporal development of the mass fluxes for solstice conditions indicates a complex picture. Whereas a permanent significant downward flux from the stratosphere into the troposphere is detected for latitude regions nearly between 25°N and 40°N and between 30°S and 50°S (initiated by the poleward branches of the Hadley cells), a non-uniform behaviour is observed at higher latitude bands. Periods of strong mass exchange from the troposphere into the stratosphere are disrupted by periods of an opposite mass exchange. A comparison of the stratoshere-troposphere (ST) exchange with the exchange at higher altitudes through surfaces, quasi-parallel to the tropopause, excludes a general connection. Only a few strong upward directed ST mass exchange events have counterparts at higher altitudes. The composition of the stratosphere may be influenced directly by the ST exchange only in a thin layer above the tropopause.  相似文献   

8.
Summary The analysis is given for an improved aspiration-type mobility chamber which suppresses the growth of boundary layers and turbulence at the electrodes by employing converging-channel geometry. The distribution of small ions in air as a function of their mobility is determined from data taken with the converging-channel chamber. The results show that the distribution of positive ions is quite stable with an average mobility of about 1.35 cm2 volt–1 sec–1 (at STP). The negative-ion distribution is broader, less stable, and the average mobility shifts from about 2.1 to 1.7 cm2 volt–1 sec–1 with the addition of water vapor. The effect of Aitken nuclei upon the mobility distribution is also discussed. The results are compared with previous measurements.  相似文献   

9.
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   

10.
Summary In Northern Bohemia 33 research flights were made during which concentration of giant condensation chloride nuclei was measured up to a height of 3,500 m above the earth's surface. Chloride particles were determined by traces left by them in a sheet of gelatine with silver nitrate (Liesegang circles). The actual size of the particles was obtained by comparison of particles of a known size, falling in a sedimentation tube, with images in the sensitive sheet, and the result was adapted to the analysis of samples during the flight. For each level at which a sample was exposed the spectrum of the sizes of nuclei was determined. During the year the average concentration of the giant chloride nuclei at a height of 100 m above the earth was 7.3×10–3 cm–3. At greater heights concentration of the nuclei decreased successively, so that at 2,000 m it was only 0.3×10–3 cm–3 and above the level of 3,000 m the nuclei occurred sporadically, on the whole. Under the influence of atmospheric exchange the concentration of the nuclei in the boundary layer up to 1,000 m above the earth's surface changes considerably both during the day and during the year. The highest concentration occurs at a height of several hundred metres above the earth in the winter month, at the morning and evening hours, i.e. during a more stable temperature lapse rate. From the established concentrations of the nuclei relation between the turbulent diffusion coefficient and the height above the earth was determined. Its average value during the year increases up to a height of 300 to 400 m above the earth. Above this level it decreases roughly according to the relation ofKz –6/7. The exponent changes not only with temperature stratification (with the time of day and year), but also with the average wind speed. For sodium-chloride particles of 2.5 in diameter the maximum value of turbulent diffusion coefficient (at level of 400 m), reaches about 18×103 cm2 sec–1 while the minimum value is about 5×103 cm2 sec–1 (above 2,000 m).  相似文献   

11.
Augustine, an island volcano in Lower Cook Inlet, southern Alaska, erupted in January, 1976, after 12 years of dormancy. By April, when the eruptions ended, a new lava dome had been extruded into the summit crater and about 0.1 km3 of pyroclastics had been deposited on the island, mainly as pyroclastic debris avalanches and pumice flows. The ventclearing phase in January was highly explosive and we have been able to document 13 major vulcanian eruptions.The timing, thermal energy, mass loading of fine particles and the horizontal dispersion of these eruption clouds were determined from radar measurements of cloud height, reports of pilots flying in plumes, satellite photography, seismic records and infrasonic detection of air waves. A lower estimate of the mass of fine (r < 68 μm) particles injected into the troposphere from the 13 main eruptions in January is 5.5–18 × 1012 g. The corresponding mass loading of fine particles within individual eruption clouds is 0.3–1 g m−3. We calculated thermal energies of 4 × 1014 to 35 × 1014 J for individual eruptions by applying convective plume rise theory to observed cloud heights and seismically determined eruption durations. This energy range compares favorably with the 4–16 × 1014 J of thermal energy, calculated from the cooling of juvenile material contained in a typical eruption cloud.The vulcanian eruption clouds stayed intact for at least 700 km downwind. Satellite images in both visible and infrared wavebands, showing the Gulf of Alaska just after sunrise on January 23, reveal a series of puffs strung out downwind from the volcano, 20–30 km in diameter and with their tops at altitudes of about 8 km, overlying a continuous plume at altitude 4 km. Each puff corresponded to a seismically and infrasonically timed eruption. A substantial portion of the material injected into the atmosphere between January 22 and 25 was rapidly transported by the subpolar jet stream through southwestern Canada and the western United States, then northeast across the States into the Atlantic. The clouds were observed passing over Tucson, Arizona, on January 25 at an elevation of 7 km.Several of the eruptions penetrated into the stratosphere. Sun photometer measurements, taken at Mauna Loa, Hawaii, six weeks after the eruption, showed an increased stratospheric optical thickness of 0.01 (wavelength 0.5 μm), which decayed in about 5 months. The maximum column mass loading of the veil was 4–10 × 10−7 g cm−2. The mass of the veil, spread-ever a fourth of the earth's surface, is 10 to 100 times larger than can be accounted for by assuming that injected ash and converted sulfate particles from the 13 main Augustine eruptions are the only components contributing to the stratospheric turbidity observed at Mauna Loa.  相似文献   

12.
We used regression analyses of water samples from 18 lakes, nine rivers, and one spring in Ethiopia to (a) test the hypothesis that water bodies of relatively higher salinity (K25>1000 μS cm−1) have a different conductivity to salinity relationship than waters of lower salinity (K25 < 1000 μS cm−1), and (b) develop models to predict total cations and salinity from conductivity that can be used for Ethiopian waters and other African aquatic systems of similar chemical composition. We found no statistical difference in the bilogarithmic relationships (total cations vs. conductivity; salinity vs. conductivity) for waters of higher salinity (K25 > 1000 μS cm−1) and waters of lower salinity (K25 < 1000 μS cm−1). However, comparison among our models and models from the literature suggests that developing separate equations for low and high salinity water bodies has some merit. We believe that the equations developed in this study can be used for Ethiopian waters and other African waters within the range of conductivity in this study.  相似文献   

13.
Height distribution of the stratospheric aerosol extinction coefficient was measured in the altitude range 10 to 20 km by a balloon-borne multi-color sunphotometer in May 1978. It is demonstrated that detailed structures of the distribution of stratospheric aerosol can be remotely measured by the solar occultation method as well as by lidar andin situ particle counter observations. In the aerosol layer appearing at 18 km altitude the extinction coefficient at 800–1000 nm wavelength reached to 3×10–7 m–1, which was reasonable compared with lidar observations. Wavelength dependence of the aerosol optical depth was crudely estimated to be proportional to –1.5.  相似文献   

14.
 Two methods were used to quantify the flux of volcanic sulphur (as the equivalent mass of SO2) to the stratosphere over different timescales during the Holocene. A combination of satellite-based measurements of sulphur yields from recent explosive volcanic eruptions with an appropriate rate of explosive volcanism for the past 200 years constrains the medium-term (∼102 years) flux of volcanic sulphur to the stratosphere to be ∼1 Mt a–1, with lower and upper bounds of 0.3 and 3 Mt a–1. The short-term (∼10- to 20-year) flux due to small magnitude (1010–1012 kg) eruptions is of the order of 0.4 Mt a–1. At any time the instantaneous levels of sulphur in the stratosphere are dominated by the most recent (0–3 years) volcanic events. The flux calculations do not attempt to address this very short timescale variability. Although there are significant errors associated with the raw sulphur emission data on which this analysis is based, the approach presented is general and may be readily modified as the quantity and quality of the data improve. Data from a Greenland ice core support these conclusions. Integration of the sulphate signals from presumed volcanic sources recorded in the GISP2 core provides a minimum estimate of the 103–year volcanic SO2 flux to the stratosphere of 0.5–1 Mt a–1 over the past 9000 years. The short-term flux calculations do not account for the impact of rare, large events. The ice-core record does not fully account for the contribution from small, frequent events. Received: 27 September 1995 / Accepted: 13 December 1995  相似文献   

15.
Summary Temperature and conductivity measurements show, that in the Southern part of Transdanubia (the part of Hungary which lies Westwards from Danube) the heat flow is about 2–2.4·10–6 cal/cm2 sec. Eastward from the Danube, in the Hungarian Plain estimates are even higher, and vary between 2.3·10–6 and 2.8·10–6 cgs. The gradient of temperature is everywhere quite high, 5.0 resp. 5.8·10–4 deg. C/cm on the average. Thus, at a depth of 1000 m, the virgin rock temperature is about 60–70 deg. C, at 2000 m about 110–130 deg. C.  相似文献   

16.
Summary The measurement of condensation nucleus concentration from an aircraft is considered and preliminary observations made with a photo-electric condensation nucleus counter discussed. It is concluded that at heights up to 6000 ft concentrations of condensation nuclei vary, from 200 cm–3 in clean maritime air to 5 × 103 cm–3 generally over large industrial areas and 35 × 103 cm–3 downwind of specific industrial sources. It appears that sea spray makes a contribution to the nucleus population.Mr. G. J.Day, B. Sc., Meteorological Research Flight, Royal Aircraft Establishment,Farnborough, Hants. (Great Britain).  相似文献   

17.
Zusammenfassung An künstlich erzeugten unterkühlten Nebeln wurde die Eiskeimbildung his –85°C untersucht. Bei tiefen Temperaturen treten so hohe Eisteilchendichten auf, daß sie erst an fotografischen Aufnahmen der Eiswolken bei geeigneter Vergrösserung bestimmt werden konnten. Die von anderer Seite bei –40°C behauptete und mit homogener Keimbildung gedeutete Vervielfachung der Eisteilchenzahl konnte nicht festgestellt werden. Meistens steigt die Teilchendichte spätestens bei –30°C stark an, bleibt dann aber zwischen –40°C und –65°C praktisch konstant bei im Mittel 174 Eisteilchen pro cm3. Dieser Uebergang, der an der vollständigen Vereisung der Tröpfchenwolke direkt zu erkennen ist, findet je nach Wetterlage zwischen –40 und –50°C statt und muß somit noch durch Gefrierkerne hervorgerufen sein.Erst bei Annäherung an –70°C bilden sich in Uebereinstimmung mit früheren Ergebnissen des Verf. ausserordentlich dichte und beständige Nebel aus feinsten Eisteilchen mit. Anzeichen von homogener Bildung.
Summary The formation of ice germs down to –85°C was investigated with artificial supercooled nebula. At low temperatures the densities of ice particles are so high that they could only be determined by photographs of the ice clouds with suitable enlargements. The multiplication of the number of ice particles which, according to assertions from another side, should take place at –40°C and which was interpreted by homogeneous formation of germs, could not be ascertained. In most cases the density of particles increases considerably at –30° at the latest, and then remains practically constant between –40 and –65°C with an average of 174 ice particles per cm3. This transition which can directly be observed at the complete icing of the cloud of droplets, takes place — according to the weather conditions —between –40 and –50°C and must, therefore, also be caused by freezing nuclei.Extremely dense and constant nebula consisting of the finest ice particles with signs of homogeneous formation are only formed with an approximation to –70°C, which is in good agreement with earlier results of the author.
  相似文献   

18.
Real-time N2O measurements have been madein situ at the South Pole, Antarctica, north and south of the equator from on board the Alpha Helix and over the Pacific Ocean on several aircraft flights from the U.S. to New Zealand, Australia and 90°S. In addition, an automated EC-GC has been operated for the past year intermittently monitoring N2O in surface air at a rural site in the wheatlands of eastern Washington state. The data obtained are consistent and in agreement with the data obtained from the analyses of a large number of samples collected both from ground stations and a variety of aircraft flights made in the southern and northern hemisphere. The observed global data show no interhemispheric differences. The present concentration of N2O in the troposphere is measured to be 330±3 ppbv. Its vertical distribution in the troposphere is very uniform. A small decrease (2–3 percent) across the tropopause is characteristically observed in the high altitude Learjet flights.  相似文献   

19.
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   

20.
An improved resonant fluorescence instrument for measuring atomic oxygen concentration was developed to avoid the Doppler effect and the aerodynamic shock effect due to the supersonic motion of a rocket. The shock effect is reduced by adopting a sharp wedge-shaped housing and by scanning of the detector field of view to change the distance between the scattering volume and the surface of the housing. The scanning enables us to determine absolute values of atomic oxygen concentration from relative variation of the scattered light signal due to the self-absorption. The instrument was calibrated in the laboratory, and the numerical simulation reproduced the calibration result. Using the instrument, the altitude profile of atomic oxygen concentration was observed by a rocket experiment at Uchinoura (31°N) on 28 January 1992. The data obtained from the rocket experiment were not perfectly free from the shock effect, but errors due to the effect were reduced by the data analysis procedure. The observed maximum concentration was 3.8× 1011 cm−3 at altitudes around 94 km. The systematic error is estimated to be less than ±0.7×1011 cm−3 and the relative random error is less than±0.07× 1011 cm−3at the same altitudes. The altitude profile of the OI 557.7-nm airglow was also observed in the same rocket experiment. The maximum volume emission rate was found to be 150 photons cm−3 s−1 at 94 km. The observed altitude profiles are compared with the MSIS model and other in situ observations.  相似文献   

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