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1.
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   

2.
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   

3.
Summary The validity ofBoltzmann's energy distribution law as applied to the charge distribution of monodisperse aerosols, i.e. aerosols which contain particles of one size only, was studied with improved equipment now available.Since monodisperse aerosols with particle size of about 10–6 cm cannot yet be produced and because aerosols in general contain particles of different sizes, polydisperse aerosols stored in a large gasometer were used for the investigation. The composition and the average radius of these aerosols heterogeneous in particle size were determined by the Exhaustion Method employing a diffusion battery without end-pieces or connecting tubing.The experimental curve found for the ratio of the uncharged (N 0) to the charged (N) nuclei versus radius (r) of the particles deviates for all investigated radii between 0.5 and 4.0·10–6 cm from the theoretical curve of a monodisperse aerosol computed according to the Boltzmann law. For radii smaller than about 1.4·10–6 cmN 0/N is smaller than that given by Boltzmann's law, for radii greater than 1.4·10–6 cm larger, or, in other words, forr<1.4·10–6 cm the number of charged nuclei found in the aerosols investigated is greater than that predicted byBoltzmann's law, and forr>1.4·10–6 cm smaller.The deviations from the theoretical curve forr>1.4·10–6 cm can be fully explained by the polydispersity of the aerosols used; forr<1.4·10–6 cm the deviations are too big to be attributed to polydispersity. From this it must be concluded thatBoltzmann's distribution law is not valid for the charge distribution of homogenous aerosols containing nuclei with radii smaller than about 1.4·10–6 cm.The equivalent radius as deduced from a substitute monodisperse aerosol in charge equilibrium for which theBoltzmann law is assumed valid, deviates in the range of 1.0·10–6<r<3.0·10–6 cm (or 90%>100N 0/Z>55%) on the average by up to 35% from the actual mean radius of the investigated polydisperse aerosols computed from the radii of their singly sized components.
Zusammenfassung Die Gültigkeit desBoltzmannschen Gesetzes der Energieverteilung für die Ladungsverteilung von monodispersen Aerosolen, das heisst Aerosolen, welche Teilchen von nur einer Grösse enthalten, wurde mit den jetzt zur Verfügung stehenden verbesserten Mitteln studiert.Da monodisperse Aerosole mit Teilchengrössen von ungefähr 10–6 cm noch nicht erzeugt werden können und Aerosole im allgemeinen Teilchen von verschiedenen Grössen enthalten, wurden für die jetzige Untersuchung polydisperse Aerosole, welche in einem grossen Gasometer gespeichert waren, benützt. Die Zusammensetzung und der mittlere Radius dieser Aerosole mit heterogener Teilchengrösse wurden nach der Exhaustions-Methode unter Benützung einer Diffusionsbatterie ohne Endstücke oder Verbindungsröhren bestimmt.Die experimentell gefundene Kurve, welche das Verhältnis der ungeladenen (N 0) und geladenen (N) Kerne als Funktion des Radius (r) darstellt, weicht für alle untersuchten Radien zwischen 0.5 und 4.0·10–6 cm von der theoretischen Kurve eines monodispersen Aerosols, wie sie nachBoltzmann's Gesetz berechnet wird, ab. Für Radien kleiner als ungefähr 1.4·10–6 cm ist das VerhältnisN 0/N kleiner als es durchBoltzmann's Gesetz gegeben wird, für Radien grössen als 1.4·10–6 cm grösser oder, mit anderen Worten, fürr<1.4·10–6 cm ist die Zahl der geladenen Teilchen, die in den untersuchten Aerosolen gefunden wurde, grösser als die vonBoltzmann's Gesetz vorausgesagte, und fürr>1.4·10–6 cm kleiner.Die Abweichungen von der theoretischen Kurve fürr>1.4·10–6cm können vollkommen durch die Polydispersität der benützten Aerosole erklärt werden; fürr<1.4·10–6 cm sind die Abweichungen zu gross, als dass sie der Polydispersität zugeschrieben werden könnten. Daraus muss geschlossen werden, dassBoltzmann's Verteilungsgesetz für die Ladungsverteilung eines homogenen Aerosols, welches Kerne mit Radien kleiner als ungefähr 1.4·10–6 cm enthält, nicht gültig ist.Der äquivalente Radius, wie er von einem im Ladungsgleichgewicht befindlichen, monodispersen Ersatz-Aerosol, für welchesBoltzmann's Gesetz als gültig angenommen wird, abgeleitet werden kann, weicht im Bereich von 1.0·10–6<r<3.0·10–6 cm (oder 90%>N 0/Z>55%) durchschnittlich bis zu 35% vom tatsächlichen mittleren Radius des untersuchten polydispersen Aerosols ab.

The research reported in this article has been supported in part by the Geophysics Research Directorate of the Air Force Cambridge Research Laboratories, through the European Office of the Air Force Research Division, United States Air Force under Contract AF 61(052)-26, by the United States Department of Army, through its European Research Office, Contract DA-91-591-EUC-1282 & 1657 and by the Instrumentation Engineering Physics & Analysis Laboratory of the General Electric Co., Schenectady, New York under Retainer Agreement.  相似文献   

4.
Summary Many writers treated on the problem of dynamic instability of westerly flow due to the excessive horizontal shear, and the present author discusses the corresponding dynamic instability due to the vertical shear. The critical vertical shear in indifferent stratification is given by the condition — the meridional component of absolute vorticity vanishes, — and is an approximate negative valueof 10–4 sec –1 in middle latitude. However the critical vertical shear in normal stable stratification is a fairly large negative value of 2 sec–1. It might be emphasized that the problem of this study differs fromRichardson's criterion of turbulence, for the present author discusses the condition under which the zonal flow is dynamically stable, whileRichardson expressed the condition under which the turbulence will decrease.  相似文献   

5.
Airborne and ground-based (correlation spectrometer, cascade impactor, and photoelectric counter together with intake filter probes) measurements are described for the volcanic emissions from Popocatépetl volcano (Mexico) from December 23, 1994 to January 28, 1995. Measurements of SO2 restarted 48 h after the eruption onset of December 21, 1994. Maximum sulfur dioxide (4560 t d−1) plus 3.8×104 t d−1 of particulate matter were ejected on December 24, 1994. The maximum rate of ejection occurred coincidentally with the maximum amplitude of harmonic tremor and the maximum number of seismic type B events. Sulfur dioxide emission rates ranged from 1790 to 2070 t d−1 (December 23–24, 1994). Afterwards, sulfur dioxide emission rates clearly indicated a consistent decline. However, frequent gas and ash emission puffs exhibited SO2 fluxes reaching values as high as 3060 t d−1. The emission SO2 baseline for the period of study (February 1994–January 1995) was about 1000 t d−1. Ejection velocity of particulate matter was approximately 270 m s−1 reaching a height of about 2.5 km over the summit. The immediate aerosol dispersion area was estimated at 6.0×104 km2 maximum. The microscopic structure of particles (aerosol and tephra) showed a fragile material, probably coming from weathered crustal layers. X-ray fluorescence and neutron-activation analysis from the impactor samples found the following elements: Si, Al, Ca, S, P, Cl, K, Ni, Fe, Ti, Sc, Cu, Zn, Mn, Sr, Cr, Co, Y, Br, Se, Ga, Rb, Hg and Pb. Morphological analysis shows that ash samples might be from pulverized basaltic rock indicating that the Popocatépetl eruption of December 21, 1994 was at low temperature. The microscopic structure of puff material showed substance aggregates consisted of fragile rock, water and adsorbed SO2. These aggregates were observed within water droplets of approximately 1 mm and even larger. Sulfur transformations in the droplets occurred intensively. Volcanic ash contained 5–6% of sulfur during the first expulsion hours. Elemental relative concentrations with respect to Al show that both Si and S have relative concentrations >1, i.e., 13.73 and 2.17, respectively in agreement with the photoelectric counter and COSPEC measurements.  相似文献   

6.
Summary The annual mean distribution of the surface stress curl over the Northern Hemisphere has been estimated from the horizontal vorticity advection in the atmosphere by using the upper-wind statistics as published byCrutcher [2]3). The results are used to compute the wind-driven mass transport (Sverdrup transport) in North Atlantic and North Pacific. The calculated intensity of the Gulf Stream is largest at the latitude 35°N, where a mass transport of 45×106 tons sec–1 is obtained; for the maximum intensity of the Kuroshio current a value of 60×106 tons sec–1 is obtained.Research supported in part by the Section of Atmospheric Sciences, National Science Foundation, Grant GP-2561.The research for this study was started by the author at the Department of Meteorology and Oceanography, The University of Michigan, Ann Arbor, Mich.  相似文献   

7.
Zusammenfassung Es wird über die Ergebnisse einer Reihe von Untersuchungen der Schwebstofftechnischen Abteilung (Aerosolgruppe) des Physikalischen Institutes der Universität Mainz auf dem Gebiet der Herstellung und Vermessung von hochdispersen Aerosolen (r=1.10–4 cm bis 1.10–5 cm) berichtet. Hierbei erstreckt sich die Vermessung eines Aerosols nicht nur auf die Bestimmung der Teilchenzahl, sondern auch auf Teilchengrössen, Grössenverteilung (Spektrum), Teilchenmassen, elektrische Teilchenladung und Ladungsverteilung.Die physikalische Untersuchung der Bewegungsvorgänge an den Grenzflächen sehr schnell bewegter Gaslamellen in Flüssigkeiten führte zu einem Zerstäubungsverfahren für Flüssigkeiten (Lösungen, Schmelzen), das mit tragbarem technischen Aufwand Aerosole (Rauche und Nebel) mit Teilchengrössen von 1.10–5 bis 1.10–4 cm in Mengen von einigen Gramm/Minute herzustellen gestattet. Hiermit ist die Möglichkeit zur Herstellung von sog. Normalaerosolen mit definierten Spektren aus physiologischer Kochsalzlösung, Sebazinsäure, Siliconoel, geschmolzenen Paraffinen und Zinn gegeben, die meßtechnisch von grosser Bedeutung sind.Als ein Ergebnis der Untersuchung rasch rotierender Gaslamellen wird gezeigt, daß es möglich ist durch spiralförmige Führungsflächen diese zu so schnellen Spiralbewegungen, mit kleinem Durchmesser (0.01 bis 0.1 cm) zu zwingen, daß Radialbeschleunigungen von 10+3 bis 10+4g auftreten, die zum Abscheiden der Aerosolteilchen (bis zur=10–4 cm) auf einem die Spiralströmung umgebenden engen Zylinder ausreichen. Durch Ueberlagerung eines starken elektrischen Radialfeldes kann der Abscheidungseffekt auf beliebig kleinere Teilchen ausgedehnt werden.Das Verfahren lässt eine Verwendung als Aerosol-Filter zu, desgleichen eine Verwendung als Aerosolspektrometer, da die einzelnen Teilchengrössen räumlich voneinander getrennt, auf durchsichtigen Zylindern aus Kunststoff-Folie aufgefangen und untersucht werden können.Eine endgültige praktische Untersuchung der bis heute meßtechnisch verwendeten Depositionsverfahren zeigt, so daß die Gravitationsdeposition besonders schonend und zuverlässig ist. Diese Erkenntnis führte zur Schaffung eines einfachen für die Praxis im Gelände, Industrie und Bergbau geeigneten Entnahmegerätes für Aerosolproben, wobei die entnommenen Aerosolproben, in einer Zentrifuge auf Glasplättchen niedergeschlagen, der mikroskopischen Untersuchung zugänglich gemacht werden.Auf dem heute wichtigen Gebiet der Untersuchungen und Nachweise radioaktiver Aerosole führt eine systematische Untersuchung und Weiterentwicklung derSilson-Kammer des Diffusionstyps durch konstruktive Verbindung mit einer Kompressionskältemaschine zu einem einfachen praktisch brauchbaren Untersuchungs-und Nachweisgerät, durch dessen Messzellen disperse Systeme beliebiger Art in kontinuierlichem Strom hindurchgeleitet und mit sehr hoher Empfindlichkeit auf vorhandene Aktivität untersucht werden können.
Summary A report is given on the results of a series of investigations regarding the production and surveying of aerosols of high dispersion (r=1.10–4 cm to 1.10–5 cm) carried out by the section dealing with suspended matter (Aerosolgroup) of the Institute of Physics in the University of Mainz.Hereby, the surveying of aerosols comprises not only the determination of the number of particles but also their size, their size distribution (spectrum), their mass, their electrical charge and charge distribution.The physical investigation of the motion phenomena at the boundary surfaces of very rapidly moving gas laminae in liquids led to a process of spraying liquids (solutions, molten masses) which with worthwhile technical effort enables production of aerosols (smokes and fogs) in quantities of several grammes per minute having particle size of from 1.10–4 to 1.10–5 cm. Thus, the possibility is given to prepare so-called normal aerosols from physiological solution of sodium chloride, from sebacic acid, silicone oil, molten paraffins and tin with defined spectra which is of great importance for measuring technique.As a result of investigating rapidly rotating gas lamellae it is shown that it is possible to force them by means of spiral guide surfaces to such rapid spiral motions, with small radius (0.01 to 0.1 cm), that radial accelerations of 10+3 to 10+4 g occur which suffice that aerosol particles (up tor=10–4 cm) are deposited on a narrow cylinder surrounding the spiral stream. By superimposing a strong electric radial field the deposition can be extended to any smaller particles.The process can be used as an aerosol filter, and also as an aerosol spectrometer so that the individual particle sizes can be separated from each other in space, caught on transparent cylinders of plastic foil and examined.A final practical investigation of the deposition methods so far used for measuring purposes shows that the deposition by gravity is particularly gentle and reliable. This knowledge led to the construction of a simple instrument for sampling aerosols suitable for outdoor use, in industry and mining whereby the aerosol samples taken are deposited on glass slides by a centrifuge and made available for microscopic investigation.In the field of examining and detecting radioactive aerosols, so important nowadays, a systematic investigation and development of theWilson-chamber of the diffusion type combined with a compression refrigerating machine leads to a simple and practical testing instrument through the measuring cells of which any disperse system can be conducted in a continuous stream and examined with very high sensitivity for any radioactivity present.
  相似文献   

8.
During a study of the growth of cloud drops by condensation the evolution of cloud drop size spectra with height above cloud base was determined for maritime aerosols, and for continental aerosols containing aerosol particles of mixed composition. Air parcel models were used in which the parcel was either completely closed to mass and heat transfer (strictly adiabatic models), or open to heat transfer and to partial or complete mass transfer (entrainment models). It was found that adiabatic models and models which consider the entraining of air devoid of aerosol particles predict drop size distributions which are considerably narrower than those observed in non-precipitating cumulus clouds, and have only a single maximum. On the other hand, relative broad drop size distributions and distributions with a double maximum — as they are observed in atmospheric clouds — are predicted if the entrainment of both air and aerosol particles are considered in the condensation model. Our results support the findings ofWarner (1973) which were obtained for a purely maritime aerosol.  相似文献   

9.
Profiles of electrical conductivity in the troposphere and stratosphere were measured by balloon-borne conductivity sondes at Garmisch-Partenkirchen, West Germany, from January to May, 1980, when volcanic activity was low. The aerosol concentration has been deduced from the relative decrease of conductivity from surrounding values by assuming the effective attachment coefficient of ions to aerosols. A prominent decrease of the conductivity near the tropopause is usually observed indicating high concentrations of Aitken particles (500–1000 cm–3). A decrease of conductivity, well above the tropopause, is sometimes observed, probably due to the transport of tropospheric Aitken particles with high concentration (200–400 cm–3) into the stratosphere.  相似文献   

10.
Summary By the «limiting sphere» method the combination coefficients for gaseous ions and aerosol particles were calculated, allowing for the jump in ion concentration at the surface of the particles. Hence the stationary charge distribution on aerosol particles in a symmetrical bipolar ionic atmosphere was determined. The use of the Boltzmann equation for this purpose proposed by some authors is theoretically wrong asthis equation applies to equilibrium rather than to stationary states. In practice, the Boltzmann equation can be used for particles with radius 3·10–5 cm (under atmospheric pressure). Within this range the image forces and the jump in ion concentration may be neglected. The conditions of the applicability of the steady diffusion equations to the theory of the stationary charge distribution in aerosols are discussed.  相似文献   

11.
Summary A new significant correlation has been sought between high magnitude global seismicity and lateral surface wave velocity gradients. Rayleigh wave velocity divisioning of Eurasia, Africa, Pacific Ocean, Atlantic Ocean and Indian Ocean into regions of similar group velocity dispersion character of 30 sec period bySanto andSato [1]3) has been mainly used for calculating the gradients. It is quite striking to note that all earthquakes of magnitude 8.6 and above during 1897–1956 have occurred in regions having gradients of the order of 1.5·10–3 sec–1.Finally, some potential areas for high magnitude earthquake occurrences are predicted and the possible velocity gradients in regions, where division pattern is not yet investigated like South America and Australia, are also estimated.N.G.R.I. Contribution No. 70-170.  相似文献   

12.
Summary In this paper an attempt has been made to analyse the World shallow focus earth-quakes by the method ofGutenberg andRichter. Frequency-magnitude analysis of various earthquakes indicate that in the relation logN=a–b M, the ratio (b/a)–1 satisfies fairly well the seismicity of a region and it is felt that this ratio may be used as a measure of seismicity for a given region.  相似文献   

13.
Ground-based spectroradiometric measurements were taken in the atmosphere of Athens during May 1995 in order to investigate various atmospheric conditions. This study focuses on the Ångström exponent α, which is the slope of the logarithm of the aerosol optical depth (AOD) versus the logarithm of the wavelength, lnλ, and is commonly used to characterize the wavelength dependence of AOD and to provide some basic information on the aerosol size distribution. Using the Volz method, Ångström exponent values, α, were derived in five narrow spectral bands, 340–380, 380–440, 440–500, 500–670 and 670–870 nm. Also using both Volz and least-squares fit methods α values were derived for the whole spectrum 340-870 nm.The results show that α depends strongly on the wavelength interval used due to the curvature of the lnAOD versus lnλ line. Using the spectral dependence of the Ångström exponent and the relationship between α computed in different spectral bands with AOD, an attempt to investigate on the aerosol types is made. The results obtained are rather contradictory and the determination of a dominant aerosol type in the Athens area is not clear. Nevertheless, in the most cases the anthropogenic aerosols seem to be the dominant type with rather significant contributions of coarse-mode particles due to particle growing or due to mixing processes with other aerosol types.  相似文献   

14.
Summary The value of three different methods for deducing aerosol size distribution from diffusional decay measurements — the exhaustion method proposed byPollak andMetnieks, the method byFuchs et al. and the method byNolan andScott — is investigated with numerical examples of known distributions and also by applying them to laboratory experiments. It was found that the exhaustion method and the method proposed byFuchs et al. are satisfactory for deducing the mean particle size and that none of the three methods is quite satisfactory for deducing dispersion of the distributions with higher accuracy.  相似文献   

15.
Eruptions of the active Karymsky stratovolcano began about 5300 (6100 14C) b.p. from within a pre-existing caldera which formed 7700 14C b.p. As indicated by 32 14C determinations on buried soils and charcoal, the volcano has gone through two major cycles of activity, separated by a 2300 year period of repose. The first cycle can be divided into two stages (6100–5100 and 4300–2800 b.p.). The earlier stage began with especially intense eruptions of basaltic andesite to dacite. The later stage was characterized by moderate-strength eruptions of andesite. The second cycle, which is characterized by weak to moderate intermittent eruptions of andesite, started 500 b.p. and continues to the present. Eruptive patterns suggest that this cycle may continue for at least another 200 years with an eruptive character similar to that of the recent past.  相似文献   

16.
Summary Data from simultaneous measurements of RaB and RaC concentration in atmospheric aerosols, taken at sites located roughly 700 and 1800 m a.s.l., are used to elucidate the relation of the ratio of the specific activities of RaB and RaC in aerosol particles on the one hand to the intensity of vertical mixing and the size of the aerosol particles on the other. The empirical relationships as found from a 15-month period of uninterrupted measurements are presented. Radioactive equilibrium is more nearly approached in aerosol particles of more than one micron in diameter than in smaller ones (including the smallest measurable sizes); this holds invariably — and for all height levels. The degree of approach to RaB/RaC equilibrium is the lowest for low altitude (700 m) and negligible vertical mixing: 65% to 75%. At the low-altitude site this figure increases to 80%–90% as the intensity of vertical mixing reaches higher levels. At 1800 m a.s.l., the degree of approach to RaB/RaC equilibrium is nearly 100% when vertical mixing is negligible, and declines with increased vertical mixing activity to a level of only 60–70% for conditions involving strong vertical mass exchange.
Zusammenfassung Simultane Messungen der RaB- und RaC-Konzentration des atmosphärischen Aerosols an benachbarten Stationen in ca 700 und ca 1800 m a.s.l. werden benutzt um die Abhängigkeit des Verhältnisses der spezifischen Aktivitäten RaB/RaC auf Aerosolpartikeln von der Stärke des Vertikalaustausches, und von der Grösse der Aerosolpartikel abzuschätzen. Es werden die während einer 15-monatigen kontinuierlichen Meßperiode gesammelten empirischen Erfahrungen dargestelit. Die Annäherung an das radioaktive Gleichgewicht ist an Aerosolpartikeln vonD>1 m stets und unabhängig von der Seehöhe weiter fortgeschritten, als an den kleineren und kleinsten Partikeln. Der Grad der Gleichgewichtseinstellung RaB/RaC ist in niedriger Höhe (700 m) bei sehr schwachem Austausch am geringsten (65–75%) und steigt mit wachsender Austauschstärke bis zu einem Maximum von 80–90% an. Umgekehrt nimmt in 1800 m der Grad der Gleichgewichts-einstellung RaB/RaC von nahe 100% bei sehr schwachem Austausch bis auf 60–70% bei starkem Austausch ab.

The research reported in this paper has been sponsored by the European Research Office, United States Army under Contract DAJA 37 67C 0254, and the Department of Defense of the Federal Republic of Germany.

Physikalisch-Bioklimatische Forschungsstelle of the Fraunhofer Gesellschaft, in Garmisch-Partenkirchen. (Director: Dr.R. Reiter.)  相似文献   

17.
The large-scale terms in the vorticity equation are evaluated usingKrishnamurti's (1971a, b) summer mean winds at 200 mb for a global belt from 25°S to 45°N. The production of vorticity by the divergent wind field is found to be imbalanced over all of the tropical and subtropical belt. As a result there is a requirement for a sub-grid scale (space or time) mechanism which removes negative vorticity from the regions of strong divergence (Tibetan and Mexican highlands) and removes positive vorticity from the regions of strong convergence (mid-oceanic troughs) at 200 mb during northern summer at a rate of approximately 4×10–10 sec–2. As suggested byHolton andColton (1972), in regions of strong and persistent convection, such as the Tibetan Plateau, deep cumulus clouds can account for this transport. However, the mechanism for removing positive vorticity in the vicinity of the upper tropospheric mid-oceanic troughs is still an intriguing and open question.On leave-of-absence at the National Science Foundation, Climate Dynamics Research Section.  相似文献   

18.
Summary It has been proved that orbital elements of perturbing bodies should be taken into account when 10–10 accuracy is required for zero-frequency tidal distortion in the second zonal Stokes parameter of the geopotential. A solution at the 10–15 level of magnitude has been presented. The zero-frequency tidal distortion in the fourth zonal Stokes parameter has been derived as 1·3×10–10 if the secular Love number is unity. It should be reflected in the geopotential models respecting the 10–10 level of magnitude.  相似文献   

19.
Summary The technique for evaluating the natural illumination of direct solar radiation introduced byÅngström andDrummond [1]2) has been applied by the authors to the pyrheliometric observations in India and the values of natural illumination derived at eight representative stations are presented in this paper. The dirunal and seasonal variations of the illumination fluxes have been discussed. —In general, illumination fluxes in India show a maximum during summer season except at Madras, where the maximum occurs during winter. The illumination fluxes at various stations vary within the range 80–110 kilolux throughout the year. However, at Calcutta, it varies within a rather narrow range of 65–85 kilolux. Both in summer and winter, the illumination flux during forenoon hours is usually more than that during afternoon hours. An increase in daylight illumination is observed with height of the station above sea level.  相似文献   

20.
Summary The dynamic spectra of the atmospheric ions with mobilities between 3.2×10–4 m2/V sec and 1.3×10–8 m2/V sec were obtained in the clean and the polluted atmosphere. Based on the results, the size spectra of the submicron aerosols were deduced which show that the distribution function in Junge's expression increases in proportion to the radius of particle. Very rapid progress of the atmospheric pollution by the submicron aerosols was inferred at a rural country. The concentration of submicron aerosol particles at the site was found to have been increasing at the rate of being doubled every three years since 1964.
Zusammenfassung Die dynamischen Spektren atmosphärischer Ionen, deren Beweglichkeiten zwischen 3.2·10–4 m2/(V sec) und 1.3·10–8 m2/(V sec) lagen, wurden in reiner und verschmutzter Luft gemessen. Auf der Grundlage dieser Messergebnisse wurden die Grössenspektren der Aerosolteilchen mit Radien unterhalb 10–6 m abgeleitet. Sie zeigen dass die verteilungsfunktion in der Formel von Junge im Verhältnis zum Teilchenradius anwächst. Sehr starkes Anwachsen der Verschmutzung durch so kleine Teilchen wurde in einer ländlichen Umgebung festgestellt. Es wurde gefunden, dass seit 1964 die Zahl der Verschmutzungsteilchen dieser Grösse an der Messtelle alle drei Jahre sich verdoppelt hat.
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