Showing papers in "Atmospheric Research in 1997"

TL;DR: In this paper, a new two-moment microphysical parameterization is described, which predicts the mixing ratio and number concentration of rain, pristine ice crystals, snow, aggregates, graupel and hail.

TL;DR: In this paper, a statistical analysis of the occurrence and variability of condensation nuclei larger than 18 rm diameter (N18) and nuclei mode particles (UCN, 7 nm < Dp < 18 nm) was performed in the mid-latitude free troposphere up to the lower stratosphere over Western Europe in summer 1994.

TL;DR: In this paper, a set of equations describing the charge transfer as a function of ice crystal size, velocity, temperature and rime accretion rate were presented to determine the importance of the new formulations on thunderstorm electrification.

TL;DR: In this article, it was pointed out that very sudden mixing events caused by breaking Kelvin-Helmholtz waves occur preferentially in just those regions where the process would be most effective.

TL;DR: In this paper, an independent statistical evaluation of a randomised hygroscopic cloud seeding experiment carried out in South Africa from 1991-1995 is presented, based on the original radar data for each storm.

TL;DR: In this paper, the authors measured the radiation components continuously over a partially cheatgrass-covered area since October 1995 and compared the measured incoming longwave (atmospheric) radiation with that computed by Brutsaert's formula.

TL;DR: In this paper, the authors describe how to measure turbulence in the atmospheric boundary layer (ABL) in order to address certain problems in modern atmospheric physics, which mainly relate to the Earth's energy budget (including the hydrological cycle) and biogeochemical cycles.

TL;DR: In this article, the authors studied the temporal variations in the aerosol-loading in the nocturnal boundary layer and found that the percentage contribution of the 50-200 m layer to the total loading in the 50 -1100 m layer is about 41% pointing to the predominant surface source of particulate matter.

TL;DR: In this paper, the authors modified a simple model for wind-driven coastal polynyas, using actual meteorological data from our coastal automatic weather stations as input, using mean monthly data for the stations, and they showed that the polynya are to be expected in the windiest area (Cape Denison-Port Martin); while to the west (Dumont d'Urville) and east (Penguin Point), the average conditions do not produce them.

TL;DR: In this article, the backscatter error from the inaccurate representation of the particle surface shape is much smaller than that from the neglect of the magnetic dipole, and the resonance occurs at different particle sizes depending upon the exact particle shapes.

TL;DR: In this article, the atmospheric boundary layer (ABLBP) vertical and horizontal structure, turbulent heat and vapor fluxes and diffusion characteristics were obtained over pack ice, cracked ice and open water during Joint German-Russian airborne studies in March-April 1994.

TL;DR: A thermal diffusion cloud condensation nuclei (CCN) counter was operated during the months January through June 1994 near the summit of Mt. Lemmon in the Catalina Mountains at about 2700 m elevation as mentioned in this paper.

TL;DR: In this paper, the authors report on aerosol data obtained during the expedition of Spring 1994 and show that haze events have been found in the east and west Arctic, containing about the same concentration of particles.

TL;DR: In this article, a land-surface module to couple a meteorological and a hydrologic model was developed to simulate the water cycle in a closed manner, and the results of 24-h simulations with and without a two-way-coupling of the models substantiate that even on a short time scale surface runoff and lateral water flows affect soil wetness, soil temperature, cloudiness and the thermal regime of the atmospheric boundary layer within the catchment.

TL;DR: The results of aircraft lidar studies of the Arctic haze are reported in this article, where the first priority was given to measuring the scattering and depolarization coefficients of troposperic aerosol at 0.53 μm wavelength.

TL;DR: In this article, a multi-spectral extinction measurements made with co-located highspectral resolution radiometer (spectroradiometer) and sunphotometer at the Indian Institute of Tropical Meteorology (IITM), Pune (18°32′N, 73°5′E, 559 m AMSL) on 188 cloud-free days between March 1993 and May 1995 are presented.

TL;DR: In this article, X-ray spectrometers have been used to study the elemental compositions of individual particles of marine aerosols, revealing the occurrence of two chemical processes over the Southern Ocean: modification of sea salts by acidic materials, where Cl − is replaced by SO 4 2− and/or NO 3 − and fractional recrystallization within evaporating seawater drops followed by shattering.

TL;DR: In this article, the authors used vector analysis and farther correlation analysis to compare the calculated storm velocities and directions with the observed wind velocity and direction from different altitudes, and found that statistically significant correlation was achieved between the calculated velocity and directions and the hourly mean surface wind veloities, in contrast to studies carried out in other climate zones.

TL;DR: In this article, the horizontal and vertical variations of 03−, SO2−, PAN-, HNO3−, nitrate- and sulfate-concentrations were measured during the 'Arctic Haze' and 'Merisec' measuring campaigns.

TL;DR: In this paper, the angular scattering behavior of the mixed phase cloud is dominated by water droplets in the forward scattering regime, and the appearance of haloes in the phase function is dependent on there being no, or very few, residual small water droppers in the ice cloud rather than on the size of the crystals.

TL;DR: In this article, the authors performed measurements of Arctic aerosol properties from an aircraft flying over the East Siberian Sea from Cherskiy (69°N, 161°E) to Bennett Island (76.5°N and 149°E).

TL;DR: In this paper, a short description of aircraft equipment for measuring atmospheric turbulence, used during the “Arctic Haze” mission in 1994, is given, including square root deviations of fluctuations, spectrum, coefficient of turbulent diffusion, fluxes of impulse, heat and water vapor.

TL;DR: In this paper, the authors measured and documented the properties of atmospheric aerosol in Novosibirsk region (Southwestern part of Siberia) and found that the main aerosol mass is in submicron aerosols, while in summer, it is in large particles.

TL;DR: In this paper, the authors present a method of observation of vertical profiles of aerosol spectral optical thickness and spectral extinction coefficients, taken during four campaigns as part of the German-Russian aircraft project "Arctic Haze/Merisec" in the years 1993, 1994 and 1995.

TL;DR: In this article, a spatial stochastic analysis is proposed based on rainfall events selected during the 1958-1993 period in the South of France, using the French weather service daily rainfall database.

TL;DR: In this article, a test of the potential of satellite data for the detection and forecasting of hail was conducted and it was found that the forecasting time from the first appearance in visible Meteosat data to the occurrence of hail is about 90 min.

TL;DR: In this paper, the empirical ion scavenging coefficients were derived from changes in ion concentration in a drizzling rain with a rain intensity of below 15 mm h −1, and these coefficients were linearly proportional to the rain intensity.

TL;DR: In this article, the applicability of the area-threshold method to the estimation of the mean areal rainfall in squall lines was demonstrated, in which the area threshold method can be separately applied to the convective line and to the stratiform area.

TL;DR: In this paper, a joint Russian-German airborne expedition in March-April 1994, measurements of direct solar radiation fluxes were conducted by using spectrophotometer which was installed aboard research aircraft Il-18 ‘Cyclone.