A simplified ion-aerosol model for balloon measurements of ion conductivity and aerosol concentration

A simplified ion-aerosol model scheme is used to predict the small ion depletion and the consequent changes in stratospheric conductivity for the conditions at Hyderabad (17.5-degrees-N, 78.6-degrees-E). The inputs to the model on ion production rate, ion-ion recombination coefficient and charged ion-aerosol recombination coefficient are obtained from parametrization formulae. The balloon experimental results on small ion conductivity and aerosol concentrations at Hyderabad are compared with the simplified model results

Seasonal and latitudinal variations of transition height

Transition height or cluster ion cut-off level, a characteristic parameter of the ionospheric D-region, can be computed from a knowledge of ion composition data from rocket experiments or by using an empirical formula proposed to be included in the IRI lower ionosphere model. A large number of available normal D-region electron density profiles (from rocket experiments) for low and middle latitudes have been used together with the empirical formula to examine the seasonal variation of transition height, and an inverse dependence on temperature at 85 km has been observed. The seasonal variation of transition height from ion composition data for high latitudes, although shows the inverse relation with the temperature, exhibits characteristics which are different from those observed at low and middle latitudes

Seasonal and Latitudinal Variations of Stratospheric Small Ion Density and Conductivity

The seasonal and latitudinal variations of stratospheric small ion density and conductivity are studied using a simplified ion-aerosol model which includes the charged aerosol-ion recombination and charged aerosol-aerosol recombination, in addition to the usual ion-ion recombination and ion-aerosol attachment processes. The charged aerosol-ion recombination coefficient is computed from the model and the desirability of such a computation is discussed. The model computations in this study assume the background stratospheric aerosols (or Hake distribution), but the model is particularly useful in the study of stratospheric ion density and conductivity under conditions of enhanced stratospheric aerosols resulting from volcanic eruptions. The model results show seasonal and latitudinal variations of both small ion density N+/- and conductivity sigma+/-. It has been shown that the latitudinal variation of sigma+/- is primarily controlled by the corresponding variation in N+/-, whereas, the seasonal and height variations of sigma+/- are largely governed by the corresponding variations in the ion mobility b+/-. The available experimental profiles for low, middle and high latitudes show good agreement with those from model prediction

Seasonal-Variation of Angstrom Turbidity from Solar-Radiation Data

The available solar radiation data (direct and diffuse components) and a nomograph are used to derive monthly variation of Angstrom turbidity coefficient, beta, for a number of locations in India. The results show significant differences in the values of beta for the summer and winter seasons (centered around June and December, respectively) when the locations are grouped under west coast, east coast, continental, industrial, high altitude and island areas

Preliminary results of UV-B measurements at Mysore

Global UV-B flux data have been recorded at Mysore (12-degrees-N, 76-degrees-E) since April 1987. The results of a preliminary analysis on the variation of UV-B flux with atmospheric ozone for the period April-May 1987 and erythemal dose in MPE units for two selected days are reported

Erythemal dose computations from UV-B irradiance model

Modelling of the ground-reaching UV-B flux (280-320 nm) in the experimental studies of this biologically harmful radiation is important from the point of validating the experimental measurements and also to predict the temporal and geographic variations of the UV-B erythema due to stratospheric ozone depletion brought by anthropogenic causes. The erythemal dose is computed as the convolution of the global UV-B flux with a suitable action spectra for human skin. More than one definition of erythemal dose unit (in terms of the absolute energy content) is currently used in UV-B studies and thus there is a need to standardize the erythemal dose unit- The global UV-B flux data from the UV-B photometer radiometer studies at Mysore (12.6-degrees-N, 76.6-degrees-E) and also computed from a UV-B irradiance model are used to estimate the seasonal variation of erythemal dose

Atmospheric electrical conductivity measurements and modeling for application to air pollution studies

The experimentally measured ground level atmospheric electrical conductivity is validated from a simplified ion-aerosol model for which the inputs are ionization rate from surface radioactivity, aerosol density and meteorological parameters. Also estimated from the model is the reduction in conductivity for assumed aerosol levels. It is seen that for an increase of ambient aerosols by threefold the percent reduction in conductivity is 7 and it is 10 for an increase by sixfold. Thus, the variations in the measured ground level conductivity can be used to examine the atmospheric pollution, if any. © 2009 COSPAR

Seasonal variation of global UV‐B flux and its dependence on atmospheric ozone and particulate at a low latitude station

Seasonal variation of the ground reaching global UV-B flux at a low latitude non-industrial location Mysore (12.6-degrees-N, 76.6-degrees-E) is examined in comparison with the seasonal variation of atmospheric ozone data from the Dobson spectrophotometer operated at Kodaikanal (10.2-degrees-N, 77.5-degrees-E). The observed dissimilar variation of the global UV-B flux with ozone for different solar zenith positions indicates the role of seasonally varying atmospheric aerosols and particulate in producing enhanced scattering of UV-B radiation in summer period. Monthly variation of atmospheric turbidity coefficient beta also indicates the seasonal variation of the atmospheric aerosol and particulate concentrations which are larger for the summer months