• R P SINGH

Articles written in Journal of Earth System Science

• Ionospheric and atmospheric perturbations due to two major earthquakes (M > 7.0)

The perturbation produced in the atmosphere/ionosphere associated with earthquake precursors during seismic activity of two major earthquakes which occurred on (1) 24 June 2019 in Indonesia (M = 7.3) and (2) on 19 August 2018 at Ndoi, Fiji (M = 8.2), are studied. Based on statistical analysis of total electron content (TEC) data, the presence of ionospheric perturbations 5 days before and after the main shock are found, which depends on the distance as well as direction of observation point from the epicentre. In general, ionospheric perturbations after the EQ at all the stations are found larger than that before the EQ. Probable mechanisms behind these perturbations associated with EQ are also being discussed. The ionospheric perturbations are observed at stations which are at larger distances from the epicentre, but not observed over other stations in different directions which are comparatively closer to the epicentre. These results suggest that seismic induced ionospheric anomaly is not isotropic in nature. Ozone data from three satellites: AIRS, OMI, and TOMS-like and MERRA-2 model are also analyzed 5 days before the EQ day and compared to the monthly average level. A strong link between anomalous variation in ionospheric TEC and atmospheric ozone data prior to both the EQs is noticed.

• Fair-weather atmospheric electric Beld measurements at Gulmarg, India

In the present study, the atmospheric electric Beld observations are reported at Gulmarg station, Kashmir (34°05'N; 74°42'E) for a period of 1 year: June 2019–May 2020. The observation site is situated in an area with high thunderstorm activity and very high radon concentration. Diurnal characteristics of PG are explained with electrode effect under summer/dry surface conditions and evaporation effect under winter/ wet surface conditions associated with sunrise. The latter effect is highly responsible for the diurnal peak of PG observed in afternoon (1300 LT) hours along with the water vapour pressure under low temperature. Similarly, excess positive charges found at the electrode layer shift the diurnal peak to an earlier time ${\sim}$1000–1100 LT under turbulent exchange from the surface. Therefore, the annual mean curve is the resultant of these two effects that act in different seasons. In addition, the annual diurnal variation of the potential gradient is in agreement with some other continental stations having two maxima and higher values of PG during the winter months. The secondary diurnal maximum (2000 LT) is likely due to African thunderstorm activity being reflected strongly at our measurement site. Comparison of our results with Carnegie leads to a weak correlation between the two, which is due to the difference in the nature of observation sites, while a comparison with the observations of B N Raina (August 1970–October 1973) at the same observatory reveals a similar nature of PG variation. Finally, simple correlation plots of PG with meteorological parameters and radon concentration have been shown. The results indicate that radon concentration and meteorological parameters like temperature, relative humidity in addition to water vapour pressure are important local factors influencing the surface PG measurements at our site.

• # Journal of Earth System Science

Volume 131, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019