Variations of Atmospheric ELF/VLF Radio Noise Due to Seismogenic Modifications in Tropospheric Conductivity

We suggest a possible explanation of the influence of pre-seismic activity on the registration rate of natural ELF(extremely low frequency)/VLF(very low frequency) pulses and the changes of their characteristics. The main idea is as follows. The distribution of the electric field around a thundercloud depends on the conductivity profile of the atmosphere. Quasi-static electric fields of a thundercloud decrease in those tropospheric regions where an increase of air conductivity is generated by pre-seismic activities due to emanation of radioactive gas and water into the lower atmosphere. The electric field becomes reduced in the lower troposphere, and the probability decreases of the cloud-to-ground (CG) strokes in such “contaminated” areas. Simultaneously, the electric field grows inside and above the thunderclouds, and hence, we anticipate a growth in the number of horizontal and tilted inter-cloud (or intra-cloud) (both termed as IC discharges) strokes. Spatial orientation of lightning strokes reduces vertical projection of their individual amplitudes, while the rate (median number strokes per a unit time) of discharges grows. We demonstrate that channel tilt of strokes modifies the spectral content of ELF/VLF radio noise and changes the rate of detected pulses during the earthquake preparation phase.

Reasons for Modern Warming:Hypotheses and Facts

Two hypotheses of modern warming are considered:natural and anthro­pogenic.The probabilities of each of them are compared.It is proved that the hypothesis of natural warming is much more likely than the hypothesis of anthropogenic warming.It is shown that the displacement of the Sun from the center of mass of the solar system directly affects the temperature of the surface atmosphere in the synoptic regions of Eurasia.This result corresponds to the model of E.P.Borysenkov with variations of the solar constant or,equivalently,with variations of the Bond albedo.

A high-resolution dataset for lower atmospheric process studies over the Tibetan Plateau from 1981 to 2020

ABSTRACT A high-resolution meteorological dataset(≤10 km)over the Tibetan Plateau(TP)is the foundation for investigating and predicting the weather and climate over Asia.The TP Subregional Dynamical Downscaling(TPSDD)dataset is a newly developed high-spatial-temporal resolution gridded dataset for land‒air exchange pro-cesses and lower atmospheric structure studies over the whole TP region,taking the climate characteristics of each TP subregion into consideration.The dataset spans from 1981 to 2020,covering the TP with a temporal resolution of 2 hr and spatial resolution of 10 km.Meteorological elements of the dataset include near-surface land-air exchange parameters,such as downward/upward long-wave/shortwave radiation flux,sensible heat flux,latent heat flux,etc.In addition,the vertical distributions of 3-dimensional wind,temperature,humidity,and pressure from the surface to the lower stratosphere are also included.Independent evaluations were con-ducted to verify the performance of the TPSDD dataset by compar-ing TPSDD/reanalysis with surface and vertical observations through the calculation of statistical parameters.The results demonstrate the accuracy and superiority of this dataset against reanalysis data,which provides great potential for future climate change research.

SEASONAL VARIATION OF LIDAR-DERIVED AEROSOL CONTENT IN THE LOWER LAYERS OF THE ATMOSPHERE

Results of the study of seasonal variation of total column content of aerosols in the 50—1100 m height region are presented,The columnar content of aerosols is computed by integrating the height profiles of nighttime aerosol number density estimated from the Argon ion lidar observations collected at the ⅡTM, Pune for the one year period from October 1986 to September 1987.The results of the study indicated that the aerosol content was higher during winter than during monsoon months by over 78% with an annual mean columnar aerosol content of 1.66×10~8 cm^(-2).The observed seasonal variaticn of aerosol content was found to be associated with that of surface wind,temperature,relative humidity(R.H.)and rainfall data recorded for the above one year period at the station.