Variations in the radiothermal radiation of the ice cover of Lake Arakhley as a geo-indicator of deformation and cracking

In January-March, 2020-2021, radiophysical studies were conducted of radiothermal radiation intensity for the testing site for Lake Arakhley, Transbaikalia, Russia. The set of equipment consisting of four microwave radiometers for the wavelengths from 0.3 to 2 cm was placed on the shore of the lake mounted on a stationary platform. The temperature and deformation of ice were simultaneously measured at the depth of 0.4 meters in two orthogonal directions: west-east and north-south. The temperature was measured with heat gauges in a vertical profile at the depths of 5, 10, 15, 20 and 40 cm. In the process of contact measurements in the period of cracking, signal impulses were recorded in the channel of the deformation sensor placed in the direction of the lake center (west-east). The measurement results were used in monitoring of the condition of the water body. It turned out that in the periods of registering the deformation impulses, changes in the radio brightness temperature and decrease in the ice temperature were observed. The microwave characteristics correlate with the temperature and deformation of the ice cover and may serve as an indicator of the meteorological conditions of the region.

Electrodynamic model of relict radiation scattering by vegetation cover to improve the accuracy of soil moisture measurement by microwave radiometer

The possibilities of electrodynamic model of relict radiation scattering by vegetation cover to improve the accuracy of soil characteristics measurement by microwave radiometer are demonstrated. The dependence of the reflective characteristics of the soil-vegetation system on the type and parameters of vegetation cover is considered. The accuracy of measuring the radio brightness temperature of the soil is estimated depending on the type and characteristics of the vegetation cover.

Observation of eruptive events with the Siberian Radioheliograph

We describe methods for monitoring eruption activity with the first phase of the multiwave Siberian Radioheliograph (SRH-48). We give examples of the recorded eruptive events: 1) rise of a prominence above the limb observed in the radio map sequence of April 24, 2017; 2) a jet recorded on August 2, 2017, whose cold matter screened a compact microwave source for several tens of minutes. The shading due to the jet appearance was observed on SRH-48 correlation curves as the so-called “negative” burst. Using the “negative” burst on the correlation curves of February 9, 2017 as an example, we show that the intervals with depression of the microwave emission of local sources are not always caused by shading of their emission. In this event, the radio brightness decreased within ten hour period of the increased quasi-stationary emission during the development of AR 12635 magnetic structure. Similar behavior was observed in EUV, SXR, and radio emission at 17 GHz.