Radio Physics and Radio Astronomy (Sep 2024)
METHOD OF THE ATMOSPHERE BRIGHTNESS TEMPERATURE MEASURING AT FREQUENCIES AROUND 100 GHZ
Abstract
Subject and Purpose. The improvement of the atmosphere brightness temperature measuring method at frequencies of about 100 GHz is considered. The possibilities of the atmospheric carbon monoxide (CO) remote sensing instrument, developed at Institute of Radio Astronomy of the National Academy of Sciences of Ukraine were analyzed. They show that the functional of this instrument can be significantly expanded. It can provide more operational information about the troposphere, useful for aeronomy and radio astronomy. The purpose of this work is to improve the atmosphere brightness temperature measuring method in relation to the existing instrument. We determine the possibility of the spectroradiometer broadband channel to measure the sky brightness temperature. Methods and Methodology. A detailed analysis of the existing installation for monitoring atmospheric CO was carried out and the measurement method was improved. It is shown that the broadband channel of this instrument, created as a service, can be used to measure atmosphere brightness temperature. Such measurement will allow creating a database of the zenith brightness temperature of the sky at frequencies of about 100 GHz. Results. It is possible to create the base data of the brightness temperature of the sky at frequencies about 100 GHz. In order to do this, it is necessary to make only some modifications of the instrument. The main thing is to make changes to the data capture file of the broadband channel and create a program to convert the data obtained from the instrument into brightness temperature values according to the specified formulas. All necessary formulas for presenting observational results in the form of brightness temperatures are given. Conclusions. It has been proven that there is a possibility to create the base date of the troposphere brightness temperature over Kharkiv (Ukraine) at the frequencies of the short-wave part of the mm range. The high stability of the radiometric part of the installation allows determining the brightness temperature of the sky with an accuracy that is sufficient for aeronomical, radioastronomical and radiophysical studies. On the basis of analytical calculations and experimental data, the necessary modifications for creating such a base data are defined.
Keywords
