Tasks which require information about energy characteristics of rains and methods for acquiring this information are briefly reviewed. A technique is suggested for estimating the kinetic energy transferred by hydrometeors based on microstructural characteristics of rainfall obtained with an OPTIOS optical precipitation gage. The technique is tested with measurement data received during a heavy rainfall occurred in Tomsk on July 22, 2023. The influence of different microstructural parameters on the amount of kinetic energy brought by raindrops to the underlying surface is analyzed. The results are compared with the values obtained by simplified methods. It is concluded that the capabilities of the optical precipitation gage make it a useful tool for solving tasks where accurate assessments of rainfall energy characteristics are required.

Techniques for calibrating optical rain gages are reviewed. The disadvantages of the existing calibration methods of the optoelectronic rain gage OPTIOS are analyzed and ways to eliminate them are suggested. The original patented method for calibrating the optical rain gage is described in detail, which makes it possible to increase the accuracy of measuring the sizes of hydrometeors by means of taking into account the effective size of each photosensitive element of the linear sensor. This calibration technique is versatile and can be applied to any optical meter of linear sizes, where a linear array of photosensitive elements is used as a measuring transducer, with the aim of improving the measurement accuracy.

We present information on the organization and the history of development of meteorological observations at Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch, Russian Academy of Sciences (IMCES), that were initiated at the second category weather station of the Optics Technological Design Institute of Scientific Instrument Engineering (TDI SIE) (since 1994) and continue to the present at the Geophysical Observatory (GO) of IMCES. A retrospective of the development of meteorological instrument-making at IMCES is presented beginning from the creation of experimental prototypes of automated complexes for operational measurement of optical and meteorological characteristics of the atmosphere (1970s–1980s) during tests of different laser systems to the development and creation of a number of meteorological instruments, including automatic ultrasonic weather stations of different purposes and spatially distributed information and measuring systems on the basis of these stations. Some of the weather stations developed are included in the State Register of Measuring Instruments.

The dependence of the optical precipitation gage calibration results on the size of reference objects is analyzed. Ways to optimize the calibration procedure are suggested, including: reducing the number of calibration zones; use of calibration coefficients instead of correction parameters; additional calibration with balls 1 mm in diameter; use of the coefficients dependent on the diameter measured for particles smaller than 2 mm. The conclusion is drawn about the efficiency of the calibration procedure suggested for optoelectronic devices designed to measure the size of small particles, for example, a snowstorm parameter gage.

Rainfall measurements with an OPTIOS optical precipitation gage and a standard Tretyakov O-1 gage for three summer months of 2020 are compared; a good agreement between them is shown. The comparison between the OPTIOS measurements with measurements with a similar optical rain gage mounted at a distance of 3 km and with the related data from the Tomsk weather station of Rosgydromet located at a distance of 6 km shows significant spatial variations in the precipitation parameters. The possibility of using OPTIOS both as an automated gage within a weather station and as a component of a precipitation gage network is shown.

The electrical state of the surface atmosphere changes significantly under the influence of cloudiness and atmospheric phenomena, including atmospheric precipitation. These features can be used for possible diagnostics of precipitation and improvement of their characteristics based on variations of atmospheric-electrical quantities in the surface layer. Studies of variations of meteorological and atmospheric-electrical quantities in the surface layer were carried out during the heavy rainfall associated with the cumulonimbus (Cb) clouds passage. Meteorological and atmospheric-electrical observations in the Geophysical Observatory of the Institute of Monitoring of Climatic and Ecological Systems are presented in this paper. Precipitation data are used to identify periods of heavy rainfall ≥ 5 mm/h. Information of weather stations and satellites is used to separate the heavy rainfall events by synoptic conditions like thunderstorms and showers of frontal or internal air masses. We find that rains associated with the frontal Cb clouds produce more abrupt changes in negative electrical conductivity in comparison with the Cb clouds in internal air masses. The significant increase in negative electrical conductivity (more than two times vs. normal values) occurs typically during the passage of frontal Cb and heavy rain with droplet size greater than 4 mm.

The description of the developed automatic weather station for the Arctic region is presented. The station provides information to the remote user measured data such as three-component vector of wind velocity, air temperature and humidity, atmospheric pressure, precipitation parameters, solar radiation intensity, snow cover depth, and soil temperature profile (including ground surface temperature). The solution to this problem is possible only through the use of automated systems that can data acquisition, process and transmit meteorological information to a remote user in an automatic mode without human intervention.

Prospects for using the optical precipitation gage OPTIOS for detecting dangerous weather phenomena associated with atmospheric precipitates are considered. The results of heavy shower (more than 50 mm/h) measurements are presented. The optical precipitation gage OPTIOS is shown to allow estimation of precipitation characteristics to provide prompt warning of the occurrence of a dangerous phenomenon.

Traditional and modern devices for measuring snow characteristics are considered. Data from measurements of snow precipitation parameters were obtained and analyzed. The features of measuring the characteristics of snow precipitation accompanied by wind are considered. The main ideas for the development of a new snowdrift meter that meets the modern requirements are outlined.

The description of scheme and control algorithms of the heating system, designed to ensure the optical precipitation gauge operation in extreme weather conditions of the Arctic, are presented. The solution is based on the temperature monitoring of optical windows, electronic components, and protective housings of the device.

Typical precipitation parameters measured with optical precipitation gage at the meteorological site of Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch, Russian Academy of Sciences, from June to October 2016 are described. The particle size distributions are presented for different precipitation types. The measured precipitation intensity and daily total rainfall are compared with the results obtained with standard precipitation gages.

Filtering algorithms for measurement data of the optical rain gauge OPTIOS are presented. Criteria for reducing measurement errors are considered. These errors are associated with registration of objects that are not precipitation particles, and droplets that are broken on elements of the device construction. The examples of the efficiency of proposed filtration methods for precipitation amount measurements are shown.

The specifics of snow precipitations characteristics measurements are considered. The paper presents the description of the method based on obtaining and analyzing precipitation particle shadow images for measurements of snow precipitations. There are results of snowfall characteristics measurements that have been registered 9 November 2015.

Система устранения внешних естественных помех в измерительном канале оптического осадкомераПриведено описание оптического осадкомера, принцип работы которого основан

The described optical rain gage is intended for the measurement and analysis of shadow images of precipitation particles. The device operation capabilities are exemplified in the study of the microstructure of liquid atmospheric precipitation that fell in Tomsk on August 26–27, 2014.

There are specifics of use of the obtaining and analyzing precipitation particle shadow images method for the hail precipitation investigations. Descriptions of the method and operation of the new optical rain gauge measuring system are presented. There are estimations of the device capabilities and prospects of its use for measurement of hail characteristics.

The main parameters of optical channels of an optoelectronic dual-channel precipitation gage are described, as well as results of laboratory experiments and preliminary field tests. A procedure is suggested for calculating the calibration parameters using 5.01-mm steel balls; it allows minimizing the error caused by imperfections in the optical system of the device. The results of liquid volume measurements show that the laboratory precipitation measurement error does not exceed 5%. Preliminary results of field measurements are shown in the form of size distributions of precipitation particles, variations in the intensity, and the total precipitation calculated.