The Laboratory Complex for the Calibration of Photometers Using the Optical Method for Determination of the Water Vapor Content in the Earth Atmosphere

TL;DR

This paper presents a laboratory complex developed for calibrating photometers used in atmospheric water vapor measurement, aiming to improve accuracy through various calibration methods and detailed equipment parameter analysis.

Contribution

It introduces a new calibration complex and compares multiple calibration techniques for atmospheric water vapor photometers, enhancing measurement precision.

Findings

Calibration accuracy potentially reaches 1-2%

Comparison of calibration methods developed

Laboratory complex operational at Pulkovo Observatory

Abstract

We describe the laboratory complex for the calibration of photometers that are used in weather service to measure the water vapor content in the Earth atmosphere. The complex was built up in Pulkovo Observatory and developed within the framework of collaboration between Pulkovo Observatory and Lindenberg Meteorological Observatory (Meteorologisches Observatorium Lindenberg - Richard-A{\ss}mann-Observatorium, Lindenberg, Germany). It is used to obtain calibration dependences for individual devices, and also to develop and compare various methods of construction of calibration dependences. These techniques are based on direct calibration of the photometers, on the use of spectral laboratory transmission functions for water vapor, on calculation methods using spectroscopical databases for individual lines. We hope that when the parameters of the equipment are taken into account in detail and new results for the absorptive power of water vapor are used, the accuracy of determination of the water vapor content in the atmosphere of 1-2% may be attained.