Impact of parallax correction on Deep Convection Clouds detection frequency.

Abstract

<p>Satellite data is becoming a progressively accurate source of weather information. An increasing resolution and the number of spectral channels allows to determine the location and recognition of clouds due to their optical and thermal properties.</p> <p>Predicting the movement of correctly defined deep convection clouds (DCC) is of great importance in forecasting the course of dangerous phenomena for households as well as human health and life. The analysis of trends and occurrence of DCC will make it possible to verify the current climate models, which estimate that the aforementioned phenomena will intensify in the future.</p> <p>The most common method of detecting DCC is based on the cloud tops temperature. The lower the temperature, the higher and more extensive the cloud is.</p> <p>The aim of the study is to determine the influence of parallax shift on the frequency of deep convection clouds (DCC).</p> <p>A geostationary satellite is located at a fixed point in the orbit, which means that the angle of view at higher latitudes is smaller. The higher the object, the greater the parallax shift of the object in relation to its true location. In order to verify the shift and its significance in the analysis of the trend of DCC occurrence, it is necessary to check what values the shift takes and whether it causes significant losses in the number of detected DCC.</p> <p>The data used for the analysis come from the geostationary satellite Meteosat Second Generation 1 (MSG1) - Meteosat-8, whose sub-satellite point has coordinates: 0<sup>o</sup>N and 3.4° W. And from the circumpolar satellite Moderate Resolution Imaging Spectroradiometer (MODIS), which it flies at an altitude of 705 km and its cycle lasts 16 days. The cloud tops temperature was obtained from both satellites and used to estimate the cloud tops height.</p> <p>The analyzes were carried out for the case study of July 4, 2005.</p> <p>To perform the parallax correction of the geostationary satellite, the existing parallax correction methods were used. For the first time, an attempt was also made to perform parallax correction for a circumpolar satellite.</p> <p>This research was funded by the National Science Institute of Poland. Grand no. UMO-2020/39/B/ST10/00850.</p>