Vol. 69, No. 2 * Pages 74–148 * April 2024

The infrasound array at Piszkés-tető, Hungary (PSZI) has been operational since May 2017. Since then, PSZI has detected more than one million infrasound signals. These include detections both from known and unknown sources. The identification and categorisation of the detections are important for future automation. The objective of this study is to identify and collect those detections that belong to thunderstorms and lightning bolts. A methodology to identify thunderstorms is presented, by which 32,000 infrasound detections were classified as of thunderstorm originated. The methodology relies on correlating lightning data from the Blitzortung database (considered as ground truth) with infrasound detections. We also analyse the distributions of the directions and distances of the detected thunderstorms which characterise the sensitivity of the station. Additionally, a detailed lightning search procedure led to the identification of 68 lightning discharges in thunderstorms close to the array (< 50 km).

Despite numerous research and methodological developments, evapotranspiration is one of the most difficult components of the water balance to estimate. One of the direct methods, with which evapotranspiration can be estimated, is the so-called eddy covariance; however, it may suffer from significant uncertainties due to many factors and basic assumptions. The current research aims to determine the rate and estimate the limits of evapotranspiration over grassland and arable land based on Hungarian long-term eddy covariance measurements.

The water surface of Lake Balaton, as well as Bakony Mountains to the north of it, can significantly modify the characteristics of weather: they influence the air temperature, wind speed and direction, furthermore the cloud cover and precipitation. Sailors know well the downslope wind blowing from the valleys of Bakony during the evening hours. Bakony also has a more significant, but less well-known effect on the wind field at the Lake: a downslope wind forced by synoptic-scale processes, just like the Adriatic bora or the Alpine foehn. This effect of Bakony at Lake Balaton can increase the speed of wind gusts by 30-40 km/h, so it is important to take this factor into account when issuing lake storm warnings. In this paper results about the synoptically forced downslope wind of Bakony Mountains are presented.

At Lake Balaton, Velencei-tó, and Tisza-tó there is a storm warning service operated by Hungarian  Meteorological Service. This was the 89th storm warning season at Lake Balaton. The storm warning service is responsible for the safety of people at lakes. When strong or stormy wind is expected, storm warnings are issued on the first or second level. The duration of the storm warning season is seven months: from 1st April until 31st October. This paper is about the significant weather cases of the season in 2023 and contains a summary of the storm warnings.

The clothing we wear is basically determined by the outdoor (weather) or indoor (local microclimate) thermal load and its perception. Experiencing or achieving thermal comfort is a fundamental aspect of our lives. In this study, we estimated the thermal load of the outdoor air environment based on a clothing thermal resistance-operative temperature model, and we also characterized the thermal load by assigning the observed thermal sensation categories. The thermal load-thermal perception relationships are analysed for „cold-weather” situations (weather in which clothing resistance values are greater than zero) in the lowland regions of the Carpathian Basin. We found that in summer in lowland areas of Hungary, in case of high irradiation and high temperature (thermal sensation category: very warm), the operative temperature (To) is about 70-80 °C. In winter, at air temperatures around -10 °C and in clear sky conditions (thermal perception category: very cold), To is less than -20 °C and clothing thermal resistance is 3-3.5 clo (measurement unit for the thermal insulation of clothes, 1 clo = 0.155 m2·°C·W-1). In such cases, there can be large interpersonal differences in people’s thermal load and thermal perception. In the thermally neutral state, clothing thermal resistance varies roughly between 0-0.5 clo and To between 20 and 30 °C. In these cases, the interpersonal variability of thermal load and thermal perception is the smallest.