Selected Meteorological Phenomena Posing a Hazard to Aviation: a Case Study on Bydgoszcz Airport, Central Poland ISSN 2080-7686
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Bulletin of Geography. Physical Geography Series, No. 18 (2020): 61–71 http://dx.doi.org/10.2478/bgeo-2020-0005 Selected meteorological phenomena posing a hazard to aviation: a case study on Bydgoszcz airport, central Poland ISSN 2080-7686 Andrzej Araźny* 1, 2a, Edward Łaszyca3 1 Nicolaus Copernicus University, Faculty of Earth Sciences and Spatial Management, Toruń, Poland 2 Nicolaus Copernicus University, Centre for Climate Change Research, Toruń, Poland 3 Institute of Meteorology and Water Management - National Research Institute (IMGW-PIB), Poland Correspondence: Nicolaus Copernicus University in Toruń, Poland. E-mail: [email protected] a https://orcid.org/0000-0002-4277-9599 Abstract. The article describes the occurrence of selected weather phenomena that are hazardous to aviation (thunderstorms, hail, fog and glaze) in Bydgoszcz. The work employs 1971–2010 data from the Bydgoszcz-Airport meteorological station. The hazardous atmospheric phenomena selected Key words: for analysis hinder or sometimes even prevent aviation. Of the analysed weather phenomena in By- weather phenomena, dgoszcz, those most hazardous to aviation are fog and thunderstorms. The average annual numbers applied climatology, of days featuring them exceed 71 and 14, respectively. The analysis shows that statistically signifi- long-term variability, cant threats to aviation have decreased, e.g. number of days with fog (by 4.76 days/10 yrs) and days Bydgoszcz, with thunderstorms (by 1.68 days/10 yrs). However, no clear trends can be seen for the number of Poland days with hail (decrease of 0.14 days/10 yrs) and days with glaze (an increase of 0.16 days/10 yrs). Introduction Bydgoszcz’s number of passengers (425,000 per year) places it further down in the ranking of Pol- ish airports (https://plb.pl/statystyki). Bydgoszcz Aerial transport is developing rapidly. The number airport has been growing rapidly in recent years. of new connections has increased, and flight routes In terms of growth in passenger numbers in Poland, and durations are getting longer. In the 21st centu- Bydgoszcz ranked second (behind Poznań) with a ry, air transport has become the safest and fastest 2018 increase of 25% over 2017). mode of transport, with passenger numbers grow- Information on weather conditions in the By- ing rapidly. The International Air Transport Asso- dgoszcz region is spread across many publications ciation revealed that present trends in air transport and based on data from various multi-annual peri- suggest passenger numbers could double to 8.2 bil- ods and measurement stations. The present study lion by 2037 (https://www.iata.org/en/pressroom/ focuses primarily on weather phenomena around pr/2018-10-24-02/). There is also a rapid growth in the turn of the 21st century, although the region’s interest in atmospheric phenomena accompanying climate was also studied in the 1920s and 1930s. air travel and negatively affecting airline transporta- The climate of the Bydgoszcz region has been well tion e.g. flight delays, cancelled flights, and various described, with many works published, e.g. on air accidents (Borsky and Unterberger 2019; Gultepe et temperature (e.g. Hohendorf 1967; Roguski et al. al. 2019). 1996; Bąk 2003; Dudek et al. 2008, 2010; Żarski Most of Poland’s passenger traffic is accounted et al. 2010; Łaszyca and Kuśmierek-Tomaszewska for by the airports of Warsaw, Kraków and Gdańsk. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selected meteorological phenomena posing a hazard to aviation... A. Araźny and E. Łaszyca 2013; Kasperska-Wołowicz and Bolewski 2015; pressure, atmospheric phenomena, type of precip- Łaszyca 2018) and on atmospheric precipitation itation, ground condition. In 1983–2010 meteoro- (e.g. Hohendorf 1967; Roguski et al. 1996; Łabędz- logical measurements were continued by military ki and Adamski 2010; Żarski et al. 2014). In Po- observers and civilian employees of the military land, issues of aviation meteorology have been at the Military Airport Meteorological Station ac- presented in monographic studies (e.g. Parczews- cording to the ICAO. In February 2007, the IMGW ki 1953; Holec and Tymański 1973; Schmidt 1982; station at the Bydgoszcz-Szwederowo airport was Kaczanowski 1987; Ostrowski 1999; Stopa-Boryczka reactivated. Station employees measure meteoro- et al. 2013; Szewczak 2014) and in works relating to logical parameters: cloud types and amount, lower the planning of the construction of the airport, and cloud base, wind direction and speed, air tempera- its operation (e.g. Wiążewski and Bąkowski 2007; ture, dew point temperature, relative humidity, at- Błażejczyk and Solon 2009; Szot 2013; Skrzyńska mospheric pressure, atmospheric phenomena, and 2019). visibility. The station also conducts meteorologi- Within Poland, Bydgoszcz is located in the “cen- cal services for civil aviation (Meteorologiczna Os- tral” bioclimatic region, and its bioclimatic condi- łona Lotnictwa Cywilnego [MOLC]). The measuring tions are typical for the country (Błażejczyk and points are located at about 800 m from each oth- Kunert 2011). Central Poland has favourable biom- er in a fenced-off, restricted part of the airport, so eteorological conditions for air transport staff and the data used for the tests were considered homo- passengers. This is due to, among other things, the geneous, meeting the measurement comparabili- unobstructed atmospheric circulation and the flat ty criterion. The stations were located on a plateau terrain, which help even out differences in thermal at the Bydgoszcz-Szwederowo Airport (φ=53˚05’N, and humidity conditions – that is, which alleviate λ=17˚58’E, h=72.0 m a.s.l.), at about 3.5 km from stimuli (Araźny and Smukała 2011). the city centre, with no anthropogenic influence, The aim of the study is to examine the variabil- which guarantees their representativeness for the ity of selected weather phenomena that are hazard- Bydgoszcz Airport (Figs 2 and 3). ous to aviation (thunderstorms, hail, fog and glaze) All data have been carefully checked and ho- in central Poland, on the example of Bydgoszcz air- mogenised using the Standard Normal Homogene- port in the period 1971–2010. ity Test (Alexandersson 1986) modified by Štěpánek (2008). The data series was determined to be ho- mogeneous. The study examined the variability of Methods and materials selected hazardous weather phenomena (thunder- storms, hail, fog and glaze) in terms of monthly, seasonal and annual values of meteorological ele- Bydgoszcz is a city in north-central Poland, on ments in the period 1971–2010. Regression analy- the Brda and Vistula rivers (Fig. 1). The work uses sis was carried out and the direction and trends of 1971–2010 meteorological data from the Bydgo- changes in the examined elements over time were szcz-Airport meteorological station. In the years determined based on a linear function. 1951–82 the station operated under the auspices According to the definition used at IMGW-PIB of the Institute of Meteorology and Water Manage- meteorological stations, a thunderstorm is consid- ment (IMGW) according to the International Civil ered to have occurred when a thunderclap is heard Aviation Organisation (ICAO). In the years 1951– less than 10 seconds after seeing the lightning, while 65, the station conducted basic measurements of for distant thunderstorms, thunder will be heard meteorological parameters such as: air temperature, more than 10 seconds after lightning is observed, or dew point temperature, amount and type of cloud thunder may be heard with no observable preceding cover, relative humidity, wind direction and speed, lighting (Derek et al. 2015). Thunderstorms are al- and visibility. Since 1966, meteorological observa- ways associated with the occurrence of cumulonim- tions have been extended to include the following bus (Cb) clouds. The occurrence of thunderstorms measurements: height of cloud base, atmospher- is associated with a strong increase in cumulus ic pressure at sea and station level, water vapour clouds, caused by thermal ground factors or the 62 Citation: Bulletin of Geography. Physical Geography Series 2020, 18, http://dx.doi.org/10.2478/bgeo-2020-0005 A. Araźny and E. Łaszyca Selected meteorological phenomena posing a hazard to aviation... Fig. 1. Location of the study area Fig. 2. Military meteorological garden at the Bydgoszcz-Szwede- Fig. 3. Bydgoszcz-Szwederowo Airport meteorological garden rowo Airport in the 1990s. (photo: J. Czop) of the Institute of Meteorology and Water Management - National Research Institute in the 21st century (pho- to: E. Łaszyca) movement of atmospheric fronts. Thunderstorms shear as downbursts or microbursts (Domicz and are often associated with heavy precipitation (Woś Szutowski 1998; Szot 2013; Szewczak 2014). In By- 1999) and are a local phenomenon. During a flight dgoszcz, which is located in lowland central Poland, in a thunderstorm zone, there is a high probability general atmospheric circulation and related inflow- of heavy turbulence, lightning, hail, icing, and wind ing air masses play a major role in the formation Citation: Bulletin of Geography. Physical Geography Series 2020, 18, http://dx.doi.org/10.2478/bgeo-2020-0005 63 Selected meteorological phenomena posing a hazard to aviation... A. Araźny and E. Łaszyca of thunderstorms (Bielec-Bąkowska 2002; Kolendo- Results wicz 2005). Research on the occurrence of thunderstorms in Bydgoszcz is supplemented by an analysis of the oc- Number of thunderstorm days currence of hail as potentially the most dangerous thunderstorm precipitation. “Hail” is the term for Analysis of the annual course shows that the thun- the precipitation of ice pellets usually of diameter derstorm maximum in Bydgoszcz occurred in July 5–50 mm (Niedźwiedź 2003). In addition to lim- (an average of 4.0 days with a thunderstorm), fol- iting visibility, hail may cause mechanical damage lowed by June, August and May (Fig. 4A). The to an aircraft, thus reducing its aerodynamic prop- greatest number of days with a thunderstorm in a erties. In addition, hailstones falling on the airport single month (13) occurred in July 1973.