The following paper compares two methods for identifying warm and cold waves, representing different methodological approaches: the ‘relative’ approach, i.e. wave identification based on the standard deviation, andthe ‘arbitrary’ approach, i.e. wave identification based on a specified thermal threshold. The 1981-2010 comparisonis based on data from eleven selected large cities of the world. The cities are located in zones C and D according to the Köppen climatic classification. More of the thermal waves and their parameters (number of waves, number of days in waves, their durations, and number of warm and cold days) were determined by means of the relative method than the arbitrary method. Cold waves and cold days distinguished by means of both methods, predominated over warm days and warm waves in a given period, whereas the number and duration of warm waves and warm days increased.
Agnieszka Krzyżewska, Maria Curie-Skłodowska University Faculty of Earth Sciences and Spatial Management al. Kraśnicka 2 cd, 20-718 Lublin: Poland