Heat and Cold Waves in an Annual Cycle Air Temperatures in Warsaw (1951-2010)
Heat and cold waves in Warsaw (the Okęcie district) have been determined determined basing on daily average air temperature values in Warsaw (the Okęcie district), measured for 60 years between 1951 and 2010. Air temperature cycles, i.e. periods, amplitudes and phases have been determined by means of a sinusoidal regression method. Especially worth noting are 15 to 18-day long cycles of air temperature in given months (e.g. 16-day long cycles during 6 months: March, April, May, August, September, and October). Heat and cold waves result from interferences of cycles whose duration ranges from several to teen days of daily temperature values, and long-term cycles of average annual temperature.
The objective of the work is to determine the periodicity and trends of change in air temperature in Warsaw and in Lviv during the 18th-20th centuries, together with the forecast for the years 2000-2100. There are interesting diagrams of temporal changes of the North Atlantic Oscillation (NAO) indicator and air temperature, with the forecast reaching the year 2100. The forecasts were obtained on the basis of interpretations of the Sun activity and the NAO indicator cycles, determined with the method of “regression sinusoids”. The fluctuations of air temperature and North Atlantic Oscillation during winter in Warsaw and in Lviv are closely correlated.
This paper outlines the results of a study of Lviv’s specific thermal characteristics. The study relied on a series of measurements taken over a 15-month period (from February 2007, through April 2008) at 6 automatic meteorological stations, representing a variety of physiogeographic conditions and land use. The study reveals substantial variations of temperature levels (annual [1-3°C], seasonal [2-4°C], and daily [2-12°C] averages), indicating the presence of an urban heat island. The result of the study is a map of the distribution of average annual air temperatures on the territory of Lviv.
The more important research results on the impact of building development and vegetation on the local climate, conducted in Warsaw in the years 1959–2009 by the Department of Climatology, are presented. Majority of the issues associated with determining the deformation of air temperature limits (urban heat islands), humidity and wind vector areas, because of buildings in housing estates, located in various parts of the city, were resolved in master’s thesis. Areas with high building density are characterized by slow cooling and warming pace, especially during the summer months. Spatial changes in the urban heat islands in the east-west direction well describe the latitudinal profiles (W-E) of air temperature differences (∆T ≥ 0) between the city and its urban fringe. The urban heat island ∆T does not appears till 5PM, initially in the Central City District. Spatial diversity of effective temperature and catathermal cooling allowed to mark off in housing estates („Stawki”, „Służew nad Dolinką”, „Sady Żoliborskie”) places with perceptible conditions, e.g. heat, warmth, comfort, cold.
In the paper, the results of field studies using automatic meteorological stations are presented. The studies were conducted in July 2005 – July 2006 in the vertical profile of Natural National Park of Carpathians. The results show that the thermal conditions in the area under research is strongly differentiated. Particularly large differences have been observed between the lowerings of the terrain (where the range of annual air temperature changes reaches almost 70°C, exceptionally high and exceptionally low temperature occurs often, and thermal inversions are frequently encountered) and the summit region (where the range of annual air temperature changes barely exceeds 50°C and the mean changes of daily air temperature are consideraly smaller).