Badania Fizjograficzne, Seria A, Tom 67, 2016
Permanent URI for this collection
Browse
Browsing Badania Fizjograficzne, Seria A, Tom 67, 2016 by Subject "atmospheric circulation"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item Fale mrozów w Poznaniu i ich cyrkulacyjne uwarunkowania(Wydawnictwo Poznańskiego Towarzystwa Przyjaciół Nauk, 2016) Tomczyk, ArkadiuszThe article aims to determine the long-term variability of frosty days and frost waves occurrence in Poznań, as well as to define the pressure conditions triggering off frost waves. A frosty day was defined as a day with the maximum temperature below the 5th percentile of the daily maximum temperature from a whole year (-1.7°C). A frost wave was defined as a sequence of at least 5 frosty days. In the analysed period, there were 44 frost waves which in total took 406 days. The most frequent were 7-day waves which represented 25% of all the frost waves. These tended to occur between November and March, with a majority of them (as much as 54.5%) in January. The occurrence of frost waves in Poznań in the discussed multiannual period was related to a ridge of high pressure above Eastern and Central Europe. During frost waves, the pressure over the analysed area was higher than the average in the winter season. According to the Grosswetterlagen (GWL) classification of weather types, frosty days forming frost waves were mainly associated with the anticyclonic circulation (54.0%).Item Fale upałów latem 2015 roku i ich uwarunkowania cyrkulacyjne(Wydawnictwo Poznańskiego Towarzystwa Przyjaciół Nauk, 2016) Sulikowska, Agnieszka; Wypych, Agnieszka; Woszczek, IzabelaThe main goal of the study was to characterize the thermal conditions during the hot summer of 2015 and to determine the circulation types with respect to the occurrence of extremely high air temperature and heat waves in Poland. The daily maximum (TMAX) and minimum (TMIN) air temperatures from 7 stations in Poland in 1951–2015 were used, as well as the Grosswetterlagen and Niedzwiedź circulation type classifications. A day with an extremely high air temperature (DTE) was defined as having TMAX above the 95th percentile and a heat wave as a sequence of at least 3 such days. The results prove that the summer of 2015 in Poland was unusually hot, especially in the south-western part of the country. The circulation types accompanying DTE and the heat waves were mainly anticyclonic with an advection of tropical air masses from the southern sector.Item Uwarunkowania cyrkulacyjne konwekcji w południowej Polsce(Wydawnictwo Poznańskiego Towarzystwa Przyjaciół Nauk, 2016) Poręba, SzymonThis work presents the influence of atmospheric circulation on CAPE values over southern Poland. The CAPE index is the one of most commonly used convection indicators. The research was based on a re-analysis from the NCEP/NCAR database, soundings and two atmospheric circulation classifications: Grosswetterlagen and T. Niedźwiedź. The research period included 13 years from 2000 to 2012 during which time the maximum CAPE value reached 3695 J/kg (derived by reanalysis) and almost 4450 J/kg (derived by sounding). According to Grosswetterlagen, the biggest average and maximum CAPE values over southern Poland occurred during three synoptic situations: Trough over Western Europe (TRW), Low over Great Britain (TB), Low over Central Europe (TM)Item Wpływ cyrkulacji atmosferycznej na ilość całkowitego promieniowania słonecznego docierającego do powierzchni ziemi w Belsku (1971-2014)(Wydawnictwo Poznańskiego Towarzystwa Przyjaciół Nauk, 2016) Nelken, KingaThis paper analyses the amount of global solar radiation reaching the ground in Belsk, depending on the atmospheric circulation type. The study used daily sums of global solar radiation from 1971–2014 as well as the calendar of circulation types as developed by Lityński. The largest differences in the amount of solar radiation among the particular circulation types occur in the summer. The largest sums of solar radiation are observed during inflows of air masses from S and SW, and the smallest during the inflow from N, NE, and NW. On sunny days, the reduction of the incoming solar radiation is associated with the S and SW directions.