Wyniki wyszukiwania - Biblioteka Nauki

1

Changes in the seasonal cycles of extreme temperatures in the Sudano-Sahelian domain in West Africa: a case study from Burkina Faso

100%

Yaméogo J.

|

2024

|

tom Vol. 12, Iss. 2

1--25

EN

Temperature is a key variable in understanding climate change. In tropical West Africa, however, temperature has been neglected because it is always hot because of the sun. Studying extreme temperatures can be a way to better understand climate change in the Sudano-Sahelian region of West Africa. The main objective of this study is to analyze changes in extreme temperatures. To this end, temperature data were obtained from Power NASA over the period 1981-2022 at monthly time steps. The methods used to analyze the data were normality and homogeneity statistics, linear regression, Mann-Kendall tests, and Spearman’s r test. Tests of Sen’s slope estimator, moving averages, and z-score. The study shows that maximum temperatures are normally distributed, unlike minimum temperatures, and that maximum temperature data are homogeneous, with breaks in the periods 1998, 2000, 2006, and 2010 before, during, and after the rainy seasons. On the other hand, minimum temperature data are generally not homogeneous and do not show many breaks. The study also shows that extreme temperatures tend to increase before, during, and after the rainy season, according to Spearman’s r test. However, the Mann-Kendall test shows that extreme temperatures generally do not show trends. Furthermore, temperatures are continuously variable, with an increase in temperature anomalies in the 1980s, 2000s, and 2020s.

2

Extremely Cold Winter Months in Europe (1951-2010)

72%

Twardosz R. , Kossowska-Cezak U. , Pełech S.

|

2016

|

tom Vol. 64, no. 6

2609--2629

EN

Investigation of extreme thermal conditions is important from the perspective of global warming. Therefore, this study has been undertaken in order to determine the frequency, timing and spatial extent of extremely cold months in winter time at 60 weather stations across Europe over a sixty-year period from 1951 to 2010. Extremely cold months (ECMs) are defined as months in which the average air temperature is lower than the corresponding multi-annual average by at least 2 standard deviations. Half of all the ECMs occurred in the years 1951-1970 (33 out of 67). The lowest number of ECMs was recorded in the decade 19912000, but since the beginning of the 21st century, their density and territorial extent has started to increase again. The extremely cold months with ECMs of the greatest spatial extent, covering at least one third of the stations (over 20 stations), included: February 1954 (22), February 1956 (36), January 1963 (25), and January 1987 (23 stations).

3

Niezwykle chłodne sezony letnie w Europie Środkowej i Wschodniej (1951-2010)

58%

Kossowska-Cezak U. , Twardosz R.

|

tom Z. 1-2

25--39

PL

W pracy podjęto zagadnienie występowania niezwykle chłodnych sezonów letnich (NZL) – zjawiska rzadkiego, ale wywołującego wiele negatywnych skutków, m.in. w rolnictwie, gospodarce i turystyce. Określono zasięg przestrzenny i dokonano charakterystyki termicznej tych sezonów na obszarze Europy Środkowej i Wschodniej. Badania oparto na wartościach średnich miesięcznych temperatury powietrza (od czerwca do sierpnia) oraz liczby dni z temperaturą maksymalną >25, >30 i >35⁰C i minimalną >20⁰C z 59 stacji meteorologicznych z lat 1951-2010. Za NZL przyjęto te, w których średnia temperatura powietrza była niższa od średniej z 60-lecia na danej stacji przynajmniej o 2 odchylenia standardowe (t≤tśr.-2σ). NZL nie występują na całym obszarze; wystąpiły na 34 spośród 59 stacji (58% stacji), po jednym lub dwa w ciągu 60 lat, głównie w północnej połowie obszaru. Wyłoniono 6 NZL: w roku 1962, 1969, 1976, 1978, 1984 i 1994, które swym zasięgiem objęły przynajmniej 5% stacji. Średnia temperatura powietrza w NZL była zwykle niższa od średniej wieloletniej o 2-3⁰C. W NZL jeden z miesięcy mógł być również niezwykle chłodny, ale w większości przypadków (58%) o niezwykle niskiej średniej temperaturze w sezonie decydowało długotrwałe utrzymywanie się względnie niskiej temperatury we wszystkich miesiącach lata.

EN

The authors analysed the occurrence of exceptionally cold summer seasons (ECS). The phenomenon is rare, but can cause several adverse effects on agriculture, industry and tourism. The study involves the spatial extent and thermal profiling of such seasons in Central and Eastern Europe. Input data included average monthly temperature (June-August) and the number of days with a maximum temperature >25, >30 and >35⁰C and a minimum temperature >20⁰C, recorded at 59 weather stations during the period 1951-2010. An ECS was defined as having an average temperature lower than the 60-year average at a given station by at least 2 standard deviations (t≤tśr.-2σ). The study showed that ECS only occurred in some parts, mostly northern, of the study area, at 34 of the 59 stations (58%), and never more than twice at a given station. Six such seasons were identified that covered at least 5% of all stations at a time, including 1962, 1969, 1976, 1978, 1984 and 1994. The average air temperature of an ECS was normally 2-3⁰C lower than the long-term average. Some ECS also had an exceptionally cold month, but in most cases (58%) the seasonal criterion of exceptional coldness was met due to the persistence of relatively low temperatures during all of the summer season.