Wyniki wyszukiwania - BazTech

1

Współczesne anomalie termiczne na historycznych ziemiach polskich

Kossowska-Cezak U., Twardosz R.

Przegląd Geofizyczny

|

2017

|

Z. 1-2

29--43

PL

W opracowaniu dokonano porównania częstości i rodzaju anomalii termicznych na historycznych ziemiach polskich na podstawie źródeł historycznych (X-XVI wiek) i danych pomiarowych (1951-2015). Stwierdzono odpowiednio 56 epizodów zimnych (głównie zimy) i 14 epizodów ciepłych (przeważnie lata) oraz 21 miesięcy anomalnie zimnych i 22 anomalnie ciepłe. Ich rozkład w czasie potwierdził znane z innych źródeł zmiany wiekowe klimatu w środkowej Europie, w tym szczególnie początek małej epoki lodowej (XV wiek) i nasilające się współczesne ocieplenie (od końca XX wieku).

EN

The study compares the frequency and type of thermal anomalies within former Polish borders (Fig. 1) using historical records (10th to 16th centuries) and data derived from actual measurements (1951-2015). Altogether 56 cold episodes (mainly winters, Table 1) and 14 warm episodes (mainly summers, Table 2) were identified, as well as 21 anomalously cold months and 22 anomalously warm months (Tables 3 and 4). The occurrence of strong disturbances in the annual air temperature profile in the form of exceptionally cold and exceptionally warm months and seasons is a natural feature of the European climate, especially in the central parts of the continent where the features of the dominant moderate climate involve transiency between maritime and continental influences. While their absolute frequency is low, the most frequent of such anomalies fall at the extreme ends of the spectrum, i.e. exceptionally cold winter months and exceptionally hot summer months. They even occur during long spells of an opposite type of climate, i.e. exceptionally hot summers during the Little Ice Age and exceptionally severe winters during the latest warming period. Despite this apparent paradox, the second conclusion that the study makes is an expected increase in the frequency of negative anomalies during cool periods and an analogous increase in positive anomalies during warm periods. This is evident in an increased number of severe winters during the early phase of the Little Ice Age, which is higher in comparison to that during the preceding period and during warm spells. The current warming period, especially the last 25 years, is marked by an exceptional dominance of hot and warm months both in comparison to the preceding period and to the number of anomalously cold months during the same warming period. The comparison made in this study of the frequency of anomalously cold and anomalously warm spells (months and seasons) recorded in historical sources (10th-16th c.) and noted from measurements (20th-21st c.) within former Polish borders has demonstrated that these spells correctly reflect longer-term climatic changes known from other sources.

2

Anomalie termiczne na Islandii (1951-2010)

Mitka K.

Problemy Klimatologii Polarnej

|

2016

|

Nr 26

97--108

PL

Opracowanie wykonano na podstawie średnich miesięcznych wartości temperatury powietrza z 10 stacji meteorologicznych na Islandii z okresu 1951-2010. Za miesiące anomalnie zimne (AZM) lub ciepłe (ACM) przyjęto takie, w których temperatura powietrza różniła się od średniej wieloletniej przynajmniej o 2 odchylenia standardowe. Przeanalizowano przebieg roczny, częstość, rozkład przestrzenny i wielkość anomalii. W analizowanym wieloleciu stwierdzono wystąpienie 143 anomalnie zimnych i 133 anomalnie ciepłych miesięcy. Najczęściej występowały one na pojedynczych stacjach, ale były też takie anomalie, które pojawiły się na 8-9 stacjach jednocześnie. Wielkość anomalii obu kategorii mieściła się w zakresie 1,1-8,0°C. Najwięcej AZM wystąpiło w dekadzie 1971-1980, a ACM w latach 2001-2010.

EN

The aim of this paper is to present anomalously cold (ACM) and warm (AWM) months in Iceland during the period of 1951-2010. The study was based on average monthly temperature data from 10 meteorological stations located in Iceland recorded during the period 1951-2010. The anomalously cold or warm months was defined as having an average temperature different from long-term average by at least 2 standard deviations. There were found 143 ACM and 133 AWM in Iceland. Exceptionally cold months appeared in 47 and exceptionally warm months in 58 from 720 examined months. Both positive and negative anomalies mostly occur at single stations (20 ACM and AWM 33), but there were examples of anomalies of range 8 and 9 stations. ACM were a bit more frequent than AWM. Moreover, ACM had a greater range - were more frequent at the same time on several stations (3 times at 8 and also 9 of them). In case of AWM there were 2 anomalies at 8 and 1 anomaly on 9 the same stations. Extremely cold months appeared most often in north-eastern part of Iceland (Raufarhöfn, Dalatangi) and also stood out in the amount of deviation from the mean monthly air temperature (6 ACM within the range -7,1 to -7,3°C). Long-lasting thermal anomaly was not varied. Exceptionally warm months occurred more often during the summer and then have a longer range at that time. ACM and AWM formed only a 2-month sequences. The number of ACM and AWM per month (respectively average 14 and 13 per month) were diverse. Anomalously cold months ranged from 5 (January and September) to 22 (October), and anomalously warm months from 2 (January) to 19 (August). Neither ACM and AWM showed no regular pattern of annual process. Large-scale atmospheric circulation does not fully explain the occurrence of thermal anomalies in Iceland. The values of the correlation coefficient between the average monthly air temperature, and the values of the North Atlantic Oscillation index were low and very varied. Advection of cold air masses from north and north-west (Arctic) favors to the incidence of ACM (Einarsson 1976, Twardosz 2013).

3

Anomalnie zimne miesiące na Alasce (1951-2010)

Sulikowska A.

Problemy Klimatologii Polarnej

|

2015

|

Nr 25

139--151

PL

Opracowanie oparto na średnich miesięcznych wartościach temperatury powietrza z 15 stacji meteorologicznych na Alasce w okresie 1951-2010. Za anomalnie zimne uznano te miesiące, w których średnia temperatura powietrza była niższa od średniej 60-letniej co najmniej o 2 odchylenia standardowe. Zbadano częstość występowania, zasięg przestrzenny i przebieg roczny anomalnie zimnych miesięcy (AZM) oraz przedstawiono ich charakterystyki termiczne. Ponadto przeprowadzono próbę powiązania występowania AZM z Dekadową Oscylacją Pacyficzną (PDO). W rozpatrywanym okresie stwierdzono 285 AZM. Obejmowały one od 1 do 11 stacji równocześnie. Wielkości anomalii mieściły się w zakresie od 1,1°C do 17,0°C. Najwięcej AZM wystąpiło w 20-leciu 1961-1980, a najmniej w okresie 2001-2010. Zaobserwowano znaczny spadek częstości AZM po zmianie fazy PDO z negatywnej na pozytywną w 1976 roku i stwierdzono, że zdecydowana większość AZM (79%) wystąpiła podczas ujemnych wartości tego wskaźnika, co wskazuje na jego duże znaczenie w kształtowaniu warunków termicznych na Alasce.

EN

The aim of this paper is to present anomalously cold months (ACM) in Alaska during the period of 1951-2010 and to refine the linkage of Pacific Decadal Oscillation (PDO) with their occurrence. The study is based on average monthly temperature data recorded during the period of 1951-2010 from 15 weather stations located in Alaska. The anomalous month was defined as having an average\ temperature different from the long-term mean (1951-2010) by at least 2 standard deviations. There were 285 ACMs observed. They appeared most often in Cold Bay (25) and stations located in central Alaska (Fairbanks, Big Delta, Northway; 22-24). Most frequently they occurred from February to April and in November and December. ACMs occurred at up to 11 weather stations simultaneously, however the majority of them was observed at a single station or at two or three neighboring stations (of the stations included in the study). The scale of the anomaly ranged from 1.1°C to 17.0°C (Northway, February 1979). There were 12 two- to four-month series of ACMs. The highest number of ACMs occurred during the decade 1961–1970 and the lowest in 2001-2010. There is a clearly visible decrease in the frequency of ACMs after the PDO shift from dominantly negative to positive values in 1976. The great majority of ACMs (79%) occurred during the negative values of the PDO index. The correlation coefficient of average monthly temperatures and PDO values was highest in the southeastern part of Alaska (up to 0.75) and from November to May. It was the lowest in the arctic part of the state and from June to September. Monthly temperature anomalies in Alaska are mainly driven by the atmospheric circulation patterns. ACMs coincide with the advection of cold air masses from the north. Also local effects, which include radiative cooling, temperature inversions and local katabatic winds contribute greatly to the occurrence of ACMs in Alaska.

4

Niezwykłe anomalie termiczne w strefie klimatu podbiegunowego obszaru atlantycko-europejskiego

Twardosz R., Kossowska-Cezak U.

Problemy Klimatologii Polarnej

|

2013

|

Nr 23

93--105

PL

Opracowanie oparto na wartościach średnich miesięcznych temperatury powietrza z 17 stacji meteorologicznych od Wybrzeży Grenlandii do Nowej Ziemi z 60-lecia 1951-2010. Do badań przyjęto stacje, w których temperatura średnia wieloletnia w najcieplejszym miesiącu, tj. w lipcu, nie przekracza 12°C. Za anomalne uznano te miesiące, w których temperatura różniła się od średniej wieloletniej przynajmniej o 2 odchylenia standardowe. Zbadano przebieg roczny występowania miesięcy o anomalii ujemnej (niezwykle zimnych) i dodatniej (niezwykle ciepłych) oraz tendencji zmian ich częstości w 60-leciu, a także rozkład przestrzenny najbardziej rozległych anomalii. Stwierdzono, ze w ciągu 60 lat były 132 miesiące niezwykle zimne i 127 miesięcy niezwykle ciepłych. Najwięcej miesięcy niezwykle zimnych (41) i najmniej niezwykle ciepłych (11) było w 10-leciu 1961-1970; najmniej miesięcy niezwykle zimnych (3) i najwięcej niezwykle ciepłych (57) było w 10-leciu 2001-2010. Wzrost częstości miesięcy ciepłych zaznaczył się głównie w zachodniej części badanego obszaru.

EN

The study is based on average monthly temperature data from 17 weather stations located along a belt between the Greenland coast and the island of Novaya Zemlya and recorded during the period 1951-2010. The stations were selected to meet the criterion of a maximum long-term average temperature of 12°C for the warmest month, i.e. July. The anomalous month was defined as having an average temperature different from the long-term average by at least 2 standard deviations. Both positive (exceptionally warm) and negative (exceptionally cold) anomalies were analysed, as well as their trends of frequency change during the study period and the spatial distribution of the cases with the largest geographical spread. However, a majority of the anomalous months of each type were only recorded at single stations or at two neighbouring stations (of those included in the study), which would suggest spatially limited or even strictly local factors effecting such an exceptional temperature increase or drop. Exceptionally cold months (ECM) were more frequent than their warm counterparts (EWM), had a greater spatial extent and the scale of their anomaly tended to be larger (i.e. down to –12°C compared to maximum +10°C for EWMs). ECMs were more often linked in two-month or three-month series (31 such series), while multiple EWM series were fewer (18), but longer, lasting up to 6 months. The highest numbers of anomalous months were recorded during the decade 1961-1970 (41 ECM and 11 EWM) and the lowest numbers in the decade 2001-2010 (3 ECM and 57 EWM). The increase in the warm month activity was largely limited to the western end of the study area. The annual pattern of anomalous months was far more defined in the eastern section of the area, along the coast of a vast continent, than in the maritime west. This clear definition of the eastern pattern was mainly down to the frequency of ECMs and their large spatial extent. In the western section of the area the distribution of ECMs and EWMs is more balanced with a recent maximum of EWM frequency located in Iceland. ECMs coincide with the advection of cold air masses from the north and northeast, while EWMs tend to occur in association with southern warm advections.