Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023

The significantly faster increase in Arctic temperature compared to the global average is causing changes in wind patterns in the mid-latitudes of the upper troposphere. Studies suggest possible changes in the geometry of wind fields, evident in the waviness of geopotential lines or in a series of...

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Main Author: Jan Degirmendžić
Format: Article
Language:English
Published: Lodz University Press 2024-12-01
Series:Acta Universitatis Lodziensis. Folia Geographica Physica
Subjects:
Online Access:https://czasopisma.uni.lodz.pl/geophysica/article/view/23726
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author Jan Degirmendžić
author_facet Jan Degirmendžić
author_sort Jan Degirmendžić
collection DOAJ
description The significantly faster increase in Arctic temperature compared to the global average is causing changes in wind patterns in the mid-latitudes of the upper troposphere. Studies suggest possible changes in the geometry of wind fields, evident in the waviness of geopotential lines or in a series of discrete circulation patterns. This study aligns with the latter research focus. The objective of the analysis is to estimate long-term trends in the Vangengeim-Girs (V-G) macroforms from 1979 to 2023, and since 1999, which is considered a breaking point in the course of Arctic warming. Trend coefficients were estimated for the 45-year period and in moving 21-year window for characteristics describing V-G forms variability. The results indicate a nonlinear trend in the annual frequency of W and E forms, the number of E episodes, and the duration of C and W episodes. Other parameters maintained a consistent direction of change (+/−) throughout the study period: frequency of C(+), number of W(+), C(+), WEC(+) episodes, duration of WEC(−) and E(−). Processes indicating an increase in meridionality include the decline in W frequency after 2005, the rise in E frequency after 2003, the increase in C frequency and the number of C episodes from 1979 to 2023, and the rise in the number of E episodes along with a significant decline in W episode duration after 1999. Additionally, significant trends in the increase (decrease) in the number (duration) of all episodes suggest an increase in day-to-day circulation variability.
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spelling doaj-art-53d27a0412484b1aa0a4ca9e6ce0ef102025-08-20T02:26:32ZengLodz University PressActa Universitatis Lodziensis. Folia Geographica Physica1427-97112353-60632024-12-012310.18778/1427-9711.23.03Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023Jan Degirmendžić0https://orcid.org/0000-0002-9022-5822University of Lodz, Faculty of Geographical Sciences, Department of Physical Geography The significantly faster increase in Arctic temperature compared to the global average is causing changes in wind patterns in the mid-latitudes of the upper troposphere. Studies suggest possible changes in the geometry of wind fields, evident in the waviness of geopotential lines or in a series of discrete circulation patterns. This study aligns with the latter research focus. The objective of the analysis is to estimate long-term trends in the Vangengeim-Girs (V-G) macroforms from 1979 to 2023, and since 1999, which is considered a breaking point in the course of Arctic warming. Trend coefficients were estimated for the 45-year period and in moving 21-year window for characteristics describing V-G forms variability. The results indicate a nonlinear trend in the annual frequency of W and E forms, the number of E episodes, and the duration of C and W episodes. Other parameters maintained a consistent direction of change (+/−) throughout the study period: frequency of C(+), number of W(+), C(+), WEC(+) episodes, duration of WEC(−) and E(−). Processes indicating an increase in meridionality include the decline in W frequency after 2005, the rise in E frequency after 2003, the increase in C frequency and the number of C episodes from 1979 to 2023, and the rise in the number of E episodes along with a significant decline in W episode duration after 1999. Additionally, significant trends in the increase (decrease) in the number (duration) of all episodes suggest an increase in day-to-day circulation variability. https://czasopisma.uni.lodz.pl/geophysica/article/view/23726Vangengeim-Girs macro-circulation formscirculation episodeslong-term trendsArctic amplification
spellingShingle Jan Degirmendžić
Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
Acta Universitatis Lodziensis. Folia Geographica Physica
Vangengeim-Girs macro-circulation forms
circulation episodes
long-term trends
Arctic amplification
title Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
title_full Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
title_fullStr Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
title_full_unstemmed Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
title_short Changes in the frequency and persistence of the Vangengeim-Girs macro-circulation forms in the period 1979–2023
title_sort changes in the frequency and persistence of the vangengeim girs macro circulation forms in the period 1979 2023
topic Vangengeim-Girs macro-circulation forms
circulation episodes
long-term trends
Arctic amplification
url https://czasopisma.uni.lodz.pl/geophysica/article/view/23726
work_keys_str_mv AT jandegirmendzic changesinthefrequencyandpersistenceofthevangengeimgirsmacrocirculationformsintheperiod19792023