North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations

Atmospheric blocking is an unusual weather phenomenon that is often associated with severe weather events such as heat waves, cold spells, and droughts. Improved understanding of the long-term variability of atmospheric blocking has important societal implication, but its mechanisms are not well und...

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Main Authors: Martinez, Carlos, Kwon, Young-Oh, Seo, Hyodae, Small, R., Bukovsky, Melissa, Bishop, Stuart, Carpenter, Eileen, Hvizdak, Candace
Format: Text
Language:unknown
Published: University Corporation For Atmospheric Research (UCAR) 2014
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Online Access:https://dx.doi.org/10.5065/c9f2-5m51
https://opensky.ucar.edu/islandora/object/manuscripts:822
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spelling ftdatacite:10.5065/c9f2-5m51 2023-05-15T16:30:26+02:00 North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations Martinez, Carlos Kwon, Young-Oh Seo, Hyodae Small, R. Bukovsky, Melissa Bishop, Stuart Carpenter, Eileen Hvizdak, Candace 2014 https://dx.doi.org/10.5065/c9f2-5m51 https://opensky.ucar.edu/islandora/object/manuscripts:822 unknown University Corporation For Atmospheric Research (UCAR) manuscript Text article-journal ScholarlyArticle 2014 ftdatacite https://doi.org/10.5065/c9f2-5m51 2021-11-05T12:55:41Z Atmospheric blocking is an unusual weather phenomenon that is often associated with severe weather events such as heat waves, cold spells, and droughts. Improved understanding of the long-term variability of atmospheric blocking has important societal implication, but its mechanisms are not well understood. Multidecadal variability of winter (DJFM) atmospheric blocking in the North Atlantic, especially its relationship with multi-decadal oceanic variability represented by the Atlantic Multidecadal Oscillation (AMO), is examined using observational datasets and the Community Earth System Model version1 Large Ensemble (CESM1LE) simulations. The CESM1LE has 30 ensemble members from 1920 to 2005 forced with the identical historical radiative forcing but slightly different initial conditions. Therefore, the internal climate variability in the 30 simulations do not necessarily exhibit identical temporal evolutions, while the externally driven variability due to the radiative forcing are likely to be coherent. The mean spatial patterns of the number of blocking days in the North Atlantic are examined in the 20th Century Reanalysis (20CR) and the 30 member CESM1LE simulations. In addition, the AMO index is examined in the Hadley Centre Sea Ice and Sea Surface Temperature data set version 1 (HadISST) and the CESM1LE. In the observations, the two primary maxima of atmospheric blocking occurrence are found over the Greenland and the British Isles. CESM1LE underestimates the mean number of blocking days in these two locations, but the time-scale of variability in these regions is comparable to that in the observations. CESM1LE also shows a reasonable AMO with similar amplitude and periodicity to the observations. In the observations, preliminary results show some correlation between the blocking in the North Atlantic and the AMO on decadal time-scales when the AMO leads the blocking by a few years. This suggests that atmospheric blocking and the associated extreme weather variability in the North Atlantic might be modulated by the multi-decadal oceanic variability associated with the AMO. In CESM1LE, the ensemble mean of AMO index and the number of blocking days show robust increasing and decreasing trends, respectively, which are likely driven by the anthropogenic radiative forcing. Text Greenland North Atlantic Sea ice DataCite Metadata Store (German National Library of Science and Technology) Greenland
institution Open Polar
collection DataCite Metadata Store (German National Library of Science and Technology)
op_collection_id ftdatacite
language unknown
description Atmospheric blocking is an unusual weather phenomenon that is often associated with severe weather events such as heat waves, cold spells, and droughts. Improved understanding of the long-term variability of atmospheric blocking has important societal implication, but its mechanisms are not well understood. Multidecadal variability of winter (DJFM) atmospheric blocking in the North Atlantic, especially its relationship with multi-decadal oceanic variability represented by the Atlantic Multidecadal Oscillation (AMO), is examined using observational datasets and the Community Earth System Model version1 Large Ensemble (CESM1LE) simulations. The CESM1LE has 30 ensemble members from 1920 to 2005 forced with the identical historical radiative forcing but slightly different initial conditions. Therefore, the internal climate variability in the 30 simulations do not necessarily exhibit identical temporal evolutions, while the externally driven variability due to the radiative forcing are likely to be coherent. The mean spatial patterns of the number of blocking days in the North Atlantic are examined in the 20th Century Reanalysis (20CR) and the 30 member CESM1LE simulations. In addition, the AMO index is examined in the Hadley Centre Sea Ice and Sea Surface Temperature data set version 1 (HadISST) and the CESM1LE. In the observations, the two primary maxima of atmospheric blocking occurrence are found over the Greenland and the British Isles. CESM1LE underestimates the mean number of blocking days in these two locations, but the time-scale of variability in these regions is comparable to that in the observations. CESM1LE also shows a reasonable AMO with similar amplitude and periodicity to the observations. In the observations, preliminary results show some correlation between the blocking in the North Atlantic and the AMO on decadal time-scales when the AMO leads the blocking by a few years. This suggests that atmospheric blocking and the associated extreme weather variability in the North Atlantic might be modulated by the multi-decadal oceanic variability associated with the AMO. In CESM1LE, the ensemble mean of AMO index and the number of blocking days show robust increasing and decreasing trends, respectively, which are likely driven by the anthropogenic radiative forcing.
format Text
author Martinez, Carlos
Kwon, Young-Oh
Seo, Hyodae
Small, R.
Bukovsky, Melissa
Bishop, Stuart
Carpenter, Eileen
Hvizdak, Candace
spellingShingle Martinez, Carlos
Kwon, Young-Oh
Seo, Hyodae
Small, R.
Bukovsky, Melissa
Bishop, Stuart
Carpenter, Eileen
Hvizdak, Candace
North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
author_facet Martinez, Carlos
Kwon, Young-Oh
Seo, Hyodae
Small, R.
Bukovsky, Melissa
Bishop, Stuart
Carpenter, Eileen
Hvizdak, Candace
author_sort Martinez, Carlos
title North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
title_short North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
title_full North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
title_fullStr North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
title_full_unstemmed North Atlantic amospheric blocking and Atlantic multidecadal oscillation in CESM1 large ensemble simulations
title_sort north atlantic amospheric blocking and atlantic multidecadal oscillation in cesm1 large ensemble simulations
publisher University Corporation For Atmospheric Research (UCAR)
publishDate 2014
url https://dx.doi.org/10.5065/c9f2-5m51
https://opensky.ucar.edu/islandora/object/manuscripts:822
geographic Greenland
geographic_facet Greenland
genre Greenland
North Atlantic
Sea ice
genre_facet Greenland
North Atlantic
Sea ice
op_doi https://doi.org/10.5065/c9f2-5m51
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