GLORIA

GEOMAR Library Ocean Research Information Access

X

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Online-Ressource
    Online-Ressource
    Greenland blocking index daily series 1851–2015: Analysis of changes in extremes and links with North Atlantic and UK climate variability and change
    Wiley ; 2018
    In:  International Journal of Climatology Vol. 38, No. 9 ( 2018-07), p. 3546-3564
    Details
    In: International Journal of Climatology, Wiley, Vol. 38, No. 9 ( 2018-07), p. 3546-3564
    Kurzfassung: We present a homogenized Greenland blocking index (GBI) daily record from 1851 to 2015, therefore significantly extending our previously published monthly/seasonal GBI analysis. This new time series is analysed for evidence of changes in extreme events, and we investigate the underlying thermodynamic and dynamic precursors. We compare occurrences and changes in extreme events between our GBI record and a recently published, temporally similar daily North Atlantic Oscillation (NAO) series, and use this comparison to test dynamic meteorology hypotheses relating negative NAO to Greenland blocking. We also compare daily GBI changes and extreme events with long‐running indices of England and Wales temperature and precipitation, to assess potential downstream effects of Greenland blocking on UK extreme weather events and climate change. In this extended analysis we show that there have been sustained periods of positive GBI during 1870–1900 and from the late 1990s to present. A clustering of extreme high GBI events since 2000 is not consistently reflected by a similar grouping of extreme low NAO events. Case studies of North Atlantic atmospheric circulation changes linked with extreme high and low daily GBI episodes are used to shed light on potential linkages between Greenland blocking and jet‐stream changes. Particularly noteworthy is a clustering of extreme high GBI events during mid‐October in 4 out of 5 years during 2002–2006, which we investigate from both cryospheric and dynamic meteorology perspectives. Supporting evidence suggests that these autumn extreme GBI episodes may have been influenced by regional sea‐ice anomalies off west Greenland but were probably largely forced by increases in Rossby‐wave train activity originating from the tropical Pacific. However, more generally our results indicate that high GBI winter anomalies are co‐located with sea‐ice anomalies, while there seems to be minimal influence of sea‐ice anomalies on the recent significant increase in summer GBI.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2018.38.issue-9
    DOI: 10.1002/joc.5516
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2018
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 2
    Online-Ressource
    Online-Ressource
    Greenland surface air temperature changes from 1981 to 2019 and implications for ice‐sheet melt and mass‐balance change
    Wiley ; 2021
    In:  International Journal of Climatology Vol. 41, No. S1 ( 2021-01)
    Details
    In: International Journal of Climatology, Wiley, Vol. 41, No. S1 ( 2021-01)
    Kurzfassung: We provide an updated analysis of instrumental Greenland monthly temperature data to 2019, focusing mainly on coastal stations but also analysing ice‐sheet records from Swiss Camp and Summit. Significant summer (winter) coastal warming of ~1.7 (4.4)°C occurred from 1991–2019, but since 2001 overall temperature trends are generally flat and insignificant due to a cooling pattern over the last 6–7 years. Inland and coastal stations show broadly similar temperature trends for summer. Greenland temperature changes are more strongly correlated with Greenland Blocking than with North Atlantic Oscillation changes. In quantifying the association between Greenland coastal temperatures and Greenland Ice Sheet (GrIS) mass‐balance changes, we show a stronger link of temperatures with total mass balance rather than surface mass balance. Based on Greenland coastal temperatures and modelled mass balance for the 1972–2018 period, each 1°C of summer warming corresponds to ~(91) 116 Gt·yr −1 of GrIS (surface) mass loss and a 26 Gt·yr −1 increase in solid ice discharge. Given an estimated 4.0–6.6°C of further Greenland summer warming according to the regional model MAR projections run under CMIP6 future climate projections (SSP5‐8.5 scenario), and assuming that ice‐dynamical losses and ice sheet topography stay similar to the recent past, linear extrapolation gives a corresponding GrIS global sea‐level rise (SLR) contribution of ~10.0–12.6 cm by 2100, compared with the 8–27 cm (mean 15 cm) “likely” model projection range reported by IPCC in 2019 (SPM.B1.2). However, our estimate represents a lower limit for future GrIS change since fixed dynamical mass losses and amplified melt arising from both melt‐albedo and melt‐elevation positive feedbacks are not taken into account here.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v41.S1
    DOI: 10.1002/joc.6771
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 3
    Online-Ressource
    Online-Ressource
    Assessing the climatic and environmental impacts of mid‐tropospheric anticyclones over Alaska
    Wiley ; 2018
    In:  International Journal of Climatology Vol. 38, No. 1 ( 2018-01), p. 351-364
    Details
    In: International Journal of Climatology, Wiley, Vol. 38, No. 1 ( 2018-01), p. 351-364
    Kurzfassung: Ongoing climatic and cryospheric changes observed throughout the greater Alaska region are interconnected and often linked to oceanic and atmospheric patterns and processes that operate on varying spatiotemporal scales. To evaluate the long‐term, mid‐tropospheric circulation field across Alaska, and possible connections to climate and environmental change in the Pacific sector of the Arctic, the Alaska Blocking Index ( ABI ) is developed over the domain (54°–76°N, 125°–180°W) using daily gridded 500  hPa geopotential height fields derived from the ERA ‐40 (1958–1978) and ERA ‐Interim (1979–2014) data sets, 1958–2014. Climatological characteristics of the seasonal and annual ABI conditions are evaluated and periods of prevalent blocking conditions are identified and subsequently linked to possible local and large‐scale forcing mechanisms. The ABI has exhibited positive trends during all seasons and annually since 1979. Many of the extreme high ABI values occurred since 2000, including the highest annual values in 2013 and 2014. Anomalous blocking patterns in all seasons are associated with diminished snow depth and sea‐ice cover, positive near‐surface air temperature anomalies, and anticyclonic flows of heat and moisture across the domain. The ABI is also shown to differ from the long‐term variability and atmospheric circulation responses associated with phases of the Pacific–North American pattern and Pacific Decadal Oscillation, revealing some notable spatial and temporal disconnects between the region‐centric, high‐latitude blocking flow and some of the predominant modes of sea surface temperature and middle tropospheric circulation variability in the Northern Hemisphere.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2018.38.issue-1
    DOI: 10.1002/joc.5180
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2018
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 4
    Online-Ressource
    Online-Ressource
    The role of blocking circulation and emerging open water feedbacks on Greenland cold‐season air temperature variability over the last century
    Wiley ; 2021
    In:  International Journal of Climatology Vol. 41, No. S1 ( 2021-01)
    Details
    In: International Journal of Climatology, Wiley, Vol. 41, No. S1 ( 2021-01)
    Kurzfassung: Substantial marine, terrestrial, and atmospheric changes have occurred over the Greenland region during the last century. Several studies have documented record‐levels of Greenland Ice Sheet (GrIS) summer melt extent during the 2000s and 2010s, but relatively little work has been carried out to assess regional climatic changes in other seasons. Here, we focus on the less studied cold‐season (i.e., autumn and winter) climate, tracing the long‐term (1873–2013) variability of Greenland's air temperatures through analyses of coastal observations and model‐derived outlet glacier series and their linkages with North Atlantic sea ice, sea surface temperature (SST), and atmospheric circulation indices. Through a statistical framework, large amounts of west and south Greenland temperature variance (up to r 2  ~ 50%) can be explained by the seasonally‐contemporaneous combination of the Greenland Blocking Index (GBI) and the North Atlantic Oscillation (NAO; hereafter the combination of GBI and NAO is termed GBI). Lagged and concomitant regional sea‐ice concentration (SIC) and the Atlantic Multidecadal Oscillation (AMO) seasonal indices account for small amounts of residual air temperature variance ( r 2   〈  ~10%) relative to the GBI. The correlations between GBI and cold‐season temperatures are predominantly positive and statistically‐significant through time, while regional SIC conditions emerge as a significant covariate from the mid‐20th century through the conclusion of the study period. The inclusion of the cold‐season Pacific Decadal Oscillation (PDO) in multivariate analyses bolsters the air temperature variance explained by the North Atlantic regional predictors, suggesting the remote, background climate state is important to long‐term Greenland temperature variability. These findings imply that large‐scale tropospheric circulation has a strong control on surface temperature over Greenland through dynamic and thermodynamic impacts and stress the importance of understanding the evolving two‐way linkages between the North Atlantic marine and atmospheric environment in order to more accurately predict Greenland seasonal climate variability and change through the 21st century.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v41.S1
    DOI: 10.1002/joc.6879
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 5
    Online-Ressource
    Online-Ressource
    Atmosphere and Ocean Impacts on Recent Western Arctic Summer Sea Ice Melt
    Wiley ; 2013
    In:  Geography Compass Vol. 7, No. 10 ( 2013-10), p. 686-700
    Details
    In: Geography Compass, Wiley, Vol. 7, No. 10 ( 2013-10), p. 686-700
    Kurzfassung: Summer sea ice in the western Arctic, specifically in the Chukchi and Beaufort Seas, has been rapidly declining during the last several decades. Annual minima in six recent Septembers (2007–2012) have witnessed the lowest western Arctic sea ice extents of the modern satellite era. The western Arctic summer sea ice has become less extensive amidst a fundamental transition from once widely prevalent and thick multi‐year ice to a thinner and readily melted first‐year ice cover. Questions remain for the Arctic climate research community involving the combination of factors that may be forcing these negative sea ice trends, particularly as current understanding of these complex ice–climate interactions evolves. Interannual variations of atmospheric pressure systems such as the Beaufort Sea High help determine the overlying wind direction and strength as well as the severity of summer ice cover. Atmospheric circulation teleconnections are important in sea ice variability but the role of some, such as the Arctic Oscillation, may in fact have changed as the western Arctic transitioned to a thinner ice cover. Reductions in summer sea ice extent became noticeable from 1998 onward and can be partly attributed to oceanic warming in the northern Pacific across the Bering Strait into the western Arctic. Warming of the northern Atlantic has had dramatic impacts in the Eurasian Arctic but a viable physical mechanism by which it can produce western Arctic ice melt is not yet established. Arctic warming induced by forcing from greenhouse gases is estimated to rival the impact of atmospheric teleconnections and helps produce the “Arctic amplification” of air temperatures that enhances summer sea ice melt. Late summer open water may in turn be altering the atmospheric circulation, weather and climate of subsequent autumn and winter seasons throughout the middle latitudes.
    Materialart: Online-Ressource
    ISSN: 1749-8198 , 1749-8198
    URL: Issue
    URL: Article
    DOI: 10.1111/gec3.v7.10
    DOI: 10.1111/gec3.12077
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2013
    ZDB Id: 2272390-0
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 6
    Online-Ressource
    Online-Ressource
    The Alaska Blocking Index, version 2: Analysis and covariability with statewide and large‐scale climate from 1948 to 2020
    Wiley ; 2022
    In:  International Journal of Climatology Vol. 42, No. 16 ( 2022-12-30), p. 9767-9787
    Details
    In: International Journal of Climatology, Wiley, Vol. 42, No. 16 ( 2022-12-30), p. 9767-9787
    Kurzfassung: Monitoring and quantifying high‐latitude atmospheric circulation variability and trends are important towards understanding the anatomy of extreme events and constraining their probabilities under continued Arctic change. The greater Alaska region stands out as one region of enhanced warming and environmental changes over the Arctic amplification era, which has shown proclivity to extreme events and speaks to the need to consistently monitor overlying atmospheric variability. In this paper, we describe the creation and analysis of an updated, daily mid‐tropospheric Alaska Blocking Index (ABI) time series from 1948 to 2020. Sensitivity testing and index modifications from the initial dataset are discussed, and the new ABI is evaluated over the full period and subperiods. Additionally, we assess the role of the ABI as a regional climate indicator by analysing its variability against surface air temperature and precipitation from 13 climate divisions across Alaska as well as broader‐scale hemispheric temperatures. Months of the highest ABI means mainly transpired in the most recent climatological period, 1991–2020, and most notably during the spring and autumn transition seasons, reflecting the nonstationary nature of the jet stream magnitude through time atop Alaska. ABI trends are positive across all months, seasons, and annually only in the 1991–2020 period. Contemporaneous ABI values are strongly and positively correlated with air temperature across all Alaskan climate divisions during the warm season, but negatively correlated with winter temperatures over southeastern Alaska. Meanwhile, the ABI is significantly anticorrelated with summer precipitation over Interior and southern Alaska, but only over southeastern Alaska in other seasons. The ABI is statistically differentiated from the primary modes of atmospheric variability as shown by its generally weak correlations with the Arctic Dipole and the Arctic Oscillation ( r  ≤ 0.40).
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v42.16
    DOI: 10.1002/joc.7864
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2022
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 7
    Online-Ressource
    Online-Ressource
    Associations between circulation pattern frequencies and sea ice minima in the western Arctic
    Wiley ; 2014
    In:  International Journal of Climatology Vol. 34, No. 5 ( 2014-04), p. 1385-1394
    Details
    In: International Journal of Climatology, Wiley, Vol. 34, No. 5 ( 2014-04), p. 1385-1394
    Kurzfassung: In this study, a synoptic climatological approach is employed to assess the relationship between the frequency of circulation patterns ( CPs ) and the latitude of mid‐September sea ice minima in the western Arctic. Fifteen CPs are created via principal component analysis and cluster analysis from daily NCEP / NCAR reanalysis sea‐level pressure ( SLP ) fields across a grid from 50 to 90°N and 150°E–100°W from 1979 to 2011. The frequency of these CPs are statistically compared with the latitude of the sea ice minimum from passive microwave data for each of 11 equally‐spaced longitudes (176°W to 126°W) extending into the Chukchi and Beaufort Seas. Monthly frequencies for each of the 15 CPs from March to September, signifying the melt season, for each year are correlated with the ice minimum for that September. These monthly frequencies are then entered into a stepwise multiple linear regression ( SMLR ) and collectively, CP frequencies explain 40–79% of the total ice retreat variance across the longitudes. The frequency of one cluster, CP 11, representing a broad high pressure area over the Beaufort Sea, is highly correlated with the latitude of the sea ice minima; June and August frequencies of this pattern are the initial predictors at 8 of the 11 longitudes and explain 22–32% of the variance. This pattern has occurred more frequently from 2007 onwards; compared with a June mean occurrence of 9 days during 1979–2006, CP 11 occurred 16 times in June 2007, and on average more than 17 days per month during June 2008–2011. The Arctic Dipole ( AD ), Arctic Oscillation ( AO ), and Pacific‐North American ( PNA ) pattern indices are significantly correlated with CPs 11–13 frequencies throughout certain summer months, further indicating strong relationships between summer circulation and sea ice minima in the region.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2014.34.issue-5
    DOI: 10.1002/joc.3767
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2014
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 8
    Online-Ressource
    Online-Ressource
    Resolving the Beaufort Sea High using synoptic climatological methods
    Wiley ; 2014
    In:  International Journal of Climatology Vol. 34, No. 11 ( 2014-09), p. 3312-3319
    Details
    In: International Journal of Climatology, Wiley, Vol. 34, No. 11 ( 2014-09), p. 3312-3319
    Kurzfassung: Melt season frequencies of the Beaufort Sea High ( BSH ) have a profound effect on western Arctic climate, making the interannual spatial and temporal monitoring of this polar anticyclone important. This manuscript presents two automated synoptic climatological analyses using a two‐step cluster procedure to classify daily mean sea level pressure ( MSLP ) over 180–120°W and 70–85°N with an emphasis on identifying BSH patterns. Separate raw and anomaly MSLP circulation pattern ( CP ) classifications are compared in order to assess the spatial characteristics of the BSH and its monthly frequency changes during the melt season from 1979 to 2012. Analysis of both classifications shows clear advantages to using the anomaly approach in terms of assessing temporal and spatial changes, particularly in light of the documented recent atmospheric circulation changes that have been observed over the region. Associations between the June anomaly circulation pattern ( ACP ) 5, a +4  hPa BSH pattern situated between 155°W and 135°W, and June indices of atmospheric teleconnections such as the Arctic Dipole and Arctic Oscillation are statistically significant. There is also a statistically significant link to the downstream Greenland Blocking Index; suggesting that the BSH may be intricately related to climatic variability outside the analysed domain as well. Further, ACP 5 occurred nearly 3 weeks more often during the melt season in recent massive Arctic Sea ice loss years (2007–2012) compared with the climatology (1979–2006). Recent increases in June ACP 5 frequencies account for a large proportion of this pattern's long‐term frequency changes.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2014.34.issue-11
    DOI: 10.1002/joc.3907
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2014
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 9
    Online-Ressource
    Online-Ressource
    Connections between north‐central United States summer hydroclimatology and Arctic sea ice variability
    Wiley ; 2017
    In:  International Journal of Climatology Vol. 37, No. 12 ( 2017-10), p. 4434-4450
    Details
    In: International Journal of Climatology, Wiley, Vol. 37, No. 12 ( 2017-10), p. 4434-4450
    Kurzfassung: Arctic sea ice has been shrinking at unprecedented rates over the past three decades. These cryospheric changes have coincided with greater incidence of global extreme weather conditions, including increased severity and frequency of summer heatwaves and extreme rainfall events. Recent studies identify potential physical mechanisms related to Rossby wave and resonance theories that may attribute the observed changes in extreme summer weather patterns to Arctic sea ice decline. This study explores the linkages between summer Arctic sea ice variability and hydroclimate of the north‐central United States (US) during the 1979 to 2013 period. Since 1979, summers with low sea ice conditions have coincided with significant increases in mean, minimum, maximum, and dew point air temperatures. Also apparent are increases in seasonal precipitation, the number of wet days, heavy ( 〉 95th percentile) precipitation days, and accumulated precipitation over the region. These moisture changes coincide with atmospheric patterns typically observed during anomalously wet summers, known to prompt flooding across the Upper Mississippi River Valley ( UMRV ) region. Low sea ice summers have coincided with (1) enhanced southerly air flow and increased activity of the Great Plains Low Level Jet ( GPLLJ ) over the study area, (2) increased occurrence of moist tropical air masses over the UMRV region, and (3) amplified 500 hPa flow over the Pacific‐North American region with a ridge situated over the central‐eastern portions of the North American continent emanating from Greenland and the central Arctic basin. The results suggest summer Arctic sea ice variability has been associated with recent hydroclimate anomalies of the north‐central United States and the UMRV region and add to our growing knowledge of the connections between a changing Arctic environment and concurrent mid‐latitude climate variability.
    Materialart: Online-Ressource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2017.37.issue-12
    DOI: 10.1002/joc.5097
    RVK:
    RA 1000
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2017
    ZDB Id: 1491204-1
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
  • 10
    Online-Ressource
    Online-Ressource
    A potentially artifact‐free oral contrast agent for gastrointestinal MRI
    Wiley ; 1993
    In:  Magnetic Resonance in Medicine Vol. 30, No. 5 ( 1993-11), p. 646-649
    Details
    In: Magnetic Resonance in Medicine, Wiley, Vol. 30, No. 5 ( 1993-11), p. 646-649
    Kurzfassung: The combination of diamagnetic barium sulfate and superparamagnetic iron oxide (SPIO) in one suspension produces a macroscopic cancellation of positive and negative magnetic susceptibility components that can potentially eliminate susceptilbllity artifacts even with gradient echo pulse sequences. The relaxation properties that make the SPIO suspension a useful negative contrast agent are retained.
    Materialart: Online-Ressource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    URL: Article
    DOI: 10.1002/mrm.v30:5
    DOI: 10.1002/mrm.1910300518
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 1993
    ZDB Id: 1493786-4
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Online-Ressource
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...