GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Arctic Humidity Inversions: Climatology and Processes
    American Meteorological Society ; 2018
    In:  Journal of Climate Vol. 31, No. 10 ( 2018-05-15), p. 3765-3787
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 31, No. 10 ( 2018-05-15), p. 3765-3787
    Abstract: The occurrence and characteristics of Arctic specific humidity inversions (SHIs) were examined on the basis of two reanalyses (ERA-Interim and JRA-55) and radiosonde sounding data from 2003 to 2014. Based on physical properties, the SHIs were divided into two main categories: SHIs below and above the 800-hPa level. Above the 800-hPa level, SHIs occurred simultaneously with relative humidity inversions and without the presence of a temperature inversion; these SHIs were probably formed when a moist air mass was advected over a dry air mass. SHIs below the 800-hPa level occurred simultaneously with temperature inversions in conditions of high relative humidity, which suggests that condensation had an important role in SHI formation. Below the 800-hPa level, SHI occurrence had a large seasonal and spatial variation, which depended on the surface heat budget. In winter, most SHIs were formed because of surface radiative cooling, and the occurrence of SHIs was high (even exceeding 90% of the time) on continents and over the ice-covered Arctic Ocean. In summer, the occurrence of SHIs was highest (70%–90%) over the coastal Arctic Ocean, where SHIs were generated by warm and moist air advection over a cold sea surface. In the reanalyses, the strongest SHIs occurred in summer over the Arctic Ocean. The comparisons between radiosonde soundings and the reanalyses showed that the main features of the seasonal and spatial variation of SHI occurrence and SHI strength were well represented in the reanalyses, but SHI strength was underestimated.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    DOI: 10.1175/JCLI-D-17-0497.1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2018
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Horizontal Moisture Transport Dominates the Regional Moistening Patterns in the Arctic
    American Meteorological Society ; 2020
    In:  Journal of Climate Vol. 33, No. 16 ( 2020-08-15), p. 6793-6807
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 33, No. 16 ( 2020-08-15), p. 6793-6807
    Abstract: Along with the amplified warming and dramatic sea ice decline, the Arctic has experienced regionally and seasonally variable moistening of the atmosphere. Based on reanalysis data, this study demonstrates that the regional moistening patterns during the last four decades, 1979–2018, were predominantly shaped by the strong trends in horizontal moisture transport. Our results suggest that the trends in moisture transport were largely driven by changes in atmospheric circulation. Trends in evaporation in the Arctic had a smaller role in shaping the moistening patterns. Both horizontal moisture transport and local evaporation have been affected by the diminishing sea ice cover during the cold seasons from autumn to spring. Increases in evaporation have been restricted to the vicinity of the sea ice margin over a limited period during the local sea ice decline. For the first time we demonstrate that, after the sea ice has disappeared from a region, evaporation over the open sea has had negative trends due to the effect of horizontal moisture transport to suppress evaporation. Near the sea ice margin, the trends in moisture transport and evaporation and the cloud response to those have been circulation dependent. The future moisture and cloud distributions in the Arctic are expected to respond to changes in atmospheric pressure patterns; circulation and moisture transport will also control where and when efficient surface evaporation can occur.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-19-0891.1
    DOI: 10.1175/JCLI-D-19-0891.s1
    RVK:
    UA 4548
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2020
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Strong Dependence of Wintertime Arctic Moisture and Cloud Distributions on Atmospheric Large-Scale Circulation
    American Meteorological Society ; 2019
    In:  Journal of Climate Vol. 32, No. 24 ( 2019-12-15), p. 8771-8790
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 32, No. 24 ( 2019-12-15), p. 8771-8790
    Abstract: This study gives a comprehensive picture of how atmospheric large-scale circulation is related to moisture transport and to distributions of moisture, clouds, and surface downward longwave radiation in the Arctic in winter. Anomaly distributions of the abovementioned variables are compared in 30 characteristic wintertime atmospheric circulation regimes, which are allocated from 15 years (2003–17) of mean sea level pressure data of ERA-Interim reanalysis applying the self-organizing map method. The characteristic circulation regimes are further related to known climate indices—the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), and Greenland blocking index—as well as to a frequent high pressure pattern across the Arctic Ocean from Siberia to North America, herein called the Arctic bridge. Effects of large-scale circulation on moisture, cloud, and longwave radiation are to a large extent occurring through the impact of horizontal moisture transport. Evaporation is typically not efficient enough to shape those distributions, and much of the moisture evaporated in the Arctic is transported southward. The positive phase of the NAO and AO increases moisture and clouds in northern Europe and the eastern North Atlantic Ocean, and a strong Greenland blocking typically increases those in the southwest of Greenland. When the Arctic bridge is lacking, the amount of moisture, clouds, and downward longwave radiation is anomalously high near the North Pole. Our results reveal a strong dependence of moisture, clouds, and longwave radiation on atmospheric pressure fields, which also appears to be important from a climate change perspective.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-19-0242.1
    DOI: 10.1175/jcli-d-19-0242.s1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2019
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Air Moisture Climatology and Related Physical Processes in the Antarctic on the Basis of ERA5 Reanalysis
    American Meteorological Society ; 2021
    In:  Journal of Climate Vol. 34, No. 11 ( 2021-06), p. 4463-4480
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 34, No. 11 ( 2021-06), p. 4463-4480
    Abstract: Atmospheric moisture is a key component in the water cycle and radiative transfer. In this study, a comprehensive picture of air moisture climatology and related physical processes is presented for the first time for the circumpolar area south of 50°S. The results are based on the most modern global reanalysis, ERA5, which manages reasonably well to close the Antarctic water budget. We show that over the ocean transient cyclones have the dominant role in determining moisture conditions, whereas over the continent the moisture conditions are largely affected by the mean circulation. Over the open sea, moisture transport from lower latitudes is an equally important source of moisture compared to the local evaporation, but practically all precipitating moisture over the plateau is provided by the horizontal transport. Over the ocean and continental slopes, southward moisture transport brings warm and moist air masses from lower latitudes, notably increasing atmospheric water vapor and cloud water, and simultaneously decreasing local evaporation over the open sea. On the Antarctic plateau, radiative cooling leads to high relative humidity and causes condensation of moisture especially near the surface, causing a nearly permanent specific humidity inversion layer. As a consequence, dry air masses with extremely low specific humidity are formed. These dry air masses are transported downward from the plateau by katabatic winds, experiencing adiabatic warming. This leads to a decrease in relative humidity and to a downward-directed sensible heat flux, which enable efficient surface evaporation on the coastal slopes and farther over coastal polynyas and leads.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-20-0798.1
    DOI: 10.1175/JCLI-D-20-0798.s1
    RVK:
    UA 4548
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2021
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Atmospheric moisture transport between mid‐latitudes and the Arctic: Regional, seasonal and vertical distributions
    Wiley ; 2019
    In:  International Journal of Climatology Vol. 39, No. 6 ( 2019-05), p. 2862-2879
    Details
    In: International Journal of Climatology, Wiley, Vol. 39, No. 6 ( 2019-05), p. 2862-2879
    Abstract: Horizontal moisture transport has a manifold role in the Arctic climate system as it distributes atmospheric water vapour and thereby shapes the radiative and hydrological conditions. Moisture transport between the Arctic and the mid‐latitudes was examined based on ERA‐Interim reanalysis. The meridional net transport is only a small part of the water vapour exchange between the Arctic and mid‐latitudes and does not give a complete view of temporal and spatial variations in the transport. Especially near the surface, most of the northwards moisture transport is balanced by the southwards transport, and therefore the meridional net moisture transport at 60°–70°N peaks approximately at 100 hPa higher altitude than the northwards and southwards moisture transports. The total moisture transport (sum of absolute northwards and southwards moisture transports) has a much larger seasonal variation than the net transport (mean meridional transport), and the strength of the total transport is related to atmospheric humidity rather than the wind field. Strong individual moisture transport events contribute to a large part of the northwards moisture transport. This is consistent with the result that the net moisture transport is essentially generated by temporal variations of moisture fluxes. The moisture transport due to stationary zonal variation in the mass flux mostly defines the spatial distribution of the meridional moisture transport. The seasonal cycle of the net moisture transport is related to the seasonal cycle of transient eddy moisture transport but inter‐annual variations of the net moisture transport are largely influenced by the stationary eddy moisture transport.
    Type of Medium: Online Resource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2019.39.issue-6
    DOI: 10.1002/joc.5988
    RVK:
    RA 1000
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1491204-1
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Evaporation over a glacial lake in Antarctica
    Copernicus GmbH ; 2022
    In:  The Cryosphere Vol. 16, No. 8 ( 2022-08-02), p. 3101-3121
    Details
    In: The Cryosphere, Copernicus GmbH, Vol. 16, No. 8 ( 2022-08-02), p. 3101-3121
    Abstract: Abstract. The study provides estimates of summertime evaporation over a glacial lake located in the Schirmacher oasis, Dronning Maud Land, East Antarctica. Lake Zub (alternately named Lake Priyadarshini and referred to throughout as Lake Zub/Priyadarshini) is the second-largest lake in the oasis, and its maximum depth is 6 m. The lake is also among the warmest glacial lakes in the oasis, and it is free of ice during almost 2 summer months. The summertime evaporation over the ice-free lake was measured using the eddy covariance method and estimated on the basis of five indirect methods (bulk-aerodynamic method and four combination equations). We used meteorological and hydrological measurements collected during a field experiment carried out in 2018. The eddy covariance method was considered the most accurate, and the evaporation was estimated to be 114 mm for the period from 1 January to 7 February 2018 (38 d) on the basis of this method. The average daily evaporation was 3.0 mm d−1 in January 2018. During the experiment period, the largest changes in daily evaporation were driven by synoptic-scale atmospheric processes rather than local katabatic winds. The bulk-aerodynamic method suggests the average daily evaporation is 2.0 mm d−1, which is 32 % less than the results based on the eddy covariance method. The bulk-aerodynamic method is much better in producing the day-to-day variations in evaporation compared to the combination equations. All selected combination equations underestimated the evaporation over the lake by 40 %–72 %. The scope of the uncertainties inherent in the indirect methods does not allow us to apply them to estimate the daily evaporation over Lake Zub/Priyadarshini. We suggested a new combination equation to evaluate the summertime evaporation over the lake's surface using meteorological observations from the nearest site. The performance of the new equation is better than the performance of the indirect methods considered. With this equation, the evaporation over the period of the experiment was 124 mm, which is only 9 % larger than the result according to the eddy covariance method.
    Type of Medium: Online Resource
    ISSN: 1994-0424
    URL: Article
    URL: Article
    DOI: 10.5194/tc-16-3101-2022
    DOI: 10.5194/tc-16-3101-2022-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2393169-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Winter thermodynamic vertical structure in the Arctic atmosphere linked to large-scale circulation
    Copernicus GmbH ; 2021
    In:  Weather and Climate Dynamics Vol. 2, No. 4 ( 2021-12-20), p. 1263-1282
    Details
    In: Weather and Climate Dynamics, Copernicus GmbH, Vol. 2, No. 4 ( 2021-12-20), p. 1263-1282
    Abstract: Abstract. Thermodynamic profiles are affected by both the large-scale dynamics and the local processes, such as radiation, cloud formation and turbulence. Based on ERA5 reanalysis, radiosoundings and cloud cover observations from winters 2009–2018, this study demonstrates manifold impacts of large-scale circulation on temperature and specific humidity profiles in the circumpolar Arctic north of 65∘ N. Characteristic wintertime circulation types are allocated using self-organizing maps (SOMs). The study shows that influence of different large-scale flows must be viewed as a progressing set of processes: (1) horizontal advection of heat and moisture, driven by circulation, lead to so-called first-order effects on thermodynamic profiles and turbulent surface fluxes, and (2) the advection is followed by transformation of the air through various physical processes, causing second-order effects. An example of second-order effects is the associated cloud formation, which shifts the strongest radiative cooling from the surface to the cloud top. The temperature and specific humidity profiles are most sensitive to large-scale circulation over the Eurasian land west of 90∘ E and the Arctic Ocean sea ice, whereas impacts over North America and Greenland are more ambiguous. Eurasian land, between 90 and 140∘ E, occasionally receives warm and moist air from the northern North Atlantic, which, with the support of radiative impacts of clouds, weakens the otherwise strong temperature and specific humidity inversions. Altitudes of maximum temperature and specific humidity in a profile and their variability between the circulation types are good indicators of the depth of the layer impacted by surface–atmosphere processes interacting with the large-scale circulation. Different circulation types typically cause variations of a few hundred metres to this altitude, and the layer impacted is deepest over north-eastern Eurasia and North America.
    Type of Medium: Online Resource
    ISSN: 2698-4016
    URL: Article
    URL: Article
    DOI: 10.5194/wcd-2-1263-2021
    DOI: 10.5194/wcd-2-1263-2021-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2021
    detail.hit.zdb_id: 2982467-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...