Papers by Gert König-langlo
Die solare und terrestrische Strahlung in der Antarktis und ihre Parametrisierung mit Hilfe von synoptischen Beobachtungen
Am 22. Mai 1985 startete Peter Plessing, Mitglied der Überwinterungsmannschaft aus der DDR, die e... more Am 22. Mai 1985 startete Peter Plessing, Mitglied der Überwinterungsmannschaft aus der DDR, die erste Ozonsonde des Typs OSE an der später nach Georg Forster benannten Antarktisstation Forster (70°46'S, 11°41'O). Die folgenden wöchentlichen Ozonaufstiege waren der deutsche Einstieg zur kontinuierlichen Untersuchung der vertikalen Verteilung des Ozons in der südpolaren Atmosphäre. Zufällig fiel der Beginn des Meßprogramms in die Zeit, als sich die Nachricht über einen vorher noch nie beobachteten Ozonschwund in der südpolaren Stratosphäre während des Polarfrühjahres im September, Oktober und November weltweit verbreitete. Die in dieser Jahreszeit sogar alle drei Tage durchgeführten Sondierungen waren in 1985 die einzigen Messungen dieser Art in der Antarktis und ermöglichten somit erstmals eine detaillierte klimatologische Beschreibung der vertikalen Ausdehnung und zeitlichen Veränderung dieses Ozonschwundes.
Time-oriented earth observation measurements from the Baseline Surface Radiation Network (BSRN) in the years 1992 to 2012, reference list of 6813 datasets
The data collection contains 6813 links to time-oriented earth observation measurements from the ... more The data collection contains 6813 links to time-oriented earth observation measurements from the Baseline Surface Radiation Network (BSRN). It covers all available measurements from the time period between 1992-01 and 2012-07 taken at BSRN stations all over the world. The data is used as a large and representative time-oriented research dataset for the investigation of innovative visual search and exploration methods in that context.
Semi-annual to decadal oscillations as recorded at Neumayer research station, Antarctica
ABSTRACT Monthly time series of temperature, wind speed and sea level pressure recorded at Neumay... more ABSTRACT Monthly time series of temperature, wind speed and sea level pressure recorded at Neumayer polar research station (70°39'S, 8°15'W) during the last 30 years are analysed in order to identify the climate oscillations and associated teleconnection patterns at time scales from half-year to decades. Oscillations with periods of six months (semi-annual) and one year (annual) were identified in all records. Both annual and semi-annual oscillations are non-stationary in time. The dominant pattern of interannual to decadal variability, which captures the out of phase variations of temperature and wind speed with sea level pressure, shows a persistent 2-3 years oscillation. This oscillation is related with a wave-train atmospheric circulation pattern similar to the Pacific South American (PSA) modes. This suggests a tropical origin of this oscillation. The second pattern of interannual to decadal variability, which captures in-phase variations of these variables, shows enhanced variability at 5-6 year time scales. This oscillation is induced by the Antarctic Oscillation (AAO) which shows enhanced variability at these time scales. Analysis of the variability of high resolution stable isotope time series from four ice cores from Neumayer region reveals similar oscillations. This suggests that ice core data from the region could be used to reconstruct the phase and amplitude of atmospheric circulation patterns associated to these oscillations during past periods.
The Meteorological Information System at the Alfred-Wegener-Institute
Surface radiation measurements from polar stations
... The shortwave net radiation varies from 0 to about 75 Wm2 and the longwave net radiation chan... more ... The shortwave net radiation varies from 0 to about 75 Wm2 and the longwave net radiation changes from about 15 to 65 Wrn2. The re sulted net radiation varies from 35 to 35 Wrn2. The largest shortwave radiation is found in 1987. ...
Daily to intraseasonal oscillations at Antarctic research station Neumayer
Antarctic Science, 2013
ABSTRACT High temporal resolution (three hours) records of temperature, wind speed and sea level ... more ABSTRACT High temporal resolution (three hours) records of temperature, wind speed and sea level pressure recorded at Antarctic research station Neumayer (70°S, 8°W) during 1982–2011 are analysed to identify oscillations from daily to intraseasonal timescales. The diurnal cycle dominates the three-hourly time series of temperature during the Antarctic summer and is almost absent during winter. In contrast, the three-hourly time series of wind speed and sea level pressure show a weak diurnal cycle. The dominant pattern of the intraseasonal variability of these quantities, which captures the out-of-phase variation of temperature and wind speed with sea level pressure, shows enhanced variability at timescales of ∼ 40 days and ∼ 80 days, respectively. Correlation and composite analysis reveal that these oscillations may be related to tropical intraseasonal oscillations via large-scale eastward propagating atmospheric circulation wave-trains. The second pattern of intraseasonal variability, which captures in-phase variations of temperature, wind and sea level pressure, shows enhanced variability at timescales of ∼ 35, ∼ 60 and ∼ 120 days. These oscillations are attributed to the Southern Annular Mode/Antarctic Oscillation (SAM/AAO) which shows enhanced variability at these timescales. We argue that intraseasonal oscillations of tropical climate and SAM/AAO are related to distinct patterns of climate variables measured at Neumayer.
Journal of Glaciology, 2010
(EPICA) drilling site Kohnen station (75800 0 S, 00804 0 E; 2892 m a.s.l.) on the plateau of Dron... more (EPICA) drilling site Kohnen station (75800 0 S, 00804 0 E; 2892 m a.s.l.) on the plateau of Dronning Maud Land reveal the presence of conserved snow dunes in the firn. In situ observations during three dune formation events in the 2005/06 austral summer at Kohnen station show that these periods were characterized by a phase of 2 or 3 days with snowdrift prior to dune formation which only occurred during high wind speeds of >10 m s -1 at 2 m height caused by the influence of a low-pressure system. The dune surface coverage after a formation event varied between 5% and 15%, with a typical dune size of (4 AE 2) m  (8 AE 3) m, a maximum height of 0.2 AE 0.1 m and a periodicity length of about 30 m. The mean density within a snow dune varied between 380 and 500 kg m -3 , whereas the mean density at the surrounding surface was 330 AE 5 kg m -3 . The firn cores covering a time-span of 22 AE 2 years reveal that approximately three to eight events per year occurred, during which snow dunes had been formed and were preserved in the firn.
Antarctic Science, 2010
A surface energy balance model is forced by 13 years of high-quality hourly observations from the... more A surface energy balance model is forced by 13 years of high-quality hourly observations from the Antarctic coastal station Neumayer. The model accurately reproduces observed surface temperatures. Surface sublimation is significant in summer, when absorbed solar radiation heats the surface. Including a first order estimate of snowdrift sublimation in the calculation more than triples the total sublimation, removing 19% of the solid precipitation, indicating that snowdrift sublimation is potentially important for the mass balance of Antarctic ice shelves. Surface melt occurs at Neumayer in all summers, but all the meltwater refreezes. In two-thirds of the cases, the refreezing is quasi-instantaneous (within the model timestep of 6 min), so that no liquid water remains in the snow. For all other events, the occurrence of liquid water in the snowpack at Neumayer agrees well with satellite-based liquid water detection.
Intraseasonal to interannual oscillations of Antarctic climate as recorded at Neumayer polar station
Possible oscillations in the Antarctic climate are investigated through statistical analysis of m... more Possible oscillations in the Antarctic climate are investigated through statistical analysis of meteorological variables recorded at Neumayer polar station, located at Ekström Shelf Ice, Atka Bay, northeast Weddell Sea (70 39'S, 08 15'W). Meteorological variables recorded at this station cover the period 1982 to 2011 with a 3 hours time resolution. At intraseasonal time scales spectral analysis reveals a strong diurnal cycle in the temperature and wind records. A wavelet analysis reveals that diurnal cycle is relatively strong (weak) ...
Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain
Journal of Geophysical Research: Oceans, 2015
ABSTRACT Ice shelves strongly interact with coastal Antarctic sea ice and the associated ecosyste... more ABSTRACT Ice shelves strongly interact with coastal Antarctic sea ice and the associated ecosystem by creating conditions favourable to the formation of a sub-ice platelet layer. The close investigation of this phenomenon and its seasonal evolution remain a challenge due to logistical constraints and a lack of suitable methodology. In this study, we characterize the seasonal cycle of Antarctic fast ice adjacent to the Ekström Ice Shelf in the eastern Weddell Sea. We used a thermistor chain with the additional ability to record the temperature response induced by cyclic heating of resistors embedded in the chain. Vertical sea-ice temperature and heating profiles obtained daily between November 2012 and February 2014 were analyzed to determine sea-ice and snow evolution, and to calculate the basal energy budget. The residual heat flux translated into an ice-volume fraction in the platelet layer of 0.18 ± 0.09, which we reproduced by a independent model simulation and agrees with earlier results. Manual drillings revealed an average annual platelet-layer thickness increase of at least 4m, and an annual maximum thickness of 10m beneath second-year sea ice. The oceanic contribution dominated the total sea-ice production during the study, effectively accounting for up to 70% of second-year sea-ice growth. In summer, an oceanic heat flux of 21 W m– 2 led to a partial thinning of the platelet layer. Our results further show that the active heating method, in contrast to the acoustic sounding approach, is well suited to derive the fast-ice mass balance in regions influenced by ocean/ice-shelf interaction, as it allows sub-diurnal monitoring of the platelet-layer thickness. This article is protected by copyright. All rights reserved.
Polarforschung
From 1888 windprofiles, measured in 1982 under neutral conditions on a 15 meter mast near the Ger... more From 1888 windprofiles, measured in 1982 under neutral conditions on a 15 meter mast near the German Antarcjic research station "Georg von Neumayer", the roughness length Z of the Ekström lee Shelf is calculated. The mean value of Zo is 1-10-" m. The roughness length shows a dependence on wind velocity whiS, is strongly correlated with snow drift. The remarkable increase of Zowith decreasing wind as mentioned by HOLMGREN (1971) and other authors for the low wind regime, was not observed, but between 20 and 30 m/s, Zo increases rapidly with increasing wind. Generally, the roughness length over the Bkström Iee Shelf is smaller than over the sea and far smaller than over pack-ice, The Charnock reiation, which generally charaeterizes the increase of the roughness length with increasing wind speed above the sea surface weil, is in a qualified sense also valid for conditions over the Eckström Iee Shelf, Zusammenfassung: Aus einer Analyse von 1888 Windprofilen bei adiabatischer Schichtung, die 1982 an der deutschen Antarktis-Forschungsstation "Georg von Neumqyer" an einem 15 Meter-Mast gewonnen wurden, wird die Rauhigkeitslänge zQdes Bkström-Schelfeis bestimmt. Sie liegt im Mittel bei 1-10-" m, ist jedoch von der Windgeschwindigkeit und der damit eng korrelierten Scnneedrift abhängig. Eine bemerkenswerte Zunahme von Zomit abnehmender Windgeschwindigkeit, wie sie HOLMGREN (1971) und andere Autoren bei geringen Windgeschwindigkeiten erwähnten, wurde nicht beobachtet, jedoch steigt Zo zwischen 20 und 30 mls mit wachsender Windgeschwindigkeit sprunghaft an. Meistens ist die Rauhigkeitslänge des Ekström-Schelfeises geringer als die einer Ozeanoberfläche und viel geringer als die von Packeis. Die Chamock-Relation, die über offenem Ozean den Anstieg der Bodenrauhigkeit mit der Windgeschwindigkeit im allgemeinen gut wiedergibt, läßt sich mit Einschränkengen auch auf die Verhältnisse über dem Bkström-Schelfeis anwenden.
Radiation budget measurements over Antarctic sea ice in late Winter
The WDC-MARE Reports aim is to publish scientific results as provided through the data management... more The WDC-MARE Reports aim is to publish scientific results as provided through the data management units of research institutes and national and international projects. These scientific results comprise collections and compilations of data accompanied by their describing meta-information as well as technical notes. Usually the reports are accompanied by a CD-ROM/DVD that contains the project related data sets in a consistent technical ASCII-format. The content of the medium represents the information as stored in the information system PANGAEA at the time of publication. WDC-MARE Reports appear in irregular intervals.
Modeling snowdrift sublimation on an Antarctic ice shelf
The Cryosphere
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Papers by Gert König-langlo