Goszczko Ilona

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Last Name
Goszczko
First Name
Ilona
ORCID
0000-0002-5719-5860

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  • Preprint
    Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean
    ( 2017-03) Polyakov, Igor V. ; Pnyushkov, Andrey ; Alkire, Matthew ; Ashik, Igor M. ; Baumann, Till M. ; Carmack, Eddy C. ; Goszczko, Ilona ; Guthrie, John D. ; Ivanov, Vladimir V. ; Kanzow, Torsten ; Krishfield, Richard A. ; Kwok, Ron ; Sundfjord, Arild ; Morison, James H. ; Rember, Robert ; Yulin, Alexander
    Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here we show that recent ice reductions, weakening of the halocline, and shoaling of intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin. The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin. This encroaching “atlantification” of the Eurasian Basin represents an essential step toward a new Arctic climate state, with a substantially greater role for Atlantic inflows.
  • Article
    Improving LADCP velocity with external heading, pitch, and roll
    (American Meteorological Society, 2017-08-11) Thurnherr, Andreas M. ; Goszczko, Ilona ; Bahr, Frank B.
    Data collected with acoustic Doppler current profilers installed on CTD rosettes and lowered through the water column [lowered ADCP (LADCP) systems] are routinely used to derive full-depth profiles of ocean velocity. In addition to the uncertainties arising from random noise in the along-beam velocity measurements, LADCP-derived velocities are commonly contaminated by bias errors due to imperfectly measured instrument attitude (heading, pitch, and roll). Of particular concern are the heading measurements, because it is not usually feasible to calibrate the internal ADCP compasses with the instruments installed on a CTD rosette, away from the magnetic disturbances of the ship. Heading data from dual-headed LADCP systems, which consist of upward- and downward-pointing ADCPs installed on the same rosette, commonly indicate heading-dependent compass errors with amplitudes exceeding 10°. In an attempt to reduce LADCP velocity errors, several dozen profiles of simultaneous LADCP and magnetometer/accelerometer data were collected in the Gulf of Mexico. Agreement between the LADCP profiles and simultaneous shipboard velocity measurements improves significantly when the former are processed with external attitude measurements. Another set of LADCP profiles with external attitude data was collected in a region of the Arctic Ocean where the horizontal geomagnetic field is too weak for the ADCP compasses to work reliably. Good agreement between shipboard velocity measurements and Arctic LADCP profiles collected at magnetic dip angles exceeding and processed with external attitude measurements indicate that high-quality velocity profiles can be obtained close to the magnetic poles.