Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017
We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at f...
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Cambridge University Press
2019
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ftdoajarticles:oai:doaj.org/article:9fe0fd4389f14ef6b160ac48b7455bc6 2023-05-15T16:57:33+02:00 Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 CHRISTIAN KIENHOLZ JASON M. AMUNDSON ROMAN J. MOTYKA REBECCA H. JACKSON JOHN B. MICKETT DAVID A. SUTHERLAND JONATHAN D. NASH DYLAN S. WINTERS WILLIAM P. DRYER MARTIN TRUFFER 2019-04-01T00:00:00Z https://doi.org/10.1017/jog.2018.105 https://doaj.org/article/9fe0fd4389f14ef6b160ac48b7455bc6 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0022143018001053/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2018.105 0022-1430 1727-5652 https://doaj.org/article/9fe0fd4389f14ef6b160ac48b7455bc6 Journal of Glaciology, Vol 65, Pp 195-211 (2019) glaciological instruments and methods icebergs ice-ocean interactions remote sensing Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2019 ftdoajarticles https://doi.org/10.1017/jog.2018.105 2023-03-12T01:30:59Z We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at frame rates of 0.5–4.0 min−1. Hourly to daily average velocity fields in map coordinates illustrate dynamic currents in the bay, with dominant downfjord velocities (exceeding 0.5 m s−1 intermittently) and several eddies. Comparisons with simultaneous Acoustic Doppler Current Profiler (ADCP) measurements yield best agreement for the uppermost ADCP levels (~ 12 m and above), in line with prevalent small icebergs that trace near-surface currents. Tracking results from multiple cameras compare favorably, although cameras with lower frame rates (0.5 min−1) tend to underestimate high flow speeds. Tests to determine requisite temporal and spatial image resolution confirm the importance of high image frame rates, while spatial resolution is of secondary importance. Application of our procedure to other fjords will be successful if iceberg concentrations are high enough and if the camera frame rates are sufficiently rapid (at least 1 min−1 for conditions similar to LeConte Bay). Article in Journal/Newspaper Journal of Glaciology Alaska Directory of Open Access Journals: DOAJ Articles Journal of Glaciology 65 250 195 211 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
glaciological instruments and methods icebergs ice-ocean interactions remote sensing Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
spellingShingle |
glaciological instruments and methods icebergs ice-ocean interactions remote sensing Environmental sciences GE1-350 Meteorology. Climatology QC851-999 CHRISTIAN KIENHOLZ JASON M. AMUNDSON ROMAN J. MOTYKA REBECCA H. JACKSON JOHN B. MICKETT DAVID A. SUTHERLAND JONATHAN D. NASH DYLAN S. WINTERS WILLIAM P. DRYER MARTIN TRUFFER Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
topic_facet |
glaciological instruments and methods icebergs ice-ocean interactions remote sensing Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
description |
We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at frame rates of 0.5–4.0 min−1. Hourly to daily average velocity fields in map coordinates illustrate dynamic currents in the bay, with dominant downfjord velocities (exceeding 0.5 m s−1 intermittently) and several eddies. Comparisons with simultaneous Acoustic Doppler Current Profiler (ADCP) measurements yield best agreement for the uppermost ADCP levels (~ 12 m and above), in line with prevalent small icebergs that trace near-surface currents. Tracking results from multiple cameras compare favorably, although cameras with lower frame rates (0.5 min−1) tend to underestimate high flow speeds. Tests to determine requisite temporal and spatial image resolution confirm the importance of high image frame rates, while spatial resolution is of secondary importance. Application of our procedure to other fjords will be successful if iceberg concentrations are high enough and if the camera frame rates are sufficiently rapid (at least 1 min−1 for conditions similar to LeConte Bay). |
format |
Article in Journal/Newspaper |
author |
CHRISTIAN KIENHOLZ JASON M. AMUNDSON ROMAN J. MOTYKA REBECCA H. JACKSON JOHN B. MICKETT DAVID A. SUTHERLAND JONATHAN D. NASH DYLAN S. WINTERS WILLIAM P. DRYER MARTIN TRUFFER |
author_facet |
CHRISTIAN KIENHOLZ JASON M. AMUNDSON ROMAN J. MOTYKA REBECCA H. JACKSON JOHN B. MICKETT DAVID A. SUTHERLAND JONATHAN D. NASH DYLAN S. WINTERS WILLIAM P. DRYER MARTIN TRUFFER |
author_sort |
CHRISTIAN KIENHOLZ |
title |
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
title_short |
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
title_full |
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
title_fullStr |
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
title_full_unstemmed |
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017 |
title_sort |
tracking icebergs with time-lapse photography and sparse optical flow, leconte bay, alaska, 2016–2017 |
publisher |
Cambridge University Press |
publishDate |
2019 |
url |
https://doi.org/10.1017/jog.2018.105 https://doaj.org/article/9fe0fd4389f14ef6b160ac48b7455bc6 |
genre |
Journal of Glaciology Alaska |
genre_facet |
Journal of Glaciology Alaska |
op_source |
Journal of Glaciology, Vol 65, Pp 195-211 (2019) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0022143018001053/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2018.105 0022-1430 1727-5652 https://doaj.org/article/9fe0fd4389f14ef6b160ac48b7455bc6 |
op_doi |
https://doi.org/10.1017/jog.2018.105 |
container_title |
Journal of Glaciology |
container_volume |
65 |
container_issue |
250 |
container_start_page |
195 |
op_container_end_page |
211 |
_version_ |
1766049116250439680 |