Time lapse imagery of the ice-off event at Darfáljávri (Lake Tarfala), Kebnekaise mountains, northern Sweden, summer 2024
Nina Kirchner, Johanna Dahlkvist, Jamie Barnett, Daniella Lillieroth Charalambous, Carl Hernqvist Larsson
This dataset contains images of Darfáljávri taken every 2 hours (irrespective of day- or nighttime) during the period from 11 May, 2024 to 1 July, 2024. During this period, the surface of Darfáljávri transitions from being ice-covered to ice-free, an event referred to as "ice-off".
The dataset can be used to observe the ice-off event and to assign a date to it. Across datasets (e.g. using the ice-on dataset of the previous year), ice cover duration can be derived. Knowledge of lake ice phenology, i.e. seasonal formation and loss of the lacustrine ice cover, is of importance since the timing of ice-off impacts lake processes such as stratification and vertical mixing.
The pictures were acquired using a camera positioned on the mountain flank along Darfáljávri’s north-eastern shore, at 1220 m above sea level. In total, there are 618 images.
LacustrineLake IceDarfáljávriLake TarfalaTarfalaLake iceLake ice phenologyIce-off
Download dataScientific highlights
This dataset allows to assign a precise date to the ice-off event at Darfáljávri in summer 2024. Defining ice-off as the first occasion after the ice-covered winter season on which the lake becomes completely ice-free and remains so for the rest of the summer, it was attained on 30 June, 2024.
Some notable events in the time-lapse imagery of the diminishing lake ice cover include:
- 13 May: Commence of ice cover melt in the northwestern lake corner where Kebnepakte glacier drains into Darfáljávri (picture 26).
- 14 May: Increasing number of melt features on the central lake ice cover, mimicking surface meltwater ponds (picture 35). Similar melt patterns re-occur repeatedly (e.g. picture 153).
- 18 May: Inflow of streamwater from stream network on the eastern lake bank where stream water from southeastern Kaskasatjåkka glacier drains into Darfáljávri (picture 88). Subsequent gradual retreat of ice cover along the eastern lake shoreline (e.g. 213).
- 9 – 20 June: Gradual weakening of central lake ice cover through cracking and surface melt (e.g. picture 444).
- 23 June: Onset of lakewide drift and disintegration of ice floes (picture 515), subsequently concentrating in the southern lake-corner where lake outflow is located (picture 524).
- 28 June: Inflow of sediment-rich streamwater from stream network on the eastern lake bank (picture 577, 591). Similar inflow at reduced intensity also seen earlier (picture 543) and indicated by sediment saturated snow-covered ice along the lake margin (picture 193).
Picture numbers in the scientific highlights correspond to picture numbers in the dataset. Note that the camera produces black-white images under certain light conditions, such as during low-visibility weather conditions.
The ice duration for the 2023 – 2024 period is 214 days (i.e. number of days from ice on in 2023 — attained 12 October — until first loss of continuous lake ice layer in 2024 — attained 13 May).
Name
Version
Citation
References
Kirchner N, Weckström J, Jansen J, Schenk F, Barnett J, Granebeck A, Leppäranta M, Korhola A (2024) Water temperature, mixing, and ice phenology in the arctic–alpine Lake Darfáljávri (Lake Tarfala), northern Sweden. Arctic, Antarctic, and Alpine Research 56. https://doi.org/10.1080/15230430.2023.2287704
Data description
The dataset consists of image files (JPG) of Darfáljávri, with the date and time (Swedish daylight saving time, UTC+2) included in each photo. Image file names are numbered in chronological order.
The pictures were acquired using a camera positioned on the mountain flank along Darfáljávri’s north-eastern shore, at ~67.9° N, 18.6° E, at 1220 m above sea level.
The data were collected using a Hunter Orion Trail Camera 4G. The camera elevation is 1.8 m above ground. Each JPG file has a size of ~2.26 MB. The total size of the dataset is ~1.40 GB.
During a few short periods, fog, snow and/or rain obscures the view of the lake.
Project
The data were collected as part of a project within the Arctic Avenue Spearhead Research project between Stockholm University and the University of Helsinki, Finland, running between 2019 and 2022. Data is collected solely by Tarfala Research Station since 2023. The support of our co-workers on the Arctic Avenue activity Lake thermal and mixing dynamics under changing climate (J. Weckström, K. Weckström, A. Korhola, and F. Schenk) is gratefully acknowledged.
Publisher
Bolin Centre Database
License
First name
Nina
Last name or organisation
Kirchner
Email address
Address
Tarfala Research Station and Department of Physical Geography; Stockholm University
Postal code
SE-106 91
City
Stockholm
Country
Sweden
GCMD science keyword
Earth science
GCMD location
Continent > Europe > Northern Europe > Scandinavia > Sweden
Dataset language
English
Begin date
2024-05-11
End date
2024-07-01