Jan Weckström, Mingzhen Zhang, Maija Heikkilä, Kaarina Weckström
This dataset provides year-round measurements of water temperatures from 12 small and shallow lakes in north-western Finnish Lapland between 2019 – 2022.
The data was collected to investigate 1) the spatial and temporal differences of lake water temperatures along a steep climatic gradient in NW Finnish Lapland, 2) the thermal structure of small and shallow subarctic lakes, and 3) the ice-cover dynamics of these 12 subarctic lakes.
Data were acquired from the deepest part of 12 subarctic lakes (67.85° – 69.17° N, 21.05° – 24.18° E) at every two hours between May 2019 and September 2022 using thermistors (HOBO Water Temperature Pro v2 Data Logger) with a nominal temperature resolution and accuracy of 0.02°C and ± 0.21°C, respectively.
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Citation
Jan Weckström, Mingzhen Zhang, Maija Heikkilä, Kaarina Weckström (2025) Water temperatures from 12 north-western Finnish Lapland subarctic lakes 2019 – 2022. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/weckstrom-2025-lapland-water-temperatures-1
References
Zhang M, Leppäranta M, Korhola A, Kirchner N, Granebeck A, Schenk F, Weckström K, Heikkilä M, Weckström J (2024) Drivers of spatio-temporal variations in summer surface water temperatures of Arctic Fennoscandian lakes (2000–21). Polar Research 43. https://doi.org/10.33265/polar.v43.9580
Zhang M, Leppäranta M, Heikkilä M, Weckström K, Korhola A, Kirchner N, Granebeck A, Schenk F, Weckström J (2025). The thermal structure of small and shallow Arctic Fennoscandian lakes. Arctic, Antarctic and Alpine Research (in press).
Strötz L, et al. (2025) Ice-cover dynamics of small Arctic Fennoscandian lakes. (in preparation).
Data description
Data are provided in two file formats:
- comma-separated values (
csv
)
- excel spreadsheet (
xlsx
)
In both cases, there are 12 files, one file for each lake. The content is the same in both file types, but the date format differs.
The files have names that correspond to the code number for each lake; see list below under Comments.
All data files, exept those for lake WFL56, have three columns with the following headers and content:
Date_time (GMT+3:00)
Observation time
- Format in
csv
files: YYYY-MM-DD HH:MM
- Format in
xlsx
files: DD/MM/YYYY HH:MM:SS (but may depend on local software system settings)
Surface Temperature,°C
Water temperatures at 30 cm water depth (°C)
Bottom Temperature,°C
Water temperatures at 30 cm from the bottom (°C)
The data files for lake WFL56 have five columns with the following headers and content:
Date_time (GMT+3:00)
Observation time
Surface Temperature,°C
Water temperatures at 30 cm water depth (°C)
3m Temperature,°C
Water temperatures at 3 m water depth (°C)
6m temperature,°C
Water temperatures at 6 cm water depth (°C)
Bottom Temperature,°C
Water temperatures at 30 cm from the bottom (°C)
All data files contain 14427 date- and timestamped water temperature measurements for each water depth.
All data are from HOBO Water Temp Pro v2 profilers.
Comments
The thermistor lines were installed on buoys to keep the sensors at about 30 cm below the lake surface and 30 cm above the lake bottom sediment. For lake WFL56 with a maximum depth of 15 m, the water temperature was also acquired at 3 m and 6 m depths.
For the groundwater fed Lake WFL29 (the bottom temperature was constantly around +3.5 °C throughout the 4 years of measurements), we confirmed later that the thermistor was not broken. Recent field measurements, instead, indicated that the lake may be chemically stratified, and that the near-bottom thermistor was likely in contact with the groundwater that keeps the temperature nearly year-round constant.
As most of these small lakes do not have an official name, they are coded with letters WFL (Western Finnish Lapland) followed by numbering. The coordinates and elevation above sea level for the lakes are as follows:
Lake |
Coordinates (~WGS84) |
Altitude (m a.s.l.) |
WFL3 |
67° 52’ 6.308” N, 24° 10’ 38.503” E |
268 |
WFL4 |
67° 59’ 25.895” N, 23° 40’ 22.391” |
262 |
WFL5 |
68° 5’ 54.745” N, 23° 23’ 37.154” E |
249 |
WFL6 |
68° 7’ 40.656” N, 23° 21’ 19.054” E |
252 |
WFL11 |
68° 23’ 52.469” N, 22° 51’ 9.661” E |
313 |
WFL12 |
68° 26’ 29.550” N, 22° 35’ 11.171” E |
332 |
WFL13 |
68° 28’ 4.914” N, 22° 25’ 56.453” E |
322 |
WFL29 |
68° 6’ 1.685” N, 23° 24’ 43.865” E |
249 |
WFL30 |
68° 7’ 55.378” N, 23° 21’ 25.304” E |
253 |
WFL54 |
69° 1’ 59.590” N, 21° 7’ 14.131” E |
796 |
WFL55 |
69° 3’ 29.806” N, 21° 12’ 49.045” E |
774 |
WFL56 |
69° 10’ 21.360” N, 21° 2’ 51.413” E |
1009 |
Acknowledgements
The support of our co-workers on the Arctic Avenue activity Lake thermal and mixing dynamics under changing climate (N. Kirchner, A. Granebeck, F. Schenk, A. Korhola and M. Leppäranta) is gratefully acknowledged. Kilpisjärvi Research Station staff are thanked for support during the field campaigns.