Underwater photosynthetically active radiation (PAR) vertical profiles collected from lakes in the McMurdo Dry Valleys, Antarctica (1993-2023, ongoing)


As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, lakes are monitored for photosynthetic active radiation (PAR) levels. This data set exemplifies the vertical profile of underwater PAR profiles in perennial ice covered lakes and ambient PAR measured at the air-ice interface. Profile data can be used to calculate extinction coefficients for the water column and ice layer.

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A Licor LI-193SA spherical quantum sensor and a LI-190SA flat sensor were attached to a Licor data logger to record instantaneous under-ice PAR and PAR incident on the surface of the lake ice. Data were recorded in an outside incubation hole covered by an opaque tarp, unless otherwise noted. The upper 3-6 meters of each profile, depending upon ice thickness for each lake, represents conditions within the ice melt hole and is not representative of actual lake water. It is advised that users of the data review the Lake Ice Thickness dataset in the MCM Database to find where the liquid water column starts for each cast.


2024-01-09: Several corrections, including depth adjustments, were made to profiles conducted during the 96-97 field season. See comments field for corrections specific to each limno run.

2023-07-11: An error was found in the 2019-2020 season data in which the wrong sensor multiplier was inadvertently used for the underwater sensor (i.e., the "multiplier in air" was used instead of the "multiplier in water"). This issue has been corrected and affected data have been replaced.

Data and metadata ported into DEIMS by Inigo in 2015.

Data from this table was submitted to INSTAAR by John Priscu's team at Montana State University. The raw data files listed under 'file name' are the names of the original files submitted. The 1993/94 and 1994/95 datasets are Microsoft Excel version 6.0 files, and the 1995/96, 1996/97 and 1997/98 datasets are ascii text files. Upon arrival at INSTAAR, the data manager fine-tuned the location codes and limno runs to match those provided in the "locations, dates, codes for lake chemistry, biology samples" file. The file was imported into Microsoft Access on INSTAAR's Unix system, and can currently be found there. The file was then exported in ascii, comma delimited text and MS-DOS text (table layout) to present on the MCM LTER web site. Both of these files are linked to this web page above. Information for the metadata was obtained from the lktemps.metadata.txt and Metaparprofile9697.rtf files. The files were called up using Microsoft Word version 6.0. Text from these files was used to create this page in html format.

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