Cristina D. Takacs-VesbachJohn C. Priscu 2014-11-04 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/e72dc49d774796767884c535e864c915 https://mcm.lternet.edu/content/lake-ice-thickness-and-density-measurements-mcmurdo-dry-valleys-antarctica-1989-2025-ongoing As part of the McMurdo Dry Valleys Long Term Ecological Research (LTER) project, ice thickness and density are measured annually for several lakes located throughout this region of Antarctica. Ice thickness is measured from the bottom of the ice cover to the piezometric water level and to the top of the ice cover. Because most limnological sampling holes are drilled in low-lying areas, it was thought that ice thickness measurements were biased. Therefore, random ice thickness measurements were performed in a 1000 m2 sampling grid on each lake in past years. Statistical analyses by Dr. Priscu have shown that measurements from three ice holes are representative of the ice thickness measured by this grid system. Problems with the Kovacs drill prevented the limnological sampling team from attaining more than one "unbiased" measurement at Lake Fryxell during the 1996-97 season. Notes about the 2004/05 season Because sampling at Lake Vanda was done as a day trip, the Aqua-Vu system was not brought to this sampling location, and the ice thickness measurement was done using  the method employed in previous years.  A 30 cm brass rod, with nylon cord attached to one end, was fastened to a 10 m tape measure and lowered through the newly drilled ice hole. Once through the ice, the tape measure was slowly pulled upward allowing the brass rod to catch on the bottom of the ice cover.  The distances from the bottom of the ice cover to the piezometric water level (z-water), and to the top of the ice cover (z-ice), were recorded. 1989-11-16 2025-01-06 ground condition The 1995/96 data from this table was submitted to INSTAAR by Ray Kepner at the Desert Research Institute. It was included in several e-mail messages sent in August 1997. Denise Steigerwald, the data manager used the information in these messages to create a file called thckness.dat.        The 1996/97 and 1997/98 data was submitted to INSTAAR by John Priscu's team at Montana State University. The former is a Microsoft Excel version 6.0 file (icethk.xls), and the latter is an ascii text file.          Upon arrival at INSTAAR, the data manager  fine-tuned the files to allow them to be merged for use on the MCM LTER web site. Adjustments included the following:          Lake Descriptions" file. added to the "Limno Holes, Dive Holes, Lake Level Measurement Locations" file.         The icethk.xls file did not contain variables for latitude and longitude, but records for each "location" represented in this dataset were added to the "Limno Holes, Dive Holes, Lake Level Measurement Locations" file (leaving the latitude and longitude fields blank). The links made possible by doing this will allow users to call up further information about a given lake (thru the link with the "McMurdo Dry Valley Lake Descriptions" file), and/or about a given sampling location on the lake (thru the link with the "Limno Holes, Dive Holes, Lake Level Measurement Locations" file).         icethk.xls file had  variables for z-water, z-ice, and z-diff. After consulting with Craig Wolf (at Montana State University), the ice thickness variable was renamed to z-ice. project (S025) which is still taking place. John Priscu requested to have these records removed from the MCM LTER web site in an August, 1998 e-mail message. Any location codes containing a "C" followed by a number  (eg. C01) were removed from this file.       Each of these adjustments allowed the all of the ice thickness measurements to be represented in one data file on the MCM LTER web site. 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 icethick.metadata.txt and Metaicethick9697.rtf files. The".rtf" file was called up using Microsoft Word version 6.0, and a simple text editor was used for the icethick.metadata.txt file. Text from these files was used to create this page in html format.      In 2006, Chris Gardner added Latitude and Longitude columns to the Ice Thickness table.  He also deleted and reloaded seasons 2001-2002 through 2003-2004 as some errors were found.  Lat/Longs were added to these dates as well. Metadata was also made conformant to the EML format, and served through the MCM webpages using an XSLT transformation. In 2014, metadata was enhanced using the Drupal Ecological Information Management System (Inigo San Gil) In 2016, enhancements to metadata and data updates were introduced using DEIMS (Inigo) As needed Lake Bonney is a saline lake with permanent ice cover at the western end of Taylor Valley in the McMurdo Dry Valleys of Victoria Land, Antarctica. It is 7 kilometres or 4.3 mi long and up to 900 metres or 3,000 ft wide. A narrow channel only 50 metres or 160 ft wide. Lake Bonney at Narrows separates the lake into East Lake Bonney 3.32 square kilometres or 1.28 sq mi and West Lake Bonney, 0.99 square kilometres or 0.38 sq mi. The west lobe is flanked by Taylor glacier. Valley: Taylor Distance to Sea : 25 Maximum Length (km): 4.8 Maximum Width (km): 0.9 Maximum Depth (m): 37 Surface Area (km^2): 3.32 Ice Thickness Average Surface (m): 3 - 4.5 Volume (m^3 * 10^6): 54.7 162.536209106445 162.353210449219 -77.697700500488 -77.724441528320 57m 57m meter Lake Bonney is a saline lake with permanent ice cover at the western end of Taylor Valley in the McMurdo Dry Valleys of Victoria Land, Antarctica. It is 7 kilometres or 4.3 mi long and up to 900 metres or 3,000 ft wide. A narrow channel only 50 metres or 160 ft wide. Lake Bonney at Narrows separates the lake into East Lake Bonney 3.32 square kilometres or 1.28 sq mi and West Lake Bonney, 0.99 square kilometres or 0.38 sq mi. Valley: Taylor Distance to Sea : 28 Maximum Length (km): 2.6 Maximum Width (km): 0.9 Maximum Depth (m): 40 Surface Area (km^2): 0.99 Ice Thickness Average Surface (m): 2.8-4.5 Volume (m^3 * 10^6): 10.1 162.354934692383 162.269104003906 -77.714805603027 -77.727287292480 57m 57m meter The Lake Fryxell basin is formed by a moraine depression in a wider portion of the Taylor Valley. It has a number of moraine islands and shallower areas, as well as several relatively well developed deltas. The lake is fed by at least 10 meltwater streams with a total drainage catchment of 230 km2. The lake is dammed to the southwest by the Canada Glacier and is topographically closed. It is perennially ice covered; during summer months, an ice-free moat generally forms around much of the lake margin. Lake levels have risen ~2 m between 1971 and 1996. There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 9 Maximum Length (km): 5.8 Maximum Width (km): 2.1 Maximum Depth (m): 20 Surface Area (km^2): 7.08 Ice Thickness Average Surface (m): 3.3 - 4.5 Volume (m^3 * 10^6): 25.2 163.259582519531 163.048782348633 -77.597076416016 -77.622711181641 18m 18m meter Lake Hoare occupies a narrower portion of the Taylor Valley, dammed by the Canada Glacier. It would drain almost completely without this dam. There are a number of islands which may be related to an old terminal of Canada Glacier. The lake is fed primarily from direct runoff from the glacier, as well as meltwater streams. (Lake level rose ~1.5 m between 1972 and 1996). There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 15 Maximum Length (km): 4.2 Maximum Width (km): 1 Maximum Depth (m): 34 Surface Area (km^2): 1.94 Ice Thickness Average Surface (m): 3.1 - 5.5 Volume (m^3 * 10^6): 17.5 162.935836791992 162.784423828125 -77.623085021973 -77.639259338379 73m 73m meter Lake Joyce lies in the Pearse Valley against the Taylor Glacier. Valley: Pearse Distance to Sea : 44 Maximum Length (km): 1 Maximum Width (km): 1 Maximum Depth (m): 35 Surface Area (km^2): 0.83 Ice Thickness Average Surface (m): 3.9 - 5.6 Volume (m^3 * 10^6): 4.9 161.662445068359 161.608886718750 -77.715972900391 -77.726486206055 301m 301m meter Lake Miers lies in the Miers Valley. Valley: Miers Distance to Sea : 20 Maximum Length (km): 1.5 Maximum Width (km): 0.7 Maximum Depth (m): 21 Surface Area (km^2): 1.3 Ice Thickness Average Surface (m): 3.4 - 6 Volume (m^3 * 10^6): 2.9 163.886840820313 163.812332153320 -78.094047546387 -78.101478576660 240m 240m meter A lake with an area of 1 square mile which occupies the north portion of Pyramid Trough, Scott Coast. Named by New Zealand Geographic Board (NZGB) (1994) in association with Pyramid Trough. 162.823226928711 162.718856811523 -77.417655944824 -77.442016601563 Lake Vanda is located in the Wright Valley, adjacent to the Taylor Valley. It is fed primarily by the Onyx River, which has its origin at Lake Brownworth, and ultimately at the Lower Wright Glacier located ~27 km east of the lake. The lake has no outflow. Valley: Wright Distance to Sea : 47 Maximum Length (km): 8 Maximum Width (km): 2 Maximum Depth (m): 75 Surface Area (km^2): 5.2 Ice Thickness Average Surface (m): 2.8 - 4.2 Volume (m^3 * 10^6): 160 161.691970825195 161.391906738281 -77.518882751465 -77.542304992676 143m 143m meter LTER Core Areas disturbance None <cntperp> <cntper>McMurdo Dry Valleys LTER Information Manager</cntper> </cntperp> <cntemail>im@mcmlter.org</cntemail> Name: Jade Lawrence Role: field technician Name: Renée F. Brown Role: data manager Name: Amy Chiuchiolo Role: former field crew Name: Chris Gardner Role: former data manager Name: Inigo San Gil Role: former data manager Not Applicable Not Applicable Field and/or Lab Methods A 30 cm brass rod, with nylon string attached to one end, was fastened to a 10m tape measure and lowered through a newly drilled ice hole. Once through the ice, the tape measure was slowly pulled upward allowing the brass rod to catch on the bottom of the ice cover. The distances from the bottom of the ice cover to the piezometric water level (z-water), and to the top of the ice cover (z-ice) were then recorded. The difference between these two measurements (z-difference) or "freebore" provides some insight into the topographical features of the ice cover as well as density of the ice. Ice thickness measurements are typically performed on each hole drilled through the ice cover. Because most limnological sampling holes are drilled in low-lying areas, ice thickness measurements have been biased. Therefore, random ice thickness measurements were performed in a 1000 m2 sampling grid on each lake. At Lakes Fryxell, Hoare, East and West Bonney the sampling grids are located along a 100 m baseline due south of the blue instrument boxes. Prior to sampling, two sets of random numbers between 0 and 100 were generated as south and east coordinates in this 100x100m grid. For example, if the sampling coordinates were (56S, 72E), the hole would be located 56 m due south along the baseline, then similarly, 72 m due east of that baseline. A new method for measuring ice thickness was employed in the 2004-2005 season using the Aqua-Vu underwater viewing system, which allows us to see the exact point where the bottom of the ice cover is located. The Aqua-Vu underwater camera is lowered through a newly drilled (and usually at least partially melted) ice hole, and the camera lowered until the bottom of the ice cover is viewed through the above-water viewing system. The distance from the bottom of the ice cover to the piezometric water level (z-water) is marked on the viewing system cord and measured with a tape measure once the viewing system is brought out of the ice hole. The distance from the piezometric water level to the top of the ice cover (z-difference) is measured using a tape measure. If more than one replicate measurement is taken for z-water or z-difference, the replicates are averaged. Z-difference, or 'freebore,' provides some insight into the topographical features of the ice cover as well as density of the ice. The addition of z-water and z-difference gives the total ice thickness (z-ice). Ice thickness measurements are typically performed on each hole drilled through the ice cover. Because most limnological sampling holes are drilled in low-lying areas, it was thought that ice thickness measurements were biased. Therefore, random ice thickness measurements were performed in a 1000 m2 sampling grid on each lake in past years. However, statistical analyses by Dr. Priscu have shown that measurements from three ice holes are representative of the ice thickness measured by this grid system. Starting during the 2004-2005 season, ice thickness measurements were done on the two holes drilled for limnological sampling, plus one additional hole. In addition, notes were taken to describe the topography of the ice surrounding the ice hole (see comments section of data file). Generally ice thickness measurements are done on the two holes drilled for limnological sampling (1 hole inside the polarhaven, designated as "Inside Hole," and 1 hole outside) plus one additional outside hole. If there is an opportunity to take measurements in other holes that have been drilled, measurements are taken. Holes that are maintained open throughout the season are measured for ice thickness throughout the season. Note that ablation occurs around the sampling polarhaven, so take note of this when reviewing the Z-difference values for the "inside" holes throughout the season. Notes are taken to describe the topography of the ice surrounding the ice hole and are detailed in the comments section of the data file. A 30 cm brass rod, with nylon string attached to one end, was fastened to a 10m tape measure and lowered through a newly drilled ice hole. Once through the ice, the tape measure was slowly pulled upward allowing the brass rod to catch on the bottom of the ice cover. The distances from the bottom of the ice cover to the piezometric water level (z-water), and to the top of the ice cover (z-ice) were then recorded. The difference between these two measurements (z-difference) or "freebore" provides some insight into the topographical features of the ice cover as well as density of the ice. Ice thickness measurements are typically performed on each hole drilled through the ice cover. Because most limnological sampling holes are drilled in low-lying areas, ice thickness measurements have been biased. Therefore, random ice thickness measurements were performed in a 1000 m2 sampling grid on each lake. At Lakes Fryxell, Hoare, East and West Bonney the sampling grids are located along a 100 m baseline due south of the blue instrument boxes. Prior to sampling, two sets of random numbers between 0 and 100 were generated as south and east coordinates in this 100x100m grid. For example, if the sampling coordinates were (56S, 72E), the hole would be located 56 m due south along the baseline, then similarly, 72 m due east of that baseline. A new method for measuring ice thickness was employed in the 2004-2005 season using the Aqua-Vu underwater viewing system, which allows us to see the exact point where the bottom of the ice cover is located. The Aqua-Vu underwater camera is lowered through a newly drilled (and usually at least partially melted) ice hole, and the camera lowered until the bottom of the ice cover is viewed through the above-water viewing system. The distance from the bottom of the ice cover to the piezometric water level (z-water) is marked on the viewing system cord and measured with a tape measure once the viewing system is brought out of the ice hole. The distance from the piezometric water level to the top of the ice cover (z-difference) is measured using a tape measure. If more than one replicate measurement is taken for z-water or z-difference, the replicates are averaged. Z-difference, or 'freebore,' provides some insight into the topographical features of the ice cover as well as density of the ice. The addition of z-water and z-difference gives the total ice thickness (z-ice). Ice thickness measurements are typically performed on each hole drilled through the ice cover. Because most limnological sampling holes are drilled in low-lying areas, it was thought that ice thickness measurements were biased. Therefore, random ice thickness measurements were performed in a 1000 m2 sampling grid on each lake in past years. However, statistical analyses by Dr. Priscu have shown that measurements from three ice holes are representative of the ice thickness measured by this grid system. Starting during the 2004-2005 season, ice thickness measurements were done on the two holes drilled for limnological sampling, plus one additional hole. In addition, notes were taken to describe the topography of the ice surrounding the ice hole (see comments section of data file). Generally ice thickness measurements are done on the two holes drilled for limnological sampling (1 hole inside the polarhaven, designated as "Inside Hole," and 1 hole outside) plus one additional outside hole. If there is an opportunity to take measurements in other holes that have been drilled, measurements are taken. Holes that are maintained open throughout the season are measured for ice thickness throughout the season. Note that ablation occurs around the sampling polarhaven, so take note of this when reviewing the Z-difference values for the "inside" holes throughout the season. Notes are taken to describe the topography of the ice surrounding the ice hole and are detailed in the comments section of the data file. unknown LIMNO_ICE_THICKNESS Ice Thickness DATASET_CODE Code that designates the name of the data table in the database The data provider Code that designates the name of the data table in the database Lake Name of lake where measurement was made The data provider Name of lake where measurement was made Location Name Specifics of ice hole site upon lake. Locations designated by numbers are distances in meters, south and east,respectively, from the blue box The data provider Specifics of ice hole site upon lake. Locations designated by numbers are distances in meters, south and east,respectively, from the blue box Date Time Date on which sample was gathered The data provider calendar date/time mm/dd/yyyy gregorian calendar Z-water (m) Distance from piezometric water level to bottom of ice (negative value) The data provider -10 0 meter 0.01 Z-ice (m) Distance from bottom of ice to top of ice (total ice thickness) The data provider 0 10 meter 0.01 Z-diff (m) Distance from piezometric water level to top of ice (positive value) The data provider 0 5 meter 0.01 Density Density of ice The data provider 0 1 dimensionless 0.0001 Tool Tool used to gather sample The data provider Tool used to gather sample Comments Helpful hints about the ice thickness measurement The data provider Helpful hints about the ice thickness measurement File Name Name of file in which data was submitted The data provider Name of file in which data was submitted Latitude Point Latitude of the whole where measurement was made The data provider 0 1 dimensionless 0.0001 Longitude Point Longitude of the whole where measurement was taken The data provider 0 1 dimensionless 0.0001 McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 \n 1 column , https://mcm.lternet.edu/sites/default/files/data/mcmlter-lake-ice_thickness-20250331.csv None 2014-11-04 2014-11-04 McMurdo Dry Valleys LTER http://mcmlter.org/ Biological Data Profile of the Content Standards for Digital Geospatial Metadata devised by the Federal Geographic Data Committee. Drupal Ecological information Management Systems, version D7, Biological Data Profile module