Spatial coverage and inter-annual persistence of cryoconite holes on Canada and Commonwealth glaciers, McMurdo Dry Valleys, Antarctica (2014-2015)

Summary

Abstract: 

This data package includes measurements pertaining to the spatial distribution and multi-annual persistence of cryoconite holes on Canada and Commonwealth Glaciers in Taylor Valley, Antarctica during two consecutive austral summers (2013-14 and 2014-15). Four circular sampling zones were established on each glacier and multiple measurements of the surface shape and absolute location of all cryoconite holes within the sampling zones were recorded. These measurements can be used to generate spatial maps and analyze the persistence of cryoconite holes from one summer to the next by tracking individual holes and identifying the number lost, gained, and persistent on a multiannual scale. The physical state of each cryoconite hole (liquid-filled, fully frozen, or drained/dry) was also recorded in order to assess the capacity for drained columns to re-initiate downward melting later in the austral summer or during the following year. The glacial surface coverage (GSC) of liquid-filled cryoconite holes can be used in order to assess the contribution of these columns to total glacial melt and drainage. A detailed description for how to use these data in subsequent analyses to spatially map and ‘track’ cryoconite holes over time is available in Water Resources Research: A.Q. Mass and D.M. McKnight (2021) The inter-annual persistence and contribution of cryoconite holes in Taylor Valley, Antarctica to the hydrologic cycle of the McMurdo Dry Valleys under a new climate regime. 

Date Range: 

January 20, 2014 to January 20, 2015
Data Citation
Mass, A.Q., Mcknight, D.M. 2021. Spatial coverage and inter-annual persistence of cryoconite holes on Canada and Commonwealth glaciers, McMurdo Dry Valleys, Antarctica (2014-2015). Environmental Data Initiative. DOI: 10.6073/pasta/731379a9253793e5c8d160b726067909. Dataset accessed 26 October 2021.
Dataset(s)

Variables (click to expand): 

DATASET_CODE
  • Label: Dataset code
  • Definition: Internal dataset code.
  • Type: Nominal
  • Missing values: None specified
SAMPLING_DATE
  • Label: Sampling date
  • Definition: Date when measurements were taken.
  • Type: Date/time
  • Date format: MM/DD/YYYY
  • Missing values: None specified
GLACIER
  • Label: Glacier name
  • Definition: Name of the glacier (Canada or Commonwealth) where the measurement was taken.
  • Type: Nominal
  • Missing values: None specified
SAMPLING_SITE
  • Label: Sampling site
  • Definition: Code referring to the sampling site where measurements were taken. Sites 1-4 are located on Commonwealth Glacier and sites 5-8 are on Canada Glacier.
  • Type: Nominal
  • Missing values: None specified
CENTERPOST_LAT
  • Label: Centerpost latitude
  • Definition: Latitude of the sampling site’s central post in decimal degrees.
  • Type: Nominal
  • Missing values: None specified
CENTERPOST_LON
  • Label: Centerpost longitude
  • Definition: Longitude of the sampling site’s central post in decimal degrees.
  • Type: Nominal
  • Missing values: None specified
CRYO_ORDER
  • Label: Measurement order
  • Definition: Consecutive order in which the cryoconite holes were measured. A code assigned to each cryoconite hole based on the transect wedge in which it was sampled (ordered numerically) and the consecutive order in which the holes were measured within that transect (labeled alphabetically). For example 05-C refers to the third (alphabetical) cryoconite hole measured in transect wedge #5. See methods for elaboration on this variable.
  • Type: Nominal
  • Missing values: None specified
START_DISTANCE_A
  • Label: Start Distance (A)
  • Definition: Distance (cm) along the transect line from the center post to the closest border of the cryoconite hole.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
END_DISTANCE_B
  • Label: End Distance (B)
  • Definition: Distance (cm) along the transect line from the center post to the farthest border of the cryoconite hole.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
PERP_DISTANCE_C
  • Label: Perpendicular Distance (C)
  • Definition: Distance (perpendicular to the transect line; cm) between the transect line and the closest edge of the cryoconite hole.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
MAJOR_DIAMETER_D
  • Label: Major Diameter (D)
  • Definition: Diameter (cm) of the major axis of the cryoconite hole.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
MINOR_DIAMETER_E
  • Label: Minor Diameter (E)
  • Definition: Diameter (cm) of the minor axis of the cryoconite hole.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
CIRCULARITY
  • Label: Circularity ratio
  • Definition: Ratio of the minor to major axis (diameter of minor:major axes), used to determine if elliptical orientation should be measured. Holes with a circularity less than 0.8 were considered significantly oval or eccentric and required Ratio of the minor to major axis, used to determine if elliptical orientation should be measured. Holes with a circularity less than 0.8 were considered significantly oval or eccentric and required measuring conical distance F.
  • Type: Nominal
  • Missing values: None specified
CONICAL_POINT_F
  • Label: Conical Point (F)
  • Definition: For eccentric or oval-shaped cryoconite holes, this records the location (along the transect line; cm) of the conical point oriented towards, rather than away from, the lesser transect tape. This is a rough measure of the angular orientation of an oval on the glacial surface; see methods for elaboration. Blank cells indicate samples for which this measurement was not applicable.
  • Type: Physical quantity
  • Unit: centimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
MELTWATER_STATE
  • Label: Meltwater state
  • Definition: Physical state of meltwater within the cryoconite hole. Classified as either “liquid” (liquid meltwater is present in the hole), “frozen” (column consists of refrozen meltwater) or “dry” (cryoconite hole is hollow/ fully drained).
  • Type: Nominal
  • Missing values: None specified
ICE_LID_PRESENT
  • Label: Ice Lid Presence
  • Definition: Indicates whether a liquid-filled cryoconite hole was open to the surface (0) or contained at least one full-coverage ice lid between the liquid layer and glacial surface (1). Note that the numeric code only indicates absence/presence and holes containing multiple stratified ice lids are still indicated by (1). Ice lids are not applicable to fully frozen or dry columns since they do not contain underlying liquid melt. Blank cells indicate missing values.
  • Type: Nominal
  • Missing values: None specified
COMMENTS
  • Label: Comments
  • Definition: Additional comments to describe the sampling site or cryoconite hole being measured.
  • Type: Nominal
  • Missing values: None specified

Short name: 

GLACIER_GSC

Dataset ID: 

2020
People

Principal Investigator(s): 

Contact: 

Associated Personnel: 

Data Manager