Density and stratigraphy of firn at Lomonosovfonna derived from shallow cores in 1997-2015

The present dataset contains measurements of density and observations of stratigraphy in the subsurface snow/firn/ice done at Lomonosovfonna during 1997-2015. The variables are named according to the year, when the data was derived: "LF" for Lomonosovfonna and "NN" corresponds to the year, e.g. 97 - 1997, 07 - 2007. Most variables contain the following fields:

rho* - density measurements: column 1 - depth of sample top, m; column 2 - depth of sample bottom, m; column 3 - density values, kg m^-3;

rho*_reg - density measurements on a regular 1 cm spaced grid, gaps are filled by linear interpolation and extrapolated using "nearest neighbor" logic; column 1 - depth, m; column 2 - density values, kg m^-3;

strat - stratigraphy: column 1 - depth of sample top, m; column 2 - depth of sample bottom, m; column 3 - stratigraphy coded as: 1 - snow, 2 - firn, 3 - ice lens;

lat* - latitude, degrees to the North of equator;

lon* - longitude, degrees to the East of the prime meridian;

h* - elevation, m above the sea level.

LF97: Six shallow cores were drilled in spring 1997 approximately along the centerline of Nordenskiöldbreen. A system of mass balance stakes at locations of the cores is maintained by Uppsala university. The density is approximated from visual stratigraphic description according to the classification suggested by Pohjola et al., 2002 (see Table 1 there). The density values are the result of averaging of density values ascribed to stratigraphic units identified in core pieces and weighted by their respective thicknesses.

LF99: Three shallow cores were drilled in the end of April 1999 at the location where in 1997 a 120 m long ice core was drilled. The cores were drilled along a North-South oriented line with a spacing of 2.5 m between the neighboring cores. The fields in the LF99 variable are named accordingly: fields with the data from the southern location contain "S", northern - "N", central - "C". The field and laboratory work was done by Håkan Samuelsson. Methods and analysis are described in detail in the Master Thesis: "Distribution of melt layers on the ice field Lomonosovfonna, Spitsbergen", defended at Uppsala University in 2001.

LF08: One shallow core was drilled by Sanja Forsström, Elisabeth Isaksson, Veijo Pohjola and Jim Hedfors within ca 100 from the location where in 1997 a 120 m long ice core was drilled. Density was measured using two different methods at the cold lab of the Norwegian Polar Institute in Tromso by Sanja Forsström and Tonu Martma. The structure field "rho" contains values calculated from measured geometrical dimensions of the core samples and weights. The fields "rhoDEPcorepieces", "rhoDEPionsamples" and "rhoDEPisotopesamples" contain density values measured using dielectric profiling in three sets of samples.

LF12: The core was drilled by Veijo Pohjola and Rickard Pettersson on the 13 of April 2012. Field notes done by Sergey Marchenko. Cold lab operations were done by Sergey Marchenko and Elena Klimenko at the University Centre in Svalbard (UNIS) in Longyearbyen, Norway during 26 April - 3 May 2012. Density was measured in cylindrical and cuboid samples prepared using a band saw to ensure regular shape. The structure field "rho_c" contains density measurements done using cylindrical core pieces. The structure field "rho_rb" contains density measurements done using relatively long cuboid samples prepared from cylindrical core pieces using a band saw. The structure field "rho_rs" contains density measurements done using shorter cuboid samples prepared from the longer pieces using a band saw. The structure field "rho_reg" is based on the "rho_rs" structure field.

LF13: The core was drilled by Christian Zdanowics, Dorothee Vallot and Veijo Pohjola in April 2013 and later analyzed by Carmen Vega in the cold lab of the Norwegian Polar Institute in Tromso, Norway.

LF14: The core was drilled by Veijo Pohjola and Ward van Pelt in the end of March 2014. Field notes are done by Veijo Pohjola. Cold lab operations were done by Sergey Marchenko, William Kohler and Elisbeth Isaksson in the Norwegian Polar Institute facilities in Tromso, Norway, during 05-10 of October 2014. Density was measured in cylindrical or cuboid samples prepared using a band saw to ensure regular shape.

LF15: the core was drilled by Veijo Pohjola and Ward van Pelt on the 15th of April 2015. Field notes are done by Veijo Pohjola. Cold lab operations were done by Sergey Marchenko, Glennda Villanflor and Elisbeth Isaksson in the Norwegian Polar Institute facilities in Tromso, Norway, during 02-05 of November 2015. Density was measured in cylindrical or cuboid samples prepared using a band saw to ensure regular shape.

The data is used in the following publications:

1) Marchenko, S., Cheng, G., Lötstedt, P., Pohjola, V., Pettersson, R., van Pelt, W., Reijmer, C., (2019). Thermal conductivity of firn at Lomonosovfonna, Svalbard, derived from subsurface temperature measurements, The Cryosphere Discussions, doi: 10.5194/tc-2018-294;

2) Marchenko, S., van Pelt, W., Claremar, B., Pohjola, V., Pettersson, R., Machguth, H., Reijmer, C., (2017). Parameterizing Deep Water Percolation Improves Subsurface Temperature Simulations by a Multilayer Firn Model, Frontiers in Earth Science, doi: 10.3389/feart.2017.00016;

3) Marchenko, S., Pohjola, V., Pettersson, R., van Pelt, W., Vega, C., Machguth, H., Bøggild C., Isaksson, E., (2017). A plot-scale study of firn stratigraphy at Lomonosovfonna, Svalbard, using ice cores, borehole video and GPR surveys in 2012-14, Journal of Glaciology, doi: 10.1017/jog.2016.118;

4) Pohjola, V., Moore, J., Isaksson, E., Jauhiainen, T., van de Wal, R., Martma, T., Meijer, H., Vaikmäe, R., (2002). Effect of periodic melting on geochemical and isotopic signals in an ice core from Lomonosovfonna, Svalbard, Journal of Geophysical Research, doi:10.1029/2000JD000149;

5) Isaksson, E., Pohjola, V., Jauhiainen, T., Moore, J., Pinglot, J., Vaikmäe, R., van De Wal, R., Hagen, J.O., Ivask, J., Karlöf, L., Martma, T., Meijer, H., Mulvaney, R., Thomassen M., van den Broeke, M., (2001). A new ice-core record from Lomonosovfonna, Svalbard: Viewing the 1920–97 data in relation to present climate and environmental conditions, Journal of Glaciology, doi:10.3189/172756501781832313;

6) Pälli, A., Kohler, J., Isaksson, E., Moore, J., Pinglot, J., Pohjola, V., & Samuelsson, H., (2002). Spatial and temporal variability of snow accumulation using ground-penetrating radar and ice cores on a Svalbard glacier, Journal of Glaciology, doi:10.3189/172756502781831205;

7) van Pelt, W, Pettersson, R., Pohjola, V., Marchenko, S., Claremar, B., and Oerlemans, J., (2014). Inverse estimation of snow accumulation along a radar transect on Nordenskiöldbreen, Svalbard, Journal of Geophysical Research, doi:10.1002/2013JF003040;

8) Vega, C., Pohjola, V., Beaudon, E., Claremar, B., van Pelt, W., Pettersson, R., Isaksson, E., Martma, T., Schwikowski, M., Bøggild, C., (2016). A synthetic ice core approach to estimate ion relocation in an ice field site experiencing periodical melt: a case study on Lomonosovfonna, Svalbard, The Cryosphere, doi:10.5194/tc-10-961-2016;