Description: The dataset contains model output presented in the manuscript 'A long-term dataset of climatic mass balance, snow conditions and runoff in Svalbard (1957-2018)', which is considered for publication in The Cryosphere. The data are structured in 3-D arrays containing spatially distributed and annual mean values of the variables specified below. The spatial resolution is 1x1-km. Variables included in the dataset: ----------------------------- - Climatic mass balance - Air temperature - Precipitation - Runoff - Refreezing - Pore space (down to 14 m) - Subsurface temperature (at 14 m depth) - Snow disappearance date - Snow onset date

Description: The dataset contains subsurface temperature measurements done at Lomonosovfonna, Svalbard, during April 2012 - 2016. All measurements are done at the site with coordinates: 78.8235 N, 17.432 E. The data is contained in four cells of a matlab structure containing data from installations deployed in April 2012 - cell 1, April 2013 - cell 2, April 2014 - cell 3 and April 2015 - cell 4. In 2012-2014 nine thermistor strings were installed in each year. The nine T-strings were arranged in a 3*3 square grid with a 3 m spacing between neighboring strings. In 2015 one t-string was installed. Hardware: Campbell Scientific CR10X data loggers in combination with several relay multiplexers (AM416 of AM16/32B) were used for temperature measurements. For that a reference temperature stable resistor (Rr Ohm) was connected is series with thermistors. Known excitation voltage (Ue) was supplied to the circuit and the voltage was measured (Um) at the leads of the reference resistor. The resistance of a thermistor (Rt) was then calculated as: Rt = Ue * Rr / Um - Rr. The resistance was then converted to temperature values provided by the manufacturer of thermistors. Technical information is contained in the variables: LF{N}.T.system. The raw temperature measurements along with the time stamps and depths are contained in the variables LF{N}.T.system.T_raw, LF{N}.T.system.t_raw and LF{N}.T.system.z_raw. After unpacking the data was subjected to the following post-processing steps: - delete data from sensors that were left above the snow surface - for the sensors installed in April 2013: delete data after 2013 July 12 - reset temperature values outsides of the range [-40 +10] degC to NaN - for the sensors installed in April 2015: correct values from one of the sensors by linear interpolation in time between the following time points: 2015 November 15 02:00 and 2015 November 15 14:00, 2015 December 18 15:00 and 2015 December 19 21:00 - introduce corrections to depths of sensors to match temperature distributions measured at different T-strings during the periods dominated by conductive heat exchange in the firn pack corrections are contained in the variable LF{N}.T.system.z_off and are given in meters. - delete data from sensors that are deemed erroneous. For the sensors installed in April 2012 that is: sensor 1 in T-string 9. For the sensors installed in April 2013 that is: sensors 1 and 2 in T-string 2, sensors 1-6 in T-string 3, sensors 1-6 in T-string 4, sensors 1-5 in T-string 5, sensors 1-7 in T-string 6. For the sensors installed in April 2014 that is: sensors 1 in T-string 1, sensor 1 in T-string 7, sensor 1 in T-string 9. - apply offsets for individual sensors defined as the mode during the time period, when the temperature is expected to be at 0 degC. For the sensors installed in April 2012 and 2015 that is the entire measurement period. For the sensors installed in April 2014 the periods are defined based on subjective data analysis and are different for individual sensors. For the sensors installed in April 2013 and some sensors installed in April 2014 the offsets are set to 0 degC. The applied temperature offsets are contained in the variables: LF{N}.T.system.off. The relation between the number of temperature values equal to the offset and the total number of values during the calibration time is saved in the variable LF{N}.T.system.f. After the above described post-processing steps the data was saved in the variable LF{N}.T.T (temperature values), LF{N}.T.z (depths of sensors) and LF{N}.T.t (time stamps). Data interpolated on a regular grid is contained in the variables: LF{N}.T.T_i (temperature values) and LF{N}.T.z_i (depth vectors). Data laterally averaged across all T-strings is contained in the variables: LF{N}.T.T_a (temperature values) and LF{N}.T.z_a (depth vectors). The standard deviation in interpolated temperature values belonging to the same depth but coming from different T-strings are contained in the variables LF{N}.T.T_sd.

Description: 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.