Satellite-based measurements of brightness temperatures (AMSR2 sensor) colocated to MOSAiC ground measurements

The file contains measurements of brightness temperatures of satellite overpasses of the research vessel Polarstern during the MOSAiC expedition from October 26, 2019 - May 26, 2020 as well as co-located measurements of different parameters. For every overpass of Polarstern, the satellite measurement closest to the hourly position of Polarstern is taken.

The satellite sensor is AMSR2 (six frequencies between 6.9 and 89 GHz and both polarizations) and we use the Level 1R (Madea et al., 2016) product available at JAXA https://gportal.jaxa.jp/gpr/

The co-located parameters are liquid water path, total water vapor, sea ice concentration, multi-year ice fraction, snow depth, snow-air interface temperature, snow-ice interface temperature, wind speed and sea surface temperature. In addition to the co-located parameters as ground truth, the dataset also contains their “uncertainties” given as temporal and/or spatial variability.

Note: The dataset contains only satellite overpasses where co-located data is available.

More information on the parameters are found below and they are described in more detail in Rückert et al., 2023 and the references given therein.

scantime: time of satellite observation as included in the satellite data from JAXA

lon: longitude in decimal degrees (DD) of satellite observations as included in the satellite data from JAXA

lat: latitude in decimal degrees (DD) of satellite observations as included in the satellite data from JAXA

distance: distance to the hourly Polarstern position

TB6.9V, TB6.9H, TB10.7V, TB10.7H, TB18.7V, TB18.7H, TB23.8V, TB23.8H, TB36.5V, TB36.5H, TB89V, TB89H: Brightness temperatures (TB) measured by AMSRE2, the name includes the frequency in GHz and the polarization (either H for horizontal or V for vertical polarization), e.g, TB6.9V is the brightness temperature at 6.9 GHz and vertical polarization

LWP: liquid water path in kg/m² measured by a radiometer onboard the ship (Walbröl et al., 2022), averaged within +/- 10 minutes of the satellite observations

sigma_LWP: temporal variability of liquid water path (see previous point) given as standard deviation within +/- 10 minutes of the satellite observation time

TWV: total water vapor (integrated water vapor) in kg/m² measured by a radiometer onboard the ship (Walbröl et al. (2022)), averaged within +/- 10 minutes satellite observation time

sigma_TWV: temporal variability of total water vapor (see previous point) given as standard deviation within +/- 10 minutes of the satellite observation time

WSP: wind speed in m/s from the vessel’s meteorological observatory (Schmithüsen et al., 2021), averaged within +/- 10 minutes of the satellite observation time

sigma_WSP: temporal variability of wind speed (see previous point) given as standard deviation within +/- 10 minutes of the satellite observation time

SST: sea water temperature in K from the vessel’s meteorological observatory (Schmithüsen et al., 2021), averaged within +/- 10 minutes of the satellite observation time

sigma_SST: temporal variability of sea water temperature (see previous point) given as standard deviation within +/- 10 minutes of the satellite observation time

SND: snow depth in m obtained from the median of daily snow depth from available Snow and Ice Mass Balance Apparatus (SIMBA) buoys (Lei et al., 2021a) in the proximity of Polarstern.

sigma_SND: spatial variability of snow depth (see previous point) given as standard deviation of all buoys available on that day.

Tsi: Snow-ice interface temperature in K obtained from the median of daily measurements from available Snow and Ice Mass Balance Apparatus (SIMBA) buoys (e.g. Lei et al., 2021b, for references of all buoys the reader is referred to the references given in Rückert et al., 2023) in the proximity of Polarstern.

sigma_Tsi: spatial variability of snow-ice interface temperature (see previous point) given as standard deviation of all buoys available on that day.

MYIF: multi-year ice fraction (from 0 to 1) based on classified TerraSAR-X scenes (Guo et al., 2023) in the proximity of Polarstern, interpolated to daily values.

sigma_MYIF: estimated (constant) uncertainty of multi-year ice fraction (see previous point).

SIC: sea ice concentration (from 0 to 1) based on classified TerraSAR-X scenes (Guo et al., 2023) in the proximity of Polarstern, interpolated to daily values.

sigma_SIC: estimated (constant) uncertainty of sea ice concentration (see previous point).

Tsa: Snow-air interface temperature in K based on infrared thermometer data (Cox et al., 2023 a)-d)) installed at four positions in the proximity of Polarstern, averaged within +/- 20 minutes of the satellite observation time.

sigma_Tsa: spatial variability of snow-ice interface temperature (see previous point), given as spatial (4 sites) and temporal (within +/- 20 minutes of the satellite observation time) standard deviation.