Winter Snow Depth on Arctic Sea Ice From Satellite Radiometer Measurements (2003–2020): Regional Patterns and Trends

Abstract

While an unambiguous climate change signature has been observed in Arctic sea ice coverage (Andersen et al., 2020;Stroeve et al., 2007), it has been difficult to quantify the changes in snow depth over the sea ice region (Webster et al., 2018). This holds in spite of snow accumulation being one of the most important geophysical parameters to understand Arctic climate, being related to albedo feedback, ice cover insulation, and associated heat transfer effects (Curry et al., 1995;Ledley, 1991;Webster et al., 2014). In addition to its importance in the polar climate system, snow depth influences the accuracy of ice thickness estimation based on satellite altimetry (Kern et al., 2015). Most knowledge regarding snow depth on Arctic sea ice is based on the climatological distribution provided by Warren et al. (1999) (W99), which was based on in situ data collected over multiyear sea ice (MYI) during the years of 1954-1991. Although W99 may not be considered as a representative Arctic snow depth distribution for the recent decades, it is still often used as a standard. For example, based on a report by Kurtz and Farrell (2011), many studies modified W99 by halving W99 snow depth over first-year ice (FYI), then using this scaled snow depth to estimate ice thickness from satellite altimeter measurements (Kwok & Cunningham, 2015;Ricker et al., 2014). A reliable data record of the snow depth is thus clearly needed by both climate and satellite communities (Webster et al., 2014).

Estimation of Arctic Winter Snow Depth, Sea Ice Thickness and Bulk Density, and Ice Freeboard by Combining CryoSat-2, AVHRR, and AMSR Measurements

“…Recently, in addition to the FYI area, the snow depth during the freezing period on multiyear sea ice (MYI) has also reduced significantly compared to the W99 snow depth [23]- [26]. This implies that the mW99 also causes an overestimation of the snow depth over the MYI area.…”

“…In mW99, this snow depth variability exists only in regions where the sea ice type changes. Additionally, recent modeling and satellite observational studies have shown that snow depth trends differ according to region, with an increase and decrease over the western and eastern Arctic Ocean, respectively [26], [27]. Therefore, snow depth that varies spatiotemporally (also referred to as "dynamic snow depth") is preferable for the estimation of sea ice thickness [28], [29].…”

“…However, a recent study by Jutila et al [31] reported that the bulk density of sea ice varies horizontally and is not a constant value for certain ice types; additionally, it can be parameterized by sea ice freeboard. Moreover, it is unclear whether a bulk density of 882 kg m -3 for the MYI is reasonable for the estimation of sea ice thickness [26], [32]. To calculate the representative MYI bulk density of 882 kg m -3 , A10 assumed that the densities of the upper and lower layers (sea ice above and below the waterline, respectively) are 550 and 920 kg m -3 , respectively, and the thicknesses of the upper and lower layers were assumed to be 0.3 and 2.6 m, respectively.…”

“…Additionally, an empirical relationship that can estimate α from air-snow interface and snow-ice interface temperatures was obtained by analyzing monthly averaged buoy temperature profiles [38], [39]. The ability of α for simultaneous estimation was demonstrated by using measurements from an Advanced Microwave Scanning Radiometer (AMSR) and an Advanced Very High Resolution Radiometer (AVHRR) [26], [38]. Although the proposed > REPLACE THIS LINE WITH YOUR MANUSCRIPT ID NUMBER (DOUBLE-CLICK HERE TO EDIT) < method can provide plausible distributions of snow depth and ice thickness, it is still affected by the use of fixed bulk sea ice density values.…”

Ground-based remote sensing of aerosol properties using high resolution infrared emission and Lidar observations in the high Arctic

“…There are several ways to measure the aerosol composition, such as remote sensing from satellite or ground-based instruments, in-situ measurement on the surface or from aircraft. Satellite instruments can provide measurements of large areas but are not very suitable in the Arctic due to the frequent existence of clouds and snow/ice on the surface, which make the measurements challenging (Lee et al, 2021). The in-situ measurements provide much more accurate measurements, but are often limited to the planetary boundary layer and a distinct position.…”