Snow particle sizes and their distributions in Dronning Maud Land, Antarctica, at sample, local and regional scales

2016 ◽  
Vol 28 (3) ◽  
pp. 219-231
Author(s):  
Susanne Ingvander ◽  
Peter Jansson ◽  
Ian A. Brown ◽  
Shuji Fujita ◽  
Shin Sugyama ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Particle Size ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Coupled Processes ◽  
Sample Type ◽  
Surface Snow ◽  
Dronning Maud Land ◽  
Size Variability ◽  
Snow Particle

AbstractIn this study, snow particle size variability was investigated along a transect in Dronning Maud Land from the coast to the polar plateau. The aim of the study was to better understand the spatial and temporal variations in surface snow properties. Samples were collected twice daily during a traverse in 2007–08 to capture regional variability. Local variability was assessed by sampling in 10×10 m grids (5 m spacing) at selected locations. The particle size and shape distributions for each site were analysed through digital image analysis. Snow particle size variability is complex at different scales, and shows an internal variability of 0.18–3.31 mm depending on the sample type (surface, grid or pit). Relationships were verified between particle size and both elevation and distance to the coast (moisture source). Regional seasonal changes were also identified, particularly on the lower elevations of the polar plateau. This dataset may be used to quantitatively analyse the optical properties of surface snow for remote sensing. The details of the spatial and temporal variations observed in our data provide a basis for further studies of the complex and coupled processes affecting snow particle size and the interpretation of remote sensing of snow covered areas.

scholarly journals Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars

2019 ◽  
Author(s):  
Katrin Lindbäck ◽  
Geir Moholdt ◽  
Keith W. Nicholls ◽  
Tore Hattermann ◽  
Bhanu Pratap ◽  
...  
Keyword(s):  
Deep Ocean ◽  
Temporal Variations ◽  
East Antarctica ◽  
Spatial And Temporal Variations ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Deep Ocean Water ◽  
Dronning Maud Land ◽  
Phase Sensitive ◽  
Basal Melting

Abstract. Thinning rates of ice shelves vary widely around Antarctica and basal melting is a major component in ice shelf mass loss. In this study, we present records of basal melting, at unique spatial and temporal resolution for East Antarctica, derived from autonomous phase-sensitive radars. These records show spatial and temporal variations of ice shelf basal melting in 2017 and 2018 at Nivlisen, central Dronning Maud Land. The annually averaged melt rates are in general moderate (~ 0.8 m yr-1). Radar profiling of the ice-shelf shows variable ice thickness from smooth beds to basal crevasses and channels. The highest melt rates (3.9 m yr-1) were observed close to a grounded feature near the ice shelf front. Daily time-varying measurements reveal a seasonal melt signal 4 km from the ice shelf front, at an ice draft of 130 m, where the highest daily melt rates occurred in summer (up to 5.6 m yr-1). This seasonality indicates that summer-warmed ocean surface water was pushed by wind beneath the ice shelf front. We observed a different melt regime 35 km into the ice-shelf cavity, at an ice draft of 280 m, with considerably lower melt rates (annual average of 0.4 m yr-1) and no seasonality. We conclude that warm deep ocean water at present has limited effect on the basal melting of Nivlisen. On the other hand, a warming in surface waters, as a result of diminishing sea-ice cover has the potential to increase basal melting near the ice-shelf front. Many ice shelves like Nivlisen are stabilized by pinning points at their ice fronts and these areas may be vulnerable to future change.

scholarly journals Editorial for the Special Issue “Combining Different Data Sources for Environmental and Operational Satellite Monitoring of Sea Ice Conditions”

2020 ◽  
Vol 12 (4) ◽  
pp. 606 ◽  
Author(s):  
Wolfgang Dierking ◽  
Marko Mäkynen ◽  
Markku Similä
Keyword(s):  
Remote Sensing ◽  
Sea Ice ◽  
Satellite Remote Sensing ◽  
Continuous Monitoring ◽  
Temporal Variations ◽  
Data Sources ◽  
Spatial And Temporal Variations ◽  
Satellite Monitoring ◽  
Special Issue ◽  
Ice Conditions

Satellite remote sensing is an important tool for continuous monitoring of sea ice covered ocean regions and spatial and temporal variations of their geophysical characteristics [...]

scholarly journals In situ sampled snow particle sizes of the East Antarctic ice sheet and their relation to physical and remotely sensed snow surface parameters

2013 ◽  
Vol 54 (62) ◽  
pp. 166-174
Author(s):  
Susanne Ingvander ◽  
Helen E. Dahlke ◽  
Peter Jansson ◽  
Sylviane Surdyk
Keyword(s):  
Remote Sensing ◽  
Particle Size ◽  
Ice Sheet ◽  
Remote Sensing Data ◽  
Antarctic Ice Sheet ◽  
Sensing Data ◽  
Snow Particle ◽  
Particle Length ◽  
East Antarctic Ice Sheet

AbstractKnowledge of snow properties across Antarctica is important in estimating how climate could potentially influence the mass balance of the Antarctic ice sheet. However, measuring these variables has proven to be challenging because appropriate techniques have not yet been developed and extensive datasets of field estimates are lacking. The goal of this study was to estimate the relationship between field-observed snow particle-size parameters from across the East Antarctic ice sheet and a suite of spatial datasets (i.e. topography, remote-sensing data) using a principal component analysis (PCA). Five snow particle-size parameters were correlated to spatial datasets of the following five groups: (1) relief properties such as elevation and slope; (2) remote-sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) and synthetic aperture radar (SAR) sensors; (3) spatially interpolated data (i.e. 10 m maps of temperature and approximate snow accumulation in kgm−2 ä−1); (4) field-retrieved data on surface roughness; and (5) in situ elevation and distance from the coast. The results show that the relief parameter slope correlated best with the snow particle length and area (r=0.76, r=0.80). Further, the PCA indicated that the different remote-sensing parameters correlated differently with the size parameters and that the most common parameter in visual analysis, particle length (grain diameter), is not always the optimal parameter to characterize the snow particle size as, for example, area correlates better to slope and aspect than length.

scholarly journals Spatial and temporal variations in snow chemistry along a traverse from coastal East Antarctica to the ice sheet summit (Dome A)

2020 ◽  
Author(s):  
Guitao Shi ◽  
Hongmei Ma ◽  
Zhengyi Hu ◽  
Zhenlou Chen ◽  
Chunlei An ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Temporal Variations ◽  
East Antarctica ◽  
Spatial And Temporal Variations ◽  
Biogenic Emissions ◽  
Dome A ◽  
Sea Salts ◽  
Snow Chemistry ◽  
Winter Snow ◽  
Surface Snow

Abstract. There is a large variability in environmental conditions across the Antarctic ice sheet, and it is of significance to investigate the snow chemistry at as many locations as possible and over time, given that the ice sheet itself, and precipitation and deposition patterns and trends are changing. The China inland Antarctic traverse from coastal Zhongshan Station to the ice sheet summit (Dome A) covers a variety of environments, allowing for a vast collection of snow chemistry conditions across East Antarctica. Surface snow and snow pit samples were collected on this traverse during five campaigns, to comprehensively investigate the spatial and temporal variations in chemical ions (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, and Ca2+) and the related controlling factors. Results show that spatial patterns of ions in surface snow are consistent among the five campaigns, with Cl−, Na+, K+, and Mg2+ decreasing rapidly with distance from the coast and NO3− showing an opposite pattern. No clear spatial trends in SO42−, NH4+ and Ca2+ were found. In the interior areas, an enrichment of Cl− versus Na+ with respect to seawater composition is ubiquitous as a result of the deposition of HCl, which can account for up to ~40 % of the total Cl− budget, while enriched K+ and Mg2+ are associated with terrestrial particle mass. Ca2+ and SO42− in surface snow are significantly enriched relative to Na+, related to terrestrial dust inputs and marine biogenic emissions, respectively. Snow NH4+ is mainly associated with marine biological activities, with higher concentrations in summer than in winter. On the coast, parts of the winter snow are characterized with a depletion of SO42− versus Na+, and a significant negative correlation between nssSO42− and Na+ was found, suggesting that sea salts originated from the sea ice. In the interior areas, the negative nssSO42− signal in winter snow resulted from inputs of sea salts being completely swamped by the contribution of marine biogenic emissions. Ternary plots of Cl−, Na+, and SO42− suggest that sea salt modification is generally negligible on the coast, while the degree of modification processes to sea salts is high in the interior areas, especially during the summertime. Ion flux assessment suggests an efficient transport of nssSO42− to at least as far inland as the ~2800 m contour line. The interannual variations in ion concentrations in surface snow on the traverse are likely linked to the changes in the Southern Indian Ocean low (SIOL) from year to year, and the deepening of the SIOL in summer tends to promote the transport of marine aerosols to Princess Elizabeth Land.

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