Comparison between in situ and MODIS-derived spectral reflectances of snow and sea ice in the Amundsen Sea, Antarctica

Abstract. Each December during four years from 2006 to 2010, the surface water carbonate system was measured and investigated in the Amundsen Sea and Ross Sea, western Antarctica as part of the Oden Southern Ocean expeditions (OSO). The I/B Oden started in Punta Arenas in Chile and sailed southwest, passing through different regimes such as, the marginal/seasonal ice zone, fronts, coastal shelves, and polynyas. Discrete surface water was sampled underway for analysis of total alkalinity (AT), total dissolved inorganic carbon (CT) and pH. Two of these parameters were used together with sea-surface temperature (SST), and salinity to obtain a full description of the surface water carbonate system, including pH in situ and calcium carbonate saturation state of aragonite (ΩAr) and calcite (ΩCa). Multivariate analysis was used to investigate interannual variability and the major controls (sea-ice concentration, SST, salinity and chlorophyll a) on the variability in the carbonate system and Ω. This analysis showed that SST and chlorophyll a were the major drivers of the Ω variability in both the Amundsen and Ross seas. In 2007, the sea-ice edge was located further south and the area of the open polynya was relatively small compared to 2010. We found the lowest pH in situ (7.932) and Ω = 1 values in the sea-ice zone and in the coastal Amundsen Sea, nearby marine out flowing glaciers. In 2010, the sea-ice coverage was the largest and the areas of the open polynyas were the largest for the whole period. This year we found the lowest salinity and AT, coinciding with highest chl a. This implies that the highest ΩAr in 2010 was likely an effect of biological CO2 drawdown, which out-competed the dilution of carbonate ion concentration due to large melt water volumes. We predict and discuss future Ω values, using our data and reported rates of oceanic uptake of anthropogenic CO2, suggesting that the Amundsen Sea will become undersaturated with regard to aragonite about 20 yr sooner than predicted by models.

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In-situ automatic observations of ice thickness of seas

Metrology and Measurement Systems ◽

10.2478/v10178-012-0051-6 ◽

2012 ◽

Vol 19 (3) ◽

pp. 583-592 ◽

Cited By ~ 1

Author(s):

Yinke Dou ◽

Xiaomin Chang

Keyword(s):

Sea Ice ◽

New Technologies ◽

Capacitive Sensor ◽

Automatic Monitoring ◽

Ice Thickness ◽

In Situ Observation ◽

Glacier Surface ◽

Sea Ice Thickness ◽

Surface Ice

Abstract Ice thickness is one of the most critical physical indicators in the ice science and engineering. It is therefore very necessary to develop in-situ automatic observation technologies of ice thickness. This paper proposes the principle of three new technologies of in-situ automatic observations of sea ice thickness and provides the findings of laboratory applications. The results show that the in-situ observation accuracy of the monitor apparatus based on the Magnetostrictive Delay Line (MDL) principle can reach ±2 mm, which has solved the “bottleneck” problem of restricting the fine development of a sea ice thermodynamic model, and the resistance accuracy of monitor apparatus with temperature gradient can reach the centimeter level and research the ice and snow substance balance by automatically measuring the glacier surface ice and snow change. The measurement accuracy of the capacitive sensor for ice thickness can also reach ±4 mm and the capacitive sensor is of the potential for automatic monitoring the water level under the ice and the ice formation and development process in water. Such three new technologies can meet different needs of fixed-point ice thickness observation and realize the simultaneous measurement in order to accurately judge the ice thickness.

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Development of a winter snow water equivalent algorithm using in situ passive microwave radiometry over snow-covered first-year sea ice

Remote Sensing of Environment ◽

10.1016/j.rse.2006.07.018 ◽

2007 ◽

Vol 106 (1) ◽

pp. 75-88 ◽

Cited By ~ 16

Author(s):

A. Langlois ◽

D.G. Barber ◽

B.J. Hwang

Keyword(s):

Sea Ice ◽

Snow Water Equivalent ◽

Passive Microwave ◽

Microwave Radiometry ◽

First Year ◽

Winter Snow ◽

Snow Water ◽

Passive Microwave Radiometry

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Accuracy assessment of sea-ice concentrations from MODIS using in-situ measurements

Remote Sensing of Environment ◽

10.1016/j.rse.2004.12.004 ◽

2005 ◽

Vol 95 (2) ◽

pp. 139-149 ◽

Cited By ~ 18

Author(s):

C. Drüe ◽

G. Heinemann

Keyword(s):

Sea Ice ◽

Accuracy Assessment ◽

In Situ Measurements

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A Preliminary Investigation of Arctic Sea Ice Negative Freeboard from in-situ Observations and Radar Altimetry

Journal of Ocean University of China ◽

10.1007/s11802-021-4380-5 ◽

2021 ◽

Vol 20 (2) ◽

pp. 307-314

Author(s):

Shutong Li ◽

Tingfeng Dou ◽

Cunde Xiao

Keyword(s):

Sea Ice ◽

Preliminary Investigation ◽

Arctic Sea Ice ◽

Radar Altimetry ◽

Arctic Sea ◽

In Situ Observations

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The Amundsen Sea Low: Variability, Change, and Impact on Antarctic Climate

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-14-00018.1 ◽

2016 ◽

Vol 97 (1) ◽

pp. 111-121 ◽

Cited By ~ 119

Author(s):

M. N. Raphael ◽

G. J. Marshall ◽

J. Turner ◽

R. L. Fogt ◽

D. Schneider ◽

...

Keyword(s):

Sea Ice ◽

Climate Model ◽

Ross Sea ◽

Ice Core ◽

Meridional Wind ◽

West Antarctica ◽

Sea Ice Extent ◽

Amundsen Sea ◽

West Antarctic ◽

Climate Model Simulations

Abstract The Amundsen Sea low (ASL) is a climatological low pressure center that exerts considerable influence on the climate of West Antarctica. Its potential to explain important recent changes in Antarctic climate, for example, in temperature and sea ice extent, means that it has become the focus of an increasing number of studies. Here, the authors summarize the current understanding of the ASL, using reanalysis datasets to analyze recent variability and trends, as well as ice-core chemistry and climate model projections, to examine past and future changes in the ASL, respectively. The ASL has deepened in recent decades, affecting the climate through its influence on the regional meridional wind field, which controls the advection of moisture and heat into the continent. Deepening of the ASL in spring is consistent with observed West Antarctic warming and greater sea ice extent in the Ross Sea. Climate model simulations for recent decades indicate that this deepening is mediated by tropical variability while climate model projections through the twenty-first century suggest that the ASL will deepen in some seasons in response to greenhouse gas concentration increases.

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Dynamic, in situ measurement of sea-ice characteristic length

Annals of Glaciology ◽

10.3189/172756401781818086 ◽

2001 ◽

Vol 33 ◽

pp. 339-344 ◽

Cited By ~ 7

Author(s):

Colin Fox ◽

Tim G. Haskell ◽

Hyuck Chung

Keyword(s):

Sea Ice ◽

Characteristic Length ◽

Ice Sheet ◽

In Situ Measurement ◽

Effective Characteristic ◽

Mcmurdo Sound ◽

Periodic Loading ◽

Flexural Response ◽

Measurement Signal

AbstractWe present a method for measuring the characteristic length of sea ice based on fitting to a recently found solution for the flexural response of a floating ice sheet subject to localized periodic loading. Unlike previous techniques, the method enables localized measurements at single frequencies of geophysical interest, and since the measurements may be synchronously demodulated, gives excellent rejection of unwanted measurement signal (e.g. from ocean swell). The loading mechanism is described and we discuss how the effective characteristic length may be determined using a range of localized measurements. The method is used to determine the characteristic length of the sea ice in McMurdo Sound, Antarctica.

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A microscopic approach to investigate bacteria under in situ conditions in sea-ice samples

Annals of Glaciology ◽

10.3189/172756401781818275 ◽

2001 ◽

Vol 33 ◽

pp. 304-310 ◽

Cited By ~ 76

Author(s):

Karen Junge ◽

Christopher Krembs ◽

Jody Deming ◽

Aaron Stierle ◽

Hajo Eicken

Keyword(s):

Sea Ice ◽

Pore Space ◽

Three Dimensional ◽

Epifluorescence Microscopy ◽

Microbial Populations ◽

Microbial Life ◽

Dimensional Network ◽

In Situ Conditions ◽

Fluorescent Stain

AbstractMicrobial populations and activity within sea ice have been well described based on bulk measurements from melted sea-ice samples. However, melting destroys the micro-environments within the ice matrix and does not allow for examination of microbial populations at a spatial scale relevant to the organism. Here, we describe the development of a new method allowing for microscopic observations of bacteria localized within the three-dimensional network of brine inclusions in sea ice under in situ conditions. Conventional bacterial staining procedures, using the DNA-specific fluorescent stain DAPI, epifluorescence microscopy and image analysis, were adapted to examine bacteria and their associations with various surfaces within microtomed sections of sea ice at temperatures from −2° to −15°C. The utility and sensitivity of the method were demonstrated by analyzing artificial sea-ice preparations of decimal dilutions of a known bacterial culture. When applied to natural, particle-rich sea ice, the method allowed distinction between bacteria and particles at high magnification. At lower magnifications, observations of bacteria could be combined with those of other organisms and with morphology and particle content of the pore space. The method described here may ultimately aid in discerning constraints on microbial life at extremely low temperatures.

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