Estimation of Thin Ice Thickness and Detection of Fast Ice from SSM/I Data in the Antarctic Ocean

Tamura, Takeshi; Ohshima, Κay I.; Markus, T.; Cavalieri, Donald J.; Nihashi, Sohey; Hirasawa, Naohiko

doi:10.1175/jtech2113.1

Cited by 110 publications

(134 citation statements)

References 30 publications

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“…Fig. S3) than the error of the ice thickness algorithm (~5 cm) 17 . For the periods 1992-2010 and 2000-2011, this study uses fast ice and iceberg mapping from SSM/I 17 and MODIS 20 data, respectively.…”

Section: Discussionmentioning

confidence: 95%

“…This study is the first observational assessment of the change in the GV region after the MGT calving. Sea ice production estimates are presented using a thin ice thickness algorithm based on satellite Special Sensor Microwave/Imager (SSM/I) data and a heat flux calculation [17][18][19] , in conjunction with a fast ice time series and climatology derived from NASA moderate resolution imaging spectroradiometer (MODIS) satellite imagery 20 . We examine the change in sea ice production in 2010 and 2011, relative to the mean annual sea ice production over the preceding years from 2000-2009.…”

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confidence: 99%

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Potential regime shift in decreased sea ice production after the Mertz Glacier calving

et al. 2012

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Variability in dense shelf water formation can potentially impact Antarctic Bottom Water (AABW) production, a vital component of the global climate system. In East Antarctica, the George V Land polynya system (142-150°E) is structured by the local 'icescape', promoting sea ice formation that is driven by the offshore wind regime. Here we present the first observations of this region after the repositioning of a large iceberg (B9B) precipitated the calving of the Mertz Glacier Tongue in 2010. Using satellite data, we find that the total sea ice production for the region in 2010 and 2011 was 144 and 134 km3, respectively, representing a 14-20% decrease from a value of 168 km3 averaged from 2000-2009. This abrupt change to the regional icescape could result in decreased polynya activity, sea ice production, and ultimately the dense shelf water export and AABW production from this region for the coming decades

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Section: Discussionmentioning

confidence: 95%

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confidence: 99%

Potential regime shift in decreased sea ice production after the Mertz Glacier calving

et al. 2012

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“…Thus, the overall mean thickness for a mixture of thin and thick ice can only be estimated in a statistical sense if the thickness distribution function is known. Sea ice deformation patterns are often described using self-similar functions, such as the lognormal distribution (Erlingsson, 1988;Key and McLaren, 1991;Tan et al, 2012). A theory of sea ice thickness distribution was developed by Thorndike et al (1975).…”

Section: The Effect Of the Subpixel-scale Heterogeneity On The Thicknmentioning

confidence: 99%

“…Passive microwave radiometer data from the Special Sensor Microwave Imager (SSM/I) (37 and 85.5 GHz channels) and Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) (36.5 and 89 GHz channels) sensors have been used to estimate the thickness of thin ice to 10-20 cm (Martin et al, 2005;Tamura et al, 2007;Nihashi et al, 2009;Tamura and Ohshima, 2011;Singh et al, 2011). The spatial resolution of the radiometer-based thin ice thickness charts (6.25 to 25 km) is much coarser than that from thermal imagery, but daily Arctic and Antarctic coverage is possible.…”

Section: Introductionmentioning

confidence: 99%

SMOS-derived thin sea ice thickness: algorithm baseline, product specifications and initial verification

Kaleschke²,

et al. 2014

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Abstract. Following the launch of ESA's Soil Moisture andOcean Salinity (SMOS) mission, it has been shown that brightness temperatures at a low microwave frequency of 1.4 GHz (L-band) are sensitive to sea ice properties. In the first demonstration study, sea ice thickness up to 50 cm has been derived using a semi-empirical algorithm with constant tie-points. Here, we introduce a novel iterative retrieval algorithm that is based on a thermodynamic sea ice model and a three-layer radiative transfer model, which explicitly takes variations of ice temperature and ice salinity into account. In addition, ice thickness variations within the SMOS spatial resolution are considered through a statistical thickness distribution function derived from high-resolution ice thickness measurements from NASA's Operation IceBridge campaign. This new algorithm has been used for the continuous operational production of a SMOS-based sea ice thickness data set from 2010 on. The data set is compared to and validated with estimates from assimilation systems, remote sensing data, and airborne electromagnetic sounding data. The comparisons show that the new retrieval algorithm has a considerably better agreement with the validation data and delivers a more realistic Arctic-wide ice thickness distribution than the algorithm used in the previous study (Kaleschke et al., 2012).

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“…Our past studies developed a thin ice thickness algorithm using satellite passive microwave data and estimated sea ice production from heat budget analysis under the assumption that all the heat loss goes towards ice formation (Tamura et al 2007;Tamura et al 2008). Thus, during the freezing period, heat flux can be estimated by the detection of thin ice thickness (0−0.2 m), and salt flux into the underlying ocean accompanying sea ice production can be estimated from heat loss under the above assumption.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Surface Heat/Salt Fluxes Associated with Sea Ice Growth/Melt in the Southern Ocean

Tamura

Ohshima

Nihashi

et al. 2011

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The sinking of dense water in the polar oceans plays a key role in global thermohaline circulation, leading to heat and material exchange between the atmosphere and deep ocean. This study provides the first surface heat and salt flux dataset for the Southern Ocean (including a treatment of sea ice growth and melt), based on heat flux calculations and satellite-derived sea ice data. The geographical distribution of annual net heat (salt) flux shows a distinct contrast: significant cooling of (salt release into) the ocean occurs in the coastal region, and net heating of (freshwater release into) the ocean occurs in the offshore region. The work tries a quantitative representation of heat and freshwater transport by sea ice formed in the coastal region to offshore. Since hemisphericscale heat and salt fluxes associated with sea ice growth and melt have not been estimated from observations to date, the present dataset will provide new information with which to validate coupled ice-ocean models while providing important boundary conditions for the various models. IntroductionThe climatically-crucial thermohaline circulation of the global ocean is largely driven by the sinking of dense water and its upwelling, and is sensitive to changes in the freshwater balance at high latitudes (Alley et al. 2003). The dense water is largely formed by cold and high salinity water (brine) rejection due to ice production in the sea-ice covered oceans. It is widely recognized that high ice production in Antarctic coastal polynyas is responsible for the formation of the Antarctic Bottom Water, which is the densest water mass in the world ocean and is the most important driver of the abyssal circulation. Antarctic coastal polynyas are formed by divergent ice motion due to prevailing winds and/or oceanic currents, with most of their area being covered with newly-forming and/or thin ice (Barber and Massom 2007). During winter, heat loss over thin ice is one or two orders of magnitude larger than that over thick ice (Maykut 1978), and is very sensitive to ice thickness. Thus, particularly high rates of ice production occur in thin ice areas including Antarctic coastal polynyas during austral winter.Sea ice growth, drift, and subsequent melt lead to redistribution of heat and salt in the ocean, and are thus important factors affecting the oceanic heat-and salt-balances and therefore thermohaline circulation. While some modeling studies have discussed heat and salt fluxes associated with sea ice redistribution in the Southern Ocean (Marsland and Wolff 2001;Stossel et al. 2002), heat and salt fluxes associated with sea ice growth and melt have not been well understood on a hemispheric scale. Most past studies have focused on estimating rates of ice production and associated heat and salt fluxes on local to regional scales (Renfrew et al. 2002;Williams and Bindoff 2003;Martin et al. 2007). In other words, there has been a lack of suitable surface heat and salt flux data from the ice-affected Southern Ocean with which to drive and valid...

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Estimation of Thin Ice Thickness and Detection of Fast Ice from SSM/I Data in the Antarctic Ocean

Cited by 110 publications

References 30 publications

Potential regime shift in decreased sea ice production after the Mertz Glacier calving

Potential regime shift in decreased sea ice production after the Mertz Glacier calving

SMOS-derived thin sea ice thickness: algorithm baseline, product specifications and initial verification

Estimation of Surface Heat/Salt Fluxes Associated with Sea Ice Growth/Melt in the Southern Ocean

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