Arctic sea-ice melt in 2008 and the role of solar heating

Perovich, Donald K.; Richter‐Menge, Jacqueline A.; Jones, Kathleen F.; Light, Bonnie; Elder, Bruce; Polashenski, C.; Laroche, Daniel; Markus, T.; Lindsay, R. W.

doi:10.3189/172756411795931714

Cited by 79 publications

(82 citation statements)

References 34 publications

(37 reference statements)

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“…4) of areas with an increased relative melt pond fraction in the beginning of June indicates the ice free areas later in September. This agrees with the statements of Perovich et al (2002bPerovich et al ( , 2011b, that early occurrence of melt ponds has a strong influence on the formation of open water areas. Clearly visible is also the appearance of homogeneous areas with a very high relative melt pond fraction up to 70 % at the end of June on the flat first year ice in the Canadian Archipelago.…”

Section: A Rösel Et Al: Melt Ponds On Arctic Sea Icesupporting

confidence: 81%

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Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

Rösel¹,

2012

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Abstract. Melt ponds on sea ice strongly reduce the surface albedo and accelerate the decay of Arctic sea ice. Due to different spectral properties of snow, ice, and water, the fractional coverage of these distinct surface types can be derived from multispectral sensors like the Moderate Resolution Image Spectroradiometer (MODIS) using a spectral unmixing algorithm. The unmixing was implemented using a multilayer perceptron to reduce computational costs.Arctic-wide melt pond fractions and sea ice concentrations are derived from the level 3 MODIS surface reflectance product. The validation of the MODIS melt pond data set was conducted with aerial photos from the MELTEX campaign 2008 in the Beaufort Sea, data sets from the National Snow and Ice Data Center (NSIDC) for 2000 and 2001 from four sites spread over the entire Arctic, and with ship observations from the trans-Arctic HOTRAX cruise in 2005. The root-mean-square errors range from 3.8 % for the comparison with HOTRAX data, over 10.7 % for the comparison with NSIDC data, to 10.3 % and 11.4 % for the comparison with MELTEX data, with coefficient of determination ranging from R 2 = 0.28 to R 2 = 0.45. The mean annual cycle of the melt pond fraction per grid cell for the entire Arctic shows a strong increase in June, reaching a maximum of 15 % by the end of June. The zonal mean of melt pond fractions indicates a dependence of the temporal development of melt ponds on the geographical latitude, and has its maximum in mid-July at latitudes between 80 • and 88 • N.Furthermore, the MODIS results are used to estimate the influence of melt ponds on retrievals of sea ice concentrations from passive microwave data. Results from a case study comparing sea ice concentrations from ARTIST Sea Ice-, NASA Team 2-, and Bootstrap-algorithms with MODIS sea ice concentrations indicate an underestimation of around 40 % for sea ice concentrations retrieved with microwave algorithms.

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Section: A Rösel Et Al: Melt Ponds On Arctic Sea Icesupporting

confidence: 81%

“…In order to better constrain the role of sea ice for the Arctic amplification and Earth's climate system, it is important to quantify the large-scale distribution of melt ponds (e.g. Holland et al, 2006;Eisenman and Wettlaufer, 2009;Notz, 2009;Tietsche et al, 2011;Serreze, 2011;Serreze et al, 2011;Kurtz et al, 2011;Perovich et al, 2011b).…”

Section: Introductionmentioning

confidence: 99%

Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

Rösel¹,

2012

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“…Pigments were extracted in 90 % acetone for 18 to 24 h in the dark at 4 • C (Parsons et al, 1984). Fluorescence of the extracted pigments was measured on board with a Turner Designs fluorometer (model 10-005R; Turner Designs, Inc.) before and after acidification with 5 % HCl.…”

Section: Phytoplankton Biomass and Enumeration Bacterial Countmentioning

confidence: 99%

“…Snow deposited at the surface of the sea ice progressively melts during the thawing season and may accumulate above sea level in depressions at the surface of the ice to form melt ponds (Lüthje et al, 2006), likely through a recently identified process of percolation blockage (Polashenski et al, 2017). In the Arctic, melt pond fraction over first-year sea ice (FYI) in late springsummer usually ranges from 50 to 60 %, locally reaching 90 % (Fetterer and Untersteiner, 1998;Eicken et al, 2004;Lüthje et al, 2006;Perovich et al, 2011). Rösel et al (2012) reported a 15 % increase of the relative melt pond fraction for the month of June during the last decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011) in the Arctic, most likely attributable to global climate change.…”

Section: Introductionmentioning

confidence: 99%

Dimethyl sulfide dynamics in first-year sea ice melt ponds in the Canadian Arctic Archipelago

et al. 2018

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Abstract. Melt pond formation is a seasonal pan-Arctic process. During the thawing season, melt ponds may cover up to 90 % of the Arctic first-year sea ice (FYI) and 15 to 25 % of the multi-year sea ice (MYI). These pools of water lying at the surface of the sea ice cover are habitats for microorganisms and represent a potential source of the biogenic gas dimethyl sulfide (DMS) for the atmosphere. Here we report on the concentrations and dynamics of DMS in nine melt ponds sampled in July 2014 in the Canadian Arctic Archipelago. DMS concentrations were under the detection limit (< 0.01 nmol L −1 ) in freshwater melt ponds and increased linearly with salinity (r s = 0.84, p ≤ 0.05) from ∼ 3 up to ∼ 6 nmol L −1 (avg. 3.7 ± 1.6 nmol L −1 ) in brackish melt ponds. This relationship suggests that the intrusion of seawater in melt ponds is a key physical mechanism responsible for the presence of DMS. Experiments were conducted with water from three melt ponds incubated for 24 h with and without the addition of two stable isotope-labelled precursors of DMS (dimethylsulfoniopropionate), (D6-DMSP) and dimethylsulfoxide ( 13 C-DMSO). Results show that de novo biological production of DMS can take place within brackish melt ponds through bacterial DMSP uptake and cleavage. Our data suggest that FYI melt ponds could represent a reservoir of DMS available for potential flux to the atmosphere. The importance of this ice-related source of DMS for the Arctic atmosphere is expected to increase as a response to the thinning of sea ice and the areal and temporal expansion of melt ponds on Arctic FYI.

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“…where, q freezing is the freezing temperature (-0.054×S may serve as a good proxy for the 632 freezing point temperature), r w is water density, c p is specific heat of seawater and z 1 For the upper boundary of the layer, for which Q is estimated, we selected the depth 645 65 m, chosen because this best determines the layer in which heat from the AW is stored 646 and released (14). The depth of winter ventilation H vent is defined using an assumption 647 that, starting from this depth, changes of water properties are not directly linked to the 648 surface processes so that, for example, increase of depth of integration for calculation of 649 Q beyond H vent would not lead to statistically significant change of Q.…”

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confidence: 99%

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean

Polyakov

Pnyushkov

Alkire

et al. 2017

Science

625

657

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Basin have increased winter ventilation in the ocean interior, making this region 46 structurally similar to that of the western Eurasian Basin. The associated enhanced 47 release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to 48 losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in 49 sea-ice cover in the eastern Eurasian Basin. This encroaching "atlantification" of the 50Eurasian Basin represents an essential step toward a new Arctic climate state, with a 51 substantially greater role for Atlantic inflows. 52 53 3 Over the last decade, the Arctic Ocean has experienced dramatic losses of sea-ice loss in 54 the summers, with record-breaking years in 2007 and 2012 for both the Amerasian Basin 55 and the Eurasian Basin (EB). More remarkably, the eastern EB has been nearly ice-free 56 (<10 % ice coverage) at the end of summer since 2011 (Fig. 1). Most sea ice-mass loss 57 results from summer solar heating of the surface mixed layer (SML) through cracks in the 58 ice and open water, and consequent melting of the lower surface of the ice (1-3). Heat 59 advected into the EB interior by Atlantic water (AW) generally has not been considered 60 an important contributor to sea-ice reduction, due to effective insulation of the overlying 61 cold halocline layer (CHL) (4) that separates the cold and fresh SML and pack ice from 62 heat carried by the warm and saline AW. 63There are, however, reasons to believe the role of AW heat in sea-ice reduction is not 64 negligible, and may be increasingly important (5). Nansen (6) warming has slowed slightly since 2008 (Fig. 2c). 74Strong stratification, which is found in most of the Arctic Ocean, prevents vigorous 75 ventilation of the AW. One notable exception is the western Nansen Basin, north and 76 4 northeast of Svalbard, where proximity to the sources of inflowing AW makes possible 77 significant interactions between the SML and the ocean interior (5). Specifically, weakly 78 stratified AW entering the Nansen Basin through Fram Strait is subject to direct 79 ventilation in winter, caused by cooling and haline convection associated with sea ice 80 formation (15). This ventilation leads to the reduction of sea-ice thickness along the 81 continental slope off Svalbard (16, 17). In the past, these conditions have been limited to 82 the western EB, since winter ventilation of AW in the eastern EB was constrained by 83 stronger stratification there. However, newly acquired data show that conditions 84 previously only identified in the western Nansen Basin now can be observed in the 85 eastern EB as well. We call this eastward progression of the western EB conditions the 86 "atlantification" of the EB of the Arctic Ocean. 87 Overview of sea ice state 88The progressive decline in sea ice coverage of the Arctic Ocean during the satellite era, at 89 13.4 % per decade during September (18), has been accompanied by decreases in average 90 sea ice thickness of at least 1.7 m in the central Arctic (19, 20). In the region of t...

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Arctic sea-ice melt in 2008 and the role of solar heating

Cited by 79 publications

References 34 publications

Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

Dimethyl sulfide dynamics in first-year sea ice melt ponds in the Canadian Arctic Archipelago

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean

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