Chapter 5 Gas Fluxes and Dynamics in Polynyas

Miller, Lisa A.; DiTullio, Giacomo R.

doi:10.1016/s0422-9894(06)74005-3

Cited by 12 publications

(9 citation statements)

References 104 publications

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“…Support for this hypothesized cycle was provided by Miller et al [2002] who observed a brief positive ΔpCO 2 before the spring opening of the Northwater polynya, followed by strongly negative ΔpCO 2 as the ice cleared. Likewise, modelling [Sweeney, 2003] and summer pCO 2sw measurements [Sweeney et al, 2000] in the Ross Sea polynya regions (Antarctica) have revealed a similar cycle (see also the review by Miller and DiTullio [2007]). …”

Section: Introductionmentioning

confidence: 69%

“…The air-sea exchange of CO 2 during time periods when polynyas occur has received considerable interest (e.g. Miller and DiTullio [2007]), but significant exchange has also been observed during other seasons [Else et al, 2011]. By tracking air-sea CO 2 transfer through an entire annual cycle in geographic areas that host polynyas (areas we term "polynya regions") we can better quantify their contribution to global and regional atmospheric carbon budgets.…”

Section: Introductionmentioning

confidence: 99%

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Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Else

Papakyriakou

Asplin

et al. 2013

Global Biogeochemical Cycles

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[1] During the Canadian International Polar Year projects in the Cape Bathurst polynya region, we measured a near-complete annual cycle of sea surface CO 2 (pCO 2sw ), atmospheric CO 2 (pCO 2atm ), sea surface temperature (SST), salinity (S), and wind speed (U ). In this paper, we combine these data with ancillary measurements of sea ice concentration (C i ) to estimate the mean annual (September 2007-September 2008) air-sea CO 2 exchange for the region. For the non-freezing seasons the exchange was calculated using a standard bulk aerodynamic approach, whereas during the freezing seasons we extrapolated eddy covariance measurements of CO 2 exchange. Our results show that in 2007-08 the region served as a net sink of atmospheric CO 2 at a mean rate of -10.1 AE 6.5 mmol m À 2 d À 1 . The strongest calculated uptake rate occurred in the fall when wind velocities were highest, pCO 2sw was significantly lower than pCO 2atm , and ice was beginning to form. Atmospheric CO 2 uptake was calculated to occur (at lower rates) throughout the rest of the year, except for a brief period of outgassing during late July. Using archival U, C i , and pCO 2sw data for the region, we found that winds in 2007-08 were 25-35 % stronger than the decadal mean and were predominately easterly, which appears to have induced a relatively late freeze-up (by $ 3 weeks relative to mean conditions) and an early polynya opening (by $ 4 weeks). In turn, these conditions may have given rise to a higher CO 2 uptake than normal. Estimated winter CO 2 exchange through leads and small polynya openings made up more than 50% of the total CO 2 uptake, consistent with recent observations of enhanced CO 2 exchange associated with open water components of the winter icescape. Our calculations for the Cape Bathurst polynya region are consistent with past studies that estimated the total winter CO 2 uptake in Arctic coastal polynyas to be on the order of 10 12 g C yr À 1 .

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Section: Introductionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Else

Papakyriakou

Asplin

et al. 2013

Global Biogeochemical Cycles

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“…The next uncertainty is related to the flaw polynyas as their combined area in the ESS is about 5 % of the ESS total, and their lifetime ranges from 90 to 174 days per year (Popov and Karelin, 2009). It has been reported that polynyas, areas of high biological productivity and active ice formation, are generally sinks of CO 2 where CO 2 is drawn into the water both by coupling with organic carbon export and by high solubility in the cold waters typical of polynyas (Anderson et al, 2004;Miller and DiTullio, 2007). However, I. I.…”

Section: Interannual Variabilitymentioning

confidence: 99%

Interannual variability of air-sea CO<sub>2</sub> fluxes and carbon system in the East Siberian Sea

et al. 2011

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Abstract. Over the past couple of decades it has become apparent that air-land-sea interactions in the Arctic have a substantial impact on the composition of the overlying atmosphere (ACIA, 2004). The Arctic Ocean is small (only ∼4 % of the total World Ocean), but it is surrounded by offshore and onshore permafrost which is thawing at increasing rates under warming conditions, releasing carbon dioxide (CO 2 ) into the water and atmosphere. The Arctic Ocean shelf where the most intensive biogeochemical processes have occurred occupies 1/3 of the ocean. The East Siberian Sea (ESS) shelf is the shallowest and widest shelf among the Arctic seas, and the least studied. The objective of this study was to highlight the importance of different factors that impact the carbon system (CS) as well as the CO 2 flux dynamics in the ESS. CS variables were measured in the ESS in September 2003September and, 2004 and in late August-September 2008. It was shown that the western part of the ESS represents a river-and coastal-erosion-dominated heterotrophic ocean margin that is a source for atmospheric CO 2 . The eastern part of the ESS is a Pacific-water-dominated autotrophic area, which acts as a sink for atmospheric CO 2 .Our results indicate that the year-to-year dynamics of the partial pressure of CO 2 in the surface water as well as the air-sea flux of CO 2 varies substantially. In one year the ESS shelf was mainly heterotrophic and served as a moderate summertime source of CO 2 (year 2004). In another year gross primary production exceeded community respiration in a relatively large part of the ESS and the ESS shelf was only a weak source of CO 2 into the atmosphere (year 2008). It was shown that many factors impact the CS and Correspondence to: I. I. Pipko (irina@poi.dvo.ru) CO 2 flux dynamics (such as river runoff, coastal erosion, primary production/respiration, etc.), but they were mainly determined by the interplay and distribution of water masses that are basically influenced by the atmospheric circulation. In this contribution the air-sea CO 2 fluxes were evaluated in the ESS based on measured CS characteristics, and summertime fluxes were estimated. It was shown that the total ESS shelf is a net source of CO 2 for the atmosphere in a range of 0.4 × 10 12 to 2.3 × 10 12 g C.

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“…The resultant large amount of brine rejection leads to the formation of dense water ), which is a major source of Antarctic Bottom Water (AABW; Gordon et al 1993;Comiso and Gordon 1998;Rintoul 1998;Williams et al 2010;Ohshima et al 2013). The sinking of the dense water plays a significant role in the global climate system by driving thermohaline (overturning) circulation (Killworth 1983) and biogeochemical cycles such as the carbon dioxide exchange between the atmosphere and deep ocean (Morales Maqueda et al 2004;Miller and DiTullio 2007;Hoppema and Anderson 2007). The polynyas can also be biological ''hot spots'' during the spring and summer seasons because of much-enhanced primary productivity (Arrigo and van Dijken 2003).…”

Section: Introductionmentioning

confidence: 99%

Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability

2015

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Sinking of dense water from Antarctic coastal polynyas produces Antarctic Bottom Water (AABW), which is the densest water in the global overturning circulation and is a key player in climate change as a significant sink for heat and carbon dioxide. Very recent studies have suggested that landfast sea ice (fast ice) plays an important role in the formation and variability of the polynyas and possibly AABW. However, they have been limited to regional and case investigations only. This study provides the first coincident circumpolar mapping of Antarctic coastal polynyas and fast ice. The map reveals that most of the polynyas are formed on the western side of fast ice, indicating an important role of fast ice in the polynya formation. Winds diverging from a boundary comprising both coastline and fast ice are the primary determinant of polynya formation. The blocking effect of fast ice on westward sea ice advection by the coastal current would be another key factor. These effects on the variability in sea ice production for 13 major polynyas are evaluated quantitatively. Furthermore, it is demonstrated that a drastic change in fast ice extent, which is particularly vulnerable to climate change, causes dramatic changes in the polynyas and possibly AABW formation that can potentially contribute to further climate change. These results suggest that fast ice and precise polynya processes should be addressed by next-generation models to produce more accurate climate projections. This study provides the boundary and validation data of fast ice and sea ice production for such models.

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Chapter 5 Gas Fluxes and Dynamics in Polynyas

Cited by 12 publications

References 104 publications

Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Interannual variability of air-sea CO<sub>2</sub> fluxes and carbon system in the East Siberian Sea

Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability

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Chapter 5 Gas Fluxes and Dynamics in Polynyas

Cited by 12 publications

References 104 publications

Annual cycle of air‐sea CO2 exchange in an Arctic Polynya Region

Annual cycle of air‐sea CO2 exchange in an Arctic Polynya Region

Interannual variability of air-sea CO&lt;sub&gt;2&lt;/sub&gt; fluxes and carbon system in the East Siberian Sea

Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability

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Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Annual cycle of air‐sea CO₂ exchange in an Arctic Polynya Region

Interannual variability of air-sea CO<sub>2</sub> fluxes and carbon system in the East Siberian Sea