Variability and trends in Laptev Sea ice outflow between 1992–2011

Abstract

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average total winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 10 5 km 2 . The average transport across the NB (2.87 × 10 5 km 2 ) is thereby higher than across the EB (0.61 × 10 5 km 2 ), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 10 5 km 2 decade −1 , p > 0.95), dominated by increasing export through the EB (0.55 × 10 5 km 2 decade −1 , p > 0.90), while the increase in export across the NB is smaller (0.3 × 10 5 km 2 decade −1 ) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. The increased transport rates are rather the consequence of a changing ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the central and southeastern Laptev Sea. Furthermore, our results imply that years of high ice export in late winter (February to May) have a thinning effect on the ice cover, which in turn preconditions the occurence of negative sea ice extent anomalies in summer.

Observing Muostakh disappear: permafrost thaw subsidence and erosion of a ground-ice-rich island in response to arctic summer warming and sea ice reduction

“…This is in accordance with a general trend of accelerating early ice retreat in the Laptev Sea, probably because of thinner sea ice (Krumpen et al, 2013). Based on our observations, on average, the open water season starts on 20 July.…”

Circumpolar polynya regions and ice production in the Arctic: results from MODIS thermal infrared imagery from 2002/2003 to 2014/2015 with a regional focus on the Laptev Sea

“…Hence, positive trends in both POLA and IP not only fit well to the previously estimated positive trend in IP from Iwamoto et al (2014) but also to the positive trend of 0.85 × 10 5 km 2 per decade in the Laptev Sea ice area flux . Other linkages and dependencies with the Arctic sea-ice extent in September (annual minimum), the timing of the freeze onset and further connections to large-scale atmospheric circulation patterns are very likely and have been proposed by various previous studies (e.g., Alexandrov et al, 2000;Deser et al, 2000;Rigor et al, 2002;Willmes et al, 2011;Krumpen et al, 2013). In particular, a significant lengthening of the melt season in recent years, and hence a later freezeup in autumn, already seems to imprint on the derived POLA (i.e., thin-ice area) and IP estimates in the early winter period (Markus et al, 2009;Parkinson, 2014;Stroeve et al, 2014).…”

“…In some cases, the shape of these areas resembles an arch-type pattern of an ice bridge mechanism, a feature that commonly appears in the Nares Strait between Ellesmere Island and Greenland, for example (Williams et al, 2007). Krumpen et al (2013) discovered that most of the ice being incorporated in the Transpolar Drift originates from the western and central part of the Laptev Sea. Furthermore, it is indicated that the contribution from polynyas, while being generally small, is limited to events in the proximity of the Laptev Sea boundaries.…”

“…As noted before, the northwestern Laptev Sea shows by far the largest contribution to the total winter ice production in the Laptev Sea polynyas, which implies a potential significant influence on the interannual variability of ice export during winter. In order to check this Krumpen et al (2013), where they were calculated as the integral of the product between the eastward and northward component of the ice drift velocity and ice concentration at the northern boundary (NB) and eastern boundary (EB) of the Laptev Sea, respectively. Similar to a high agreement between polynya area and across-boundary ice export , there is also a significant correlation between calculated ice production and the areal ice export (r = 0.69 with p = 0.009).…”

Quantification of ice production in Laptev Sea polynyas and its sensitivity to thin-ice parameterizations in a regional climate model

“…The Laptev Sea (Siberia) is a very shallow shelf sea with water depths between 15 and 200 m and comprises an area of about 500 × 10 3 km 2 (Timokhov, 1994;Krumpen et al, 2013). It is one of the most significant regions where a considerable amount of the total Arctic sea ice is produced (Aagard et al, 1981;Dmitrenko et al, 2009;Dethleff et al, 1998;Willmes et al, 2011a;Tamura and Ohshima, 2011;Iwamoto et al, 2014).…”