Multiyear ice replenishment in the Canadian Arctic Archipelago: 1997–2013

Abstract

In the Canadian Arctic Archipelago (CAA), multiyear ice (MYI) replenishment from first‐year ice aging (CAAMYI‐Oct‐1) and Arctic Ocean MYI exchange (CAAMYI‐exchange) contribute to the CAA's relatively heavy sea ice conditions at the end of the summer melt season. We estimate these components using RADARSAT and the Canadian Ice Service Digital Archive and explore processes responsible for interannual variability from 1997 to 2013. CAAMYI‐Oct‐1 (52 ± 36 × 103 km2) provides a larger contribution than CAAMYI‐exchange (13 ± 11 × 103 km2). CAAMYI‐Oct‐1 represents ∼10% of the amount that occurs in the Arctic Ocean. CAAMYI‐exchange represents ∼50% of Nares Strait MYI export to Baffin Bay and ∼12% of Fram Strait MYI export to the Greenland Sea. CAAMYI‐Oct‐1 exhibits dependence on warmer (cooler) summers that increase (decrease) melt evident from strong relationships to surface air temperature (SAT), albedo and total absorbed solar radiation (Qtotal). CAAMYI‐exchange is influenced by summer sea level pressure (SLP) anomalies over the Beaufort Sea and Canadian Basin which shifts the primary source of CAAMYI‐exchange between less obstructed M'Clure Strait (low SLP anomalies) and the more obstructed Queen Elizabeth Islands (high SLP anomalies). Over the 17‐record, appreciable replenishment occurred for most years from 1997 to 2004, reduced replenishment from 2005 to 2012, and large replenishment in 2013. The reduced replenishment period was associated with positive SAT, negative albedo, and positive Qtotal anomalies that facilitated more melt and less CAAMYI‐Oct‐1, together with high SLP anomalies that facilitated less CAAMYI‐exchange. Large replenishment in 2013 was primarily from CAAMYI‐Oct‐1 attributed to strongly negative SAT and Qtotal anomalies and strongly positive albedo that impeded melt.

Improving Multiyear Ice Concentration Estimates With Reanalysis Air Temperatures

“…It is shown that the stable MYI area decreased gradually from about 4.0 × 10 5 km 2 in 2004 to about 2.5 × 10 5 km 2 in 2008. This impact of the well-recognized warming trend of the Arctic region has been confirmed in [46]. There are two obvious warm air spells in September 2006, as shown by the temperature record in the graph (September 7 and 15), resulting in MYI area increases of 1.0 × 10 5 km 2 after the correction.…”

“…In Region 7, which mainly encompasses the narrow passages in the Canadian Arctic Archipelago, MYI replenishment from FYI contributes to heavy sea ice conditions. The interannual variability of this ice from 1997 to 2013 is presented in [46].…”

Canadian Snow and Sea Ice: Trends (1981–2015) and Projections (2020–2050)

“…This was nearly repeated in 2016. As previously reported, the CAA eclipsed the previous and long standing record low ice year of 1998 in both 2011 and 2012 (Howell et al, 2013b). A contributing factor to the decline of sea ice across the 255 Canadian Arctic is increasing spring air temperature (see Figure 2) coupled with longer melt seasons resulting in the The Cryosphere Discuss., https://doi.org/10.…”

The Ocean CO2 Sink in the Canadian Arctic Archipelago: A Present‐Day Budget and Past Trends Due to Climate Change

“…The calculated fluxes are low (< −2 mmol CO 2 ·m −2 ·day −1 ) or near 0 in the northern extent of the CAA (e.g., around Queen Elizabeth Islands and Ellesmere Island), associated with very limited open water (Figure S1). The multiyear ice that still exists in Queen Elizabeth Islands and around Ellesmere Island (Howell et al, ) acts as a significant barrier to air‐sea CO 2 exchange in our model. Throughout the central CAA, moderate air‐sea CO 2 fluxes (−5 to −3 mmol CO 2 ·m −2 ·day −1 ) are associated with two to six average weeks of open water, indicating that this region is a moderate sink for atmospheric CO 2 .…”

“…Figure S1). The multiyear ice that still exists in Queen Elizabeth Islands and around Ellesmere Island (Howell et al, 2015) acts as a significant barrier to air-sea CO 2 exchange in our model. Throughout the central CAA, moderate air-sea CO 2 fluxes (−5 to −3 mmol CO 2 ·m −2 ·day −1 ) are associated with two to six average weeks of open water, indicating that this region is a moderate sink for atmospheric CO 2 .…”