Summer hydroclimatology of an extensive low-gradient wetland: Polar Bear Pass, Bathurst Island, Nunavut, Canada

Abstract

Polar Bear Pass (PBP) (75°40'N, 98°30'W) is considered a critical wetiand area for migratory birds, caribou and muskox. Little is known of its climatology and hydroiogy. Here we evaiuate both the short-term and long-term summer climatic record for this wetland. A 10 m high automatic weather station (AWS) was established here 27 years ago, and in 2007 this centraiiy located AWS was suppiemented by three more weather stations placed across the wetiand pass.The iong-term climate record here indicates little significant departure when compared to the long-term climate means at Resolute Bay, a government weather station lying 90 km to the southwest (74°43'N, 94°59'W). Exceptions exist for July minimum air temperature (PBP > Resoiute) and number of days in June, July and August < 0°C (PBP < Resolute).Climate variabiiity from year to year remains the norm. Radiation receipt, air temperature, humidity and wind speed vary little across the wetiand pass, whiie terrain-modified fluxes do.The precipitation regime is similar to Resolute Bay but local site conditions modify the amounts. In 2007, July evaporation levels were twice as high as that of 2008; more akin to Low Arctic sites. As yet, no clear trend in iong-term climatic signals can be established.

Snow cover variability at Polar Bear Pass, Nunavut

“…Due to warmer and sheltered conditions, plant cover and diversity are richer here than in polar desert regions at the same latitude . Presently, Polar Bear Pass can be considered to be a biological oasis due to its lush wet meadows though it experiences a polar desert climate similar to Resolute (Young and Labine 2010). However, Table 1 suggests that the snow cover at PBP is more akin to high arctic regions experiencing polar oasis-type climates.…”

“…1 For previous years (2008)(2009)(2010), see Young and Labine (2010) and Miller and Young (2016). A photograph of the site can be found in Fig.…”

“…Aspect and a shallower snowpack in the northern half of the Pass are not the only factors accounting for differences. Because the predominant winds at PBP blow from the northern sector (Young and Labine 2010), strong winter winds erode sediment from the thinly snow covered plateau, transporting it onto the surrounding late-lying snowpack and adjacent wet meadow. This accelerates melt by lowering the surface albedo, eventually enhancing Q* receipt (Assini and Young 2012;Young et al 2013;and Supplementary Figs.…”

“…Any alteration in the snowpack or melt season will have implications for the timing and duration of streamflow (Young et al 2015), with earlier snowmelt seasons leading to larger evaporation losses, wetland drying and potential shifts in wetland vegetation (Young and Labine 2010;Woo and Young 2014;Young et al 2015). If deeper snowpacks occur, this may alter the thermal qualities of the snowpack, i.e., thicker hoar frost layers could warm the ground, potentially thawing the upper permafrost and (or) enhance the growth and height of woody shrubs.…”

Spatio-temporal sensitivity of MODIS land surface temperature anomalies indicates high potential for large-scale land cover change detection in Arctic permafrost landscapes

“…1a). It has a typical polar desert climate with long, cold winters and short, cool summers (Young & Labine, 2010 (Mekis & Vincent, 2011). Air temperatures have been warming at both Resolute Bay and Polar Bear Pass over the last decade (Woo & Young, 2014).…”