In the Queen Elizabeth Islands, regional distributions of vegetation and many summer climate patterns show similar, distinctive S-shaped patterns, a response to the interaction between regional topography and persistent northwesterly flow from the central Arctic Ocean. The cool and cloudy central polar pack ice climate bulges almost unimpeded into the low-lying islands of the northwest and north-central sector. This region has the least vascular plant diversity and is dominated almost entirely by the herbaceous species. The mountains of Axel Heiberg and Ellesmere islands create a barrier that effectively shelters an intermontane region from both the central Arctic Ocean climate and travelling cyclonic systems. In this large intermontane zone regional minimums of cloud cover and maximums of temperatures and melt season duration are found. This area contains the most dense and diverse vascular plant assemblages. Woody species and sedges dominate, and many species with more southerly limits occur as disjuncts. The plateaus and highlands in the southern islands modify the central Arctic Ocean climate sufficiently to produce an intermediate climate. Woody species and sedges also dominate this area; however, the density and diversity are less than that of the intermontane area. Several phytogeographic limits occur in the Queen Elizabeth Islands, including the northern limits of woody plants and sedges, and the northern limits of the dominance of woody plants and sedges. These regional boundaries roughly coincide with regional mean July isotherms of 3 and 4°C respectively. Key words: Arctic, High Arctic, arctic vegetation, Canada, climate, summer climate, bioclimatic zones, Queen Elizabeth Islands, phytogeographical boundaries

http://pubs.aina.ucalgary.ca/arctic/Arctic42-1-3.pdf

Regional Congruence of Vegetation and Summer Climate Patterns in the Queen Elizabeth Islands, Northwest Territories, Canada

Asteroid and comet impacts on Earth are commonly viewed as agents of ecosystem destruction, be it on local or global scales. However, for some microbial communities, impacts may represent an opportunity for habitat formation as some substrates are rendered more suitable for colonization when processed by impacts. We describe how heavily shocked gneissic crystalline basement rocks exposed at the Haughton impact structure, Devon Island, Nunavut, Arctic Canada, are hosts to endolithic photosynthetic microorganisms in significantly greater abundance than lesser-shocked or unshocked gneisses. Two factors contribute to this enhancement: (a) increased porosity due to impact fracturing and differential mineral vaporization, and (b) increased translucence due to the selective vaporization of opaque mineral phases. Using biological ultraviolet radiation dosimetry, and by measuring the concentrations of photoprotective compounds, we demonstrate that a covering of 0.8 mm of shocked gneiss can provide substantial protection from ultraviolet radiation, reducing the inactivation of Bacillus subtilis spores by 2 orders of magnitude. The colonisation of the shocked habitat represents a potential mechanism for pioneer microorganisms to invade an impact structure in the earliest stages of post-impact primary succession. The communities are analogous to the endolithic communities associated with sedimentary rocks in Antarctica, but because they occur in shocked crystalline rocks, they illustrate a mechanism for the creation of microbial habitats on planetary surfaces that do not have exposed sedimentary units. This might have been the case on early Earth. The data have implications for the microhabitats in which biological signatures might be sought on Mars.

/pdf/impact-induced-microbial-endolithic-habitats-268n6ps7s8.pdf

Impact‐induced microbial endolithic habitats

http://www.geo.umass.edu/courses/geo458/Readings/Guidelines_Research_Papers.pdf

Holocene Paleoclimatology of the Queen Elizabeth Islands, Canadian High Arctic

A detailed analysis of the spatial and temporal changes in mean seasonal and annual surface air temperatures over the period of instrumental observations in the Arctic is presented. In addition, the role of atmospheric circulation in controlling the instrumental and decadal-scale changes of air temperature in the Arctic is investigated. Mean monthly temperature and temperature anomalies data from 37 Arctic, 7 sub-Arctic and 30 grid-boxes were used for analysis.



The presented analysis shows that the observed variations in air temperature in the real Arctic (defined on the basis of climatic as opposed to other criteria, e.g. astronomical or botanical) are in many aspects not consistent with the projected climatic changes computed by climatic models for the enhanced greenhouse effect. The highest temperatures since the beginning of instrumental observation occurred clearly in the 1930s and can be attributed to changes in atmospheric circulation. The second phase of contemporary global warming (after 1975) is, at most, weakly marked in the Arctic. For example, the mean rate of warming for the period 1991–1995 was 2–3 times lower in the Arctic than the global average. Temperature levels observed in Greenland in the last 10–20 years are similar to those observed in the 19th century.



Increases of temperature in the Arctic are more significant in the warm half-year than in the cold half-year. This seasonal pattern in temperature change confirms the view that positive feedback mechanisms (e.g. sea-ice–albedo–temperature) as yet play only a small role in enhancing temperature in the Arctic. Hypotheses are presented to explain the lack of warming in the Arctic after 1975.



It is shown that in some parts of the Arctic atmospheric circulation changes, in particular in the cold half-year, can explain up to 10–50% of the temperature variance. For Arctic temperature, the most important factor is a change in the atmospheric circulation over the North Atlantic. The influence of atmospheric circulation change over the Pacific (both in the northern and in the tropical parts) is significantly lower. Copyright © 2000 Royal Meteorological Society

/pdf/temporal-and-spatial-variation-of-surface-air-temperature-1zoosrw5jh.pdf

Temporal and spatial variation of surface air temperature over the period of instrumental observations in the Arctic

Although cruise travel to the Canadian Arctic has grown steadily since 1984, some commentators have suggested that growth in this sector of the tourism industry might accelerate, given the warming effects of climate change that are making formerly remote Canadian Arctic communities more accessible to cruise vessels. Using sea-ice charts from the Canadian Ice Service, we argue that Global Climate Model predictions of an ice-free Arctic as early as 2050–70 may lead to a false sense of optimism regarding the potential exploitation of all Canadian Arctic waters for tourism purposes. This is because climate warming is altering the character and distribution of sea ice, increasing the likelihood of hull-penetrating, high-latitude, multi-year ice that could cause major pitfalls for future navigation in some places in Arctic Canada. These changes may have negative implications for cruise tourism in the Canadian Arctic, and, in particular, for tourist transits through the Northwest Passage and High Arctic regions.

Sea Ice in Canada's Arctic: Implications for Cruise Tourism

As a result of a comprehensive assessment of the climate of the Canadian Arctic Islands and adjacent waters, five climatic regions were identified. The regional boundaries were delineated by an analysis of the influence of the major climatic controls while further regional subdivisions were arrived at through consideration of the fields of the standard observed meteorological elements. Short discussions of the climatic characteristics of each sub-region are given and tables outlining values of selected climatic elements are presented. A brief discussion of climatic change across the entire area is included. Key words: Canadian Arctic Islands, climate, climatic change, meteorology

http://pubs.aina.ucalgary.ca/arctic/Arctic34-3-225.pdf

J.B. Maxwell

Papers

Climatic Regions of the Canadian Arctic Islands