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Climate change is already occurring in the Arctic and the Arctic Climate Impact Assessment recently concluded that future climate change could be devastating for Inuit. This paper characterises vulnerability to climate change in two Inuit communities in the Canadian territory of Nunavut, focusing on the resource harvesting sector. In both communities, Inuit have demonstrated significant adaptability in the face of current changes in climatic conditions. This adaptability is facilitated by traditional Inuit knowledge, strong social networks, flexibility in resource use, and institutional support. Changing Inuit livelihoods, however, have undermined certain aspects of adaptive capacity and have resulted in emerging vulnerabilities. Global and regional climate projections indicate that climatic conditions which currently pose risks are expected to be negatively affected by future climate change. These projections are not without precedent and analysis of current vulnerability and identification of adaptation constraints by Inuit in the two communities indicate the continued importance of traditional coping mechanisms. The ability to draw on these coping mechanisms in light of future climate change, however, will be unequal and the research indicates that young Inuit and those without access to economic resources, in particular, are vulnerable. [ABSTRACT FROM AUTHOR]

We present the climatology of mesopause temperatures using high‐latitude and middle‐latitude meteor radars. The daily mesopause temperatures are estimated using ambipolar diffusion coefficient data from the meteor radars at Davis Station (68.6°S, 77.9°E), in Antarctica, Svalbard (78.3°N, 16°E), Tromsø (69.6°N, 19.2°E) in the Arctic, and Mohe (53.5°N, 122.3°E) and Beijing (40.3°N, 116.2°E) in the northern middle latitudes. The seasonal variations in the meteor radar‐derived temperatures are in good agreement with the temperatures from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the TIMED satellite. Interhemispheric observations indicate that the mesopause temperatures over the southern and northern polar regions show a clear seasonal asymmetry. The seasonal variations in the Davis Station meteor radar temperatures in the southern polar mesopause are dominated by an annual oscillation (AO) with a relatively weak semiannual oscillation (SAO), which show a clear minimum during summer and a maximum during winter. The mesopause temperatures in the northern high and middle latitudes observed by the Svalbard, Tromsø, Mohe, and Beijing meteor radars mainly show an AO, with a maximum during winter and a minimum during summer. The AO in the northern polar regions is stronger than that in the southern polar regions, while the SAO in the southern polar regions is relatively strong compared to that in the northern polar regions. Key Points: Interhemispheric mesopause temperatures estimated by using high‐latitude and middle‐latitude meteor radarsMesopause temperatures estimated from meteor radars agree with the SABER and MLS temperaturesInterhemispheric comparisons indicate that the mesopause temperature over the southern and northern polar regions show a seasonal asymmetry [ABSTRACT FROM AUTHOR]

Abstract: The polar vortices play a central role in vertically coupling the atmosphere from the ground to geospace by shaping the background wind field through which atmospheric waves propagate. This work extends the vertical range of previous polar vortex climatologies into the upper mesosphere. The mesospheric polar vortices are defined using the CO gradient method with Microwave Limb Sounder satellite data; the stratospheric polar vortices are defined using a stream function‐based algorithm with data from meteorological reanalyses. Strengths and weaknesses of the two vortex definitions are given, as well as recommendations for when, where, and why to use each definition. Midwinter mean vortex geometry in the mesosphere is funnel shaped in the Arctic, with a wide top and narrow bottom. The Antarctic mesospheric vortex tapers with height in early winter and broadens with height in late winter. The seasonal evolution of mesospheric vortex frequency of occurrence, size, and zonal symmetry in both hemispheres is presented. Unexpected behavior above 60 km includes late season vortex broadening in both hemispheres, especially following winters without sudden stratospheric warmings. Following extreme stratospheric disturbances the polar night jet in the mesosphere strengthens and shifts poleward, resulting in a mesospheric vortex that contracts. Overall, the mesospheric polar vortices are more similar between the two hemispheres than their stratospheric counterparts. The vortex climatology presented here serves as an observational benchmark to which the mesospheric polar vortices in high‐top climate models can be evaluated. [ABSTRACT FROM AUTHOR]