| 1. |
- Biskaborn, Boris K., et al.
(författare)
-
Permafrost is warming at a global scale
- 2019
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. Over the same period, discontinuous permafrost warmed by 0.20 ± 0.10 °C. Permafrost in mountains warmed by 0.19 ± 0.05 °C and in Antarctica by 0.37 ± 0.10 °C. Globally, permafrost temperature increased by 0.29 ± 0.12 °C. The observed trend follows the Arctic amplification of air temperature increase in the Northern Hemisphere. In the discontinuous zone, however, ground warming occurred due to increased snow thickness while air temperature remained statistically unchanged.
|
|
| 2. |
- Bjørnarå, Helga Birgit, et al.
(författare)
-
The impact of weather conditions on everyday cycling with different bike types in parents of young children participating in the CARTOBIKE randomized controlled trial
- 2023
-
Ingår i: International Journal of Sustainable Transportation. - : Taylor & Francis Group. - 1556-8318 .- 1556-8334. ; 17:2, s. 128-135
-
Tidskriftsartikel (refereegranskat)abstract
- Knowledge about how weather conditions affect travel behavior in different user groups and contexts is relevant for planners and policymakers to facilitate sustainable transportation systems. We aimed to assess the influence of day-to-day weather on cycling for transportation among parents of young children with access to different bike types (e-bike vs non e-bike) in a natural study setting over nine months. We hypothesized less impact of weather variability on cycling when using an e-bike compared with a non e-bike. A randomized, controlled trial was conducted in Southern Norway. The intervention group (n = 18) was in random order equipped with an e-bike with trailer for child transportation (n = 6), a cargo (longtail) bike (n = 6) and a traditional bike with trailer (n = 6), each for three months. These 18 participants reported cycling on 832 out of 3276 person-days (25%). We used dynamic structural equation modeling for intensive longitudinal data to examine the relations between daily weather conditions, bike type (e-bike vs traditional bike), and cycling (dichotomized daily at yes or no). Air temperature (positively) and wind speed (negatively) were both credible predictors of cycling, whereas the other predictors (precipitation in the morning (yes or no) and presence of snow (yes or no) were not. We added interaction terms between bike type and weather conditions, but none of the interaction terms had a credible effect on cycling. Thus, the relations between weather conditions and cycling were not moderated by bike type among parents of young children.
|
|
| 3. |
- Gisnås, Kjersti, et al.
(författare)
-
Permafrost Map for Norway, Sweden and Finland
- 2017
-
Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1045-6740 .- 1099-1530. ; 28:2, s. 359-378
-
Tidskriftsartikel (refereegranskat)abstract
- A research-based understanding of permafrost distribution at a sufficient spatial resolution is important to meet the demands of science, education and society. We present a new permafrost map for Norway, Sweden and Finland that provides a more detailed and updated description of permafrost distribution in this area than previously available. We implemented the CryoGRID1 model at 1km(2) resolution, forced by a new operationally gridded data-set of daily air temperature and snow cover for Finland, Norway and Sweden. Hundred model realisations were run for each grid cell, based on statistical snow distributions, allowing for the representation of sub-grid variability of ground temperature. The new map indicates a total permafrost area (excluding palsas) of 23 400km(2) in equilibrium with the average 1981-2010 climate, corresponding to 2.2 per cent of the total land area. About 56 per cent of the area is in Norway, 35 per cent in Sweden and 9 per cent in Finland. The model results are thoroughly evaluated, both quantitatively and qualitatively, as a collaboration project including permafrost experts in the three countries. Observed ground temperatures from 25 boreholes are within +/- 2 degrees C of the average modelled grid cell ground temperature, and all are within the range of the modelled ground temperature for the corresponding grid cell. Qualitative model evaluation by field investigators within the three countries shows that the map reproduces the observed lower altitudinal limits of mountain permafrost and the distribution of lowland permafrost.
|
|
| 4. |
- Killie, Mari Anne, et al.
(författare)
-
Svalbard snow and sea-ice cover : comparing satellite data, on-site measurements, and modelling results (SvalSCESIA)
- 2021
-
Ingår i: SESS report 2020. - Longyearbyen : Svalbard Integrated Arctic Earth Observing System. - 9788269152883 - 9788269152890 ; , s. 220-235
-
Bokkapitel (refereegranskat)abstract
- Fundamental knowledge gaps and scaling issues hamper efforts to determine how changes in snow cover and snow distribution affect ecosystems. The presence of snow cover has huge impact on Arctic ecosystems, human activities, atmospheric processes and Earth’s surface energy balance. Mapping snow cover over large regions is challenging because of its variability over time and space. Also, the small number of weather stations that measure snow cover contributes to a poor observational base. Svalbard is located on the border between the ice-covered Arctic Ocean and the warmer North Atlantic, which means the sea is a controlling factor for Svalbard’s climate. By using remote sensing monitoring it is possible to get a better overview of snow conditions on land. This information can be compared with on-site observations of snow, output from snow models, and evaluated in relation to the sea-ice extent in the adjacent sea. A 34-year satellite data record for snow cover indicates that snow now starts melting more than a week earlier. The total number of snow-free days in summer is increasing fastest in regions dominated by lowland valleys and coastal plains. Most noticeable are the trends centred near the large valleys of Nordenskiöld Land. Negative trends dominate the extent of the sea ice as well. There is significant and positive correlation between sea-ice area and snow-cover extent at elevations up to 250 m in June, the month when snow melt begins. Snow melt, again, is probably strongly affected by ocean–air interactions and energy exchange when warm (or cold) winds from an open (or ice-covered) ocean come in over land.
|
|
| 5. |
- Zdanowicz, Christian, 1966-, et al.
(författare)
-
An agenda for the future of Arctic snow research : the view from Svalbard
- 2024
-
Ingår i: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 42
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic region is warming at over twice the mean rate of the Northern Hemisphere and nearly four times faster than the globe since 1979. The local rate of warming is even higher in the European archipelago of Svalbard. This warming is transforming the terrestrial snow cover, which modulates surface energy exchanges with the atmosphere, accounts for most of the runoff in Arctic catchments and is also a transient reservoir of atmospherically deposited compounds, including pollutants. Improved observations, understanding and modelling of changes in Arctic snow cover are needed to anticipate the effects these changes will have on the Arctic climate, atmosphere, terrestrial ecosystems and socioeconomic factors. Svalbard has been an international hub of polar research for many decades and benefits from a well-developed science infrastructure. Here, we present an agenda for the future of snow research in Svalbard, jointly developed by a multidisciplinary community of experts. We review recent trends in snow research, identify key knowledge gaps, prioritize future research efforts and recommend supportive actions to advance our knowledge of present and future snow conditions pertaining to glacier mass balance, permafrost, surface hydrology, terrestrial ecology, the cycling and fate of atmospheric contaminants, and remote sensing of snow cover. This perspective piece addresses issues relevant to the circumpolar North and could be used as a template for other national or international Arctic research plans.
|
|
