scholarly journals Synoptic control on snow avalanche activity in central Spitsbergen

2021 ◽  
Author(s):  
Holt Hancock ◽  
Jordy Hendrikx ◽  
Markus Eckerstorfer ◽  
Siiri Wickström
Keyword(s):  
Environmental Change ◽  
Atmospheric Circulation ◽  
High Arctic ◽  
Snow Avalanche ◽  
Atmospheric Conditions ◽  
Svalbard Archipelago ◽  
Atmospheric Circulation Patterns ◽  
Wind Speeds ◽  
Air Temperatures ◽  
Synoptic Conditions

Abstract. Atmospheric circulation exerts an important control on a region's snow avalanche activity by broadly determining the mountain weather patterns which influence snowpack development and avalanche release. In central Spitsbergen, the largest island in the high-Arctic Svalbard archipelago, avalanches are a common natural hazard throughout the winter months. Previous work has identified a unique snow climate reflecting the region's climatically dynamic environmental setting but has not specifically addressed the synoptic-scale control of atmospheric circulation on avalanche activity here. In this work, we investigate atmospheric circulation's control on snow avalanching in the Nordenskiöld Land region of central Spitsbergen by first constructing a four-season (2016/2017–2019/2020) regional avalanche activity record using observations available on a database used by the Norwegian Water Resources and Energy Directorate (NVE). We then analyze the synoptic atmospheric conditions on days with differing avalanche activity situations. Our results show synoptic conditions conducive to elevated precipitation, wind speeds, and air temperatures near Svalbard are associated with increased avalanche activity in Nordenskiöld Land, but different synoptic signals exist for days characterized by dry, mixed, and wet avalanche activity. Differing upwind conditions help further explain differences in the frequency and nature of avalanche activity resulting from these various atmospheric circulation patterns. We further employ a daily atmospheric circulation calendar to help contextualize our results in the growing body of literature related to environmental change in this location. This work helps expand our understanding of snow avalanches in Svalbard to a broader spatial scale and provides a basis for future work investigating the impacts of environmental change on avalanche activity in Svalbard and other locations where avalanche regimes are impacted by changing climatic and synoptic conditions.

scholarly journals Synoptic control on snow avalanche activity in central Spitsbergen

2021 ◽  
Vol 15 (8) ◽  
pp. 3813-3837
Author(s):  
Holt Hancock ◽  
Jordy Hendrikx ◽  
Markus Eckerstorfer ◽  
Siiri Wickström
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
High Arctic ◽  
Snow Avalanche ◽  
Atmospheric Conditions ◽  
Svalbard Archipelago ◽  
Atmospheric Circulation Patterns ◽  
Wind Speeds ◽  
Air Temperatures ◽  
Synoptic Conditions

Abstract. Atmospheric circulation exerts an important control on a region's snow avalanche activity by broadly determining the mountain weather patterns that influence snowpack development and avalanche release. In central Spitsbergen, the largest island in the High Arctic Svalbard archipelago, avalanches are a common natural hazard throughout the winter months. Previous work has identified a unique snow climate reflecting the region's climatically dynamic environmental setting but has not specifically addressed the synoptic-scale control of atmospheric circulation on avalanche activity here. In this work, we investigate atmospheric circulation's control on snow avalanching in the Nordenskiöld Land region of central Spitsbergen by first constructing a four-season (2016/2017–2019/2020) regional avalanche activity record using observations available on a database used by the Norwegian Water Resources and Energy Directorate (NVE). We then analyze the synoptic atmospheric conditions on days with differing avalanche activity situations. Our results show atmospheric circulation conducive to elevated precipitation, wind speeds, and air temperatures near Svalbard are associated with increased avalanche activity in Nordenskiöld Land, but different synoptic signals exist for days characterized by dry, mixed, and wet avalanche activity. Differing upwind conditions help further explain differences in the frequency and nature of avalanche activity resulting from these various atmospheric circulation patterns. We further employ a daily atmospheric circulation calendar to help contextualize our results in the growing body of literature related to climate change in this location. This work helps expand our understanding of snow avalanches in Svalbard to a broader spatial scale and provides a basis for future work investigating the impacts of climate change on avalanche activity in Svalbard and other locations where avalanche regimes are impacted by changing climatic and synoptic conditions.

scholarly journals The Importance of Spring and Autumn Atmospheric Conditions for the Evaporation Regime of Lake Superior

2013 ◽  
Vol 14 (5) ◽  
pp. 1647-1658 ◽  
Author(s):  
C. Spence ◽  
P. D. Blanken ◽  
J. D. Lenters ◽  
N. Hedstrom
Keyword(s):  
Numerical Models ◽  
Lake Superior ◽  
Ice Cover ◽  
Heat Fluxes ◽  
Atmospheric Conditions ◽  
Air Temperatures ◽  
Synoptic Conditions ◽  
Annual Evaporation ◽  
Evaporative Flux ◽  
Early Breakup

Abstract Feedbacks between ice extent and evaporation have long been suspected to be important for Lake Superior evaporation because it is during autumn and winter when latent heat fluxes are highest. Recent direct measurements of evaporation made at the Stannard Rock Lighthouse have provided new information on the physical controls on Lake Superior evaporation, in particular that evaporation can react within hours to days to a change in synoptic conditions. However, the large heat capacity of the lake creates a strong seasonal cycle of energy storage and release. There is a complex interaction among heat storage, evaporation, and ice cover that is highly dependent on atmospheric conditions in the spring and autumn “shoulder seasons.” Small changes in conditions in November and March caused by synoptic-scale events can have profound impacts on annual evaporation, the extent of ice cover, and the length of the ice-covered period. Early winter air temperatures in November and December dictate the nature of ice formation and much of the winter evaporative flux. Decreased ice cover, by itself, does not necessarily lead to enhanced annual evaporation losses. Rather, a combination of low ice cover and warm spring air temperatures, leading to an early breakup, can significantly lengthen the next evaporation season and cause greater cumulative water loss the subsequent year. The influence of individual synoptic events on annual evaporation is notable enough that the research community should ensure that their role is properly captured in numerical models to provide sound predictions of future Laurentian Great Lakes evaporation regimes.

scholarly journals Moisture sources and synoptic conditions of summer precipitation in the glacial zone of the East Sayan Range

2020 ◽  
Vol 17 ◽  
pp. 1-8
Author(s):  
Eduard Y. Osipov ◽  
Olga P. Osipova
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Summer Precipitation ◽  
Reanalysis Data ◽  
High Mountain ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Precipitation Record ◽  
Macro Scale ◽  
Synoptic Conditions

Abstract. Precipitation in high-mountain regions is characterized by a strong heterogeneity due to complex interaction between atmospheric circulation and steep topography, however, extremely rare network of high elevation stations hampers the adequate high resolution regional climate modeling. In this study we present new data of precipitation directly measured in high-mountain catchment, on the continental glacier (East Sayan Range, south of East Siberia) during the summer periods of 2015–2017 using automatic weather station. The precipitation record was compared with near located weather stations and ERA Interim and NCEP/NCAR reanalysis data. Precipitation mode similar to the glacier site was found at the stations located west and northwest, while ERA Interim and NCEP/NCAR reanalysis data underestimated the precipitation by 40 % and 70 %, respectively. Atmospheric circulation patterns in days with precipitation were analyzed by using mean sea level pressure, geopotential height at 700 and 500 hPa and classification of macro scale atmospheric processes of the Northern Hemisphere by Dzerdzeevskii. Summer precipitation was mostly associated with meridional southern group of large scale circulation the Northern Hemisphere, while at synoptic scale it basically fell in cyclonic (49 % of precipitation) and low-gradient cyclonic (30 %) baric fields. Six typical atmospheric circulation patterns over the East Sayan were identified for days with precipitation. The sources and atmospheric moisture transfer to the glacier was defined by using the HYSPLIT trajectory model. The most of summer precipitation (70 %) was related with western cyclones, while about 25 % of rainfalls (mainly of moderate to strong intensity) was originated from the south-east (Pacific monsoon influence).

scholarly journals Ideas and perspectives: Heat stress: more than hot air

2016 ◽  
Author(s):  
Hans J. De Boeck ◽  
Helena Van De Velde ◽  
Toon De Groote ◽  
Ivan Nijs
Keyword(s):  
Heat Stress ◽  
Air Temperature ◽  
Heat Waves ◽  
Balance Model ◽  
Plant Responses ◽  
Atmospheric Conditions ◽  
Change Models ◽  
Wind Speeds ◽  
Air Temperatures ◽  
The Impact

Abstract. Climate change models project an important increase in the frequency and intensity of heat waves. In gauging the impact on plant responses, much of the focus has been on air temperatures while a critical analysis of leaf temperatures during heat extremes has not been made. Nevertheless, direct physiological consequences from heat depend primarily on leaf rather than on air temperatures. We discuss how the interplay between various environmental variables and the plants' stomatal response affects leaf temperatures and the potential for heat stress by making use of both an energy balance model and field data. The results demonstrate that this interplay between plants and environment can cause leaf temperatures fluctuations in excess of 10 °C (for narrow leaves) to even 20 °C (for big broad leaves) at the same air temperature. In general, leaves tended to heat up when radiation was high and when stomates were closed, as expected. But perhaps counterintuitively, also high air humidity raised leaf temperatures, while humid conditions are typically regarded as benign with respect to plant survival since they limit water loss. High wind speeds brought the leaf temperature closer to the air temperature, which can imply either cooling or warming (i.e. abating or reinforcing heat stress) depending on other prevailing conditions. The results thus indicate that heat waves characterized by similar extreme air temperatures may pose little danger under some atmospheric conditions, but could be lethal in other cases. The trends illustrated here should give ecologists and agronomists a more informed indication about which circumstances are most conductive for heat stress to occur.

scholarly journals Identification and phenotypic plasticity of Pseudanabaena catenata from the Svalbard archipelago

2017 ◽  
Vol 38 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Zoya Khan ◽  
Wan Maznah Wan Omar ◽  
Faradina Merican Mohd Sidik Merican ◽  
Asmimie Asmawarnie Azizan ◽  
Choon Pin Foong ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Apical Cell ◽  
High Arctic ◽  
Culture Conditions ◽  
Rrna Gene ◽  
Molecular Characterisation ◽  
Liquid Media ◽  
Svalbard Archipelago ◽  
Temperature Regimes ◽  
Cell Dimensions

Abstract A filamentous benthic cyanobacteria, strain USMAC16, was isolated from the High Arctic Svalbard archipelago, Norway, and a combination of morphological, ultrastructural and molecular characterisation (16S rRNA gene sequence) used to identify to species level. Cell dimensions, thylakoid arrangement and apical cell shape are consistent with the Pseudanabaena genus description. The molecular characterisation of P. catenata gave 100% similarity with Pseudanabaena catenata SAG 1464-1, originally reported from Germany. Strain USMAC16 was cultured under a range of temperature and photoperiod conditions, in solid and liquid media, and harvested at exponential phase to examine its phenotypic plasticity. Under different culture conditions, we observed considerable variations in cell dimensions. The longest cell (5.91±0.13 μm) was observed at 15°C under 12:12 light:dark, and the widest cell (3.24±0.06 μm) at 4°C under 12:12 light: dark in liquid media. The study provides baseline data documenting the morphological variation of P. catenata in response to changing temperature regimes.

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