Jens K Ehn
Biographic Data
| ID | 5593032 |
|---|---|
| NAME | Jens K Ehn |
| GIVEN NAMES | Jens K |
| FAMILY NAME | Ehn |
| SIGNATURE | EHN J K |
| AFFILIATIONS | University of Manitoba |
| ORCID | 0000-0002-8885-7441 |
| VERIFIED | Yes |
| TOTAL WORKS | 13 |
| TOTAL CITATIONS | 0 |
| AUTHOR COUNT | 13 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2018 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 0 |
Assessment of warm bias in ERA5 surface skin temperature over Arctic landfast sea ice
ERA5 is one of the most widely used gridded reanalysis datasets; however, its 0.25° spatial resolution may not be sufficient to resolve the narrow band of landfast sea ice near coastlines, possibly leading to the misrepresentation of the thermodynamic forcing of sea ice growth and melt. In this study, the performance of ERA5 surface skin temperature (SKTERA5) over landfast sea ice was assessed through comparison with in situ observations of surfa…
Influence of altered freshwater discharge on the seasonality of nutrient distributions near La Grande River, northeastern James Bay, Québec
In subarctic marine environments, nutrient stocks are replenished through physical and biogeochemical processes in winter, largely setting an upper limit on new primary production for the next growing season. In spring, marine nutrient stocks are modified by freshwater-associated additions, especially in coastal areas. Hydroelectric development of the La Grande River (LGR) in northern Québec has shifted the timing of peak freshwater discharge fro…
An overview of the Nemo modelling for the BaySys project
This article is intended as an introduction to discuss the development of a modelling framework to examine simulated climate change and river discharge regulation and their combined impact on marine conditions in the Hudson Bay Complex as a contribution to BaySys, a collaborative project between Manitoba Hydro, Hydro-Quebec, the University of Manitoba, the University of Alberta, Université Laval and Ouranos. In support of this work, a sea ice and…
Plume dispersion from the Nelson and Hayes rivers into Hudson Bay using satellite remote sensing of CDOM and suspended sediment
Change in the dispersion pattern of Arctic river plumes due to climate change and hydroelectric regulation is challenging to monitor, calling for synoptic and continuous observation using satellite remote sensing. Algorithms for colored dissolved organic matter (CDOM) and total suspended solids (TSS) were applied to moderate resolution imaging spectroradiometer (MODIS) imagery to study Nelson and Hayes river plume dispersion into southwestern Hud…
Landfast sea ice in Hudson Bay and James Bay
Through analysis of Canadian Ice Service ice charts, we have characterized the temporal and spatial variability of landfast sea ice (or fast ice) surrounding Hudson Bay and James Bay from 2000 to 2019. Over this 19-year period, we observed contrasting changes in fast-ice persistence between the western and eastern sides of Hudson Bay and James Bay. Fast ice in western Hudson Bay and James Bay trended towards later freeze-up and earlier break-up t…
On the Intermittent Formation of an Ice Bridge (Nunniq) across Roes Welcome Sound, Northwestern Hudson Bay, and Its Use to Local Inuit Hunters
Ice bridges are unique features that form when sea ice consolidates and remains immobilized within channels. They form in many locations throughout the Arctic and are typically noted for the polynyas that form on their lee side. However, ice bridges also provide a temporary platform that may be used by both humans and wildlife to cross otherwise impassable channels. For generations, Inuit in Coral Harbour, Nunavut, have used an ice bridge to cros…
The ice factory of Hudson Bay
Within the dynamic seasonal ice cover of Hudson Bay, the Kivalliq Polynya is a large latent heat polynya that forms throughout winter in the northwest as a result of strong northwesterly offshore surface winds. Polynyas are known to be physically, biologically, and geochemically important and contribute to the regional ice mass balance; however, the Kivalliq Polynya has yet to be characterized in terms of spatiotemporal variability and ice produc…
Environmental drivers of spring primary production in Hudson Bay
Pertinent environmental factors influencing the microalgal bloom during sea-ice breakup in Hudson Bay were investigated in June 2018, producing the first observations of late spring primary production in the offshore waters of this vast inland sea. Phytoplankton production was found to commence at the onset of ice melt, with surface nutrient depletion leading to the formation of a subsurface chlorophyll maximum in the open waters of western Hudso…
Sediment-laden sea ice in southern Hudson Bay
During a research expedition in Hudson Bay in June 2018, vast areas of thick (>10 m), deformed sediment-laden sea ice were encountered unexpectedly in southern Hudson Bay and presented difficult navigation conditions for the Canadian Coast Guard Ship Amundsen. An aerial survey of one of these floes revealed a maximum ridge height of 4.6 m and an average freeboard of 2.2 m, which corresponds to an estimated total thickness of 18 m, far greater tha…
Atmospheric vorticity sets the basin-scale circulation in Hudson Bay
Hudson Bay of northern Canada receives upward of 700 km3 of river discharge annually. Cyclonic water circulation in Hudson Bay transports this massive volume of riverine water along the coast toward Hudson Strait and into the Labrador Sea. However, synoptic, seasonal and interannual variability of the freshwater transport in Hudson Bay remains unclear. Using yearlong observations of current velocity profiles, collected from oceanographic moorings…
Environmental factors influencing the seasonal dynamics of spring algal blooms in and beneath sea ice in western Baffin Bay
Arctic sea ice is experiencing a shorter growth season and an earlier ice melt onset. The significance of spring microalgal blooms taking place prior to sea ice breakup is the subject of ongoing scientific debate. During the Green Edge project, unique time-series data were collected during two field campaigns held in spring 2015 and 2016, which documented for the first time the concomitant temporal evolution of the sea ice algal and phytoplankton…
Average cosine coefficient and spectral distribution of the light field under sea ice
The Arctic spring phytoplankton bloom has been reported to commence under a melting sea ice cover as transmission of photosynthetically active radiation (PAR; 400–700 nm) suddenly increases with the formation of surface melt ponds. Spatial variability in ice surface characteristics, i.e., snow thickness or melt pond distributions, and subsequent impact on transmitted PAR makes estimating light-limited primary production difficult during this time…
Pan-arctic winter drift speeds and changing patterns of sea ice motion
Monthly mean passive microwave-derived sea-ice motion maps for 36 winters (October–April) are used to examine pan-Arctic sea-ice drift speeds and patterns. The mean Arctic Ocean sea-ice motion consists of three well-known primary circulation regimes: the Beaufort Gyre (BG), transpolar drift (TPD), and a motion system from the Kara Sea (KS). The 36-year mean winter sea-ice drift pattern is used to identify the average boundaries between the circul…
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Pan-arctic winter drift speeds and changing patterns of sea ice motion
Monthly mean passive microwave-derived sea-ice motion maps for 36 winters (October–April) are used to examine pan-Arctic sea-ice drift speeds and patterns. The mean Arctic Ocean sea-ice motion consists of three well-known primary circulation regimes: the Beaufort Gyre (BG), transpolar drift (TPD), and a motion system from the Kara Sea (KS). The 36-year mean winter sea-ice drift pattern is used to identify the average boundaries between the circul…
Environmental factors influencing the seasonal dynamics of spring algal blooms in and beneath sea ice in western Baffin Bay
Arctic sea ice is experiencing a shorter growth season and an earlier ice melt onset. The significance of spring microalgal blooms taking place prior to sea ice breakup is the subject of ongoing scientific debate. During the Green Edge project, unique time-series data were collected during two field campaigns held in spring 2015 and 2016, which documented for the first time the concomitant temporal evolution of the sea ice algal and phytoplankton…
Average cosine coefficient and spectral distribution of the light field under sea ice
The Arctic spring phytoplankton bloom has been reported to commence under a melting sea ice cover as transmission of photosynthetically active radiation (PAR; 400–700 nm) suddenly increases with the formation of surface melt ponds. Spatial variability in ice surface characteristics, i.e., snow thickness or melt pond distributions, and subsequent impact on transmitted PAR makes estimating light-limited primary production difficult during this time…
Atmospheric vorticity sets the basin-scale circulation in Hudson Bay
Hudson Bay of northern Canada receives upward of 700 km3 of river discharge annually. Cyclonic water circulation in Hudson Bay transports this massive volume of riverine water along the coast toward Hudson Strait and into the Labrador Sea. However, synoptic, seasonal and interannual variability of the freshwater transport in Hudson Bay remains unclear. Using yearlong observations of current velocity profiles, collected from oceanographic moorings…
The ice factory of Hudson Bay
Within the dynamic seasonal ice cover of Hudson Bay, the Kivalliq Polynya is a large latent heat polynya that forms throughout winter in the northwest as a result of strong northwesterly offshore surface winds. Polynyas are known to be physically, biologically, and geochemically important and contribute to the regional ice mass balance; however, the Kivalliq Polynya has yet to be characterized in terms of spatiotemporal variability and ice produc…
Environmental drivers of spring primary production in Hudson Bay
Pertinent environmental factors influencing the microalgal bloom during sea-ice breakup in Hudson Bay were investigated in June 2018, producing the first observations of late spring primary production in the offshore waters of this vast inland sea. Phytoplankton production was found to commence at the onset of ice melt, with surface nutrient depletion leading to the formation of a subsurface chlorophyll maximum in the open waters of western Hudso…
Sediment-laden sea ice in southern Hudson Bay
During a research expedition in Hudson Bay in June 2018, vast areas of thick (>10 m), deformed sediment-laden sea ice were encountered unexpectedly in southern Hudson Bay and presented difficult navigation conditions for the Canadian Coast Guard Ship Amundsen. An aerial survey of one of these floes revealed a maximum ridge height of 4.6 m and an average freeboard of 2.2 m, which corresponds to an estimated total thickness of 18 m, far greater tha…
Landfast sea ice in Hudson Bay and James Bay
Through analysis of Canadian Ice Service ice charts, we have characterized the temporal and spatial variability of landfast sea ice (or fast ice) surrounding Hudson Bay and James Bay from 2000 to 2019. Over this 19-year period, we observed contrasting changes in fast-ice persistence between the western and eastern sides of Hudson Bay and James Bay. Fast ice in western Hudson Bay and James Bay trended towards later freeze-up and earlier break-up t…
On the Intermittent Formation of an Ice Bridge (Nunniq) across Roes Welcome Sound, Northwestern Hudson Bay, and Its Use to Local Inuit Hunters
Ice bridges are unique features that form when sea ice consolidates and remains immobilized within channels. They form in many locations throughout the Arctic and are typically noted for the polynyas that form on their lee side. However, ice bridges also provide a temporary platform that may be used by both humans and wildlife to cross otherwise impassable channels. For generations, Inuit in Coral Harbour, Nunavut, have used an ice bridge to cros…
Plume dispersion from the Nelson and Hayes rivers into Hudson Bay using satellite remote sensing of CDOM and suspended sediment
Change in the dispersion pattern of Arctic river plumes due to climate change and hydroelectric regulation is challenging to monitor, calling for synoptic and continuous observation using satellite remote sensing. Algorithms for colored dissolved organic matter (CDOM) and total suspended solids (TSS) were applied to moderate resolution imaging spectroradiometer (MODIS) imagery to study Nelson and Hayes river plume dispersion into southwestern Hud…
Influence of altered freshwater discharge on the seasonality of nutrient distributions near La Grande River, northeastern James Bay, Québec
In subarctic marine environments, nutrient stocks are replenished through physical and biogeochemical processes in winter, largely setting an upper limit on new primary production for the next growing season. In spring, marine nutrient stocks are modified by freshwater-associated additions, especially in coastal areas. Hydroelectric development of the La Grande River (LGR) in northern Québec has shifted the timing of peak freshwater discharge fro…
An overview of the Nemo modelling for the BaySys project
This article is intended as an introduction to discuss the development of a modelling framework to examine simulated climate change and river discharge regulation and their combined impact on marine conditions in the Hudson Bay Complex as a contribution to BaySys, a collaborative project between Manitoba Hydro, Hydro-Quebec, the University of Manitoba, the University of Alberta, Université Laval and Ouranos. In support of this work, a sea ice and…
Assessment of warm bias in ERA5 surface skin temperature over Arctic landfast sea ice
ERA5 is one of the most widely used gridded reanalysis datasets; however, its 0.25° spatial resolution may not be sufficient to resolve the narrow band of landfast sea ice near coastlines, possibly leading to the misrepresentation of the thermodynamic forcing of sea ice growth and melt. In this study, the performance of ERA5 surface skin temperature (SKTERA5) over landfast sea ice was assessed through comparison with in situ observations of surfa…
Arctic and Antarctic ice dynamics (12 works) · Geology (12 works) · Oceanography (12 works) · Bay (10 works) · Environmental Science (9 works) · Sea ice (9 works) · Climatology (7 works) · Climate change and permafrost (6 works) · Arctic (5 works) · Arctic ice pack (5 works)