scholarly journals On Warm and Moist Air Intrusions into Winter Arctic

2021 ◽  
Author(s):  
Cheng You ◽  
Michael Tjernström ◽  
Abhay Devasthale
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
Barents Sea ◽  
Turbulent Flux ◽  
Turbulent Fluxes ◽  
Surface Energy Budget ◽  
Moist Air ◽  
Total Surface Energy ◽  
The Barents Sea

Abstract. In this study, warm and moist air intrusions (WaMAI) over the Arctic Ocean sectors of Barents, Kara, Laptev, East Siberian, Chukchi and Beaufort Seas in recent 40 winters (from 1979 to 2018) are identified from ERA5 reanalysis using both Eulerian and Lagrangian views. The analysis shows that WaMAIs, fuelled by Arctic blockings, causes a relative surface warming and hence a sea ice reduction by exerting positive anomalies of net thermal irradiances and turbulent fluxes to the surface. Over Arctic Ocean sectors with land-locked sea ice in winter, such as Laptev, East Siberian, Chukchi and Beaufort Seas, total surface energy budget is dominated by net thermal irradiance. From a Lagrangian perspective, total water path (TWP) increases linearly with the downstream distance from the sea ice edge over the completely ice-covered sectors, inducing almost linearly increasing net thermal irradiance and total surface energy-budget. However, over the Barents Sea, with an open ocean to the south, total net surface energy-budget is dominated by the surface turbulent flux. With the energy in the warm-and-moist air continuously transported to the surface, net surface turbulent flux gradually decreases with distance, especially within the first 2 degrees north of the ice edge, inducing a decreasing but still positive total surface energy budget. The boundary-layer energy-budget patterns over the Barents Sea can be categorized into three classes: radiation-dominated, turbulence-dominated and turbulence-dominated with cold dome, comprising about 52 %, 40 % and 8 % of all WaMAIs, respectively. Statistically, turbulence-dominated cases with or without cold dome occur along with one order of magnitude larger large-scale subsidence than the radiation-dominated cases. For the turbulence-dominated category, larger turbulent fluxes are exerted to the surface, probably because of stronger wind shear. In radiation-dominated WaMAIs, stratocumulus develops more strongly and triggers intensive cloud-top radiative cooling and related buoyant mixing that extends from cloud top to the surface, inducing a thicker well-mixed layer under the cloud. With the existence of cold dome, fewer liquid water clouds were formed and less or even negative turbulent fluxes could reach the surface.

scholarly journals Atmospheric components of the surface energy budget over young sea ice: Results from the N-ICE2015 campaign

2017 ◽  
Vol 122 (16) ◽  
pp. 8427-8446 ◽  
Author(s):  
Von P. Walden ◽  
Stephen R. Hudson ◽  
Lana Cohen ◽  
Sarah Y. Murphy ◽  
Mats A. Granskog
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
Surface Energy Budget

scholarly journals On the surface energy budget of sea ice

1997 ◽  
Vol 43 (143) ◽  
pp. 122-130 ◽  
Author(s):  
Gerd Wendler ◽  
Ute Adolphs ◽  
Adrian Hauser ◽  
Blake Moore
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
High Surface ◽  
Open Water ◽  
Ice Cover ◽  
Surface Energy Budget ◽  
Net Radiation ◽  
Pack Ice ◽  
Ice Concentration

AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were: The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo. The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.

scholarly journals On the surface energy budget of sea ice

1997 ◽  
Vol 43 (143) ◽  
pp. 122-130 ◽  
Author(s):  
Gerd Wendler ◽  
Ute Adolphs ◽  
Adrian Hauser ◽  
Blake Moore
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
High Surface ◽  
Open Water ◽  
Ice Cover ◽  
Surface Energy Budget ◽  
Net Radiation ◽  
Pack Ice ◽  
Ice Concentration

AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were:The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo.The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.

scholarly journals Arctic Summer Airmass Transformation, Surface Inversions, and the Surface Energy Budget

2019 ◽  
Vol 32 (3) ◽  
pp. 769-789 ◽  
Author(s):  
Michael Tjernström ◽  
Matthew D. Shupe ◽  
Ian M. Brooks ◽  
Peggy Achtert ◽  
John Prytherch ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
Longwave Radiation ◽  
Temperature Inversion ◽  
Surface Energy Budget ◽  
Surface Heating ◽  
The Arctic ◽  
Turbulent Heat

During the Arctic Clouds in Summer Experiment (ACSE) in summer 2014 a weeklong period of warm-air advection over melting sea ice, with the formation of a strong surface temperature inversion and dense fog, was observed. Based on an analysis of the surface energy budget, we formulated the hypothesis that, because of the airmass transformation, additional surface heating occurs during warm-air intrusions in a zone near the ice edge. To test this hypothesis, we explore all cases with surface inversions occurring during ACSE and then characterize the inversions in detail. We find that they always occur with advection from the south and are associated with subsidence. Analyzing only inversion cases over sea ice, we find two categories: one with increasing moisture in the inversion and one with constant or decreasing moisture with height. During surface inversions with increasing moisture with height, an extra 10–25 W m−2 of surface heating was observed, compared to cases without surface inversions; the surface turbulent heat flux was the largest single term. Cases with less moisture in the inversion were often cloud free and the extra solar radiation plus the turbulent surface heat flux caused by the inversion was roughly balanced by the loss of net longwave radiation.

scholarly journals Influence of Subfacet Heterogeneity and Material Properties on the Urban Surface Energy Budget

2014 ◽  
Vol 53 (9) ◽  
pp. 2114-2129 ◽  
Author(s):  
Prathap Ramamurthy ◽  
Elie Bou-Zeid ◽  
James A. Smith ◽  
Zhihua Wang ◽  
Mary L. Baeck ◽  
...  
Keyword(s):  
Surface Energy ◽  
Energy Budget ◽  
Material Properties ◽  
Sensible Heat Flux ◽  
Role Reversal ◽  
Surface Energy Budget ◽  
Urban Surface ◽  
Urban Site ◽  
Peak Time ◽  
Sensible Heat

AbstractUrban facets—the walls, roofs, and ground in built-up terrain—are often conceptualized as homogeneous surfaces, despite the obvious variability in the composition and material properties of the urban fabric at the subfacet scale. This study focuses on understanding the influence of this subfacet heterogeneity, and the associated influence of different material properties, on the urban surface energy budget. The Princeton Urban Canopy Model, which was developed with the ability to capture subfacet variability, is evaluated at sites of various building densities and then applied to simulate the energy exchanges of each subfacet with the atmosphere over a densely built site. The analyses show that, although all impervious built surfaces convert most of the incoming energy into sensible heat rather than latent heat, sensible heat fluxes from asphalt pavements and dark rooftops are 2 times as high as those from concrete surfaces and light-colored roofs. Another important characteristic of urban areas—the shift in the peak time of sensible heat flux in comparison with rural areas—is here shown to be mainly linked to concrete’s high heat storage capacity as well as to radiative trapping in the urban canyon. The results also illustrate that the vegetated pervious soil surfaces that dot the urban landscape play a dual role: during wet periods they redistribute much of the available energy into evaporative fluxes but when moisture stressed they behave more like an impervious surface. This role reversal, along with the direct evaporation of water stored over impervious surfaces, significantly reduces the overall Bowen ratio of the urban site after rain events.

scholarly journals Measuring the impact of a new snow model using surface energy budget process relationships

2020 ◽  
Author(s):  
Jonathan Day ◽  
Gabriele Arduini ◽  
Irina Sandu ◽  
Linus Magnusson ◽  
Anton Beljaars ◽  
...  
Keyword(s):  
Surface Energy ◽  
Energy Budget ◽  
Surface Energy Budget ◽  
Budget Process ◽  
Snow Model ◽  
The Impact

Arctic Freshwater in CMIP6: Declining Sea Ice, Increasing Ocean Storage and Export

2021 ◽  
Author(s):  
Hannah Zanowski ◽  
Alexandra Jahn ◽  
Marika Holland
Keyword(s):  
Sea Ice ◽  
21St Century ◽  
Barents Sea ◽  
The Arctic ◽  
Historical Period ◽  
Freshwater Flux ◽  
Bering Strait ◽  
The Barents Sea ◽  
Late 21St Century ◽  
Freshwater Export

<p>Recently, the Arctic has undergone substantial changes in sea ice cover and the hydrologic cycle, both of which strongly impact the freshwater storage in, and export from, the Arctic Ocean. Here we analyze Arctic freshwater storage and fluxes in 7 climate models from the Coupled Model Intercomparison Project phase 6 (CMIP6) and assess their agreement over the historical period (1980-2000) and in two future emissions scenarios, SSP1-2.6 and SSP5-8.5. In the historical simulation, few models agree closely with observations over 1980-2000. In both future scenarios the models show an increase in liquid (ocean) freshwater storage in conjunction with a reduction in solid storage and fluxes through the major Arctic gateways (Bering Strait, Fram Strait, Davis Strait, and the Barents Sea Opening) that is typically larger for SSP5-8.5 than SSP1-2.6. The liquid fluxes through the gateways exhibit a more complex pattern, with models exhibiting a change in sign of the freshwater flux through the Barents Sea Opening and little change in the flux through the Bering Strait in addition to increased export from the remaining straits by the end of the 21st century. A decomposition of the liquid fluxes into their salinity and volume contributions shows that the Barents Sea flux changes are driven by salinity changes, while the Bering Strait flux changes are driven by compensating salinity and volume changes. In the straits west of Greenland (Nares, Barrow, and Davis straits), the models disagree on whether there will be a decrease, increase, or steady liquid freshwater export in the early to mid 21st century, although they mostly show increased liquid freshwater export in the late 21st century. The underlying cause of this is a difference in the magnitude and timing of a simulated decrease in the volume flux through these straits. Although the models broadly agree on the sign of late 21st century storage and flux changes, substantial differences exist between the magnitude of these changes and the models’ Arctic mean states, which shows no fundamental improvement in the models compared to CMIP5.</p>

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