scholarly journals Dynamic Europa ocean shows transient Taylor columns and convection driven by ice melting and salinity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yosef Ashkenazy ◽  
Eli Tziperman
Keyword(s):  
Ocean Dynamics ◽  
Ice Thickness ◽  
Ice Melting ◽  
Extraterrestrial Life ◽  
Critical Elements ◽  
Zonal Jets ◽  
Axis Of Rotation ◽  
Ocean Salinity ◽  
Bottom Heating ◽  
Weak Stratification

AbstractThe deep (~100 km) ocean of Europa, Jupiter’s moon, covered by a thick icy shell, is one of the most probable places in the solar system to find extraterrestrial life. Yet, its ocean dynamics and its interaction with the ice cover have received little attention. Previous studies suggested that Europa’s ocean is turbulent using a global model and taking into account non-hydrostatic effects and the full Coriolis force. Here we add critical elements, including consistent top and bottom heating boundary conditions and the effects of icy shell melting and freezing on ocean salinity. We find weak stratification that is dominated by salinity variations. The ocean exhibits strong transient convection, eddies, and zonal jets. Transient motions organize in Taylor columns parallel to Europa’s axis of rotation, are static inside of the tangent cylinder and propagate equatorward outside the cylinder. The meridional oceanic heat transport is intense enough to result in a nearly uniform ice thickness, that is expected to be observable in future missions.

Europa's dynamic ocean: Taylor columns, eddies, convection, ice melting and salinity

2020 ◽  
Author(s):  
Yosef Ashkenazy ◽  
Eli Tziperman
Keyword(s):  
Boundary Conditions ◽  
Deep Ocean ◽  
Equatorial Region ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
Ocean Bottom ◽  
Extraterrestrial Life ◽  
Zonal Jets ◽  
Ocean Salinity ◽  
Bottom Heating

<p class="p1">The deep ocean (~100 km) of Europa, Jupiter’s moon, is covered by a thick (tens of km) icy shell, and is one of the most probable places in the solar sys- tem to find extraterrestrial life. Yet, its ocean dynamics and its interaction with the ice cover have so far received little attention. Previous studies sug- gested that Europa’s ocean is turbulent, yet neglected to take into account the effects of ocean salinity and appropriate boundary conditions for the ocean’s temperature. Here, the ocean dynamics of Europa is studied using global ocean models that include non-hydrostatic effects, a full Coriolis force, con- sistent top and bottom heating boundary conditions, and including the effects of melting and freezing of ice on salinity. The density is found to be dominated by salinity effects and the ocean is very weakly stratified. The ocean exhibits strong transient vertical convection, eddies, low latitude zonal jets and Tay- lor columns parallel to Europa’s axis of rotation. In the equatorial region, the Taylor columns do not intersect the ocean bottom and propagate equatorward, while off the equator, the Taylor columns are static. The meridional oceanic heat transport is intense enough to result in a nearly uniform ice thickness, that is expected to be observable in future missions.</p>

scholarly journals A STUDY INTO ICE BUILD-UP AND MELTING ON VERTICAL COOLED PIPES

2016 ◽  
Vol 52 (3) ◽  
Author(s):  
Y. Zasiadko ◽  
O. Pylypenko ◽  
A. Forsiuk ◽  
R. Gryshchenko
Keyword(s):  
Thermal Energy ◽  
Experimental Unit ◽  
Ice Thickness ◽  
Ice Melting ◽  
Empirical Correlations ◽  
Time Intervals ◽  
Ice Accumulation ◽  
Time Periods ◽  
Semi Empirical

The use of cold accumulators based on the principle of ice build up on the cooled surfaces during off-peak periods and ice melting during on-peak periods is an effective method of electricity bills reduction. Within comparatively short periods of on-peak demand a noticeable amount of thermal energy related to ice melting is to be released, it becomes clear that not only sizing of ice accumulators based on balance calculations is actual, but also the determination of time periods of ice accumulation becomes critical. This work presents experimental unit for obtaining data on the ice build-up on the vertical cooled pipes and later on to continuously register data on the ice thickness diminishing at the regimes of ice melting when cooling of pipe stops. The data for ice build-up and melting for some regimes have been presented and analyzed. The data form the base for deriving semi-empirical correlations allowing to determine a time intervals necessary to generate of ice layers of a given thickness.

scholarly journals How does salinity shape ocean circulation and ice geometry on Enceladus and other icy satellites?

2021 ◽  
Author(s):  
Wanying Kang ◽  
Tushar Mittal ◽  
Suyash Bire ◽  
Jean Michel ◽  
John Marshall
Keyword(s):  
Ocean Circulation ◽  
Freezing Point ◽  
Ocean Dynamics ◽  
Icy Satellites ◽  
Heating Rates ◽  
Ocean Salinity ◽  
Thickness Variations ◽  
Tidal Heating ◽  
Ice Shell ◽  
Shell Geometry

Abstract Of profound astrobiological interest is that not only does Enceladus have a water ocean, but it also appears to be salty, important for its likely habitability. Here, we investigate how salinity affects ocean dynamics and equilibrium ice shell geometry and use knowledge of ice shell geometry and tidal heating rates to help constrain ocean salinity. We show that the vertical overturning circulation of the ocean, driven from above by melting and freezing and the temperature dependence of the freezing point of water on pressure, has opposing signs at very low and very high salinities. In both cases, heat and freshwater converges toward the equator, where the ice is thick, acting to homogenise thickness variations. In order to maintain observed ice thickness variations, ocean heat transport should not overwhelm tidal heating rates within the ice, which are small in equatorial regions. This can only happen when the ocean’s salinity has intermediate values, order 20 psu. In this case polar-sinking driven by meridional temperature variations is largely canceled by equatorial-sinking circulation driven by salinity variations and a consistent ocean circulation, ice shell geometry and tidal heating rate can be achieved.

Research and Validation on Melting Ice of Overhead Transmission Line

2014 ◽  
Vol 543-547 ◽  
pp. 653-657
Author(s):  
Ye Zhou Hu ◽  
Shao Feng Yu ◽  
Lin Zhang ◽  
Pai Liu
Keyword(s):  
Transmission Line ◽  
Research Capacity ◽  
Ice Thickness ◽  
Ice Melting ◽  
Technology Research ◽  
Current Generator ◽  
Overhead Lines ◽  
Overhead Transmission Line ◽  
Temperature And Humidity

In order to further grasp the overhead rules of transmission line de-icing, this thesis designed and developed a newly transmission line icing apparatus, which can acquire the needed ice thickness covered upon a certain transmission line in laboratory. Combined with the walk-in temperature and humidity box, the temperature tester, current generator and other equipment, enhance the technology research capacity of overhead lines ice-melting. And the software can simulate the overlying ice temperature and cloud distribution changes with time, verify the line ice-melting rules. The method can be easily extended to other types of wires, and has certain application value.

The relation between the zonal jets and ammonia anomalies in Jupiter

2021 ◽  
Author(s):  
Nimrod Gavriel ◽  
Keren Duer ◽  
Eli Galanti ◽  
Yohai Kaspi ◽  
Keyword(s):  
Wind Profile ◽  
Ammonia Concentration ◽  
Equatorial Region ◽  
Meridional Gradient ◽  
Zonal Jets ◽  
Axis Of Rotation ◽  
Different Depths ◽  
Eddy Fluxes ◽  
Abundance Anomalies ◽  
Latitudinal Variations

<div> <div>Juno's six‐channel MWR measurements might reveal information about the structure of the wind profile below the cloud level. These measurements are used to calculate the nadir brightness temperature (T<sub>b</sub>), a profile determined by temperature and by the opacity of the atmosphere. This opacity for the relevant frequencies of the MWR is determined mostly by ammonia abundance. The T<sub>b</sub> vary considerably between the different channels (indicating on different depths) and between latitudes. Here, we take the <!-- mathfontold --> T<sub>b</sub> as an indicator for ammonia concentration and examine the relation to the zonal jets. We find that different theoretical mechanisms can explain this relation at different latitudes. At the equatorial region, the superrotation is accompanied by vertical upwelling. This vertical advection, driven by a convergence of eddy fluxes directed perpendicular to the axis of rotation, is shown to explain the equatorial ammonia enrichment. At the mid-latitudes, assuming that the ammonia is enriched with depth, alternating Ferrel-like cells framed by opposite vertical velocities redistributes the ammonia, maximizing its meridional gradient where the jet peaks. This hypothesis is well apparent in the data, using both correlation analysis and theoretical arguments. We find that dynamical reasoning, suggesting on vertical velocities through the cloud-level zonal jets, can explain the latitudinal variations in <!-- mathfontold --> T<sub>b,</sub> under the assumption that they are caused by ammonia abundance anomalies.</div> </div>

scholarly journals Estimation of sea ice parameters from sea ice model with assimilated ice concentration and SST

2018 ◽  
Vol 12 (12) ◽  
pp. 3949-3965 ◽  
Author(s):  
Siva Prasad ◽  
Igor Zakharov ◽  
Peter McGuire ◽  
Desmond Power ◽  
Martin Richard
Keyword(s):  
Sea Ice ◽  
Remote Sensing Data ◽  
Labrador Sea ◽  
Ice Thickness ◽  
Ridge Height ◽  
Ocean Salinity ◽  
Ice Concentration ◽  
The Difference ◽  
Interpolation Analysis ◽  
Ice Model

Abstract. A multi-category numerical sea ice model CICE was used along with data assimilation to derive sea ice parameters in the region of Baffin Bay and Labrador Sea. The assimilation of ice concentration was performed using the data derived from the Advanced Microwave Scanning Radiometer (AMSR-E and AMSR2). The model uses a mixed-layer slab ocean parameterization to compute the sea surface temperature (SST) and thereby to compute the freezing and melting potential of ice. The data from Advanced Very High Resolution Radiometer (AVHRR-only optimum interpolation analysis) were used to assimilate SST. The modelled ice parameters including concentration, ice thickness, freeboard and keel depth were compared with parameters estimated from remote-sensing data. The ice thickness estimated from the model was compared with the measurements derived from Soil Moisture Ocean Salinity – Microwave Imaging Radiometer using Aperture Synthesis (SMOS–MIRAS). The model freeboard estimates were compared with the freeboard measurements derived from CryoSat2. The ice concentration, thickness and freeboard estimates from the model assimilated with both ice concentration and SST were found to be within the uncertainty in the observation except during March. The model-estimated draft was compared with the measurements from an upward-looking sonar (ULS) deployed in the Labrador Sea (near Makkovik Bank). The difference between modelled draft and ULS measurements estimated from the model was found to be within 10 cm. The keel depth measurements from the ULS instruments were compared to the estimates from the model to retrieve a relationship between the ridge height and keel depth.

scholarly journals On the retrieval of sea-ice thickness using SMOS polarization differences

2019 ◽  
Vol 65 (251) ◽  
pp. 481-493
Author(s):  
MUKESH GUPTA ◽  
CAROLINA GABARRO ◽  
ANTONIO TURIEL ◽  
MARCOS PORTABELLA ◽  
JUSTINO MARTINEZ
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Concentration ◽  
Sea Ice Thickness ◽  
Operational Application ◽  
Ocean Salinity ◽  
Ice Concentration

ABSTRACTArctic sea ice is going through a dramatic change in its extent and volume at an unprecedented rate. Sea-ice thickness (SIT) is a controlling geophysical variable that needs to be understood with greater accuracy. For the first time, a SIT-retrieval method that exclusively uses only airborne SIT data for training the empirical algorithm to retrieve SIT from Soil Moisture Ocean Salinity (SMOS) brightness temperature (TB) at different polarization is presented. A large amount of airborne SIT data has been used from various field campaigns in the Arctic conducted by different countries during 2011–15. The algorithm attempts to circumvent the issue related to discrimination between TB signatures of thin SIT versus low sea-ice concentration. The computed SIT has a rms error of 0.10 m, which seems reasonably good (as compared to the existing algorithms) for analysis at the used 25 km grid. This new SIT retrieval product is designed for direct operational application in ice prediction/climate models.

scholarly journals Circumpolar Thin Arctic Sea Ice Thickness and Small-Scale Roughness Retrieval Using Soil Moisture and Ocean Salinity and Soil Moisture Active Passive Observations

2019 ◽  
Vol 11 (23) ◽  
pp. 2835
Author(s):  
Suna Jo ◽  
Hyun-Cheol Kim ◽  
Young-Joo Kwon ◽  
Sungwook Hong
Keyword(s):  
Soil Moisture ◽  
Sea Ice ◽  
Microwave Remote Sensing ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Arctic Sea ◽  
Ocean Salinity ◽  
Arctic Sea Ice Thickness

The variations in the Arctic sea ice thickness (SIT) due to climate change have both positive and negative effects on commercial human activities, the ecosystem, and the Earth’s environment. Satellite microwave remote sensing based on microwave reflection signals reflected by the sea ice surface has been playing an essential role in monitoring and analyzing the Arctic SIT and sea ice concentration (SIC) during the past decades. Recently, passive microwave satellites incorporating an L-band radiometer, such as soil moisture and ocean salinity (SMOS) and soil moisture active passive (SMAP), have been used for analyzing sea ice characteristics, in addition to land and ocean research. In this study, we present a novel method to estimate thin SIT and sea ice roughness (SIR) using a conversion relationship between them, from the SMAP and SMOS data. Methodologically, the SMAP SIR is retrieved. The SMAP thin SIT and SMOS SIR are estimated using a conversion relationship between thin SIT data from SMOS data and SMAP-derived SIR, which is obtained from the spatial and temporal collocation of the SMOS thin SIT and the SIR retrieved from SMAP. Our results for the Arctic sea ice during December for four consecutive years from 2015 to 2018, show high accuracy (bias = −2.268 cm, root mean square error (RMSE) = 15.919 cm, and correlation coefficient (CC) = 0.414) between the SMOS-provided thin SIT and SMAP-derived SIT, and good agreement (bias = 0.03 cm, RMSE = 0.228 cm, and CC = 0.496) between the SMOS-estimated SIR and SMAP-retrieved SIR. Consequently, our study could be effectively used for monitoring and analyzing the variation in the Arctic sea ice.

scholarly journals Combined SMAP/SMOS Thin Sea Ice Thickness Retrieval

2017 ◽  
Author(s):  
Cătălin Pațilea ◽  
Georg Heygster ◽  
Marcus Huntemann ◽  
Gunnar Spreen
Keyword(s):  
Soil Moisture ◽  
Sea Ice ◽  
Incidence Angle ◽  
Low Frequency ◽  
Retrieval Algorithm ◽  
Ice Thickness ◽  
Polar Regions ◽  
Sea Ice Thickness ◽  
Brightness Temperatures ◽  
Ocean Salinity

Abstract. The spaceborne passive microwave sensors Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) provide brightness temperature data at L-band (1.4 GHz). At this low frequency the atmosphere is close to transparent and in polar regions the thickness of thin sea ice can be derived. SMOS data covers a large incidence angle range whereas SMAP observes at a fixed 40° incidence angle which makes thin sea ice thickness retrieval more stable as incidence angle effects do not have to be taken into account. Here we transfer a retrieval algorithm for thickness of thin sea ice (up to 50 cm) from SMOS data at 40° to 50° incidence angle to the fixed incidence angle of SMAP. Now the SMOS brightness temperatures (TBs) at a given incidence angle are estimated using empirical fit functions. SMAP TBs are calibrated to SMOS for providing a merged SMOS/SMAP Sea Ice Thickness product.

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