scholarly journals Radiative penetration dominates the thermal regime and energetics of a shallow ice-covered lake in an arid climate

2021 ◽  
Author(s):  
Wenfeng Huang ◽  
Wen Zhao ◽  
Cheng Zhang ◽  
Matti Leppäranta ◽  
Zhijun Li ◽  
...  
Keyword(s):  
Heat Flux ◽  
Water Temperature ◽  
Water Column ◽  
Shallow Lake ◽  
Thermal Structure ◽  
High Water ◽  
Bulk Water ◽  
Transmitted Radiation ◽  
Salt Exclusion ◽  
Ice Water

Abstract. The Central Asia is characterized by cold and arid winter with very little precipitation (snow), strong solar insolation, and dry air. But little is known about the thermal regimes of ice and ice-covered lakes and their response to the distinct meteorology and climate in this region. In a typical large shallow lake, ice/snow processes and under-ice thermodynamics were observed for four winters between 2015 and 2019. Heat budgets at the ice-water interface and within the water column were investigated. Results reveal that persistent bare ice permits 20 %–35 % of incident solar radiation to transmit into the under-ice water, providing background source for under-ice energy flows and causing/maintaining high water temperature (up to 6–8 °C) and high water-to-ice heat flux (annually mean 20–45 W m−2) in mid-winter. Heat balancing indicates that the transmitted radiation and water-to-ice heat flux are the dominators and highly correlated. Both bulk water temperature and its structure respond sensibly to solar transmittance and occasional snow events. Complicated evolution of thermal structure was observed and under-ice convective mixing does not necessarily occur because of the joint governance of strong irradiance, sediment heating and salinity profile. Especially, salt exclusion of freezing changes both the bulk salinity and its structure, which plays a more important role in stability/mixing of the water column in the shallow lake.

scholarly journals Observation and Analysis of Water Temperature in Ice-Covered Shallow Lake: Case Study in Qinghuahu Lake

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3139
Author(s):  
Falong Ding ◽  
Zeyu Mao
Keyword(s):  
Heat Flux ◽  
Thermal Diffusivity ◽  
Water Temperature ◽  
Shallow Lake ◽  
Water Environment ◽  
Thermal Conditions ◽  
Late Winter ◽  
Relative Depth ◽  
Effective Thermal Diffusivity ◽  
Water Ice

Water temperature serves as a key environmental factor of lakes and the most basic parameter for analyzing the thermal conditions of a water body. Based on the observation and analysis of the water temperature of Qinghuahu Lake in the Heilongjiang Province of China, this paper analyzed the variation trend of the heat flux, effective thermal diffusivity of the icebound water, and revealed the temporal and spatial variation law of the water temperature and the transfer law beneath the ice on a shallow lake in a cold region. The results suggested a noticeable difference existing in the distribution of water temperature beneath the ice during different periods of ice coverage. During the third period, the water temperature vertically comprised three discrete layers, each of which remained unchanged in thickness despite the alternation of day and night. Sediment–water heat flux and water–ice heat flux both remained positive values throughout the freezing duration, averaging about 3.8–4.1 W/m2 and 9.8–10.3 W/m2, respectively. The calculated thermal diffusivity in late winter was larger than molecular, and the time-averaged values increased first and then decreased with water depth, reaching a maximum at a relative depth of 0.5. This research is expected to provide a reference for studies on the water environment of icebound shallow lakes or ponds in cold regions.

scholarly journals 13 Years of Storms: An Analysis of the Effects of Storms on Lake Physics on the Atlantic Fringe of Europe

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 318 ◽  
Author(s):  
Mikkel René Andersen ◽  
Elvira de Eyto ◽  
Mary Dillane ◽  
Russell Poole ◽  
Eleanor Jennings
Keyword(s):  
Water Column ◽  
Western Europe ◽  
Thermal Structure ◽  
Winter Storms ◽  
Water Column Stability ◽  
Physical Conditions ◽  
Order Of Magnitude ◽  
Storm Frequency ◽  
Summer Storm ◽  
Lake Physics

While winter storms are generally common in western Europe, the rarer summer storms may result in more pronounced impacts on lake physics. Using long-term, high frequency datasets of weather and lake thermal structure from the west of Ireland (2005 to 2017), we quantified the effects of storms on the physical conditions in a monomictic, deep lake close to the Atlantic Ocean. We analysed a total of 227 storms during the stratified (May to September, n = 51) and non-stratified (November to March, n = 176) periods. In winter, as might be expected, changes were distributed over the entire water column, whereas in summer, when the lake was stratified, storms only impacted the smaller volume above the thermocline. During an average summer (May–September) storm, the lake number dropped by an order of magnitude, the thermocline deepened by an average of 2.8 m, water column stability decreased by an average of 60.4 j m−2 and the epilimnion temperature decreased by a factor of five compared to the average change in winter (0.5 °C vs. 0.1 °C). Projected increases in summer storm frequency will have important implications for lake physics and biological pathways.

scholarly journals Sea-ice habitat minimizes grazing impact and predation risk for larval Antarctic krill

Polar Biology ◽  
2021 ◽  
Author(s):  
Carmen L. David ◽  
Fokje L. Schaafsma ◽  
Jan A. van Franeker ◽  
Evgeny A. Pakhomov ◽  
Brian P. V. Hunt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Predation Risk ◽  
Water Column ◽  
Antarctic Krill ◽  
Standing Stock ◽  
Euphausia Superba ◽  
Grazing Impact ◽  
Water Interface ◽  
Winter Habitat ◽  
Ice Water

AbstractSurvival of larval Antarctic krill (Euphausia superba) during winter is largely dependent upon the presence of sea ice as it provides an important source of food and shelter. We hypothesized that sea ice provides additional benefits because it hosts fewer competitors and provides reduced predation risk for krill larvae than the water column. To test our hypothesis, zooplankton were sampled in the Weddell-Scotia Confluence Zone at the ice-water interface (0–2 m) and in the water column (0–500 m) during August–October 2013. Grazing by mesozooplankton, expressed as a percentage of the phytoplankton standing stock, was higher in the water column (1.97 ± 1.84%) than at the ice-water interface (0.08 ± 0.09%), due to a high abundance of pelagic copepods. Predation risk by carnivorous macrozooplankton, expressed as a percentage of the mesozooplankton standing stock, was significantly lower at the ice-water interface (0.83 ± 0.57%; main predators amphipods, siphonophores and ctenophores) than in the water column (4.72 ± 5.85%; main predators chaetognaths and medusae). These results emphasize the important role of sea ice as a suitable winter habitat for larval krill with fewer competitors and lower predation risk. These benefits should be taken into account when considering the response of Antarctic krill to projected declines in sea ice. Whether reduced sea-ice algal production may be compensated for by increased water column production remains unclear, but the shelter provided by sea ice would be significantly reduced or disappear, thus increasing the predation risk on krill larvae.

scholarly journals Effects of Temperature and Salinity on Vibrio vulnificus Population Dynamics as Assessed by Quantitative PCR

2004 ◽  
Vol 70 (9) ◽  
pp. 5469-5476 ◽  
Author(s):  
Mark A. Randa ◽  
Martin F. Polz ◽  
Eelin Lim
Keyword(s):  
Population Dynamics ◽  
Water Temperature ◽  
Water Column ◽  
Quantitative Pcr ◽  
Vibrio Vulnificus ◽  
Most Probable Number ◽  
Salinity Regime ◽  
Optimal Salinity ◽  
Probable Number ◽  
Barnegat Bay

ABSTRACT The abundance of Vibrio vulnificus in coastal environments has been linked to water temperature, while its relationship to salinity is less clear. We have developed a culture-independent, most-probable-number quantitative PCR approach to examine V. vulnificus population dynamics in Barnegat Bay, N.J. Based on the combined analysis of our results from Barnegat Bay and from the literature, the present data show that (i) V. vulnificus population dynamics are strongly correlated to water temperature and (ii) although the general trend is for V. vulnificus abundance to be inversely correlated with salinity, this relationship depends on salinity levels. Irrespective of temperature, high abundances of V. vulnificus are observed at 5 to 10 ppt, which thus appears to be the optimal salinity regime for their survival. At 20 to 25 ppt, V. vulnificus abundances show a positive correlation to salinity. Unsuccessful attempts to resuscitate V. vulnificus, combined with our inability to detect cells during the winter despite an assay adapted to detect viable but nonculturable (VBNC) cells, suggest that the decline and eventual disappearance of V. vulnificus from the water column during the winter months is due primarily to a significant reduction in population size and is not only the consequence of cells entering the VBNC state. These findings are in line with the hypothesis that the sediment serves as a refuge for a subpopulation of V. vulnificus over the winter and weather-driven mixing events during the spring initiate a summer bloom in the water column.

scholarly journals Baseline biogeochemical data from Australia's continental margin links seabed sediments to water column characteristics

2017 ◽  
Vol 68 (9) ◽  
pp. 1593 ◽  
Author(s):  
Lynda Radke ◽  
Tony Nicholas ◽  
Peter A. Thompson ◽  
Jin Li ◽  
Eric Raes ◽  
...  
Keyword(s):  
Water Column ◽  
Oxygen Demand ◽  
High Water ◽  
Sediment Oxygen Demand ◽  
Continental Margins ◽  
Global Standards ◽  
Moderate Resolution ◽  
Timor Sea ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Surficial marine sediments are an important source of nutrients for productivity and biodiversity, yet the biogeochemistry of these sediments is poorly known in Australia. Seabed samples were collected at >350 locations in Australia’s western, northern and eastern continental margins during Federal Government surveys (2007–14). Parameters analysed included measures of organic matter (OM) source (δ13C, δ15N and C:N ratios), concentration (percentage total organic carbon,%TOC, and surface area-normalised TOC, OC:SA) and bioavailability (chlorin indices, total reactive chlorins, total oxygen uptake, total sediment metabolism (TSM), sediment oxygen demand (SOD) and SOD and TSM normalised against TOC). The aim of the present study was to summarise these biogeochemical ‘baseline’ data and make contextualised inferences about processes that govern the observed concentrations. The OM was primarily from marine sources and the OC:SA broadly reflected water column productivity (based on Moderate Resolution Imaging Spectroradiometer, MODIS). Approximately 40% of sediments were organic poor by global standards, reflecting seawater oligotrophy; ~12% were organic rich due to benthic production, high water column productivity and pockmark formation. OM freshness varied due to pigment degradation in water columns and dilution with refractory OM in reworked sediments. δ15N values confirmed the importance of N2 fixation to Timor Sea productivity, and point to recycling of fixed nitrogen within food chains in Western Australia.

Water temperature and heat flux at the base of river ice covers

1987 ◽  
Vol 14 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Philip Marsh ◽  
Terry D Prowse
Keyword(s):  
Heat Flux ◽  
Water Temperature ◽  
River Ice

scholarly journals The thermal structure of Israel

2011 ◽  
Vol 3 (1) ◽  
pp. 431-452 ◽  
Author(s):  
E. Shalev ◽  
V. Lyakhovsky ◽  
Y. Weinstein ◽  
Z. Ben-Avraham
Keyword(s):  
Heat Flux ◽  
Thermal Structure ◽  
Local Heating ◽  
Arabian Shield ◽  
Supporting Evidence ◽  
Hydrologic Models ◽  
Average Value ◽  
Water Wells ◽  
Shear Heating ◽  
Deep Seismicity

Abstract. Heat flux at the Arabian Shield is a significant component in reconstructing tectonic, seismic, and hydrologic models. In this paper we analyze temperature data from all the available oil and water wells in Israel. We show that the average heat flux in Israel is 40–45 mW m−2. A supporting evidence for the low heat flux is the relatively deep seismicity, extending almost to the mantle in the region. A Heat flux anomaly that exists in Northern Israel and Jordan could be attributed to groundwater flow or young magmatic activity (~100 000 years) that is common in this area. Xenoliths that yield relatively steep geothermal gradients could be the result of local heating by magmas or by lithospheric necking and shear heating. The higher Heat flux in Southern Israel and Jordan probably reflects the opening of the Red Sea and the Gulf of Eilat and does not reflect the average value of the Arabian Shield.

Flow, thermal structure, and subglacial conditions of a surge-type glacier

1984 ◽  
Vol 21 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Garry K. C. Clarke ◽  
Sam G. Collins ◽  
David E. Thompson
Keyword(s):  
Energy Source ◽  
Heat Flux ◽  
Thermal Structure ◽  
Drainage System ◽  
Temperature Measurements ◽  
Bottom Temperature ◽  
Water Percolation ◽  
Geothermal Flux

Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area the glacier is cold based, but bottom temperature has increased as much as 0.5 °C between 1981 and 1982, and the basal heat flux is roughly 10 times the expected geothermal flux. Water percolation through permeable subglacial material is the probable energy source. Deformation of the substrate could destroy this drainage system and trigger a surge.

Effect of Water Temperature on Spray Cooling Heat Transfer on Hot Steel Plate

2010 ◽  
Author(s):  
Jungho Lee ◽  
Cheong-Hwan Yu ◽  
Sang-Jin Park
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Water Temperature ◽  
Steel Plate ◽  
Cooling Water ◽  
Local Heat ◽  
Spray Cooling ◽  
Transfer Coefficients ◽  
Cooling Water Temperature ◽  
Local Heat Flux

Water spray cooling is an important technology which has been used in a variety of engineering applications for cooling of materials from high-temperature nominally up to 900°C, especially in steelmaking processes and heat treatment in hot metals. The effects of cooling water temperature on spray cooling are significant for hot steel plate cooling applications. The local heat flux measurements are introduced by a novel experimental technique in which test block assemblies with cartridge heaters and thermocouples are used to measure the heat flux distribution on the surface of hot steel plate as a function of heat flux gauge. The spray is produced from a fullcone nozzle and experiments are performed at fixed water impact density of G and fixed nozzle-to-target spacing. The results show that effects of water temperature on forced boiling heat transfer characteristics are presented for five different water temperatures between 5 to 45°C. The local heat flux curves and heat transfer coefficients are also provided to a benchmark data for the actual spray cooling of hot steel plate cooling applications.

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