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.

The Effect of Absorbed Solar Radiation on the Thermal Diffusion in Antarctic Fresh-Water Ice and Sea Ice

1967 ◽  
Vol 6 (48) ◽  
pp. 859-878 ◽  
Author(s):  
G. Weller
Keyword(s):  
Heat Flux ◽  
Thermal Diffusivity ◽  
Solar Radiation ◽  
Sea Ice ◽  
Classical Model ◽  
Heat Diffusion ◽  
Water Ice ◽  
Depth Data ◽  
One Year ◽  
Improved Model

Ice temperatures were measured on the ice plateau at Mawson, Antarctica, for one year down to depths of 11 m. and through a floating sea-ice cover for six months. The plateau data were examined by harmonic analysis and the thermal diffusivity of the ice was obtained from the classical model of heat diffusion. An improved model of heat diffusion proposed by Lettau (1954) was also used to derive the diffusivity. The results show that absorbed radiation affects the computed diffusivity values down to 6–8 in. depth and a model is put forward to explain these apparent changes with depth. Data on the extinction of radiation in the ice have been published elsewhere (Weller and Schwerdtfeger, in press). The diffusivity of the ice is determined for periods with no radiation in winter and the value of 0.011 cm2. sec−1agrees well with values at 8 m. depth where the effect of radiation becomes negligible.Heat-flux plates embedded in the ice were used to determine the diffusivity independently and also to give numerical values of the heat flux at any moment. The geometry and characteristics of these flux plates are discussed elsewhere (Schwerdtfeger and Weller, 1967). They are also used to derive the diffusivity of sea ice and enable a detailed analysis of the diurnal heat flux in such complex substances as sea ice to be made.

scholarly journals Resonance Generation of Short Internal Waves by the Barotropic Seiches in an Ice-Covered Shallow Lake

2020 ◽  
Vol 27 (4) ◽  
Author(s):  
S. Yu. Volkov ◽  
S. R. Bogdanov ◽  
R. E. Zdorovennov ◽  
N. I. Palshin ◽  
G. E. Zdorovennova ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Internal Waves ◽  
Shallow Lake ◽  
Molecular Diffusion ◽  
Bottom Topography ◽  
Internal Tides ◽  
Buoyancy Frequency ◽  
Effective Thermal Diffusivity ◽  
Transfer Processes ◽  
Temperature Pulsations

Purpose. The observation measurements testify the fact that heat and mass transfer processes in the shallow ice-covered lakes are not limited to the molecular diffusion only. In particular, the effective thermal diffusivity exceeds the molecular one by up to a few orders of magnitude. Now it is widely accepted that the transfer processes, in spite of their low intensity, are controlled by intermittent turbulence. At the same time, its nature and generation mechanism are still studied insufficiently. The paper represents one of such mechanisms associated with resonance generation of short internal waves by the barotropic seiches. Methods and Results. The temperature measurements in a shallow lake in winter were used as an experimental base. Having been analyzed, the temperature profiles’ dynamics observed during a few weeks after freezing revealed the anomalous values of thermal diffusivity. At that the temperature pulsations’ spectra clearly demonstrate the peak close to the main mode of barotropic seiches. Counter-phase oscillations at the different depths and pronounced heterogeneity of the amplitudes of temperature pulsations over depth indicate presence of internal waves. Based on these data, the mechanism of energy transfer from the barotropic seiches to the internal waves similar to the “tidal conversion” (the latter governs resonance generation of internal tides in the ocean), is proposed. The expressions for heat flux, energy dissipation rate and effective thermal diffusivity are derived. Conclusions. Internal waves can play an essential role in the processes of interior mixing and heat transfer in the ice-covered lakes. Though direct wind-induced turbulence production is inhibited, baric perturbations in the atmosphere can give rise to barotropic seiches, which play the role of an intermediate energy reservoir and can generate short resonant internal waves resulted from interaction with the undulate lake floor. The internal wave field parameters strongly depend on the barotropic seiche amplitudes, buoyancy frequency and the bottom topography features.

The Effect of Absorbed Solar Radiation on the Thermal Diffusion in Antarctic Fresh-Water Ice and Sea Ice

1967 ◽  
Vol 6 (48) ◽  
pp. 859-878
Author(s):  
G. Weller
Keyword(s):  
Heat Flux ◽  
Thermal Diffusivity ◽  
Solar Radiation ◽  
Sea Ice ◽  
Classical Model ◽  
Heat Diffusion ◽  
Water Ice ◽  
Depth Data ◽  
One Year ◽  
Improved Model

Ice temperatures were measured on the ice plateau at Mawson, Antarctica, for one year down to depths of 11 m. and through a floating sea-ice cover for six months. The plateau data were examined by harmonic analysis and the thermal diffusivity of the ice was obtained from the classical model of heat diffusion. An improved model of heat diffusion proposed by Lettau (1954) was also used to derive the diffusivity. The results show that absorbed radiation affects the computed diffusivity values down to 6–8 in. depth and a model is put forward to explain these apparent changes with depth. Data on the extinction of radiation in the ice have been published elsewhere (Weller and Schwerdtfeger, in press). The diffusivity of the ice is determined for periods with no radiation in winter and the value of 0.011 cm2. sec−1 agrees well with values at 8 m. depth where the effect of radiation becomes negligible.Heat-flux plates embedded in the ice were used to determine the diffusivity independently and also to give numerical values of the heat flux at any moment. The geometry and characteristics of these flux plates are discussed elsewhere (Schwerdtfeger and Weller, 1967). They are also used to derive the diffusivity of sea ice and enable a detailed analysis of the diurnal heat flux in such complex substances as sea ice to be made.

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 Influence of Northern Hemispheric Winter Warming on the Pacific Storm Track

2021 ◽  
Author(s):  
Hyung-Ju Park ◽  
Kwang-Yul Kim
Keyword(s):  
Heat Flux ◽  
Global Warming ◽  
Energy Conversion ◽  
Storm Track ◽  
The Arctic ◽  
Late Winter ◽  
Turbulent Heat ◽  
Early Winter ◽  
Eddy Heat Flux ◽  
Northern Hemispheric

AbstractEffect of global warming on the sub-seasonal variability of the Northern Hemispheric winter (NDJFM) Pacific storm-track (PST) activity has been investigated. Previous studies showed that the winter-averaged PST has shifted northward and intensified, which was explained in terms of energy exchange with the mean field. Effect of global warming exhibits spatio-temporal heterogeneity with predominance over the Arctic region and in the winter season. Therefore, seasonal averaging may hide important features on sub-seasonal scales. In this study, distinct sub-seasonal response in storm track activities to winter Northern Hemispheric warming is analyzed applying cyclostationary empirical orthogonal function analysis to ERA5 data. The key findings are as follows. Change in the PST is not uniform throughout the winter; the PST shifts northward in early winter (NDJ) and intensifies in late winter (FM). In early winter, the combined effect of weakened baroclinic process to the south of the climatological PST and weakened barotropic damping to the north is responsible for the northward shift. In late winter, both processes contribute to the amplification of the PST. Further, change in baroclinic energy conversion is quantitatively dominated by eddy heat flux, whereas axial tilting of eddies is primarily responsible for change in barotropic energy conversion. A close relationship between anomalous eddy heat flux and anomalous boundary heating, which is largely determined by surface turbulent heat flux, is also demonstrated.

Effects of thermal oxidation on the effective thermal diffusivity of titanium alloys

2014 ◽  
Vol 47 (38) ◽  
pp. 385306 ◽  
Author(s):  
A Somer ◽  
F Camilotti ◽  
G F Costa ◽  
A R Jurelo ◽  
A Assmann ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Titanium Alloys ◽  
Thermal Oxidation ◽  
Effective Thermal Diffusivity

Notable increases in nutrient concentrations in a shallow lake during seasonal ice growth

2016 ◽  
Vol 74 (12) ◽  
pp. 2773-2783 ◽  
Author(s):  
Yang Fang ◽  
Li Changyou ◽  
Matti Leppäranta ◽  
Shi Xiaonghong ◽  
Zhao Shengnan ◽  
...  
Keyword(s):  
Liquid Water ◽  
Shallow Lake ◽  
Water Environment ◽  
Open Water ◽  
Middle Layer ◽  
Nutrient Concentrations ◽  
Unfrozen Water ◽  
Total N ◽  
Water And Sediment ◽  
Increased Risk

Nutrients may be eliminated from ice when liquid water is freezing, resulting in enhanced concentrations in the unfrozen water. The nutrients diluted from the ice may contribute to accumulated concentrations in sediment during winter and an increased risk of algae blooms during the following spring and summer. The objective of this study was to evaluate the influence of ice cover on nitrogen (N) and phosphorus (P) concentrations in the water and sediment of a shallow lake, through an examination of Ulansuhai Lake, northern China, from the period of open water to ice season in 2011–2013. The N and P concentrations were between two and five times higher, and between two and eight times higher, than in unfrozen lakes, respectively. As the ice thickness grew, contents of total N and total P showed C-shaped profiles in the ice, and were lower in the middle layer and higher in the bottom and surface layers. Most of the nutrients were released from the ice to liquid water. The results confirm that ice can cause the nutrient concentrations in water and sediment during winter to increase dramatically, thereby significantly impacting on processes in the water environment of shallow lakes.

scholarly journals Life histories and distribution of ostracods with depth in western Lake Geneva (Petit-Lac), Switzerland: a reconnaissance study

Crustaceana ◽  
2014 ◽  
Vol 87 (8-9) ◽  
pp. 1095-1123 ◽  
Author(s):  
Laurent Decrouy ◽  
Torsten W. Vennemann
Keyword(s):  
Life History ◽  
Water Temperature ◽  
Water Depth ◽  
Organic Matter Content ◽  
Environmental Parameters ◽  
Late Winter ◽  
Lake Geneva ◽  
Monthly Basis ◽  
Sampling Campaign ◽  
Western Lake

Because environmental conditions within a given basin are different for each season and at different water depth, knowledge of the life history and depth distribution of target species is important for environmental and palaeoenvironmental interpretations based on ostracod species assemblages and/or the geochemical compositions of their valves. In order to determine the distribution of species with depth as well as the life history of species from Lake Geneva, a one-year sampling campaign of living ostracods was conducted at five sites (2, 5, 13, 33 and 70 m water depth) on a monthly basis in the Petit-Lac (western basin of Lake Geneva, Switzerland). Based on the results, the different species can be classified into three groups. Littoral taxa are found at 2 and 5 m water depth and include, in decreasing numbers of individuals,Cypridopsis vidua(O. F. Müller, 1776),Pseudocandona compressa(Koch, 1838),Limnocythere inopinata(Baird, 1843),Herpetocypris reptans(Baird, 1835),Potamocypris smaragdina(Vávra, 1891),Potamocypris similis(G. W. Müller, 1912),Plesiocypridopsis newtoni(Brady & Robertson, 1870),Prionocypris zenkeri(Chyzer & Toth, 1858) andIlyocyprissp. Brady & Norman, 1889. Sublittoral species are found in a majority at 13 m water depth and to a lesser extend at 33 m water depth and include, in decreasing numbers of individuals,Fabaeformiscandona caudata(Kaufmann, 1900),Limnocytherina sanctipatricii,Candona candida(O. F. Müller, 1776) andIsocypris beauchampi(Paris, 1920). Profundal species are found equally at 13, 33 and 70 m water depth and includes, in decreasing numbers of individuals,Cytherissa lacustris(Sars, 1863),Candona neglectaSars, 1887 andCypria lacustrisLilljeborg, 1890. The occurrence ofLimnocytherina sanctipatricii(Brady & Robertson, 1869) is restricted from late winter to late spring when temperatures are low, whileC. vidua,L. inopinata,P. smaragdina,P. similis,P. newtoniandIlyocyprissp. occur predominantly from spring to early autumn when temperatures are high. Individuals ofC. neglecta,C. candida,F. caudata,P. compressa,C. lacustris,H. reptansandCp. lacustrisoccur throughout the year with juveniles and adults occurring during the same period (C. neglectaat 70 m,C. lacustrisat 13, 33 and 70 m, andH. reptansat 2, 5 and 13 m water depth) or with juveniles occurring during a different period of the year than adults (C. neglectaat 13 and 33 m andC. candida,F. caudataandP. compressaat their respective depth of occurrence). Among the environmental parameters investigated, an estimate of the relationship between ostracod autoecology and environmental parameters suggests that in the Petit-Lac: (i) water temperature and substrate characteristics are important factors controlling the distribution of species with depth, (ii) water temperature is also important for determining the timing of species development and, hence, its specific life history, and (iii) water oxygen and sedimentary organic matter content is less important compared to the other environmental parameter monitored.

Firefighter Equipment Operational Environment: Evaluation of Thermal Conditions

2017 ◽  
Author(s):  
Daniel Madrzykowski ◽  
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Protective Clothing ◽  
Thermal Conditions ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Hot Gas ◽  
Performance Requirements ◽  
Fire Environment ◽  
Fire Ground

The goal of this study was to review the available literature to develop a quantitative description of the thermal conditions firefighters and their equipment are exposed to in a structural fire environment. The thermal exposure from the modern fire environment was characterized through the review of fire research studies and fire-ground incidents that provided insight and data to develop a range of quantification. This information was compared with existing standards for firefighting protective equipment to generate a sense of the gap between known information and the need for improved understanding. The comparison of fire conditions with the thermal performance requirements of firefighter protective gear and equipment demonstrates that a fire in a compartment can generate conditions that can fail the equipment that a firefighter wears or uses. The review pointed out the following: 1. The accepted pairing of gas temperature ranges with a corresponding range of heat fluxes does not reflect all compartment fire conditions. There are cases in which the heat flux exceeds the hazard level of the surrounding gas temperature. 2. Thermal conditions can change within seconds. Experimental conditions and incidents were identified in which firefighters would be operating in thermal conditions that were safe for operation based on the temperature and heat flux, but then due to a change in the environment the firefighters would be exposed to conditions that could exceed the protective capabilities of their PPE. 3. Gas velocity is not explicitly considered within the thermal performance requirements. Clothing and equipment tested with a hot air circulating (convection) oven are exposed to gas velocities that measure approximately 1.5 m/s (3 mph). In contrast, the convected hot gas flows within a structure fire could range from 2.3 m/s (5 mph) to 7.0 m/s (15 mph). In cases where the firefighter or equipment would be located in the exhaust portion of a flow path, while operating above the level of the fire, the hot gas velocity could be even higher. This increased hot gas velocity would serve to increase the convective heat transfer rate to the equipment and the firefighter, thereby reducing the safe operating time within the structure. 4. Based on the limited data available, it appears currently available protective clothing enables firefighters to routinely operate in conditions above and beyond the "routine" conditions measured in the fire-ground exposure studies conducted during the 1970s. The fire service and fire standards communities could benefit from an improved understanding of: • real world fire-ground conditions, including temperatures, heat flux, pressure, and chemical exposures; • the impact of convection on the thermal resistance capabilities of firefighting PPE and equipment; and • the benefits of balancing the thermal exposures (thermal performance requirements) across different components of firefighter protective clothing and safety equipment. Because it is unlikely due to trade offs in weight, breathe-ability, usability, cost, etc., that fireproof PPE and equipment will ever be a reality, fire officers and fire chiefs need to consider the capabilities of the protection that their firefighters have when determining fire attack strategies and tactics to ensure that the PPE and equipment is kept within its design operating environment, and that the safety buffer it provides is maintained.

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