![]() Whereas shallow lakes are usually polymictic and regularly mix to the bottom, deep lakes tend to stratify seasonally, separating surface water from deep sediments and deep water from the atmosphere. The mixing regime is fundamental to the biogeochemisty and ecology of lakes because it determines the vertical transport of matter such as gases, nutrients, and organic material. Generalized scaling of seasonal thermal stratification in lakes These model improvements, especially the new sigma-zed vertical discretization, accurately capture thermal-stratification patterns with low root-mean-squared errors when using the Vinçon-Leite vertical mixing scheme. Model skill was evaluated by comparing measured and simulated vertical temperature profiles at shallow (20 m) and deep (180 m) locations on the Lake. ![]() The model was calibrated by adjusting solar-radiation absorption coefficients in addition to background horizontal and vertical mixing parameters. A new vertical mixing scheme from Vinçon-Leite that implements different eddy diffusivity formulations above and below the thermocline was compared to results from the original Mellor-Yamada vertical mixing scheme. EFDC+'s evaporation algorithm was updated to more accurately simulate net surface heat fluxes. Lawrence River in conjunction with hourly meteorological data from seven local weather stations plus three-hourly data from the North American Regional Reanalysis govern the hydrodynamic and thermodynamic responses of the Lake. Inflow from the Niagara River and outflow to the St. Lake Ontario bathymetry was interpolated onto a 2-km-resolution curvilinear grid with vertical layering using a new approach in EFDC+, the so-called "sigma-zed" coordinate system which allows the number of vertical layers to be varied based on water depth. Time-varying thermal stratification patterns can be accurately simulated with the versatile Environmental Fluid Dynamics Code (EFDC). ![]() Accurate simulation of vertical mixing and seasonal stratification of large lakes is a crucial element of the thermodynamic coupling between lakes and the atmosphere in integrated models. Seasonal temperature variations establish strong vertical density gradients (thermoclines) between the epilimnion and hypolimnion. Investigating Summer Thermal Stratification in Lake Ontario Convection occurs frequently in fall and winter, whereas long-lasting and stable stratification causes Due to lack of solar radiation, convection occurs more easily in nighttime than in daytime. Moreover, wind-induced convection is detected during thermal stratification. A daily average wind speed greater than 6 m s-1 can maintain the mixed state in Lake Taihu. When solar radiation increases, stronger wind is required to prevent the lake from becoming stratified. Other than the diurnal stratification and convection, the representative responses of thermal stratification to these two factors with contrary effects are also discussed. A prominent response of thermal stratification to weather conditions is found, being controlled by the stratifying effect of solar radiation and the mixing effect of wind disturbance. Prominent differences on the duration and frequency of long-lasting thermal stratification are found in these lakes, which may result from the differences of local climate, lake depth, and fetch. Shallow polymictic lakes share the characteristic of diurnal mixing. Therefore, compared to a deep lake at similar latitude, the thermal stratification in Lake Taihu exhibits small seasonal differences, but the wide variation in the short term becomes important. The water temperature in the entire layer changes in a relatively consistent manner. The thermal stratification in Lake Taihu has shallow depths in the upper region and a large amplitude in the temperature gradient, the maximum of which exceeds 5Â☌ m-1. ![]() Lake Taihu is a warm polymictic lake whose thermal stratification varies in short cycles of one day to a few days. Here, the variation in thermal stratification in Lake Taihu, a shallow fresh water lake, is studied systematically. In temperate zones, shallow lakes show significant differences in thermal stratification compared to deep lakes. Yang, Yichen Wang, Yongwei Zhang, Zhen Wang, Wei Ren, Xia Gao, Yaqi Liu, Shoudong Lee, XuhuiĪmong several influential factors, the geographical position and depth of a lake determine its thermal structure. Diurnal and Seasonal Variations of Thermal Stratification and Vertical Mixing in a Shallow Fresh Water Lake
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