Vertical Temperature Stratification Research Articles

Meteorological Characteristics of a Continuous Ice-Covered Event on Ultra-High Voltage Transmission Lines in Yunnan Region in 2021

Yunnan plays a pivotal role in transmitting electricity from west to east within China’s Southern Power Grid. During 7–13 January 2021, a large-scale continuous ice-covering event of ultra-high voltage (UHV) transmission lines occurred in the Qujing area of eastern Yunnan Province. Based on ERA5 reanalysis data and meteorological observation data of UHV transmission line icing in China’s Southern Power Grid, the synoptic causes of the icing are comprehensively analyzed from various perspectives, including weather situations, vertical stratification of temperature and humidity, local meteorological elements, and atmospheric circulation indices. The results indicate a strong East Asian trough and a blocking high directing northern airflow southward ahead of the ridge. Cold air enters the Qujing area and combines with warm and moist air from the subtropical high pressure of 50–110° E. As warm and cold air masses form a quasi-stationary front over the northern mountainous area of Qujing due to topographic uplift, the mechanism of “supercooling and warm rain” caused by the “warm–cold” temperature profile structure leads to freezing rain events. Large-scale circulation indices in the Siberian High, East Asian Trough, and 50–110° E Subtropical High regions provided clear precursor signals within 0–2 days before the icing events.

Exploring the Sensitivity of Water Temperature Models for High Dams and Large Reservoirs: A Case Study of the Nuozhadu Reservoir in China

The parameters governing a water temperature model play a pivotal role in determining the uncertainties associated with the model’s outcome. In this study, a two-dimensional (2D) hydrodynamic and water temperature coupling model is constructed, focusing on the Nuozhadu Reservoir situated along the Lancang River. Employing a single-factor analysis approach, the sensitivity of the thermal balance parameters and hydrodynamic parameters in the model is assessed. This study overcomes the shortcomings of previous sensitivity analyses of hydrodynamic parameters in reservoir water temperature models. The findings reveal that the attenuation parameters of light and Beer’s law parameter exhibit minimal sensitivity to the vertical temperature structure. Conversely, radiation parameter A and radiation parameter B exert tenfold disparate influences on the surface and bottom temperatures of the reservoir. Among the hydrodynamic parameters considered, the horizontal viscosity factor shows no sensitivity to the vertical temperature structure, whereas the vertical viscosity factor serves as a crucial determinant, directly influencing the intensity of vertical temperature stratification. An increased vertical viscosity factor promotes heat exchange between the upper and lower water layers, thereby reducing the vertical temperature gradient and weakening stratification. Conversely, diminishing this factor intensifies stratification. Thus, when conducting water temperature simulations in high dams and large reservoirs, careful attention should be given to calibrating vertical viscosity factor.

Impact of an eddy dipole of the Mozambique channel on mesopelagic organisms, highlighted by multifrequency backscatter classification.

The impact of a cyclonic (C), an anticyclonic (AC) eddy and transition zone (TZ), which is the area between the two eddies, on acoustic groups representing various mesopelagic organisms, was investigated using a semi-supervised multifrequency classification approach (hereafter, Escore algorithm). The Escore algorithm involved selecting regions of interest (ROIs) within multifrequency (18, 38, 70, and 120 kHz) echograms and classifying into four clusters or echo-classes using Sv differences (Sv18-38, Sv70-38, and Sv120-38). Acoustic densities and diel vertical migration strength varied between the AC, C, and TZ according to the frequency. The vertical stratification of temperature, salinity and fluorescence within the oceanographic structures had varied influences on the vertical structure of each echo-class which represent zooplankton-like organisms, small and large fish with swimbladders, and small and large siphonophores with pneumatophores. The echo-classes within the C were influenced by surface fluorescence, whereas in the AC and TZ, the echo-classes were influenced by deeper fluorescence and strong EKE. Our study provides new insights into the environmental variables within mesoscale and sub-mesoscale features impacting different groups of mesopelagic communities in the Indian Ocean.

Performance investigation on the ventilation systems of high-speed railway train depots in hot summer regions

As a place for the maintenance of high-speed trains, the current ventilation system in the train depot cannot meet comfort requirements according to the feedback from the inspection department. The poor thermal environment could seriously affect the physical health and work efficiency of staff. This study provides some basic data and design methods for improving the thermal environment in high-speed railway depots. Field studies were conducted in five different high-speed railway depots in hot summer regions of China, including the form and the operation of the ventilation system, the thermal and humid environment and the characteristics of the heat sources. According to the survey results, the maximum temperature in the depot can reach 41.2°C in summer. There is a clear vertical temperature stratification in the afternoon of the depot, and the maximum temperature difference between three working platforms can reach more than 4°C. The cooling effect of ventilation systems in depot was investigated and compared. The recommended ventilation mode is natural ventilation system + bottom mechanical air supply system + ceiling fan system, and it is recommended to combine the west window louvers with external sun shading to achieve the best cooling effect in high-speed railway depot.

Experimental study on the vertical temperature and thermal stratification for subway station fire

Experimental study on the vertical temperature and thermal stratification for subway station fire

Temperature stratification in the Guanabara Bay and its relationship with wind-induced coastal upwelling off Cabo Frio, Brazil

This study investigates the mechanisms that control the occurrence of cold water intrusion events observed in Guanabara Bay, Rio de Janeiro, Brazil. To achieve this, we used multiple time-series data comprising in-situ temperatures recorded at depths of 5 m and 20 m in three sites in the Guanabara Bay region, wind velocities from three meteorological stations along the Brazilian coast, and sea level data from a tidal gauge located in the interior of Guanabara Bay. We found that from October 2014 to May 2016, near-bed temperatures in Guanabara Bay were dominated by subinertial variability. We identified subinertial cold water events, defined by temperature values below 18 °C, that were associated with South Atlantic Central Water intrusions. We obtained a total of 21 cold water events during the 18-month (545-day) sampling period, corresponding to 92.5 days or 17% of the time. Additionally, we found statistically significant lag-adjusted correlation coefficients (0.37-0.95) between near-bed (20 m) temperatures in Guanabara Bay and alongshore winds from the Arraial do Cabo meteorological station, which act in the well-known Cabo Frio upwelling system along the coast. These upwelling-favorable winds led near-bed temperature values in Guanabara Bay by 12 to 56 h and provided the remote forcing mechanism for the cold water intrusions in Guanabara Bay. Locally, the shelf-bay intrusion velocity values ranged from 0.04 to 0.50 m⋅s−1, consistent with a gravity current enhanced by baroclinic pressure gradient, the local forcing mechanism. The cold water intrusions caused an increase in the vertical temperature stratification within Guanabara Bay, as verified for all analyzed events. We also identified subinertial oscillations due to Coastal Trapped Waves (CTWs) propagation from our sea level data records and evaluated their impacts on cold water events.

Thermal expansion of atmosphere and stability of vertically stratified fluids

The influence of thermal expansion of the Earth's atmosphere on the stability of vertical stratification of fluid density and temperature is studied. We show that such an influence leads to the instability of incompressible flows. Modified by the thermal expansion coefficient, a new expression for the Brunt-Väisälä frequency is derived, and a critical value of the thermal expansion coefficient for which the instability occurs is revealed.

Thermal comfort of novel low-momentum ventilation concepts for passengers in long-distance trains

Thermal comfort is essential to increase the modal share of rail transport by attracting more passengers. In this study, three novel low-momentum ventilation concepts were analyzed regarding the thermal comfort of railway passengers and compared to a conventional ventilation setting. Using an experimental approach, objective measurements of climate parameters and subjective assessments from 146 test subjects in a generic train compartment were analyzed. Results revealed significant differences in perceived thermal comfort amongst the four ventilation settings. Subjects reported comparatively higher thermal comfort in hatrack integrated low-momentum ventilation and hybrid ventilation (HV) than in cabin displacement ventilation (CDV) and microjet ventilation (MJV). Vertical temperature stratification was strongest in CDV, leading to losses in the comfort of the lower body parts. In MJV, some temporary and local exceedances of air velocities were observed, which contributed to lower comfort evaluations at heads and shoulders. For all ventilation settings, warmer air temperatures were preferred. Our findings demonstrated that subjective comfort assessments reasonably complement earlier results derived from thermal manikin studies. Therefore, low-momentum ventilation, especially in terms of HV, has the significant potential to improve thermal conditions for long-distance journeys in passenger rail cars.

Sensitivity of boundary layer parameterization schemes in a marine boundary layer jet and associated precipitation during a coastal warm-sector heavy rainfall event

The sensitivity of planetary boundary layer (PBL) parameterization schemes in a marine boundary layer jet and associated precipitation is investigated in this study. Six PBL parameterization schemes in the Weather Research and Forecasting Model, including YSU, MYJ, MYNN, ACM2, BouLac, and UW schemes, are examined in simulating a marine boundary layer jet (BLJ) over South China Sea and associated coastal precipitation during a warm-sector heavy rainfall event (19–20 May 2015) near the coast of South China. The results show that YSU, MYJ, MYNN, and BouLac schemes can generally reproduce the coastal warm-sector heavy rainfall with 6-h accumulated precipitation exceeding 50 mm, but not for the ACMs and UW schemes. No convection initiation occurs in the ACM2 run, while rainfall is located to further north with weaker intensity in the UW run. Meanwhile, weakest and strongest BLJs are simulated in the ACM2 and UW runs, respectively. In the ACM2 run, the weaker BLJ with the maximum wind speed less than 17 m s−1 induces weaker convergence and lifting in the upwind side of the coastal terrain as well as less water vapor transport to the coastal area, which thus inhibit convection initiation. On the contrary, the too strong BLJ in the UW run with large area of wind speed greater than 18 m s−1 causes the northward movement of convection along with cold pools, and rainfall moves further north accordingly. The differences in BLJs’ strength among PBL schemes are attributed to varying simulated low-level vortex on the northern side of the BLJ through veering ageostrophic winds. The intensity of the simulated low-level vortex is affected by variations in boundary layer mixing over land and associated vertical temperature stratification under different PBL schemes.

Study on the water temperature distribution characteristics of a mixed pumped storage power station reservoir: A case study of Jinshuitan Reservoir

With the development of the social economy and the demand for environmental protection, people's requirements for clean and renewable energy are gradually increasing. Generally, renewable energy, such as wind power and photovoltaic energy, has natural intermittency to varying degrees. Consequently, renewable energy sources, due to their fluctuating nature, cannot provide a continuous supply of power and hence require bulk electricity storage. Additionally, energy storage is important to electrical systems, allowing load levelling, peak shaving, frequency regulation, damping energy oscillations, and improving power quality and reliability. Pumped storage power stations are notable for their ability to efficiently store energy on a large scale. The construction of a reservoir inevitably changes the water temperature situation of the original river channel. The expansion of pumping and storage units on a pre-existing reservoir, namely, a mixed pumped storage power station, is different from a conventional power station in terms of the thermal structure of the reservoir area. This study focuses on the Jinshuitan hydropower station and uses the MIKE3 model to analyse the influence of different outlet elevations and pumping flows on the water temperature structure of the reservoir area. The water pumping had no impact on the surface water body but did have a significant impact on the middle and bottom water bodies. The vertical water temperature stratification intensity weakened under different pumping scenarios, and the temperatures of the middle and bottom water bodies increased. The influence of the outlet elevation on the water temperature structure in the reservoir area was much greater than that of the pumping flow. The lower the elevation of the water outlet was, the greater the impact. For the Jinshuitan hydropower station, when the elevation of the water outlet was 130 m, the water temperature of the bottom column rose significantly, the stratification intensity of the water column weakened significantly, and the reservoir reached a vertically isothermal state in December. In summary, water pumping dramatically changed the original water temperature structure in the reservoir. The final research results can provide an effective reference for follow-up studies on relevant ecological and environmental issues associated with the development of pumped storage power stations and for setting the outlet elevation and pumping flow.

Airflow characteristics of attachment ventilation in a nursery pig house under heating mode

In the current energy saving context, it is important to study the airflow that regulates the environment of an animal-occupied zone (AOZ) and reduces the heating load of the barn in a nursery pig house. Forced convection heating regulates the overall thermal environment in a nursery barn using hot air while reducing the pollutant concentration. This improves air quality and has energy-saving attributes. In this study, we investigated a pen-attached ventilation (PAV) airflow system in a nursery pig house based on the hot air heating method during winter. The air distribution, temperature field diffusion characteristics, and ventilation effectiveness of the PAV were investigated using a full-scale test bench and computational fluid dynamics (CFD) during the heating mode. The results show that PAV can effectively deliver fresh air and heat to the lying area of nursery pigs, as well as reduce the vertical temperature stratification inside the pig house. In addition, the average temperature in the lying area increased by 3.77 °C, the energy utilization coefficient increased by 0.2, and the energy saving rate was 12.7% when compared to the mixing ventilation (MV) airflow regulation mode for the same heat input. The PAV airflow approach reduced the energy consumption in the operation stage of the barn and theoretically justified its application to the thermal regulation of the environment of nursery pigs. • We investigated a PAV airflow system for the hot air heating method. • The average pig house temperature increased by 3.77 °C with this method. • This method reduced energy consumption in the operation stage of the barn by 12.7%.

Dynamical mass measurements of two protoplanetary discs

ABSTRACT ALMA observations of line emission from planet forming discs have demonstrated to be an excellent tool to probe the internal disc kinematics, often revealing subtle effects related to important dynamical processes occurring in them, such as turbulence, or the presence of planets, that can be inferred from pressure bumps perturbing the gas motion, or from the detection of the planetary wake. In particular, we have recently shown for the case of the massive disc in Elias 2-27 as how one can use such kind of observations to measure deviations from Keplerianity induced by the disc self-gravity, thus constraining the total disc mass with good accuracy and independently on mass conversion factors between the tracer used and the total mass. Here, we refine our methodology and extend it to two additional sources, GM Aur and IM Lup, for which archival line observations are available for both the 12CO and the 13CO line. For IM Lup, we are able to obtain a consistent disc mass of $M_{\rm disc}=0.1 \, \mathrm{M}_{\odot }$, implying a disc-star mass ratio of 0.1 (consistent with the observed spiral structure in the continuum emission) and a gas/dust ratio of ∼65 (consistent with standard assumptions), with a systematic uncertainty by a factor of ≃ 2 due to the different methods to extract the rotation curve. For GM Aur, the two lines we use provide slightly inconsistent rotation curves that cannot be attributed only to a difference in the height of the emitting layer, nor to a vertical temperature stratification. Our best-fitting disc mass measurement is $M_{\rm disc}=0.26 \, \mathrm{M}_{\odot }$, implying a disc-star mass ratio of ∼0.35 and a gas/dust ratio of ∼130. Given the complex kinematics in the outer disc of GM Aur and its interaction with the infalling cloud, the CO lines might not well trace the rotation curve and our results for this source should then be considered with some caution.

Occupant-centered evaluation on indoor environments and energy savings of radiant cooling systems with high-intensity solar radiation

Solar radiation has an overwhelming influence on indoor thermal and light environments, as well as building energy consumption. In this study, radiant cooling systems were applied to reduce the negative effects of solar radiation. The tests were carried out with the floor radiant cooling system (FRC), ceiling radiant cooling system (CRC), ·and conventional air conditioning system (AC), under typical warm days. An occupant-centered body model was presented to comprehensively evaluate the non-uniform thermal environment caused by solar heat. Besides, the effects on the cooling performance of cooling systems were evaluated by simulation and experiments. The results demonstrate that the cooling capacity rapidly increased with the intensity of the solar radiation. During beam-exposed period, cooling capacity of FRC system increased from 55.6 W/m2 to 210.0 W/m2 and the proportion of shortwave radiant heat flux qsr reached 84%. Furthermore, solar radiation also deteriorated the non-uniform thermal environment. The FRC system could reduce the mean radiant temperature by the maximum of 8.0 °C. Exposed to the beam solar radiation was the main reason that caused large vertical stratification of temperature and dissatisfaction. The FRC system effectively performed better with the maximum percentage dissatisfied value reduced by 14.76 %. Finally, the energy-saving potential of RC systems was analyzed. After the set-point temperature was corrected, the FRC system reduced the typical day’s energy consumption by 21.7% and annual energy consumption by 12.2%. Appropriate adoption of RC systems is an energy-saving method to improve thermal comfort of indoor environments with high-intensity solar radiation.

Simulation and experimental study of uniformity of temperature field of electrically heated water

With the aim of investigating the non-uniformity of the temperature field of electrically heated water in a horizontal stationary circular tube, we numerically simulated the axial and radial temperature fields in a horizontal circular tube using the Fluent CFD package. We then designed a sectioned grouping heating scheme based on a two-position controller for experimental verification. The results show that the axial temperature in the tube is non-uniform if the tube is not placed horizontally. In the heating stage, uniform heating of the entire tube surface leads to significant vertical temperature stratification, with higher temperature in the upper part and lower temperature in the lower part of the circular tube. However, heating only the lower half of the tube's surface can reduce the temperature difference between the upper and lower layers from more than to less than, effectively improving the uniformity of the temperature field. During steady-state operation, due to the limitations of the two-position controller algorithm, the radial temperature deviation rises to a maximum of for the sectioned grouping heating mode. Compared with the whole-tube uniform heating mode, the grouping heating mode, especially the four-group heating mode, has obvious advantages with regard to the time to reach steady-state and the uniformity of the steady-state temperature field. This paper provides a reference for the design of heating schemes for horizontal isobaric closed circular tubes with high precision, minimal overshoot and good temperature field uniformity.

What lies beneath: Vertical temperature heterogeneity in a Mediterranean woodland savanna

As the availability of satellite and airborne thermal infrared remote sensing (TIR-RS) data increases and their spatial, temporal, and spectral resolutions improve, researchers are finding diverse applications for TIR-RS measurements. TIR-RS is now commonly applied in regional- and continental-scale analyses, such as those focused on fire and surface energy balance. However, its application lags in plant physiology and ecology, for which a finer-scale understanding of plant canopy temperatures would be useful to elucidate plant water dynamics, for example. In particular, while methods to disaggregate TIR-RS pixels in horizontal space have advanced, possible vertical stratification of plant canopy temperature and its implications for understanding the correspondence between TIR-RS and finer-scale, field-based thermal measurements (e.g. made with a thermal camera) remain unexplored. Here, we use data from a thermal camera deployed concurrently with the recent ECOSTRESS mission to quantify vertical temperature gradients within tree canopies and temperatures of over- vs. under-story plants in a Mediterranean woodland savanna. We then leverage diverse ancillary data to maximize the geometric comparability of ECOSTRESS and thermal camera measurements, in order to assess the extent to which the two forms of thermal measurements correspond. Specifically, we ask: (1) What are the patterns of intra-canopy and over- vs. under-story vertical temperature in a Mediterranean woodland savanna?, and (2) How can vertically-resolved, but spatially-limited field-based temperature measurements be reconciled with spatially-extensive, but surface-only, temperature measurements of a space-borne remote sensor? We found consistent patterns of vertical thermal heterogeneity both within tree canopies and between ecosystem over- and under-stories. The daytime difference between the top and bottom thirds of blue oak canopies was, on average, 0.48 ° C – and sometimes several times larger. Notably, canopy tops are cooler, likely associated with the under-story grass reaching daytime temperatures often exceeding over-story temperatures by 10° C. Given the consistency of the intra-canopy temperature gradients, we expected the ECOSTRESS sensor would be in better agreement with camera measurements of canopy tops than bulk canopies or canopy bottoms. However, within-canopy gradients were overwhelmed by other sources of disagreement between the measurements, in part associated with upscaling camera measurements across space. Overall, thermal camera and ECOSTRESS measurements were largely in agreement at night (pixel RMSE = 1.1°C), but they were more divergent during times of low (but >0 W/m2) and high incoming solar radiation (daytime pixel RMSE = 3.5°C).

Investigation of airborne particle exposure in an office with mixing and displacement ventilation.

Effective ventilation could reduce COVID-19 infection in buildings. By using a computational fluid dynamics technique and advanced experimental measurement methods, this investigation studied the air velocity, air temperature, and particle number concentration in an office under a mixing ventilation (MV) system and a displacement ventilation (DV) system with different ventilation rates. The results show reasonably good agreement between the computed results and measured data. The air temperature and particle number concentration under the MV system were uniform, while the DV system generated a vertical stratification of the air temperature and particle number concentration. Because of the vertical stratification of the particle number concentration, the DV system provided better indoor air quality than the MV system. An increase in ventilation rate can reduce the particle concentration under the two systems. However, the improvement was not proportional to the ventilation rate. The increase in ventilation rate from 2 ACH to 4 ACH and 6 ACH for MV system reduced the particle concentration by 20% and 60%, respectively. While for the DV system, increasing the ventilation rate from 2 ACH to 4 ACH and 6 ACH reduced the particle concentration by only 10% and 40%, respectively. The ventilation effectiveness of the MV system was close to 1.0, but it was much higher for the DV system. Therefore, the DV system was better than the MV system.

Experimental investigation of air distribution in an airliner cabin mockup with displacement ventilation

The commercial airliner cabin environment is very important for passengers and crew, and airflow and contaminant concentration distributions in cabins play a key role in creating a comfortable and healthy cabin environment. To study the airflow and the contaminant concentration distributions in airliner cabins, this investigation used a seven-row aircraft cabin mockup with well-controlled thermo-fluid boundary conditions. This study measured air temperature and velocity distributions with displacement ventilation by using T-type thermocouples and ultrasonic anemometers (UA), and contaminant distributions by using tracer gas and particle from a generator to simulate contaminant breathed out by a passenger. This paper discusses our effort to control the thermo-fluid boundary conditions with high accuracy. The measured results show that the air temperature was stratified and the air velocity was low. The contaminant was not transported to the other side of the cabin by the displacement ventilation system and was removed effectively through the ceiling exhaust. The Richardson number (Ri) indicated that the airflow was dominated by natural convection. However, the vertical temperature stratification may create discomfort for passengers.

Vertical Temperature Stratification of the Atmosphere Depending on the Length of the Annual Insolation Cycle from Simulations with the Coupled General Circulation Model

The numerical simulations are conducted with the coupled general circulation model for various lengths of the annual cycle. The modeling results confirm a previous conclusion, which is based on analysis of climate data using a special method of amplitude phase characteristics, that the thickness of the troposphere (the height of the tropopause) corresponds to the height of the temperature skin layer for the atmosphere under periodic heating from the surface related with the annual insolation cycle. In particular, the model height of the tropopause for half of the duration of the annual cycle is lower by $$\sqrt 2 $$ in comparison with the present-day length of the annual cycle.

Air distribution system suitable for tea brick fermentation process – Upward vertical wall attached ventilation

In tea brick fermentation, the temperature in the fermentation chamber has an important influence on the reproduction and growth of the golden flower bacteria inside tea bricks. In order to form a uniform and suitable fermentation temperature, the study introduced an upward vertical wall attached ventilation based on the load distribution characteristics of the tea brick fermentation chamber and the practical placement of tea bricks on the shelf. The air distribution of upward vertical wall attached ventilation under different supply air temperature differences was numerically investigated by a mathematical model of flow and heat transfer. Furthermore, the results were compared with two other traditional ventilation modes, which are diffuser ventilation and displacement ventilation. The upward vertical wall attached ventilation demonstrated higher ventilation efficiency and least vertical temperature stratification due to its lower flow resistance. Thus, the temperature unevenness coefficient in the product area could be reduced by between 54.3% and 77.5% compared with the diffuser dilute ventilation and displacement ventilation. Moreover, the upward vertical wall attached ventilation could help to eliminate the indoor heat load during the fermentation of tea bricks, which increases the energy utilisation rate of supply air by 1.7%–18.5%. Therefore, the vertical wall attached ventilation can effectively improve the temperature distribution of the tea brick fermentation chamber and improve the energy utilisation of the air supply. • Attached ventilation flow and heat and mass transfer were simulated numerically. • Air distribution could reduce heat load effect giving more uniform fermentation environment. • Better distribution avoided temperature stratification and improved energy use.

Impact of Freshwater Inflow From the Volturno River on Coastal Circulation

The coastal area located in front of the Volturno river’s estuary (Gulf of Gaeta, central-eastern Tyrrhenian Sea) has been synoptically sampled during seven surveys, between June 2012 and October 2014. The vertical profiles of temperature and salinity have been acquired on a high resolution nearly-regular grid, in order to describe the spatial and temporal variability of the water masses characteristics. Moreover, to provide a first assessment of the steady circulation at small scale, the three-dimensional velocity field associated to each survey has been obtained through the full momentum equations of the Princeton Ocean Model. The data analysis has shown the entire water column characterized by an evident thermal cycle and a vertical thermohaline structure dominated by three types of water masses: the freshwater of river’s origin, the saltier coastal Tyrrhenian waters and transitional waters, resulting from the mixing of them. The freshwater inflow strongly affected the density distribution, causing a strong temporal variability in the upper layer. Its impact was more evident in winter inducing also a temperature inversion along the water column. In case of rainy events, its effect was clear also in condition of high vertical temperature stratification, forming a surface-trapper layer characterized by high density gradients. Together with wind forcing, they contributed to the formation of small scale shallow features, such as longshore currents, cyclonic and anticyclonic eddies. The latter influenced the vertical stratification and modify the coastal circulation preserving the transitional waters from the surrounding saltier ones.