Definition of Thermohaline Circulation & Thermocline Layers
What is Thermohaline?
Thermohaline refers to the thermal property changes that occur in water when it gets hotter or colder. It also refers to the relation of salt content with water temperature and pressure, which has a significant impact in ocean circulation.
Thermo means to heat or temperature. Haline means related to saltwater as opposed to freshwater. The term is derived from the Greek word “thermos,” which means hot.
Oceanographers and meteorologists use it to describe seawater and sea ice’s physical properties that produce ocean circulation. Hydrographers also use it for calculating volume or capacity.
Thermohaline is a seawater’s physical property related to the water’s salt content, temperature, and pressure. It also refers to the sum of thermal properties and salinity. Thermohaline dynamics are driven by density stratification in the ocean, with warmer, less dense surface water being displaced by cooler, denser water from below.
Thermohaline Circulation is a major mechanism for maintaining the ocean’s circulatory structure. Its temperature and salinity determine the density of subsurface seawater. At the surface, this density gradient causes water to flow clockwise in the North Atlantic and counterclockwise in the South Atlantic. The North Atlantic Thermohaline Circulation (NATC) is an ocean circulation pattern that drives many global climates.
Thermohaline circulation is driven by density stratification in the ocean, with warmer, less dense surface water being displaced by cooler, denser water from below.
The cooler, denser water found below the surface of an ocean moves toward the surface at a certain rate. Due to oceanic circulation, warm, saltier ocean water is pushed to the surface. The temperature differentials between the top and bottom layers cause heat to be transported from the deeper layers of water to the top layer, evaporating into warmer air near land.
When it evaporates, this additional heat is released as latent heat and warms air temperatures near land, and increases precipitation rates in that region.
What is a thermocline?
A thermocline is a layer of water in which temperature becomes rapidly cooler the deeper one goes. This rapid cooling occurs because the thermocline water is usually denser than the water above it, and the density of water increases as it cools.
A thermocline (temperature layer) is a stable horizontal temperature zone located in the deep ocean below the surface mixed layer. In this layer, temperature decreases uniformly with depth. This zone separates higher temperature surface waters from colder, deeper waters. In a sense, it creates a barrier between two different water masses or layers of water.
The main Thermocline is located at the zone where there is a sharp change in temperature with depth. There are regions where the temperature undergoes a rapid drop in deep ocean environments in the ocean’s deeper levels.
In mid-depth regions of the world’s seas, seasonal changes in wind drive vertical water movements in a process known as upwelling and downwelling. During upwelling, cooler surface waters are carried below by combining winds and currents that form the thermocline.
The thermocline divides the upper from the lower ocean and plays an important role in several physical processes of importance to oceanographers and marine scientists.
The thermocline Layer is a thin layer of ocean water where the temperature changes rapidly with depth, with the temperature being decreased as you go down. The thermocline develops due to differences in the vertical distribution of heat energy and water chemistry.
The depth to which this layer of the ocean extends depends on many factors, such as salinity and temperature. The thermocline is a boundary or layer between two different density regions.
Thermohaline dynamics are driven by density stratification in the ocean, with warmer, less dense surface water being displaced by cooler, denser water from below.
Oceans play a significant role in climate and weather as they store large amounts of energy and impact global climate. Oceans also impact weather by influencing the formation of storms. The changes that occur to Earth’s oceans due to warming temperatures are also important in understanding how our planet responds to the greenhouse effect.
Thermocline Currents are named after their deep-water layers, and thermoclines are places where the surface water is cooler than the underlying water. Thermoclines are caused by differences in salinity or density of surface water and deep-water masses.
Thermocline and Halocline
The difference between Thermocline and Halocline is when the layers of water change in salinity. There are thermocline layers that are shallow through the sea, where the upper layer is colder than the lower layer.
However, at times, these thermoclines become so deep that they cease to be clearly distinct: instead, they merge into a single feature called a halocline (or sometimes meld). In coastal seas, haloclines may be associated with extensive mixing and are associated with cold sea-surface temperatures.
The presence of thermocline and halocline formed due to the ocean currents in the colder oceans, which are rich in salt. As a result, warm water with low salt content tends to remain above the colder water masses, which get richer and richer in salt.
In this case, the thermocline or halocline divides two layers that differ from each other in salinity – regardless of their temperature.
What is the thermocline depth of the ocean?
The thermocline depth increases on average as follows, from tropical to temperate to cold seas: about 200 meters, 400 m, 800 m. Besides, the bottom layer of water tends to become less salty with increasing depth (the exact opposite occurs in rivers).
These two effects mean that the thermoclines in tropical seas are particularly shallow, even when they may be several thousand meters deep.
Thermocline Lures or Thermoclinors are mainly deployed near the thermocline, and these are used to induce a current that allows the fisherman to take fish from the thermocline or halocline.
Thermoclinor use has been widely spread in the region of the Pacific Ocean. The Thermoclinor’s main product is shrimp.
Thermocline fishing is an effective way of catching fish at night and cooling these fish in ice.
Thermocline in Lakes
Thermocline in Lakes is a layer of water in lakes that is stable in temperature. In lakes where heated from the sun by the surrounding land, cold water can be stored in this layer.
As warm air rises and cools, this cold water releases its heat into the atmosphere, causing a temperature gradient to develop between the surface and deeper layers of water as we go deeper into the lake.
The temperature difference in a lake directly relates to the difference between the air temperature at the surface and the water temperature at different depths.
Water absorbs more heat than land and is warmed above its surrounding air temperature as a result. This process allows some lakes to maintain higher temperatures than nearby areas, even when there are no large water bodies nearby.
In lakes with no thermocline layer, year-round mixing occurs, resulting in relatively stable temperatures at all depths.
Thermocline depth in lakes
Thermocline depth in lakes is variable but typically ranges from less than 10 ft (3 m) to as much as 200 ft (60 m). As they get deeper into lakes, thermoclines can create temperature gradients that are too small to support fish without special adaptations or a biological mechanism that amplifies the effect.
Fish that can tolerate cold temperatures are found in lakes at varying depths and differ from each other based on their particular species’ physical and biochemical characteristics.
Thermocline fishing is a method of catching fish at night and cooling these fish in ice.