Sea spray refers to aerosol particles that are formed directly from the ocean, mostly by ejection into the atmosphere by bursting bubbles at the air-sea interface.Sea spray contains both organic matter and inorganic salts that form sea salt aerosol (SSA). SSA has the ability to form cloud condensation nuclei (CCN) and remove anthropogenic aerosol pollutants from the atmosphere. Sea spray is directly (and indirectly, through SSA) responsible for a significant degree of the heat and moisture fluxes between the atmosphere and the ocean, affecting global climate patterns and tropical storm intensity. Sea spray also influences plant growth and species distribution in coastal ecosystems and increases corrosion of building materials in coastal areas.
An aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog, dust, forest exudates and geyser steam. Examples of anthropogenic aerosols are haze, particulate air pollutants andThe liquid or solid particles have diameters typically <1 μm; larger particles with a significant settling speed make the mixture a suspension, but the distinction is not clear-cut. In general conversation, aerosol usually refers to an aerosol spray that delivers a consumer product from a can or similar container. Other technological applications of aerosols include dispersal of pesticides, medical treatment of respiratory illnesses, and convincing technology. Diseases can also spread by means of small droplets in the breath, also called aerosols.
An ocean is a body of water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. The word "ocean" is often used interchangeably with "sea" in American English. Strictly speaking, a sea is a body of water partly or fully enclosed by land, though "the sea" refers also to the oceans.
Sea salt aerosol, which originally comes from sea spray, is one of the most widely distributed natural aerosols. Sea salt aerosols are characterized as non-light-absorbing, highly hygroscopic, and having coarse particle size. Some sea salt dominated aerosols could have a single scattering albedo as large as ~0.97. Due to the hygroscopy, a sea salt particle can serve as a very efficient cloud condensation nuclei (CCN), altering cloud reflectivity, lifetime, and precipitation process. According to the IPCC report, the total sea salt flux from ocean to atmosphere is ~3300 Tg/yr.
When wind, whitecaps, and breaking waves mix air into the sea surface, the air regroups to form bubbles, floats to the surface, and bursts at the air-sea interface. cm from the sea surface. Film droplets make up the majority of the smaller particles created by the initial burst, while jet droplets are generated by a collapse of the bubble cavity and are ejected from the sea surface in the form of a vertical jet. In windy conditions, water droplets are mechanically torn off from crests of breaking waves. Sea spray droplets generated via such a mechanism are called spume droplets and are typically larger in size and have less residence time in air. Impingement of plunging waves on sea surface also generates sea spray in the form of splash droplets . The composition of the sea spray depends primarily on the composition of the water from which it is produced, but broadly speaking is a mixture of salts and organic matter. Several factors determine the production flux of sea spray, especially wind speed, swell height, swell period, humidity, and temperature differential between the atmosphere and the surface water. Production and size distribution rate of SSAs are thus sensitive to the mixing state. A lesser studied area of sea spray generation is the formation of sea spray as a result of rain drop impact on the sea surface .When they burst, they release up to a thousand particles of sea spray, which range in size from nanometers to micrometers and can be expelled up to 20
Organic matter, organic material, or natural organic matter (NOM) refers to the large pool of carbon-based compounds found within natural and engineered, terrestrial and aquatic environments. It is matter composed of organic compounds that have come from the remains of organisms such as plants and animals and their waste products in the environment. Organic molecules can also be made by chemical reactions that don't involve life. Basic structures are created from cellulose, tannin, cutin, and lignin, along with other various proteins, lipids, and carbohydrates. Organic matter is very important in the movement of nutrients in the environment and plays a role in water retention on the surface of the planet.
A swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air and thus are often referred to as surface gravity waves. These series of surface gravity waves are not wind waves, which are generated by the immediate local wind, but instead are generated by distant weather systems, where wind blows for a duration of time over a fetch of water. More generally, a swell consists of wind-generated waves that are not—or are hardly—affected by the local wind at that time. Swell waves often have a long wavelength, but this varies due to the size, strength and duration of the weather system responsible for the swell and the size of the water body. Swell wavelength also varies from event to event. Occasionally, swells which are longer than 700 m occur as a result of the most severe storms. Swells have a narrower range of frequencies and directions than locally generated wind waves, because swell waves have dispersed from their generation area, have dissipated and therefore lost an amount of randomness, taking on a more defined shape and direction. Swell direction is the direction from which the swell is coming. It is measured in degrees, and often referred to in general directions, such as a NNW or SW swell.
In addition to the local conditions that influence sea spray formation, there are also consistent spatial patterns in sea spray production and composition. Because sea spray is generated when air is mixed into the ocean, formation gradients are established by turbulence of the surface water.Wave action along coastal shorelines is generally where turbulence is greatest, so this is where sea spray production is the highest. Particles generated in turbulent coastal areas can travel horizontally up to 25 km within the planetary boundary layer. As distance from shore decreases, sea spray production declines to a level sustained almost exclusively by white caps. The proportion of the ocean surface area that is turbulent enough to produce significant sea spray is called the white cap fraction. The only other production mechanism of sea spray in the open ocean is through direct wind action, where strong winds actually break the surface tension of the water and lift particles into the air. However, particles of seawater generated in this way are often too heavy to remain suspended in the atmosphere and usually are deposited back to the sea within a few dozen meters of transport.
In fluid dynamics, turbulence or turbulent flow is any pattern of fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow regime, which occurs when a fluid flows in parallel layers, with no disruption between those layers.
In meteorology the planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL) or peplosphere, is the lowest part of the atmosphere and its behaviour is directly influenced by its contact with a planetary surface. On Earth it usually responds to changes in surface radiative forcing in an hour or less. In this layer physical quantities such as flow velocity, temperature, moisture, etc., display rapid fluctuations (turbulence) and vertical mixing is strong. Above the PBL is the "free atmosphere", where the wind is approximately geostrophic, while within the PBL the wind is affected by surface drag and turns across the isobars.
During winter months, the ocean typically experiences stormy, windy conditions that generate more air inundation into the sea and therefore more sea spray.Calmer summer months result in lower overall production of sea spray. During peak primary productivity in the summer, increased organic matter in the surface ocean drives subsequent increases in sea spray. Given that sea spray retains the properties of the water from which it was produced, the composition of sea spray experiences extreme seasonal variation. During the summer, dissolved organic carbon (DOC) can constitute 60-90% of sea spray mass. Even though much more sea spray is produced during the stormy winter season, the composition is nearly all salt because of the low primary production.
In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through chemosynthesis, which uses the oxidation or reduction of inorganic chemical compounds as its source of energy. Almost all life on Earth relies directly or indirectly on primary production. The organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role. Ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not.
The organic matter in sea spray consists of dissolved organic carbon(DOC) and even microbes themselves, like bacteria and viruses. The amount of organic matter in sea spray depends on microbiological processes, though the total effect of these processes is still unknown. Chlorophyll-a is often used as a proxy for primary production and organic matter content in sea spray, but its reliability for estimating DOC concentrations is controversial. Biomass often enters sea spray through the death and lysis of algal cells, often caused by viral infections. Cells are broken apart into DOC that is propelled into the atmosphere when surface bubbles pop. When primary productivity peaks during the summer, algal blooms can generate an enormous amount of organic matter that is eventually incorporated into sea spray. In the right conditions, aggregation of the DOC can also form surfactant or sea foam.
Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. It also reflects green-yellow light, and as such contributes to the observed green color of most plants. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria and prochlorophytes because of its role as primary electron donor in the electron transport chain. Chlorophyll a also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located.
Lysis refers to the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a lysate. In molecular biology, biochemistry, and cell biology laboratories, cell cultures may be subjected to lysis in the process of purifying their components, as in protein purification, DNA extraction, RNA extraction, or in purifying organelles.
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems, and is recognized by the discoloration in the water from their pigments. Cyanobacteria were mistaken for algae in the past, so cyanobacterial blooms are sometimes also called algal blooms. Blooms which can injure animals or the ecology are called "harmful algal blooms" (HAB), and can lead to fish die-offs, cities cutting off water to residents, or states having to close fisheries. Also, a bloom can block out the sunlight from other organisms, and deplete oxygen levels in the water. Also, some algae secrete poisons into the water.
At high winds the droplet evaporation layer (DEL) influences the surface energy heat exchange of the ocean.The latent heat flux of sea spray generated at the DEL has been cited as an important addition to climate modeling efforts, particularly in simulations assessing air/sea heat balance as related to hurricanes and cyclones formed during high wind events. During the formation of whitecaps, sea spray droplets exhibit the same properties as the ocean surface, but rapidly adapt to surrounding air. Some sea spray droplets immediately reabsorb into the sea while others evaporate entirely and contribute salt particles like dimethyl sulfide (DMS) to the atmosphere where they can be transported via turbulence to cloud layers and serve as CCN. The formation of these CCN like DMS have climate implications as well, due to their influence on cloud formation and interaction with solar radiation. Additionally, the contribution of sea spray DMS to the atmosphere is linked to the global sulfur cycle. Understanding total forcing from natural sources like sea spray can illuminate critical constraints posed by anthropogenic influence and can be coupled with ocean chemistry, biology and physics to predict future ocean and atmospheric variability.
Dimethyl sulfide (DMS) or methylthiomethane is an organosulfur compound with the formula (CH3)2S. Dimethyl sulfide is a flammable liquid that boils at 37 °C (99 °F) and has a characteristic disagreeable odor. It is a component of the smell produced from cooking of certain vegetables, notably maize, cabbage, beetroot and seafoods. It is also an indication of bacterial contamination in malt production and brewing. It is a breakdown product of dimethylsulfoniopropionate (DMSP), and is also produced by the bacterial metabolism of methanethiol.
The sulfur cycle is the collection of processes by which sulfur moves to and from rock, waterways and living systems. Such biogeochemical cycles are important in geology because they affect many minerals. Biochemical cycles are also important for life because sulfur is an essential element, being a constituent of many proteins and cofactors.
The proportion of organic matter in sea spray can impact reflectance, determine the overall cooling effect of SSAs,and slightly alter the capacity for SSAs to form CCN (17). Even small changes in SSA levels can affect the global radiation budget leading to implications for global climate. SSA has a low albedo, but its presence overlaid on the darker ocean surface affects absorption and reflectance of incoming solar radiation.
The influence of sea spray on the surface heat and moisture exchange peaks during times of greatest difference between air and sea temperatures.When air temperature is low, sea spray sensible heat flux can be nearly as great as the spray latent heat flux at high latitudes. In addition, sea spray enhances the air/sea enthalpy flux during high winds as a result of temperature and humidity redistribution in the marine boundary layer. Sea spray droplets injected into the air thermally equilibrate ~1% of their mass. This leads to the addition of sensible heat prior to ocean reentry, enhancing their potential for significant enthalpy input.
The effects of sea spray transport in the atmospheric boundary layer is not yet completely understood. Sea spray droplets alter the air-sea momentum fluxes by being accelerated and decelerated by the winds . In hurricane-force winds, it is observed that there is some reduction in the air/sea momentum flux . This reduction in momentum flux manifests as saturation of air/sea drag coefficient. Some studies have identified spray effects as one of the potential reasons for the air/sea drag coefficient saturation. It has been shown through several numerical and theoretical studies that sea spray, if present in significant amounts in the atmospheric boundary layer, leads to saturation of air-sea drag coefficients.
Salt deposition from sea spray is the primary factor influencing distribution of plant communities in coastal ecosystems.Ion concentrations of sea spray deposited on land generally mirror their concentrations in the ocean, except that potassium is often higher in sea spray. Deposition of salts on land generally decreases with distance from the ocean but increases with increasing wind speed. Salt deposition from sea spray is correlated with a decrease in plant height and significant scarring, shoot reduction, stem height decrease, and tissue death on the windward side of shrubs and trees. Variation in salt deposition also influences competition between plants and establishes gradients of salt tolerance.
While the salts within sea spray can severely inhibit plant growth in coastal ecosystems, selecting for salt-tolerant species, sea spray can also bring vital nutrients to these habitats. For example, one study showed that sea spray in Wales, UK delivers roughly 32 kg of potassium per hectare to coastal sand dunes each year. Because dune soils leach nutrients very quickly, sea spray fertilization could be very influential to dune ecosystems, especially for plants that are less competitive in nutrient-limited environments.
Viruses, bacteria, and plankton are ubiquitous in sea water, and this biodiversity is reflected in the composition of sea spray.Generally speaking, sea spray has slightly lower concentrations of microbes than the water it is produced from. However, the microbial community in sea spray is often distinct from nearby water and sandy beaches, suggesting that some species are more biased towards SSA transportation than others. Sea spray from one beach can contain thousands of operational taxonomic units (OTUs). Nearly 10,000 different OTUs have been discovered in sea spray just between San Francisco, CA and Monterey, CA, with only 11% of them found ubiquitously. This suggests that sea spray in every coastal region likely has its own unique assemblage of microbial diversity, with thousands of new OTUs yet to be discovered. Many of the more common OTUs have been identified to the following taxa: Cryptophyta (order), Stramenopiles (order) and OM60 (family). Many have even been identified to genus: Persicirhabdus, Fluviicola, Synecococcus, Vibrio, and Enterococcus.
Scientists have conjectured a stream of airborne microorganisms circles the planet above weather systems but below commercial air lanes.Some of these peripatetic microorganisms are swept up from terrestrial dust storms, but most originate from the marine microorganisms in sea spray. In 2018 a team of scientists reported that hundreds of millions of viruses and tens of millions of bacteria are deposited daily on every square meter around the planet.
Sea spray is largely responsible for corrosion of metallic objects near the coastline, as the salts accelerate the corrosion process in the presence of abundant atmospheric oxygen and moisture.Salts do not dissolve in air directly, but are suspended as fine particulates, or dissolved in microscopic airborne water droplets.
The salt spray test is a measure of material endurance or resistance to corrosion, particularly if the material will be used outdoors and must perform in a mechanical load bearing or otherwise critical role. These results are often of great interest to marine industries, whose products may suffer extreme acceleration of corrosion and subsequent failure due to salt water exposure.
Global dimming is the gradual reduction in the amount of global direct irradiance at the Earth's surface that was observed for several decades after the start of systematic measurements in the 1950s. The effect varies by location, but worldwide it has been estimated to be of the order of a 4% reduction over the three decades from 1960–1990. However, after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991, a very slight reversal in the overall trend has been observed.
A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion. When the tensional forces are strong enough to cause the plate to split apart, a center block drops between the two blocks at its flanks, forming a graben. The drop of the center creates the nearly parallel steeply dipping walls of a rift valley when it is new. That feature is the beginning of the rift valley, but as the process continues, the valley widens, until it becomes a large basin that fills with sediment from the rift walls and the surrounding area. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.
Cloud condensation nuclei or CCNs are small particles typically 0.2 µm, or 1/100th the size of a cloud droplet on which water vapor condenses. Water requires a non-gaseous surface to make the transition from a vapour to a liquid; this process is called condensation. In the atmosphere, this surface presents itself as tiny solid or liquid particles called CCNs. When no CCNs are present, water vapour can be supercooled at about −13°C (8°F) for 5–6 hours before droplets spontaneously form. In above freezing temperatures the air would have to be supersaturated to around 400% before the droplets could form.
The Galileo Probe was an atmospheric-entry probe carried by the main Galileo spacecraft to Jupiter, where it directly entered a hot spot and returned data from the planet. The 339-kilogram (747 lb) probe was built by Hughes Aircraft Company at its El Segundo, California plant, and measured about 1.3 meters (4.3 ft) across. Inside the probe's heat shield, the scientific instruments were protected from extreme heat and pressure during its high-speed journey into the Jovian atmosphere, entering at 47.8 kilometers (29.7 mi) per second. It entered Jupiter on December 7 1995, 22:04 UTC and stopped functioning at 23:01 UTC, 57 minutes and 36 seconds later.
In oceanic biogeochemistry, the continental shelf pump is proposed to operate in the shallow waters of the continental shelves, acting as a mechanism to transport carbon from surface waters to the interior of the adjacent deep ocean.
Atmospheric icing occurs when water droplets in the atmosphere freeze on objects they contact. This can be extremely dangerous to aircraft, as the built-up ice changes the aerodynamics of the flight surfaces, which can increase the risk of a subsequent stalling of the airfoil. For this reason, ice protection systems are often considered critical components of flight, and aircraft are often deiced prior to take-off in icy environments.
The Journal of Geophysical Research is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the understanding of the Earth, Sun, and solar system. It has seven sections: A, B, C (Oceans), D (Atmospheres), E (Planets), F, and G (Biogeosciences). All current and back issues are available online for subscribers.
The sea surface microlayer (SML) is the top 1000 micrometers of the ocean surface. It is the boundary layer where all exchange occurs between the atmosphere and the ocean. The chemical, physical, and biological properties of the SML differ greatly from the sub-surface water just a few centimeters beneath.
Arctic methane release is the release of methane from seas and soils in permafrost regions of the Arctic. While a long-term natural process, it is exacerbated by global warming. This results in negative effects, as methane is itself a powerful greenhouse gas.
Dissolved load is the portion of a stream's total sediment load that is carried in solution, especially ions from chemical weathering. It is a major contributor to the total amount of material removed from a river's drainage basin, along with suspended load and bed load. The amount of material carried as dissolved load is typically much smaller than the suspended load, though this is not always the case, particularly when the available river flow is mostly harnessed for purposes such as irrigation or industrial uses. Dissolved load comprises a significant portion of the total material flux out of a landscape, and its composition is important in regulating the chemistry and biology of the stream water.
Stratospheric sulfur aerosols are sulfur-rich particles which exist in the stratosphere region of the Earth's atmosphere. The layer of the atmosphere in which they exist is known as the Junge layer, or simply the stratospheric aerosol layer. These particles consist of a mixture of sulfuric acid and water. They are created naturally, such as by photochemical decomposition of sulfur-containing gases, e.g. carbonyl sulfide. When present in high levels, e.g. after a strong volcanic eruption such as Mount Pinatubo, they produce a cooling effect, by reflecting sunlight, and by modifying clouds as they fall out of the stratosphere. This cooling may persist for a few years before the particles fall out.
Marine cloud brightening is a proposed solar radiation management climate engineering technique that would make clouds brighter, reflecting a small fraction of incoming sunlight back into space in order to offset anthropogenic global warming. Along with stratospheric aerosol injection, it is one of the two solar radiation management methods that may most feasibly have a substantial climate impact. The intention is that increasing the Earth's albedo, in combination with greenhouse gas emissions reduction, carbon dioxide removal, and adaptation, would reduce climate change and its risks to people and the environment. If implemented, the cooling effect is expected to be felt rapidly and to be reversible on fairly short time scales. However, technical barriers remain to large-scale marine cloud brightening. There are also risks with such modification of complex climate systems.
Frost flowers are ice crystals commonly found growing on young sea ice and thin lake ice in cold, calm conditions. The ice crystals are similar to hoar frost, and are commonly seen to grow in patches around 3–4 cm in diameter. Frost flowers growing on sea ice have extremely high salinities and concentrations of other sea water chemicals and, because of their high surface area, are efficient releasers of these chemicals into the atmosphere.
Atmospheric aerosol particles – also known as atmospheric particulate matter, particulate matter (PM), particulates, or suspended particulate matter (SPM) – are microscopic solid or liquid matter suspended in the atmosphere of Earth. The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health.
The oceanic carbon cycle is composed of processes that exchange carbon between various pools within the ocean as well as between the atmosphere, Earth interior, and the seafloor. Carbon is an element that is essential to all living things; the human body is made up of approximately 18% carbon. The carbon cycle is a result of many interacting forces across multiple time and space scales that circulates carbon around the planet, ensuring that carbon is available globally. The Oceanic carbon cycle is a central process to the global carbon cycle and contains both inorganic carbon and organic carbon. Part of the marine carbon cycle transforms carbon between non-living and living matter.
Regional Ocean Modeling System (ROMS) is a free-surface, terrain-following, primitive equations ocean model widely used by the scientific community for a diverse range of applications. The model is developed and supported by researchers at the Rutgers University, University of California Los Angeles and contributors worldwide.
Sreedharan Krishnakumari Satheesh is an Indian meteorologist and a professor at the Centre for Atmospheric and Oceanic Sciences of the Indian Institute of Science (IISc). He holds the chair of the Divecha Centre for Climate Change, a centre under the umbrella of the IISc for researches on climate variability, climate change and their impact on the environment. He is known for his studies on atmospheric aerosols and is an elected fellow of all the three major Indian science academies viz. Indian Academy of Sciences Indian National Science Academy and the National Academy of Sciences, India as well as The World Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Earth, Atmosphere, Ocean and Planetary Sciences in 2009. He received the TWAS Prize of The World Academy of Sciences in 2011.In 2018, he received the Infosys Prize, one of the highest monetary awards in India that recognize excellence in science and research, for his work in the field of climate change.
Anne M. Thompson is an American scientist, who specializes in atmospheric chemistry and climate change. Her work notably focuses on how human activities have changed the chemistry of the atmosphere, climate forcings, and the Earth's oxidizing capacity, "essentially the global burden of oxidants in the lower atmosphere". Thompson was elected as a fellow to the American Meteorological Society, American Geophysical Union, and AAAS. She is a current member of NASA's Health and Air Quality Science Team.
Kimberly (Kim) Prather is an Atmospheric Chemist and Distinguished Chair in Atmospheric Chemistry and Distinguished Professor at the Scripps Institution of Oceanography and Dept. of Chemistry and Biochemistry at UC San Diego. She studies how humans are influencing the atmosphere and climate. She is an elected Fellow of the American Geophysical Union, the American Association for the Advancement of Science, and the American Academy of Arts and Sciences.
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