80 Sentences With "polar front" | Random Sentence Generator

But the Antarctic Polar Front is expected to change as the world keeps warming up.

The birds feed in a particularly rich band of water circling Antarctica, called the Antarctic Polar Front.

Braving the region for the past two weeks, he reached the Antarctic Polar Front and is swimming southwest.

This upwelling happens near a place called the Antarctic Polar Front — where icy Antarctic oceans meet the warmer Atlantic.

If they can't reach this polar front and can't swim back within about a week, their chicks will starve to death.

What's next: As sea ice continues to decline, the Atlantic Ocean waters may push the polar front further north, effectively displacing the Arctic waters back toward the pole.

King penguins leave their young and swim south to forage for fish and squid in the waters of the Antarctic polar front, where cold, deep water mixes with more temperate seas.

This will force king penguins to swim farther to forage: birds living on the Crozet Islands, for instance, will have to swim about 435 miles (700 kilometers) to reach the Antarctic Polar Front.

Bright orange sand in the Sahara Desert was dusted in a layer of snow earlier this week after a strong polar front from the Mediterranean pushed past the Atlas Mountains near the coast of Algeria.

Trilobites Their little chicks fast for more than a week while they forage for fish and krill in the waters of the Antarctic polar front, an upwelling where cold, deep seas mix with more temperate seas.

Protecting the fish in the polar front will be crucial for the king penguins, "to ensure they have the best chance of surviving climate change," said Gemma Clucas, a postdoctoral research assistant at the University of New Hampshire, who was not involved in the new study.

The second is a "comma-shaped" signature that is found more frequently with systems closer to the polar front.

This cold period sees an expansion of the polar front, with ice floating further south across the North Atlantic Ocean.

The bases of the two polar vortices are located in the middle and upper troposphere and extend into the stratosphere. Beneath that lies a large mass of cold, dense Arctic air. The interface between the cold dry air mass of the pole and the warm moist air mass farther south defines the location of the polar front. The polar front is centered, roughly at 60° latitude.

This results in the formation of planetary wind circulations that experience a strong Coriolis deflection and thus can be considered 'quasi-geostrophic'. The polar front jet stream is closely linked to the frontogenesis process in midlatitudes, as the acceleration/deceleration of the air flow induces areas of low/high pressure respectively, which link to the formation of cyclones and anticyclones along the polar front in a relatively narrow region.

400px In meteorology, the polar front is the boundary between the polar cell and the Ferrel cell around the 60° latitude in each hemisphere. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures. The polar front arises as a result of cold polar air meeting warm tropical air. It is a stationary front as the air masses are not moving against each other.

Due to the difficulty to survey populations, 38% of marine mammals are data deficient, especially around the Antarctic Polar Front. In particular, declines in the populations of completely marine mammals tend to go unnoticed 70% of the time.

The coldest month is usually quite mild, although freezes are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front. The Köppen Climate Classification subtype for this climate is "Cfa". (Humid Subtropical Climate).

Churned up sea off the west coast of Scotland as photographed from the FAAM research aircraft at about above sea level. At 00:00 UTC on 8 December 2011, the Met Office noted a strong mid-latitude cyclone along the polar front to the west of Scotland. The polar front supported multiple cold fronts moving southeastward through the Atlantic toward mainland Europe, as well as an eastward-moving warm front approaching Great Britain. In conjunction with strong high pressure to the south, an extremely tight pressure gradient developed along the deep low and produced a large area of high winds.

Electrona subaspera, also known as the rough lanternfish, is a marine, mesopelagic fish. This species is usually found between at night. It occurs circumglobally between the subtropical convergence and the Antarctic polar front, in the southern Atlantic, Indian, and Pacific Oceans. Its maximum length is .

The predominant global pattern that affects the climate is the polar cell. This system cycles the cool polar easterlies with the polar front westerlies and in doing so creates the cold climate but also allows for a moderate amount of precipitation in the region.

The coldest month is usually quite mild, although frosts are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front. The Köppen Climate Classification subtype for this climate is "Cfa". (Humid Subtropical Climate). The average temperature for the year in Bageshwar is 20.4 °C (68.8 °F).

Karlodinium antarcticum is a species of unarmored dinoflagellates from the genus Karlodinium. It was first isolated from the Australian region of the Southern Ocean, near the polar front. It is medium-sized and is characterized by its long ovoid cell shape and rather long apical groove. It is considered potentially ichthyotoxic.

Climate is characterized by relatively high temperatures and evenly distributed precipitation throughout the year. The coldest month is usually quite mild, although frosts are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front. The Köppen Climate Classification subtype for this climate is "Cfa". (Humid Subtropical Climate).

South of the SAF is another marine zone, called the Polar Frontal Zone (PFZ). The SAZ and the PFZ together form the subantarctic region. The southernmost boundary of the PFZ (and hence, the southern border of the subantarctic region) is the Antarctic Convergence, located approximately 200 kilometers south of the Antarctic Polar Front (APF).

On November 1 Clara turned to the north and transitioned into an extra- tropical low after encountering a polar front. Clara remained mostly over open ocean during its life; however, its path did near a few minor islands. No damage was reported, but there were possibilities that damage to shipping or small islands occurred.

South of the Campbell Plateau, the eastward-flowing Antarctic Circumpolar Current (ACC) is bounded by the Antarctic Polar Front (APF) and the Subantarctic Front (SAF). It reaches New Zealand with an average volume of c. 130×106 m3/s. South of New Zealand it is partly deflected in the Tasman Sea as a broad, weak flow.

Takayama tuberculata is a species of unarmored dinoflagellates from the genus Takayama, being closely related to T. tasmanica. It was first isolated from the Australian region of the Southern Ocean, just north of the polar front. It is medium-sized and is characterized by its long ovoid cell shape and rather long apical groove. It is considered potentially ichthyotoxic.

The large typhoon continued almost straight north, maintaining its intensity, before encountering a polar front. It merged with the associated low pressure area near the Kuril Islands on October 30\. At this point Billie had completely translated into an extra- tropical low and passed over the Kamchatka Peninsula. Despite Billie's rather large size it did not pass over any significant land mass.

Agnes was the second tropical cyclone and first named storm of the 1972 Atlantic hurricane season. It developed as a tropical depression on June 14 from the interaction of a polar front and an upper trough over the Yucatán Peninsula. The storm emerged into the western Caribbean Sea on June 15, and strengthened into Tropical Storm Agnes the next day.

Karlodinium corrugatum is a species of unarmored dinoflagellates from the genus Karlodinium. It was first isolated from the Australian region of the Southern Ocean, just south of the polar front. It is small-sized and is characterized by having distinctive striations on the epicone surface which are parallel, and a distinctively shaped and placed ventral pore. It is considered potentially ichthyotoxic.

Antarctic Intermediate Water (AAIW) is a cold, relatively low salinity water mass found mostly at intermediate depths in the Southern Ocean. The AAIW is formed at the ocean surface in the Antarctic Convergence zone or more commonly called the Antarctic Polar Front zone. This convergence zone is normally located between 50°S and 60°S, hence this is where almost all of the AAIW is formed.

Moderately warm, oceanic climate (Cfb in the Köppen climate classification) This climate is dominated all year round by the polar front, leading to changeable, often overcast weather. Summers are cool due to cool ocean currents, but winters are milder than other climates in similar latitudes, but usually very cloudy. Average temperature changes between 7-8,3 °C. August is the warmest month in the year, and January – the coldes.

Polar lows are small-scale, short-lived atmospheric low-pressure systems that occur over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. They are part of the larger class of mesoscale weather-systems. Polar lows can be difficult to detect using conventional weather reports and are a hazard to high-latitude operations, such as shipping and gas- and oil- platforms.

Temperatures are high and can lead to warm, oppressive nights. Summers are usually somewhat wetter than winters, with much of the rainfall coming from convectional thunderstorm activity; tropical cyclones also enhance warm-season rainfall in some regions. The coldest month is usually quite mild, although frosts are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front. The Köppen climate classification subtype for this climate is "cwa".

Summers are usually somewhat wetter than winters, with much of the rainfall coming from convectional thunderstorm activity; tropical cyclones also enhance warm-season rainfall in some regions. The coldest month is usually quite mild, although frosts are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front. The Köppen climate classification subtype for this climate is Cwa (Humid Subtropical Climate). The average temperature for the year in Almora is .

Traces of endolithic fungi have been found in rock samples from the seamount. Life on Vesteris has formed a variety of structures, including hedges, mats, mounds, spurs and thickets, and a dense layer of biogenic sediments and living specimens covers large areas of the upper Vesteris Seamount. This environment has been compared to a coral reef. The seamount lies close to the polar front with the East Greenland Current transporting freshwater from ice melt and ice to the seamount.

The close relatives of Antarctic notothenioids, like Halaphritis, Bovichtus and Pseudaphritis, inhabited these seas. With the cleavage of Australia, South America and Africa from each other, species of marine life separated. As Antarctica cleaved from South America 122 Ma, the Drake Passage formed, fully isolating Antarctica geographically by establishing the Antarctic Circumpolar Current and the Antarctic Polar Front. The cooling of Antarctica's seas prompted a mass extinction of most of the organisms off the coasts of Antarctica and in the Southern ocean.

Carl-Gustaf Rossby was born in Stockholm, Sweden. He was the first of five children born to Arvid and Alma Charlotta (Marelius) Rossby. He attended Stockholm University, where he developed his first interest in mathematical physics. Rossby came into meteorology and oceanography while studying geophysics under Vilhelm Bjerknes at the Geophysical Institute, University of Bergen in Bergen, Norway during 1919, where Bjerknes' group was developing the groundbreaking concepts that became known as the Bergen School of Meteorology, including theory of the polar front.

A polar front and an upper trough over the Yucatán Peninsula spawned a tropical depression on June 14\. The storm emerged into the western Caribbean Sea on June 15, and by the following day, it strengthened into Tropical Storm Agnes. The storm curved northward and brushed western Cuba on June 17\. Agnes continued to intensify, and on June 18, it was upgraded to a hurricane. Minimal fluctuations in intensity occurred before the storm made landfall near Panama City, Florida, on June 19\.

In fluid mechanics, potential vorticity (PV) is a quantity which is proportional to the dot product of vorticity and stratification. This quantity, following a parcel of air or water, can only be changed by diabatic or frictional processes. It is a useful concept for understanding the generation of vorticity in cyclogenesis (the birth and development of a cyclone), especially along the polar front, and in analyzing flow in the ocean. Potential vorticity (PV) is seen as one of the important theoretical successes of modern meteorology.

DOC is also exported with subduction in the gyres. In regions where DOCenriched subtropical water is prevented by polar frontal systems from serving as a precursor for overturning circulation (such as at the sites of Antarctic Bottom Water formation in the Southern Ocean) DOC export is a weak component of the biological pump. Waters south of the Antarctic Polar Front lack significant exportable DOC (depicted by light blue field) during winter.Hansell DA and Craig AC (2015) "Marine Dissolved Organic Matter and the Carbon Cycle".

In total, runoff at the time of Lake Manly was at least 3.5 times larger than today. A southward shift of the polar front may have aided the formation of Lake Manly. Further water reached the lake from streams in the Amargosa Mountains and the Panamint Mountains, where water originates from snowmelt. Presently, the main inflows are from Salt Creek from the north and the Amargosa River, with springs around the basin contributing a large proportion of the present day water budget in the valley.

40% of the sediment of the Indian Ocean is found in the Indus and Ganges fans. The oceanic basins adjacent to the continental slopes mostly contain terrigenous sediments. The ocean south of the polar front (roughly 50° south latitude) is high in biologic productivity and dominated by non- stratified sediment composed mostly of siliceous oozes. Near the three major mid-ocean ridges the ocean floor is relatively young and therefore bare of sediment, except for the Southwest Indian Ridge due to its ultra-slow spreading rate.

Different air masses tend to be separated by frontal boundaries. The Arctic front separates Arctic from Polar air masses, while the Polar front separates Polar air from warm air masses. (cA is continental arctic; cP is continental polar; mP is maritime polar; cT is continental tropic; and mT is maritime tropic.) A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front.

Until the Winter War (1939–40), Finland's territory also reached to the Barents Sea. Its harbor at Petsamo was Finland's only ice-free winter harbor. There are three main types of water masses in the Barents Sea: Warm, salty Atlantic water (temperature >3 °C, salinity >35) from the North Atlantic drift; cold Arctic water (temperature <0 °C, salinity <35) from the north; and warm, but not very salty, coastal water (temperature >3 °C, salinity <34.7). Between the Atlantic and Polar waters, a front called the Polar Front is formed.

The Return Atlantic Current is directly east of the East Greenland Current. The high salinity and warm temperatures of the Return Atlantic Current compared to the cold temperatures and low salinities of the EGC contribute to the existence of the East Greenland Polar Front a result of the strong gradient in both salinity and temperature. There is a current that splits off from the Yermak Branch and flows towards the Northeast at a higher latitude. This current is not well understood in the literature, and thus more information is needed.

The blue petrel inhabits the southern oceans ranging as far north as South Africa, Australia and portions of South America. They mostly only breed in a narrow latitudinal band from 47° to 56° S on either side of the Antarctic Polar Front. Nesting on subantarctic islands, such as Marion Island, the Crozet Islands, Kerguelen Islands, Macquarie Island, South Georgia, Prince Edward Island. In 2014 a breeding colony was discovered on Gough Island (40° S, 10° W), central South Atlantic Ocean, more than 700 km north of its known and usual breeding range.

However, he was soon re-appointed to a new post - as Jagdfliegerführer Norwegen on 5 January 1942. Again this was a role to co- ordinate a number of scattered units, this time across Norway, facing both the Russian Polar Front, the North Sea and Arctic Ocean. This subsequently also got further centralised with the formation of the new Jagdgeschwader 5 in May 1942. In late February 1943 he was sent to Romania, and in May became head of the Luftwaffe mission to oversee the training of the Romanian air-force.

The thermal wind relation does not explain why the winds are organized into tight jets, rather than distributed more broadly over the hemisphere. One factor that contributes to the creation of a concentrated polar jet is the undercutting of sub-tropical air masses by the more dense polar air masses at the polar front. This causes surface low pressure and higher pressure at altitude. At high altitudes, lack of friction allows air to respond freely to the steep pressure gradient with low pressure at high altitude over the pole.

Fragilariopsis kerguelensis is well preserved in the fossil record and commonly referenced as a paleoceanographic or paleoclimatic proxy. F. kerguelensis comprises the largest deposit of biogenic silica in the world (~75%) despite only accounting for 20% of global production. It is an open water species and is found in its highest abundance between the Antarctic Circumpolar Current and the Subtropical Front. This, along with its tendency to increase valve size near polar fronts, makes F. kerguelensis an ideal indicator of paleoclimate polar front or low-carbon, high-silica exporting regimes.

The fronts develop at the leading edge of that cold air mass and wrap around (counter-clockwise in the northern hemisphere) about the low pressure zone. A polar front may form approximately along the equatorward edge of the high-level polar jet. Fronts are guided by winds aloft, but they normally move at lesser speeds than those winds. In the northern hemisphere, they usually travel from west to east, although they can move in a north-south direction as well as they may wrap around an associated low pressure zone.

Polar front theory was developed by Jacob Bjerknes, derived from a dense network of observation sites in Scandinavia during World War I. This theory proposed that the main inflow into a cyclone was concentrated along two lines of convergence, one ahead of the low and another trailing behind the low. The trailing convergence zone was referred to as the squall line or cold front. Areas of clouds and rainfall appeared to be focused along this convergence zone. The concept of frontal zones led to the concept of air masses.

The Antarctic vortex of the Southern Hemisphere is a single low-pressure zone that is found near the edge of the Ross ice shelf, near 160 west longitude. When the polar vortex is strong, the mid-latitude Westerlies (winds at the surface level between 30° and 60° latitude from the west) increase in strength and are persistent. When the polar vortex is weak, high-pressure zones of the mid-latitudes may push poleward, moving the polar vortex, jet stream, and polar front equatorward. The jet stream is seen to "buckle" and deviate south.

A polar low is a small-scale, symmetric, short- lived atmospheric low pressure system (depression) that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. The systems usually have a horizontal length scale of less than and exist for no more than a couple of days. They are part of the larger class of mesoscale weather systems. Polar lows can be difficult to detect using conventional weather reports and are a hazard to high-latitude operations, such as shipping and gas and oil platforms.

Doñana Park has a mild, typically Mediterranean climate, characterized by dry summers and relatively wet winters resulting from variations in the polar front and the subtropical ridge of high pressure. The rainy seasons are intermediate, occurring in spring and in autumn; autumn especially can produce torrential rains caused by the accumulation during the summer of heat in nearby large bodies of water, and the arrival of polar air masses. In winter, however, thermal anticyclones may occur locally. Temperatures are mild throughout the year, with maximum temperatures varying about 17 °C from winter to summer.

Size and distribution of phytoplankton are also related to fronts. Microphytoplankton (>20μm) are found at fronts and at sea ice boundaries, while nanophytoplankton (<20μm) are found between fronts. Studies of phytoplankton stocks in the southern sea have shown that the Antarctic Circumpolar Current is dominated by diatoms, while the Weddell Sea has abundant coccolithophorids and silicoflagellates. Surveys of the SW Indian Ocean have shown phytoplankton group variation based on their location relative to the Polar Front, with diatoms dominating South of the front, and dinoflagellates and flagellates in higher populations North of the front.

These results were confirmed and further refined by the study of drilling in Greenland ice. Today, rapid climatic variations are recognized as a major feature of climate change.Bard E., et al., « Retreat velocity of the North Atlantic Polar front during the last deglaciation determined by means of 14C accelerator mass spectrometry », Nature, 1987, 328, p. 791-794 While developing this research and a group of marine paleoclimatology, he has endeavoured to bring to light in France the study of biogeochemical cycles within the surface envelopes of our planet.

They organized an analysis and forecasting branch which would evolve into a weather bureau by 1919. The scientific team at Bergen also included the Swedish meteorologists Carl-Gustaf Rossby and Tor Bergeron. As pointed out in a key paper by Jacob Bjerknes and Halvor Solberg (1895-1974) in 1922, the dynamics of the polar front, integrated with the cyclone model, provided the major mechanism for north-south heat transport in the atmosphere. For this and other research, Jacob Bjerknes was awarded the Ph.D. from the University of Oslo in 1924.

Charney earned his undergraduate and graduate degrees at UCLA, culminating in a Ph.D. in physics in 1946. His Ph.D. dissertation, titled “The Dynamics of Long Waves in a Baroclinic Westerly Current” comprised the entire October 1947 issue of the Journal of Meteorology. The paper was influential because it emphasized the influence of “long waves” in the upper atmosphere on the behavior of the entire atmosphere rather than the more traditional emphasis on the polar front and also provided a way of analyzing perturbations along these waves that was both physically insightful and mathematically rigorous.

Scientifically, the Indian Ocean remained poorly explored before the International Indian Ocean Expedition in the early 1960s. However, the Challenger expedition 1872–1876 only reported from south of the polar front. The Valdivia expedition 1898–1899 made deep samples in the Indian Ocean. In the 1930s, the John Murray Expedition mainly studied shallow-water habitats. The Swedish Deep Sea Expedition 1947–1948 also sampled the Indian Ocean on its global tour and the Danish Galathea sampled deep-water fauna from Sri Lanka to South Africa on its second expedition 1950–1952.

Gulf of Mondello seen from Monte Pellegrino Palermo experiences a hot-summer subtropical Mediterranean climate (Köppen climate classification: Csa) with moderate seasonality. Summers are very long, hot and dry due to the domination of subtropical high pressure system, while winters are mild and changeable, with rainy weather due to the polar front. Temperatures in autumn and spring are typically warm. Palermo is one of the warmest cities in Europe (mainly due to its warm nights), with an average annual air temperature of ; it is one of the warmest cities in Italy.

Different air masses which affect North America, as well as other continents, tend to be separated by frontal boundaries. In this illustration, the Arctic front separates Arctic from Polar air masses, while the Polar front separates Polar air from warm air masses. (cA is continental arctic; cP is continental polar; mP is maritime polar; cT is continental tropic; and mT is maritime tropic.) The Arctic front is the semipermanent, semi-continuous weather front between the cold arctic air mass and the warmer air of the polar cell. It can also be defined as the southern boundary of the Arctic air mass.

Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a curve continuously encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the Subantarctic. Antarctic waters predominantly sink beneath the warmer subantarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill. This line, like the arctic tree line, is a natural boundary rather than an artificial one, such as the borders of nations and time zones. It not only separates two hydrological regions, but also separates areas of distinctive marine life and climates.

Upon tracking inland on July 16, interaction with China's mountainous terrain disrupted the organization of Billie, weakening it down to tropical storm intensity. However, the tropical cyclone's stint over land was short-lived as the system quickly curved northward into the Yellow Sea by July 17. Despite moving back over water, Billie continued to weaken, and made landfall on the western coast of North Korea with winds of 75 km/h (40 mph). Over the Korean peninsula, Billie began to intake cold air from a polar front, enabling the system to transition into an extratropical cyclone by 1800 UTC that day.

Over longer timespans, precipitation in the region increases whenever iceberg discharge and cooling occur in the North Atlantic. This was the case during the Heinrich events and the Younger Dryas when lakes formed on the Bolivian Altiplano: The Sajsi formed about 25,000–19,000years ago, Tauca about 18,000–14,000 and Coipasa 13,000–11,000years ago. Cold periods in the Southern Hemisphere such as the Antarctic Cold Reversal between 14,500 and 12,900years ago may have pushed the polar front north and increased precipitation as well. That increased precipitation may have delayed the retreat of Coropuna's glaciers after the end of the last glacial maximum.

Hurd Curtis Willett (January 1, 1903 - March 26, 1992) was an American meteorologist known for his role in developing five-day weather forecasting techniques and widely known for his attempts at very long-range forecasting. Born in Providence, Rhode Island, Willett grew up on a farm near Pittsburgh, Pennsylvania. He graduated with a B.S. degree from Princeton University in 1924, then worked at the U.S. Weather Bureau, and earned a doctorate in meteorology from George Washington University (GWU) in 1929. Willett won a Guggenheim Fellowship to study then burgeoning polar front theory, what became known as the Bergen School of Meteorology, in Norway.

They are typically nonmigrating mammals, with the exception of the northern fur seal, which has been known to travel distances up to 10,000 km. Fur seals are often found near isolated islands or peninsulas, and can be seen hauling out onto the mainland during winter. Although they are not migratory, they have been observed wandering hundreds of miles from their breeding grounds in times of scarce resources. For example, the subantarctic fur seal typically resides near temperate islands in the South Atlantic and Indian Oceans north of the Antarctic Polar Front, but juvenile males have been seen wandering as far north as Brazil and South Africa.

The current is accompanied by three fronts: the Subantarctic front (SAF), the Polar front (PF), and the Southern ACC front (SACC). Furthermore, the waters of the Southern Ocean are separated from the warmer and saltier subtropical waters by the subtropical front (STF). The northern boundary of the ACC is defined by the northern edge of the SAF, this being the most northerly water to pass through Drake Passage and therefore be circumpolar. Much of the ACC transport is carried in this front, which is defined as the latitude at which a subsurface salinity minimum or a thick layer of unstratified Subantarctic mode water first appears, allowed by temperature dominating density stratification.

Light tables were important to the construction of surface weather analyses into the 1990s The use of frontal zones on weather maps began in the 1910s in Norway. Polar front theory is attributed to Jacob Bjerknes, derived from a coastal network of observation sites in Norway during World War I. This theory proposed that the main inflow into a cyclone was concentrated along two lines of convergence, one ahead of the low and another trailing behind the low. The convergence line ahead of the low became known as either the steering line or the warm front. The trailing convergence zone was referred to as the squall line or cold front.

Meteorologisches Observatorium Lindenberg He also studied at the University of Leipzig and at the Lindenberg Observatory (Meteorologisches Observatorium Lindenberg) in Brandenburg where upper air measurements by kite and balloon were researched. In 1921 he returned to Stockholm to join the Meteorological and Hydrographic Office (which later became the Swedish Meteorological and Hydrological Institute) where he served as a meteorologist on a variety of oceanographic expeditions. While ashore between expeditions, he studied mathematical physics at the University of Stockholm (Filosofie Licentiat, 1925). In 1925 Rossby was granted a fellowship from the Sweden- America Foundation "to study the application of the polar front theory to American weather".

Mesoscale eddies are usually seen in areas of intense, winding currents such as the Gulf Stream and the Antarctic Circumpolar Current that feeds into the South Pacific and Indian oceans, but in general can be caused by a combination of factors such as cooling of sea surface temperature, convection, direct generation from wind, or water flow past an irregular coastline. Cycolic cold-core eddies are frequently formed at the polar front by the Gulf Stream and Labrador Current. The cold, nutrient-rich waters from the Labrador Sea flow south and get caught in the eastward meandering of the Gulf Stream, traveling east across the Atlantic Ocean.

A polar low over the Sea of Japan in December 2009 A polar low is a small- scale, short-lived atmospheric low pressure system (depression) that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres, as well as the Sea of Japan. The systems usually have a horizontal length scale of less than and exist for no more than a couple of days. They are part of the larger class of mesoscale weather systems. Polar lows can be difficult to detect using conventional weather reports and are a hazard to high-latitude operations, such as shipping and gas and oil platforms.

A polar low over the Sea of Japan in December 2009 A polar low is a small-scale, short-lived atmospheric low-pressure system (depression) that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. Polar lows were first identified on the meteorological satellite imagery that became available in the 1960s, which revealed many small-scale cloud vortices at high latitudes. The most active polar lows are found over certain ice-free maritime areas in or near the Arctic during the winter, such as the Norwegian Sea, Barents Sea, Labrador Sea and Gulf of Alaska. Polar lows dissipate rapidly when they make landfall.

Somerset has a humid continental climate that is affected by the high elevation, rendering it colder much of the winter than Altoona, Johnstown, or State College, despite being well south of these locations. Its climate is quite similar to those seen in northern Pennsylvania, although the average winter high temperatures are a bit higher. Somerset holds the June and November record lows for the state of Pennsylvania. Somerset is also the only place in Pennsylvania to receive accumulations of snow in June (other places received a partial dusting at most) when it received 3 inches of snow from the same polar front that caused it to drop to 20 degrees on June 10, 1913.

He joined the Massachusetts Institute of Technology (MIT) faculty in 1929, where he headed the development and adoption of the polar front theory of five-day weather prediction by the Weather Bureau. In 1951 he received a plaque from the American Meteorological Society (AMS) for Extraordinary Scientific Achievement. This was the initial prize award of what is now known as the Carl-Gustaf Rossby Research Medal. Willett was a member of the American Academy of Arts and Sciences (AASC), the American Meteorological Society, the Royal Meteorological Society (RMetS), the Association of American Geographers (AAG), the American Geophysical Union (AGU), the American Association for the Advancement of Science (AAAS), Sigma Xi, and Phi Beta Kappa.

A weather map of an extratropical cyclone affecting Great Britain and Ireland. The "L" symbol denotes the center of the "low", and the occluded, cold, and warm frontal boundaries are depicted. Polar front theory is attributed to Jacob Bjerknes, and was derived from a coastal network of observation sites in Norway during World War I. This theory proposed that the main inflow into a cyclone was concentrated along two lines of convergence, one ahead (or east) of the low and another trailing equatorward (south in the Northern Hemisphere and north in the Southern Hemisphere) and behind (or west) of the low. The convergence line ahead of the low became known as either the steering line or the warm front.

The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along the polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from to . For example, Biskra, Algeria, and Ouarzazate, Morocco, are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of the Intertropical Convergence Zone from the south and the annual average rainfall ranges from to .

Indeed, the extreme aridity of the Sahara is not only explained by the subtropical high pressure: the Atlas Mountains of Algeria, Morocco and Tunisia also help to enhance the aridity of the northern part of the desert. These major mountain ranges act as a barrier, causing a strong rain shadow effect on the leeward side by dropping much of the humidity brought by atmospheric disturbances along the polar front which affects the surrounding Mediterranean climates. The primary source of rain in the Sahara is the Intertropical Convergence Zone, a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular rainy season to the Sahel and southern Sahara. Rainfall in this giant desert has to overcome the physical and atmospheric barriers that normally prevent the production of precipitation.

Southern Ocean sediments are a major sink for biogenic silica (50-75% of the oceanic total of 4.5 × 1014 g SiO2 yr−1; DeMaster, 1981), but only a minor sink for organic carbon (<1% of the oceanic 2 × 1014 g of organic C yr−1). These relatively high rates of biogenic silica accumulation in the Southern Ocean sediments (predominantly beneath the Polar Front) relative to organic carbon (60:1 on a weight basis) results from the preferential preservation of biogenic silica in the Antarctic water column. In contrast to what was previously thought, these high rates of biogenic silica accumulation are not the result from high rates of primary production. Biological production in the Southern Ocean is strongly limited due to the low levels of irradiance coupled with deep mixed layers and/or by limited amounts of micronutrients, such as iron.