Climate Change · Part One
Climate Change · Part Two
Introduction to Astronomy
Life in the Universe
Glossary: Climate Change
Glossary: Life in Universe
Glossary of Terms - A to F
Index: A to F | G to L | M to R | S to Z
Absorption lines - (n.)
Any portion of the electromagnetic spectrum (including visible light) that is trapped by free atoms or molecules in the path of the radiation, thus reducing their transmission. In the climate context, this is important for the greenhouse effect since water vapor, carbon dioxide and methane absorb certain wavelengths of infrared radiation.
Adiabatic expansion/compression - (n.)
Expansion (or compression) of a gas (e.g. air) without exchange of heat with the surroundings. Air cools upon expansion and heats up upon compression, and this is the main reason for the vertical temperature gradient seen in the lower atmosphere (i.e. the troposphere). The adiabatic temperature gradient in dry air is near 1°C for every 100 m change in elevation. The actual gradient on Earth is less because of the presence of water in the air.
Aerosol - (n.)
Any small particle, solid or fluid, that is suspended in air. Abundance values typically range from 100 to 10,000 particles per cubic centimeter for air over land with higher values found in cities. Sizes vary greatly, but typically are near 0.1 μm or less. The particles originate from wind-blown sea-salt or dust, volcanic eruptions, burning of vegetation, combustion of coal and petroleum products, and other natural and anthropogenic processes. Aerosol particles serve as nuclei for condensation of water droplets and for growth of ice crystals and also influence the radiation balance directly. In the lower stratosphere, concentrations are extremely low; much of the aerosol here consists of droplets of sulfuric acid.
Agassiz, Jean Louis Rudolphe -
(1807-1877): Swiss naturalist, paleontologist and geologist. He received his degree in medical sciences 1830 and followed by studying with Cuvier at the Musée d'Histoire Naturelle in Paris (1831-32). In 1832 he became a professor in Neuchâtel, and then in 1848 he served as professor at Harvard, where he founded the Museum of Comparative Zoology in 1858. A world expert on fishes, mollusks and echinoderms, Agassiz was also the originator of the concept of the "Great Ice Age," an idea which proved to be useful for the investigation of climate change and for the reconstruction of ice age history. He was the last distinguished paleontologist to reject Darwin's evolutionary theories in favor the ideas of repeated extinction and creation events, in the tradition of d'Orbigny and Cuvier.
Albedo - (n.)
Meaning "whiteness,” albedo is a measure of the reflectivity of a surface. If a surface has an albedo of 40%, it means that 40% of the light falling on a surface is reflected. The planetary albedo of Earth is its reflectivity as seen from space (near 30%). Also, there is cloud albedo and ground albedo. The ocean, on the whole, has a low albedo, as do forests. The deserts have high albedo, while fresh snow has the highest albedo of the common surfaces on Earth.
Alleroed - (n.)
A village in Denmark whose name is used for a warm period at the end of the last glacial.
Arrhenius, Gustaf -
(born 1922): Swedish-American geochemist and a member of the Swedish Deep-Sea Expedition (1947-1949). He discovered cyclic sedimentation in the long cores taken in the equatorial Pacific and related these observations to climate cycles in the ice ages. He is currently a professor at the Scripps Institution of Oceanography at UC San Diego.
Arrhenius, Svante -
(1859-1927): Swedish physicist and chemist who discovered ionic dissociation and its role in making solutions conduct an electric current. He predicted global warming from the release of carbon dioxide to the atmosphere and made calculations on the magnitude of the effect.
Atlantic Heat Conveyor - (n.)
The considerable heat transfer from south to north by near-surface waters moving across the equator in the Atlantic. This movement is required to balance a southward flow of water in the ocean depths. This deep water, called the "North Atlantic Deep Water," moves sluggishly but the flow is considerable - some 20 Sverdrup - and is rather cold (between about 2°C and 4°C). So since the North Atlantic trades cold water for warm, it gains lots of heat in the process. This is the reason regions well north of 60°N, such as in Scandinavia, have comparably mild climates. The graph below shows the flow of heat (in units of 1013 Watts) across the present Atlantic (“+” symbol), across the Atlantic during glacial times (“o” symbol), and the world ocean average (thick solid line bordered by thin lines that represent the upper and lower limits ). The general trend to take from the graph is that heat is transported from southern to northern latitudes.
Axelrod, Daniel I. -
(1910-1998): American paleoecologist who who reconstructed past climates, vegetation types, and entire landscapes from fossil impressions of leaves, stems, cones, and fruits.
Barron, Eric -
American climatologist who pioneered the application numerical climate models to climate history and change.
Index: A to F | G to L | M to R | S to Z
Berger, André L. -
Belgian astronomer and climatologist. He calculated the solar input on Earth's surface on a very detailed time scale, for millions of years into the past and into the future. His calculations provided the basis for assigning a detailed ice age chronology using Milankovitch theory (see below, Milutin Milankovitch).
Bergeron, Tor H. P. -
(1891-1977): Swedish meteorologist. While working at the Geophysical Institute in Bergen, Norway, he conducted research on cloud formation and, in 1935, he proposed that the formation of ice crystals is crucial in producing rain in a paper entitled, "On the Physics of Clouds and Precipitation." His contributions include the theory of polar fronts (in collaboration with Jacob Bjerknes), methods of weather forecasting, and studies on the growth of ice sheets.
Berger, Wolfgang H. -
(born 1937): German-American geologist and oceanographer currently working at Scripps Institution of Oceanography, UC San Diego. His research includes the history of carbonate sedimentation and ice age climate as recorded in ocean sediments as well as contributions to the history of ocean productivity.
Berner, Robert -
American geochemist. His contributions to biogeochemistry include the reconstruction of the carbon dioxide content of the atmosphere through the last 100 million years.
Biogeochemistry - (n.)
Life on our planet is made up of an incredible variety of carbon molecules - in essence, life processes can simply be viewed as carbon chemistry. Conversely, the carbon cycle, the movement of carbon atoms through the various reservoirs in the climate-driven part of Earth, is intimately tied to life processes. In the study of the carbon cycle, biology and geochemistry merge to form a new scientific discipline, called "biogeochemistry." Biogeochemists study the carbon cycle in its interconnections with the cycles of other elements involved in life processes, mainly nitrogen, oxygen and phosphorus, but also sulfur and iron and certain trace metals. Also, the water cycle helps drive the carbon cycle, and this is where climate and the carbon cycle are most intimately connected.
Biogeochemistry includes the history of the great carbon reservoirs in the crust of the Earth, the limestones and the coal deposits, as well as the distribution of nitrate and phosphate in the ocean. It seeks to explain the composition of the atmosphere, consisting of nitrogen, oxygen and the trace gases, as a result of bacterial action and photosynthesis. And it records the exchange of matter at the interfaces such as the decay of organic matter in soils and the resulting gases released into the air, the uptake of oxygen by the ocean and its utilization at depth, and the leaching of nutrients from the soil and their transport into the sea. In a sense, biogeochemistry treats the dynamic systems near the surface of Earth as a few interacting organisms living in symbiosis, where the waste products of one become the stuff of life for the other. For example, the ocean takes up oxygen (the waste product of plants) and releases an equivalent amount of carbon dioxide (the waste product of decay and the stuff of growth for plants). The all-important role of life processes in maintaining Earth's environments was stressed early in the 20th century by the Russian chemist Vladimir Vernadsky (1863-1945), who may be considered the father of biogeochemistry, although that term had not been invented at the time. The American limnologist and geochemist G. Evelyn Hutchinson (1903-1991) first outlined the broad scope and principles of the new field and led the way. More recently, the basic elements of the discipline of biogeochemistry have been restated and popularized by the British engineer and science writer James Lovelock (born 1919) under the label of the "Gaia Hypothesis." Lovelock emphasizes a concept that life processes regulate the radiation balance of Earth to keep it habitable.
Biological pump - (n.)
On short time scales, when compensating geochemical adjustments (e.g. changes in weathering processes on land and deposition and dissolution of calcium carbonate-rich sediments) can be neglected, the ocean's “productivity” (see definition below) is an important control on the partial pressure of atmospheric CO2. The biological pump runs on photosynthesis, which can be visualized as the fixation of dissolved carbon into particles, and relies on the settling of such particles out of the sunlit zone into deeper waters. In this manner, the biological pump removes carbon from the interface between ocean and atmosphere. The atmosphere, as a result, has less carbon dioxide than it would have otherwise. The efficiency of the pump is controlled by the amount of nutrients available to drive the process. Thus, if somehow the nutrient content of the ocean were increased, the biologic pump would be more efficient, and the CO2 of the atmosphere would drop. An increase in nutrients in the ocean during glacial periods was proposed by Wallace Broecker to explain the lowered CO2 content of the atmosphere measured in the air recovered from polar ice. The effect is one of many that must be considered when attempting to explain the fluctuations in CO2 during the ice ages.
Bjerknes, Jacob -
(1897-1975): Norwegian meterologist (son of Vilhelm Bjerknes, see above). His theory of polar fronts (in collaboration with Tor Bergeron) applied the term "front" to the boundaries between two air masses having different properties (temperature, vapor content, density). The polar front theory was used to explain the origin of cyclones (low-pressure centers) from interaction between warm and cold air masses in the northern Atlantic Ocean.
Bjerknes, Vilhelm -
(1862-1951): Norwegian meteorologist who developed mathematical models of atmospheric and oceanic motions, and co-founded modern physical oceanography.
Breakthrough - (n.)
An unexpected solution to a difficult problem of long standing. Finding a breakthrough is like winning the scientific lottery. Breakthroughs are claimed and rejected (e.g. cold fusion) in a manner akin to drawing a check on expected winnings but with the wrong number on the ticket.
Broecker, Wallace S. -
(born 1931): American oceanographer who made many important contributions in the study of the ocean's carbon cycle, rates of deep circulation and heat transport, nutrient budget, and climate history during the ice ages. He has been a Professor of Geology at Columbia University since 1961 and a member of the staff of the Lamont-Doherty Earth Observatory in Palisades, New York.. His major project, GEOSECS, is a global net of profiles through the ocean designed to define the chemical properties of the ocean in detail.
Brückner, Eduard -
(1862-1927): Austrian meteorologist. He was a pioneer in reconstructing climatic conditions in northern Europe for the last 1000 years and discovered the 35-year fluctuations of damp-cold and warm-dry intervals known as "Brückner Cycles." He co-authored a major work with Albrecht Penck on the geology of the Alps as well as contributing to our understanding of the dynamics of mountain glaciers.
Index: A to F | G to L | M to R | S to Z
Bryan, Kirk -
American climatologist. He applies computer models toward the comparison of the atmosphere and the ocean and their complimentary roles in the global heat and water balance. He also uses ocean-atmosphere models to determine climate predictability in middle and high latitude areas.
Btu - (n.)
British Thermal Unit is a unit of energy (energy is the ability to do work). The definition for Btu is the amount of energy required to raise the temperature of 1 pound of water 1 degree Fahrenheit (°F). Practically speaking, a Btu is equivalent to about the heat from a kitchen match. The unit 1 quadrillion Btu (1015 Btu) is often used for reporting fossil fuel use.
Budyko, Mikail I. -
Russian climatologist. By applying mathematical climate modeling and climate history reconstruction, Buyko was one of the first scientists to attempt calculation of carbon dioxide levels for the distant past.
Buffer factor - (n.)
See “Revelle Buffer Factor.”
Carbon isotopes - (n.)
Both the stable isotope carbon-13 and the unstable carbon-14 are used as tracers of climate-related processes. (see also "radiocarbon." for more on carbon-14) Carbon isotopes are useful in documenting the rate and amount of input of carbon dioxide into the atmosphere from human activities (the burning of fossil fuels and deforestation) and in tracing the path of this added carbon through the carbon cycle. Carbon dioxide in the atmosphere provides the raw material for making the wood in tree trunks and analysis of tree rings shows how the composition of the atmosphere changed. Since 1950, there has been a marked decrease in the ratio of 14C to 12C due to the input of 14C-free carbon from fossil fuels (a phenomenon known as the "Suess Effect"). A similar change is seen in the ratio of 13C to 12C because fossil fuels have less 13C than does the atmosphere (as is true for all carbon compounds derived from photosynthesis). Long-term trends in 14C in tree rings show that the atmospheric concentration of this isotope has changed in the past several thousand years due to natural causes, including changes in production within the atmosphere and changes in the exchange between atmosphere and ocean. On long time-scales, 13C in marine carbonates is useful in reconstructing the productivity history of the ocean, as well as yielding clues to CO2 levels in the geological past.
Climate contrarians - (n.)
See "greenhouse skeptics."
Climate versus weather - (n.)
Weather is the day-to-day pattern of atmospheric flow with its associated cloud cover, temperature, and humidity. To answer the question "Will it rain in Los Angeles tomorrow?" a weather forecast is required. The season-to-season or year-to-year variability of weather in an overall or average sense is called climate. To address the question "Will the ongoing drought persist for another two years?", a climate forecast is required to find the probable answer. Climate is typically described by the regional patterns of seasonal temperature and precipitation. Average annual temperature, average rainfall, average cloud cover, and average depth of frost penetration are typical climate-related statistics.
Clouds - (n.)
Clouds consist of fine water particles floating in air and which are dense enough to prevent the direct transmission of light. The particles can be frozen, as with ice clouds. Condensation of water occurs when the moisture in the air exceeds the capability of the air to hold the water vapor (upon cooling moist air or mixing it with cold air) and when microscopic particles called aerosols are present on which the vapor can condense. Clouds come in many different types, depending on particle size and density, temperature and phase, thickness and elevation, cloud size and dynamics of change. The properties and the response of different types of clouds is crucial to the improvement of prediction of how the Earth's climate will respond to global warming. On the whole, higher temperature will produce greater moisture in the air, which will favor the formation of clouds in the cool regions of the atmosphere, which may move upward as the surface warms. The general increase of pollution of the atmosphere that is associated with increased human activity (e.g. burning, agriculture, and diesel engines) should favor the availability of cloud nuclei. Clouds also provide for "cloud albedo," since they reflect much of the sunlight into space, but they also trap infrared radiation. How the balance between these two effects will shift is uncertain. From a geological viewpoint (considering the climate patterns on a warm Earth, before the presence of large glaciers) it seems reasonable to expect that increasing clouds in the tropics will cool the tropics and increasing clouds in high latitudes will warm the cold regions.
Coastal upwelling - (n.)
Along many coastlines, especially at the western coasts of continents, there is a strong upward motion of cold deep waters called "coastal upwelling." Coastal upwelling is driven by winds related to the trade-wind system. Strong seasonal coastal upwelling occurs off the shores of California (whose cold water forces surfers wear wetsuits), Peru, northwestern Africa, Namibia, and in the Arabian Sea. The cold water coming from below the surface layer is rich in the nutrients nitrate and phosphate. The nutrients stimulate the growth of microscopic green algae called phytoplankton. These serve as food for small animals called zooplankton. The plankton is eaten by fish, mostly anchovies and sardines, which are in turn caught by bigger fish, sea lions, birds, and people. See also “productivity,” below. (Side note: whales off the coast of Namibia feed in the green upwelling waters, hence the name "Walvis Bay," given during the heydays of whaling.)
Columbus, Christopher -
(1451-1506): Genoese explorer and adventurer. He first crossed the Atlantic at its widest and discovered the trade wind route from the Canary Islands to the Bahamas. Commonly credited with discovering America, he commanded three modest-size vessels, the "Santa Maria", the "Niña" and the "Pinta", which set out from Spain to discover a westward passage to India. On making landfall in the Bahamas in October 1492 after a 36 day voyage across the Atlantic, he wrote in his logbook: "What will we get to see? Marble bridges? Golden-roofed temples? Spice gardens? People like us, or some strange race of giants? Did we reach an island or Japan itself?" What he found were harmless natives, "mighty forests", a clear brook, and "enormous unknown fruits" - but no signs of wealth. Columbus named the island "San Salvador", made contact with the friendly "Indians", claimed their land for the Spanish Crown, and started looking for Japan, thinking it could not be far off.
Concentration Units - (n.)
For very small concentrations of gases, atmospheric scientists use the following units:
ppmv: parts per million (106) by volume; the fraction of volume of gas occupied by a component multiplied by 1,000,000. If there is 3 ppm of CO2 in a bottle filled with gas, then for every 1,000,000 molecules in the bottle, 3 of those molecules are CO2.
ppbv: parts per billion (109) by volume; the fraction of volume of gas occupied by a component multiplied by 1,000,000,000. If there is 3 ppb of CO2 in a bottle filled with gas, then for every 1,000,000,000 molecules in the bottle, 3 molecules of those are CO2.
pptv: parts per trillion (1012) by volume; the fraction of volume of gas occupied by a component multiplied by 1,000,000,000,000. If there is 3 ppt of CO2 in a bottle filled with gas, then for every 1,000,000,000,000 molecules in the bottle, 3 of those molecules are CO2.
Index: A to F | G to L | M to R | S to Z
Coriolis Force - (n.)
A force describing the acceleration on particles on a rotating sphere, in the case where the rotating sphere is the frame of reference. In principle, this force works as follows when considering motions on the surface of Earth: any particle at any latitude rotates east around the Earth's axis once in 24 hours. At the equator, this movement is associated with a maximum velocity. Here a particle moves by 1/24 of the circumference of Earth each hour (close to 1000 miles per hour). Places away from the equator have a lower eastward velocity equal to 1/24 of the circumference times the sine of the latitude per hour. Therefore, if a particle moves from the equator to higher latitudes, it will tend to outrun whatever is there already, deflecting it to the east (e.g. the westerlies). Conversely, if a particle moves toward the equator, it will tend to lag behind what is there already, and therefore be deflected to the west, with respect to the Earth's surface (e.g. the trade-winds). Particles that initially move straight east will tend to stay on a great circle, by inertia, and soon find themselves crossing latitudes, which again results in the familiar deflection, and the same is true for particles initially moving straight west. Due to the Coriolis Force, movement in gyres, cyclones and anticylones is the natural way for air and ocean currents to move on the rotating sphere of the Earth.
Craig, Harmon -
American geochemist. A chief scientist on numerous ocean expeditions, his work includes major contributions to the understanding of Earth's carbon cycle and the application of helium and argon isotope analysis to oceanography. After being trained in Chicago by his Ph.D. adviser, Harold Urey, Craig came to Scripps Institution of Oceanography at UC San Diego in 1955, and has worked there since. He is deeply involved in the GEOSECS project, a global net of profiles through the ocean designed to define the chemical properties of the ocean in detail.
Crutzen, Paul J. -
(born 1933): Dutch meteorologist and a world expert on the chemical interactions of trace gases and trace components in the atmosphere. He is originator of a viable theory for the causes of rapid ozone loss in the Antarctic winter and was involved in international negotiations regarding the restriction of the use of CFC’s (Chloroflourocarbons) that destroy ozone. In 1980, he became director of the Department of Atmospheric Chemistry at the Max Planck Institute for Chemistry in Mainz. In 1995 Crutzen, M.J. Molina and F.S. Rowland together won the Nobel Prize with for their work on the depletion of the ozone layer.
Cuvier, Georges Leopold Chrétien Frédéric Dagobert -
(1769-1832). A pioneer of paleontology, this French zoologist and statesman began his studies in business administration at the Academie Caroline in Stuttgart but subsequently became an expert in natural sciences while making a living as a private instructor in Normandy. A leading vertebrate expert of his time, Cuvier wrote a formal description of the now extinct mammoth as a zoological species and applied fossils in stratigraphy. He also believed in immutability of species. He was a professor of natural history at the Ecole Centrale in Paris and a professor for anatomy at the Musée d'Histoire Naturelle in Paris in 1795. He became Chancellor of the University of Paris in 1814 and a member of the Académie Française in 1818. In 1819 Cuvier received the title of baron.
Cyclones - (n.)
Weather is typically described by a weather map, showing lines of equal pressure (isobars), boundaries between air masses (fronts), and direction of motion. A commonly seen map, in mid-latitudes, describes a large cyclonic eddy in the air, which forms when a tongue of warm, moist tropical air invades cold, dry polar air masses. The center of the cyclone is a region of low pressure (indicated by the letter L on maps). There are two fronts (air-mass boundaries): a warm front and a cold front. An observer on the ground sees first the warm front, as the cyclone moves eastward. Air pressure drops, temperature rises with the arrival of the tropical air, and so does humidity. Cloudiness increases and a rainstorm may follow. The reason for the rain is that warm air surrounded by cold air must rise, and as it rises, it cools and loses its ability to hold water. The condensation of the water vapor within the rising air releases heat, so that the air warms and keeps rising until condensation stops. A few days later the cold front arrives, restoring cooler, drier weather. The cyclones are separated by high pressure centers (marked by the letter H). Air moves clockwise around these H centers (anticyclonic circulation), while it flows anti-clockwise within the cyclones in the northern hemisphere. The reason that the air moves in eddies, rather than in straight paths, is the rotation of the Earth. The great centers of cyclone creation in the northern hemisphere are the Aleutian Low and the Iceland Low. Cyclones are extremely common in the bad-weather belt in the sub-Antarctic, with the worst region being the Drake Passage.
Dansgaard, Willi -
(born 1922): Danish climatologist. He applies environmental isotopes to meteorological, hydrological, and glaciological problems, particularly to the climate of the last 100,000 years. With his groundbreaking work in the early 1960’s, Dansgaard made careful measurement of the oxygen isotope levels in Greenland ice cores and was thereby able to reconstruct the climatic history of the last 100,000 years.
Doldrums - (n.)
Zone, on or close to the equator, where the air shows mainly vertical motion and there is little wind. A doldrum is “a dull person or a long sleeper,” and Doldrums refers to the becalmed ships with flapping sails (as in the phrase, "in the doldrums," a depressed state). See also “Intertropical Convergence Zone.”
Douglass, Andrew Ellicott -
(1867-1962): An American astronomer who established the science of dendrochronology. As a professor of astronomy and physics at the University of Arizona, Douglass was interested in the history of the 11-year sunspot cycle and searched for this cycle in tree rings hoping that trees would respond to climate change provoked by the solar cycle. He was able to produce a 2000-year chronology for the Southwest, and his Arizona Tree-Ring Laboratory became the leading institution in the world for tree-ring studies.
Duplessy, J.C. -
French paleoceanographer who reconstructed deep-sea circulation through the ice ages.
Index: A to F | G to L | M to R | S to Z
El Niño - (n.)
(Pronounced “El Nin-yo”) The term refers to the “Christ Child” and originates with the fishermen in Ecuador and Peru who apply it to a warm current that appears every few years in their fishing areas around Christmas. Normally, the cold Peru Current (or Humboldt Current) flows offshore from south to north. Associated with the cold current is a process called "coastal upwelling,” the rising of cold subsurface water. This water is rich in nutrients, nitrate and phosphate. The nutrients stimulate the growth of microscopic green algae, called phytoplankton, that produces food for zooplankton and fish. Whenever the warm current appears, upwelling ceases and phytoplankton production is greatly diminished. This happens every three or four years or so, in December (hence the term “Christ Child”) but not on a predictable schedule. The appearance of the warm current off Peru is a spill-over from a much larger event: a general warming in the eastern tropical Pacific during certain years. Normally, the Pacific trade winds move warm tropical surface waters to the west, piling it up in the "warm pool" region between Indonesia, the Philippines and New Guinea. The water there has a year-round temperature close to 29°C (85°F). For some reason, during certain years, the trade-winds weaken and warm surface water is no longer carried westward. On the contrary, during El Niño the piled-up warm-pool water starts moving east, taking the convection region with it, and the tropical rain that is associated with warm surface waters. The surface waters in the eastern region become warm. Now suddenly tropical storms occur in the region of Tahiti,and the coral there suffer from being too warm, shedding their color-giving algal symbionts. In contrast, drought strikes in the western areas, which are no longer in the convection center (e.g. New Guinea, Indonesia). Extraordinary events of precipitation in southern California (which produce high stream flow or flooding) are commonly associated with El Niño conditions, when the eastern Pacific is unusually warm. Winter storms, generated in the North Pacific, move farther south than at "normal" times and have the opportunity to pick up moist tropical air along the way. Absent an offshore high which acts as a barracade, the storm systems can invade the region and dump their load. The question is why El Niño events occur at all, and why they come at intervals of typically three or four years. The answer is not known, but apparently, the buildup of the western warm pool by the trade winds sets up an unstable situation. Once decay of the pool is triggered, the process feeds on itself since the redistribution of warm water interferes with normal trade wind patterns. It then takes well over a year to get things back to "normal."
How will global warming change affect the occurrence of El Niño events? Using variations in several indicators (air pressure, temperature, cloud, etc.), climatologists observe a tendency toward more frequent occurrence in El Niño conditions, for the last twenty years. Also, there are fewer "colder-than-normal" conditions, with especially strong trade winds and a corresponding warm pool pile-up. It is not clear, at this point, whether this change is permanent and whether mankind's activities have anything to do with it. Conceivably, the ongoing addition of greenhouse gases to the atmosphere is making conditions more favorable for the development of El Niño conditions. Alternatively, the climate system will eventually return to a previous state of fewer and less pronounced El Niño events, and their recent greater abundance is simply part of long-term climate cycles. Research on laminated sediments in Santa Barbara Basin, which contain a record of floods in the drainage region of Santa Barbara, suggests that such long-term cycles exist. One prominent cycle lasts a hundred years or so, another about fifty years. The answers will come from a more detailed study of the historical record, and from improved models of climate, which will including the strange anomalies called El Niño. See the table below for a list of the El Niño years in San Deigo since 1950.
Table of years of El Niño conditions in San Diego County (From 1950 onward, these years had strong rains in December):
Emiliani, Cesare -
(1922-1995): Italian paleoceanographer who applied Urey's oxygen isotope method to deep-sea sediments recovered during the Swedish Deep-Sea Expedition and by subsequent expeditions carried out by Lamont Geologic Observatory and the University of Miami. He discovered that the temperature of the ocean and the ice masses on Earth changed through time in cycles and showed that these cycles could be recognized and correlated throughout the Atlantic. On the basis of oxygen isotopes in sediment samples from the seafloor he suggested an overall cooling of the deep ocean since Eocene time. Emiliani also pioneered deep drilling into the seafloor for the purposes of climate reconstruction.
Export production - (n.)
The amount of matter produced in the photic zone of the oceans (where light can penetrate) which is then exported to deeper waters. It is commonly used to mean organic matter export or organic carbon flux downward. When measuring the amount of material settling from the sunlit zone it is found that the export production is much greater in the coastal ocean close to land than in the open ocean. However, there is one exception to this rule: right at the equator the export also is rather large over much of the ocean, due to the high productivity found there. See also "Productivity."
Ferrel, William -
(1817-1891): American meteorologist. His major work was Essay on the Winds and Currents of the Oceans, written in 1856. He studied reflection of air and ocean currents by the rotation of the Earth and found that air tends to move in circles, especially in the higher latitudes. Other contributions include the understanding of cyclonic storms.
Flohn, Hermann -
(1912-1997): German meteorologist who emphasized the importance of cross-equatorial heat flow from the southern to the northern hemisphere and related this asymmetry to the presence of the large ice mass on Antarctica.
Franklin, Benjamin -
(1706-1790): Although known as a statesman and and experimenter on electricity in lightning, Franklin also made a map of the Gulf Stream and determined that the Gulf Stream formed a link between the westward flowing North-Equatorial Current and the eastward flowing North Atlantic Current.
Index: A to F | G to L | M to R | S to Z