Tasa Graphic Arts, Inc.
1210B Salazar Road - Taos, NM USA 87571
Phone: (800) 293-2725 or (575) 758-5535 - Fax: (575) 758-5536
E-mail: info@tasagraphicarts.com
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Tasa Graphic Arts, Inc. 1210B Salazar Road - Taos, NM USA 87571 Phone: (800) 293-2725 or (575) 758-5535 - Fax: (575) 758-5536 E-mail: info@tasagraphicarts.com |
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Tasa Portfolio Volume 4 Captions |
The images on Tasa Portfolio Volume 4 are related to these subjects:
The Atmosphere Pressure and Wind Moisture Weather Patterns Climate The Solar System Light and the Sun Beyond Our Solar System TGA301.jpg Proportional volume of gases composing dry air. Nitrogen and oxygen clearly dominate. TGA302.jpg Major primary pollutants and their sources. Percentages are calculated on the basis of weight. (Data from the U. S. Environmental Protection Agency) TGA303.jpg Atmospheric pressure variation with altitude. The rate of pressure decrease with an increase in altitude is not constant. Rather, pressure decreases rapidly near Earth's surface and more gradually at greater heights. TGA304.jpg This satellite image shows ozone distribution in the Southern Hemisphere in October 1998. The area of greatest depletion is called the "ozone hole". The hole is that region where ozone concentrations are less than 220 Dobson units. The ozone hole forms over Antarctica during the Southern Hemisphere spring. In 1998 it extended over about 26 million square kilometers (10 million square miles). For comparison, the area of continental United States is about 9.4 million square kilometers (3.7 million square miles). (Data from NOAA) TGA305.jpg Thermal structure of the atmosphere. TGA306.jpg Changes in the Sun's angle causes variations in the amount of solar energy reaching Earth's surface. The higher the angle, the more intense the solar radiation. TGA307.jpg Rays striking Earth at a low angle (toward the poles) must travel through more of the atmosphere than rays striking at a high angle (around the equator) and thus are subject to greater depletion by reflection and absorption. TGA308.jpg Earth-Sun relationships. TGA309.jpg Characteristics of the solstices and equinoxes. TGA310.jpg The three mechanisms of heat transfer: conduction, convection, and radiation. TGA311.jpg The electromagnetic spectrum, illustrating the wavelengths and names of various types of radiation. TGA312.jpg Average distribution of incoming solar radiation by percentage. More solar energy is absorbed by Earth's surface than by the atmosphere. Consequently, the air is not heated directly by the Sun, but is heated indirectly from Earth's surface. TGA313.jpg The heating of the atmosphere. Most of the short-wavelength radiation from the Sun passes through the atmosphere and is absorbed by Earth's land-sea surface. This energy is then emitted from the surface as longer-wavelength radiation, much of which is absorbed by certain gases in the atmosphere. Some of the energy absorbed by the atmosphere will be reradiated Earthward. This so-called greenhouse effect is responsible for keeping Earth's surface much warmer than it would be otherwise. TGA314.jpg Isothermal map. Isotherms are lines that connect points of equal temperature. Showing temperature distribution in this way makes patterns easier to see. On television, and in many newspapers, temperature maps are in color. Rather than labeling isotherms, the area between isotherms is labeled. For example, the zone between the 60 degrees and 70 degrees isotherms is labeled "60". TGA315.jpg Mean monthly temperatures for Vancouver, British Columbia, and Winnipeg, Manitoba. Vancouver has a much smaller annual temperature range owing to the strong marine influence of the Pacific Ocean. Winnipeg illustrates the greater extremes associated with an interior location. TGA316.jpg Monthly mean temperatures for Eureka, California, and New York City. Both cities are coastal and located at about the same latitude. Because Eureka is strongly influenced by prevailing winds from the ocean and New York City is not, the annual temperatures range at Eureka is much smaller. TGA317.jpg Clouds reduce the daily temperature range. A. During daylight hours, clouds reflect solar radiation back to space. Therefore, the maximum temperature is lower than if the sky were clear. B. At night, the minimum temperature will not fall as low because clouds retard the loss of heat. TGA318.jpg World mean sea-level temperatures in January in degrees Celsius. TGA319.jpg World mean sea-level temperatures in July in degrees Celsius. TGA320.jpg Changes of state. TGA321.jpg When the temperature remains constant, relative humidity will increase as water vapor is added to the air. Here the water vapor capacity remains constant at 20 grams per kilogram, while the relative humidity rises from 25 percent to 100 percent as the water vapor content (specific humidity) increases. TGA322.jpg When the water vapor content remains constant, the relative humidity can be changed by increasing or decreasing the air temperature. In this example, when the temperature of the air in the flask was lowered from 20 degrees C to 10 degrees C, the relative humidity increased from 50 percent to 100 percent. Thus, 10 degrees C is the dew point. Further cooling (from 10 degrees C to 0 degrees C) causes one-half of the water vapor to condense because colder air holds less moisture. In nature, cooling of air below its dew point generally causes condensation in the form of clouds, dew, or fog. TGA323.jpg Typical daily variations in temperature and relative humidity during a spring day at Washington, D.C. When temperature increases, relative humidity drops. TGA324.jpg Rising air cools at the dry adiabatic rate of 10 degrees per 1000 meters, until the air reaches the dew point and condensation (cloud formation) begins. As air continues to rise, the latent heat released by condensation reduces the rate of cooling. The wet adiabatic rate is therefore always less than the dry adiabatic rate. TGA325.jpg In a stable atmosphere, as an unsaturated parcel of air is lifted, it expands and cools at the dry adiabatic rate of 10 degrees C per 1000 meters. Because the temperature of the rising parcel of air is lower than that of the surrounding environment, it will be heavier and, if allowed to do so, will sink to its original position. TGA326.jpg Absolute stability prevails when the environmental lapse rate is less than the wet adiabatic rate. The rising parcel of air is therefore always cooler and denser than the surrounding air. When stable air is forced to rise, it spreads out, producing flat, layered clouds. TGA327.jpg Absolute instability illustrated using an environmental lapse rate of 12 degrees C per 1000 meters. The rising air is always warmer and therefore lighter than the surrounding air. TGA328.jpg A. Generalized temperature profile for a surface inversion. B. Inversions aloft frequently develop in association with slow-moving centers of high pressure where the air aloft subsides and warms by compression. The turbulent surface zone does not subside as much. Thus, an inversion often forms between the lower turbulent zone and the subsiding layers above. TGA329.jpg Conditional instability illustrated using an environmental lapse of 8 degrees per 1000 meters, which lies between the dry adiabatic rate and the wet adiabatic rate. The rising parcel of air is cooler than the surrounding air below 4000 meters and warmer above 4000 meters. TGA330.jpg Four processes that lift air. A. Orographic lifting: Air is forced over a topographic barrier. B. Frontal wedging: Cold dense air displaces warm, less dense air along their boundary. C. Convergence: When surface air converges, it increases in height to allow for the decreased area it occupies. D. Localized convection lifting: Unequal heating of Earth's surface causes pockets of air to be warmed more than the surrounding air. TGA331.jpg A. When stable air is lifted, layered clouds usually result. B. When warm unstable air is forced to rise over cooler air, "towering" clouds develop. TGA332.jpg Classification of clouds according to height and form. TGA333.jpg The Bergeron process. Ice crystals grow at the expense of cloud droplets until they are large enough to fall. The size of these particles has been greatly exaggerated. TGA334.jpg The collision-coalescence process. Because large cloud droplets fall more rapidly than smaller droplets, they are able to sweep up the smaller ones in their path and grow. Most cloud droplets are so small that the motion of the air keeps them suspended. Even if these small cloud droplets were to fall, they would evaporate long before reaching the surface. TGA335.jpg Precipitation measurement. The standard rain gauge allows for accurate rainfall measurement to the nearest 0.025 centimeter (0.01 inch). Because the cross-sectional area of the measuring tube is only one-tenth as large as the collector, rainfall is magnified 10 times. TGA336.jpg A. Simple mercury barometer. The weight of the column of mercury is balanced by the pressure exerted on the dish of mercury by the air above. If the pressure decreases, the column of mercury falls; if the pressure increases, the column rises. B. An aneroid barograph makes a continuous record of pressure changes. One important advantage of the aneroid barometer is that it is easily adapted to a recording mechanism. TGA337.jpg The black lines are isobars that connect places of equal barometric pressure. They show the distribution of pressure on weather maps. The lines usually curve and often join around cells of high and low pressure. The flags indicate the airflow surrounding cells of high and low pressure and are plotted like flags flying with the wind. Wind speed is indicated by flags and "feathers" as shown along the right-hand side of this drawing. TGA338.jpg The Coriolis effect illustrated using a 1-hour flight of a rocket traveling from the North Pole to a location on the equator. A. On a nonrotating Earth, the rocket would travel straight to its target. B. However, Earth rotates 15 degrees each hour. Thus, although the rocket travels in a straight line, when we plot the path of the rocket on Earth's surface, it follows a curved path that veers to the right of the target. TGA339.jpg The geostrophic wind. The only force acting on a stationary parcel of air is the pressure-gradient force. Once the air begins to accelerate, the Coriolis effect deflects it to the right in the Northern Hemisphere, Greater wind speeds result in a stronger Coriolis effect (deflection) until the flow is parallel to the isobars. At this point the pressure-gradient force and Coriolis effect are in balance and the flow is called a geostophic wind. It is important to note that in the "rea" atmosphere, airflow is continually adjusting for variations in the pressure field. As a result, the adjustment to geostrophic equilibrium is much more irregular than shown. TGA340.jpg Upper-air winds. This map shows the direction and speed for the upper-air wind for a particular day. Note that the airflow is nearly parallel to the contours. These isolines are height contours for the 500-millibar level. A. Upper-level weather chart. B. Representation of upper-level chart. TGA341.jpg Comparison between upper-level winds and surface winds showing the effects of friction on airflow. Friction slows surface wind speed, which weakens the Coriolis effect, causing the winds to cross the isobars and move toward the lower pressure. A. Upper-level wind (no friction). B. Surface wind (effect on friction). TGA342.jpg Cyclonic and anticyclonic winds in the Northern Hemisphere. Arrows show that winds blow into and counterclockwise around a low. By contrast, around a high, winds blow outward and clockwise. TGA343.jpg Airflow associated with surface cyclones and anticyclones. A low, or cyclone, has converging surface winds and rising air, causing cloudy conditions. A high, or anticyclone, has diverging surface winds and descending air, which leads to clear skies and fair weather. TGA344.jpg Global circulation on a nonrotating earth. A simple convection system is produced by unequal heating of the atmosphere on a nonrotating Earth. TGA345.jpg Idealized global circulation. TGA346.jpg Average surface barometric pressure in millibars for January, with associated winds. TGA347.jpg Average surface barometric pressure in millibars for July, with associated winds. TGA348.jpg The relationship between the Southern Oscillation and El Ni–o is illustrated on these simplified maps. A. Normally, the trade winds and strong equatorial currents flow toward the west. At the same time, the strong Peruvian current causes upwelling of cold water along the west coast of South America. B. When the Southern Oscillation occurs, the pressure over the eastern and western Pacific flip-flops. This causes the trade winds to diminish, leading to an eastward movement of warm water along the equator. As a result, the surface waters of the central and eastern Pacific warm, with far-reaching consequences to weather problems. TGA349.jpg Illustration of a sea breeze and a land breeze. A. During the daylight hours the air above the land heats and expands, creating an area of lower pressure. Cooler and denser air over the water moves onto the land, generating a sea breeze. B. At night the land cools more rapidly than the sea, generating an offshore flow called a land breeze. TGA350.jpg Valley and mountain breezes. A. Heating during the daylight hours warms the air along the mountain slopes. This warm air rises, generating a valley breeze. B. After sunset, cooling of the air near the mountain can result in cool air drainage into the valley, producing the mountain breeze. TGA351.jpg Average annual precipitation in millimeters. TGA352.jpg Air masses are classified on the basis of their source region. The designation continental (c) or maritime (m) gives an indication of moisture content, whereas polar (P) and tropical (T) indicate temperature conditions. TGA353.jpg During winter, maritime polar (mP) air masses in the North Pacific usually begin as continental polar (cP) air masses in Siberia. The cP air is modified to mP as it slowly crosses the ocean. TGA354.jpg The snowbelts of the Great Lakes region are the zones that most frequently experience lake-effect snowstorms. As continental polar air crosses the lakes in winter, it acquires moisture and is made unstable because of warming from below. Snow showers on the lee side of the lakes are often the consequence of this air-mass modification. TGA355.jpg Warm front produced as warm air glides up over a cold air mass. Precipitation is moderate and occurs within a few hundred kilometers of the surface front. TGA356.jpg Fast-moving cold front and cumulonimbus clouds. Thunderstorms occur if the warm air is unstable. TGA357.jpg Stages in the formation of an occluded front. TGA358.jpg Stages in the life cycle of a hypothetical middle-latitude cyclone. TGA359.jpg Cloud patterns typically associated with a mature middle-latitude cyclone. The middle section is a map view. Note the cross-section lines (F-G, A-E). Above the map is a vertical cross section along line F-G. Below the map is a section along A-E. TGA360.jpg Idealized diagram depicting the support that divergence and convergence aloft provide to cyclonic and anticyclonic circulation at the surface. Divergence aloft initiates upward movement, reduced surface pressure, and cyclonic flow. In contrast, convergence along the jet stream results in general subsidence of the air column, increased surface pressure, and anticyclonic surface winds. TGA361.jpg Average number of days per year with thunderstorms. Because of its close proximity to the source region for warm, humid, and unstable air masses, the Gulf Coast receives much of its precipitation from thunderstorms. (Source: Environmental Data Service, NOAA) TGA362.jpg Stages in the development of a thunderstorm. During the cumulus stage, strong updrafts act to build the storm. The mature stage is marked by heavy precipitation and cool downdrafts in part of the storm. When the warm updrafts disappear completely, precipitation becomes light, and the cloud begins to evaporate. TGA363.jpg Some tornadoes have multiple suction vortices. These small and very intense vortices are roughly 10 meters (30 feet) across and move in a counterclockwise path around the tornado center. Because of this multiple vortex structure, one building might be heavily damaged and another one, just 10 meters away, might suffer little damage. (After Fujita) TGA364.jpg Average number of tornadoes and tornado days each month in the United States for a 27-year period. (After NOAA) TGA365.jpg Average annual tornado incidence per 10,000 square miles (26,000 square kilometers) for a 27-year period. TGA366.jpg Paths of Illinois tornadoes (1916-1969). Because most tornadoes occur slightly ahead of a cold front, in the zone of southwest winds, they tend to move toward the northeast. Tornadoes in Illinois verify this. Over 80 percent exhibited directions of movement toward the northeast through east. (After John W. Wilson and Stanley A. Changnon, Jr., Illinois Tornadoes, Illinois State Water Survey Circular 103, 1971, pp. 10,24) TGA367.jpg Cross section of a hurricane. Note that the vertical dimension is greatly exaggerated. The eye, the zone of relative calm at the center of the storm, is a distinctive hurricane feature. Sinking air in the eye warms by compression. Surrounding the eye is the eye wall, the zone where winds and rain are most intense. Tropical moisture spiraling inward creates rain bands that pinwheel around the storm center. Outflow of air at the top of the hurricane is important because it prevents the convergent flow at lower levels from "filling in" the storm. (After NOAA) TGA368.jpg Climates of the world based on the Köppen classification. TGA369.jpg By comparing these three climatic diagrams, the primary differences among the A climates can be seen. A. Iquitos, the Af station, is wet throughout the year. B. Monrovia, the Am station, has a short, dry season. C. As is true for all Aw stations, Normanton has an extended dry season and a higher annual temperature range than the others. TGA370.jpg Arid and semiarid climates cover about 30 percent of Earth's land surface. No other climate group covers so large an area. TGA371.jpg Climate diagrams for representative arid and semiarid stations. Stations, A. and B. are in the subtropics, whereas C. is in the middle-latitudes. Cairo and Lovelock are classified as deserts; Monterey is a steppe. Lovelock, Nevada, may also be called a rainshadow desert. TGA372.jpg Each of these climatic diagrams represents one of the three main types of C climates: A. humid subtropical, B. marine west coast, and C. dry-summer subtropical. TGA373.jpg D climates are associated with the interiors of large landmasses in the mid-to-high latitudes of the Northern Hemisphere. Although winters can be harsh in Chicago's humid continental (Dfa) climate, the subarctic environment (Dfc) of Moose Factory is more extreme. TGA374.jpg These climatic diagrams represent the two basic types of polar climates. A. Barrow, Alaska, exhibits a tundra (ET) climate. B. Eismitte, Greenland, a station located on a massive ice sheet, is classified as an ice cap (EF) climate. TGA375.jpg Apparent movement of a pendulum at the North Pole caused by Earth rotating beneath it. TGA376.jpg Orientation of the Sun's rays at Syene (Aswan) and Alexandria in Egypt on June 21 when Eratosthenes calculated Earth's circumference. TGA377.jpg The universe according to Ptolemy, second century A.D. A. Ptolemy believed that the star-studded celestial sphere made a daily trip around a motionless Earth. In addition he proposed that the Sun, Moon, and planets made trips of various lengths along individual orbits. B. Retrograde motion as explained by Ptolemy. TGA378.jpg Retrograde (backward) motion of Mars as seen against the background of distant stars. When viewed from Earth, Mars moves eastward among the stars each day, then periodically appears to stop and reverse direction. This apparent westward drift is a result of the fact that Earth has a faster orbital speed than Mars and overtakes it. As this occurs, Mars appears to be moving backward; that is, it exhibits retrograde motion. TGA379.jpg Drawing ellipses with various eccentricities. Using two straight pins for foci and a loop of string, trace out a curve while keeping the string taut, and you will have drawn an ellipse. The farther the pins (the foci) are moved apart, the more flattened (more eccentric) is the resulting ellipse. TGA380.jpg Kepler's law of equal areas. A line connecting a planet (Earth) to the Sun sweeps out an area in such a manner that equal areas are swept out in equal times. Thus, Earth revolves slower when it is farther from the Sun (aphelion) and faster when it is closest (perihelion). The eccentricity of Earth's orbit is greatly exaggerated in this diagram. TGA381.jpg Using a telescope, Gallileo discovered that Venus has phases just like the Moon. A. In the Ptolemaic (Earth-centered) system, the orbit of Venus lies between the Sun and Earth. Thus, in an Earth-centered solar system, only the crescent phase of Venus would be visible from Earth. B. In the Copernican (Sun-centered) system, Venus orbits the Sun and hence all of the phases of Venus should be visible from Earth. TGA382.jpg Orbital motion of Earth and other planets. TGA383.jpg Astronomical coordinate system on the celestial sphere. TGA384.jpg Locating the North Star (Polaris) from the pointer stars in the Big Dipper, which is part of the constellation Ursa Major. The Big Dipper is shown soon after sunset in December (lower figure), April (upper figure), and August (left). TGA385.jpg The difference between a solar day and a sidereal day. Locations X and Y are directly opposite each other. It takes Earth 23 hours and 56 minutes to make one rotation with respect to the stars (sidereal day). However, notice that after Earth has rotated once with respect to the stars, point Y is not yet returned to the "noon position" with respect to the Sun. Earth has to rotate another 4 minutes to complete the solar day. TGA386.jpg Earth's orbital motion causes the apparent position of the Sun to shift about 1 degree each day on the celestial sphere. TGA387.jpg The apparent position of the Sun plotted on the celestial sphere. The path of the Sun (ecliptic) crosses the celestial equator on two occasions each year, March 20-21 and September 22-23. These are known as the equinox positions because the lengths of daylight and darkness on Earth are equal. TGA388.jpg A. Precession illustrated by a spinning top. B. Precession of Earth causes the North Pole to point to different parts of the sky during a 26,000-year cycle. Today, the North Pole points to Polaris (North Star). In 13,000 years, Vega will be the North Star. TGA389.jpg Phases of the Moon. The outer figures show the phases as seen from Earth. TGA390.jpg The difference between the sidereal month (27 1/3 days) and the synodic month (29 1/2 days). Distances and angles are not shown to scale. TGA391.jpg A. Solar eclipse. Observers in the zone of the umbral shadow see a total solar eclipse. Those in the penumbra see a partial eclipse. The path of the solar eclipse moves eastward across the globe. B. Lunar eclipse. During a total lunar eclipse the Moon's orbit carries it into the dark shadow of Earth (umbra). During a partial eclipse only a portion of the Moon enters the umbra. TGA392.jpg The Moon's orbit is inclined about 5 degrees to the plane that contains the Sun and Earth. Thus, during most new-Moon phases, the shadow of the Moon misses Earth (passes above and below), and during most full-Moon phases, the shadow of Earth misses the Moon. Only when a new- or full-Moon phase occurs where the Moon's orbit crosses the Earth-Sun plane can an eclipse take place. These conditions are met at roughly 6-month intervals. TGA393.jpg Orbits of the planets. Scale shown below. TGA394.jpg Block diagram illustrating major topographic features on the lunar surface. TGA395.jpg Formation of an impact crater. The energy of the rapidly moving meteoroid is transformed into heat energy and compressional waves. The rebound of the compressed rock causes debris to be ejected from the crater, and the heat melts some material, producing glass beads. Small secondary craters are formed by the material "splashed" from the impact crater. (After E. M. Shoemaker). TGA396.jpg Formation of lunar maria. A. Impact of an asteroid-sized mass produced a huge crater hundreds of kilometers in diameter and disturbed the lunar crust far beyond the crater. B. Filling of the impact area with fluid basalts, perhaps derived from partial melting deep within the lunar mantle. TGA397.jpg The structure of Jupiter's atmosphere. The areas of light clouds (zones) are regions where gases are ascending and cooling. Sinking dominates the flow in the darker cloud layers (belts). This convective circulation, along with the rapid rotation of the planet, generates the high-speed winds observed between the belts and zones. TGA398.jpg A view of the dramatic ring system of Saturn. TGA399.jpg The orbits of most asteroids lie between Mars and Jupiter. Also shown are the orbits of a few known near-Earth asteroids. Perhaps a thousand or more asteroids have near-Earth orbits. Luckily, only a few dozen are thought to be larger than 1 kilometer in diameter. TGA400.jpg Orientation of a comet's tail as it orbits the Sun.