Answers¶
Contents
Answers
`14-1: <>`__ Runoff (water in transit across the land surface and in streams) accounts for the least voluminous step in the hydrologic cycle. Soil moisture is not mentioned but it is destined to either be taken up by plant or to evaporate into the atmosphere.**BACK**
` <>`__14-2: A wide field of view is a prime requisite for most meteorological satellites. In looking at weather systems, it is especially useful to get a broad synoptic picture of the cloud patterns, temperature variations, etc. so as to interrelate these locational variations with the climate models used to predict both short and longer period movements and changes in the relevant meteorological conditions. Either a wide angle lens on the telescope optics or a high orbital altitude will accomplish this. `BACK <Sect14_01.html#14-2>`__
` <>`__14-3: Cloud circulation; water vapor; clusters of clouds that associate with storms; jet stream plots; temperature maps. When appropriate, time-lapse hurricane movements. `BACK <Sect14_01.html#14-3>`__
` <>`__14-4: Bands 2 through 5 are infrared; 3 through 5 are thermal as well. `BACK <Sect14_02.html#14-4>`__
` <>`__14-5: This is a clear air mass, called the hurricane’s “eye”, forming a vortex of counterclockwise rapidly moving air at its outer boundary. Air from above pushes down on the air within the eye, heating it up by compression; heat also is transferred from the warm ocean waters. The air inside does not experience much of the wild circulation in the main hurricane, so that the eye is often described as the calm center of the otherwise violent wind motions of the hurricane itself. Eye diameter ranges from a few miles to 20 or more miles. `BACK <Sect14_02.html#14-5>`__
` <>`__14-6: This may have tricked you. The bottommost map shows the warmest colors in yellow rather than the reds of the next two up. You may have been inclined to have the profile which has been rising in temperatures reverse direction near the surface. But this is not the case, it actually continues to rise. Note the color scale has an increasing value to the right from the first to the fourth map but the temperature range in which red occurs is not the same in the individual maps. `BACK <Sect14_03.html#14-6>`__
` <>`__14-7: The geostationary type. It sees the same wide regional view all day (and night) long. Just record a series of images every thirty minutes or so and one gets a sequence much like the succession of individual panels in a movie film. Strung together, these give the sense of continuous cloud motions (which a bit of jerkiness if the imaging interval is too long or the clouds are moving too fast). `BACK <Sect14_03.html#14-7>`__
` <>`__14-8: This was made from an orbital rather than geostationary satellite. When images taken at different times and orbital locations are collected, time has elapsed and even extensive cloud banks have undergone changes (e.g., clear gaps). There are parts of three pictures making up this set. `BACK <Sect14_04.html#14-8>`__
` <>`__14-9: They are almost certainly clouds. Look for the Mississippi Delta. We have seen before that this river carries a lot of silt into the Gulf and its water temperature is different from the seawater. One would expect to see evidence of this water entry but that is absent, leading to the conclusion that the swirls are not circulating thermal currents but clouds instead. `BACK <Sect14_04.html#14-9>`__
` <>`__14-10: The Wind River Mountains are the dominant ones in the Landsat mosaic, slanting to the southeast. Near their southeast end is the town of Lander and 20 miles east of it is Hudson, home of the two finest steak houses I’ve ever eaten at - the steaks fill your plate and are in an excess of an inch thick. On a more mundane note, back to the Nimbus image. The long, narrow ranges on the left side of the mosaic are the Wyoming and Hoback Ranges which lead northward into the Grand Tetons and Yellowstone Park. At the bottom of the Nimbus image is an east-west range, the Uinta Mountains of Utah; these appear near the bottom of the mosaic. The mosaic shows the Bighorn, Medicine Bow, and Laramie mountain ranges; these are beyond the coverage in the Nimbus image.**BACK**
` <>`__14-11: Igneous rocks are classified (in part) by their varying SiO2 contents - granites being high in silica (around 70%) and basalts lower (45 - 50%). The reststrahlen effect could, in principle, be used to map the igneous rocks of the world (but most sedimentary and metamorphic rocks also contain silica). `BACK <Sect14_04.html#14-11>`__
` <>`__14-12: The hurricane has no (well-developed, visible) EYE. `BACK <Sect14_05.html#14-12>`__
` <>`__14-13: The green is concentrated in the equatorial zone, in the so-called tropics. It’s much warmer on average there and with increased temperatures, the air can hold more moisture.**BACK**
` <>`__14-14: Note that the purple linear features are in the southern hemisphere, where it is summer in December. These features are probably the leading edges of the fronts of major air masses, where rain tends to concentrate. The hurricane is just of the coast of southern Mexico. `BACK <Sect14_05.html#14-14>`__
` <>`__14-15: You can imagine the motion to be like that of a moving wheel. The curvature of the swirls gives the impression of forward movement. That movement is counterclockwise, which is the circulation pattern associated with pressure lows in the northern hemisphere. `BACK <Sect14_06.html#14-15>`__
` <>`__14-16: In the northern hemisphere, a poorly organized low on January 2nd becomes well-organized by the 4th, where it is visible in the top center. As it moves eastward, it tends to become less distinct by the 7th. In the southern hemisphere a vast bank of clouds hugs the lower left limb of the half globe and remains generally intact over the entire period.`BACK <Sect14_07.html#14-16>`__
` <>`__14-17: There is a definite swirly pattern that indicated a counterclockwise (ccw) circulation and a possible storm low. But the spiral arms are still open, so this system has not organized into a continuous cloud mass as is characteristic of a hurricane. `BACK <Sect14_07.html#14-17>`__
` <>`__14-18: The area covered by the storm is much larger than usual for hurricanes. Of course, there is no eye in this continental disturbance. The counterclockwise circulation is suggested by the curving cloud patterns but the number of swirls is less than customary for hurricanes. While widespread, the clouds are not as thick as in typical hurricanes. `BACK <Sect14_07.html#14-18>`__
` <>`__14-19: The Strait is the west end of the Mediterranean, between southern Spain and Morocco. Both countries are largely cloudfree and viewing would be excellent. `BACK <Sect14_08.html#14-19>`__
` <>`__14-20: The Arabian Peninsula and India. `BACK <Sect14_08.html#14-20>`__
` <>`__14-21: The geostationary mosaic seems to be showing the entire Earth as one image. The several geostationary satellites took their pictures together at the same time. Simple photographic corrections could be made to minimize any join effects. The polar orbiters take their pictures over a short period but at different times, so there are inevitable discontinuities in cloud patterns from one picture to adjacent ones. `BACK <Sect14_08.html#14-21>`__
` <>`__14-22: The units for the ERBS plot are in W/m2 which is watts per square meter. Watts is a unit that represents the time rate of flow of energy on to or off of or through a surface. This radiance flux density is also known as the radiance. SAGE measures the optical density of the atmospheric profile as the sensor looks at the column of air from surface to outer limits as seen at the limb of the Earth (side view as though peering at the edge of the globe seen as the horizon). Increased amounts of absorbing gases and scattering particles increases the optical density.`BACK <Sect14_09.html#14-22>`__
` <>`__14-23: The maximum occurs around 15° N latitude. There could be a second maximum north of 30°, where this diagram cuts off. Methane is a minor by-product of gasoline engine combustion. Other sources: anaerobic decay of plant matter (e.g., rice fields), enteric fermentation by ruminant animals; by-products from coal mining and natural gas processing (information courtesy Katherine Hayhoe). The observed maximum could result from redistribution from northern continents by surficial trade winds in the subtropics. North of the horse latitudes (30°) the gas might be pushed northward by the westerlies. In the southern hemisphere there is less methane because of fewer sources, both natural and manmade, in southern hemisphere continents. `BACK <Sect14_09.html#14-23>`__
` <>`__14-24: Jets fly around 10-12 kilometers (6 to 10 miles) altitudes. The ozone curve is approaching a low value at those heights. But ozone is released from jet engine exhaust, adding to the ozone content of the atmosphere; the ozone, being a light gas, migrates outward to its maximum around 40 km. The green bars are “error” bars - in effect a measure of uncertainty in the actual values. `BACK <Sect14_09.html#14-24>`__
` <>`__14-25: Hurricanes that enter the Gulf of Mexico tend to follow three optional paths: they can move across and hit the eastern Mexico coast; they can strike into Texas and die out inland in that state or northward; or commonly they begin to veer from a westward to an eastward direction. Andrew turned to the northeast and dumped heavy rains in the Tennessee area and surroundings. `BACK <Sect14_10.html#14-25>`__
` <>`__14-26: Waters off the California coast extend into deep oceanic areas as swirls (gyres) that don’t appear severely disrupted by the offshore California current (which moves from north to south). The apparently quite warm waters of the big Island of Hawaii form roughly a triangular pattern similar to the island itself but slightly “rotated”. The areas farther away from the island shores become cool quite rapidly. This thermal pattern is at least partly influenced by the nature of the island. It rises from great depths, so that its total vertical height, from the abyssal floor of the ocean to the top at Mauna Loa, makes it the largest single peak in the world. `BACK <Sect14_11.html#14-26>`__
` <>`__14-27: Among the birds they look for are shearwaters, terns, albatrosses, jaegers, auks, murres, and puffins. These feed mostly on plankton and small fish. They, in turn, flourish in warmer waters. The boat trips try to get close to or even in the Gulf Stream since that is a “river” of warmer water with abundant nutrients to support aquatic life. `BACK <Sect14_11.html#14-27>`__
` <>`__14-28: Nothing at present, or the foreseeable future. These changes in atmospheric and oceanographic conditions are at too large scale to be modified by anything Man can do at this time. El and La Nino(a) have been around for a long time (probably predates mankind) as part of the natural long term variability of climate and weather cycles. What we now can do is monitor the progression and effects of each phenomenon, helping to make predictions as meteorologists come to better understand their modus operandi. This will allow improved preparations for the changes and responses as they occur. `BACK <Sect14_11.html#14-28>`__
` <>`__14-29: Wind patterns are powerful indicators of atmospheric circulation which in turn has a profound influence on the formation, movement and dissipation of weather systems. They aid in forecasting storm paths and predicted severity. The surface winds are the cause of waves, and the heights they reach and directions they move. Winds can be used to predict wave response; in turn, wave motions reveal much about the winds that initiate and sustain the water vibrations.**BACK**
` <>`__14-30: Assuming the display on your monitor favors details, on careful inspection you should pick out a dominant set of numerous close-spaced waves trending NE arranged in patches that give a linear grain to the image. There is a second well-developed NW set of similar dimensions. Several clusters of large, curved, widely-spaced waves may be internal waves near shore.**BACK**
` <>`__14-31: There is a correlation between wind speed, wave height, and wave length. Rougher seas, from higher wind velocities, lead to higher waves spaced farther apart. `BACK <Sect14_12.html#14-31>`__
` <>`__14-32: The highest oceans are the western two-thirds of the Pacific and the southern Indian Ocean. When a ship passes through the Panama Canal, the Pacific Ocean side is slightly higher (but more variable because of greater tidal variations).**BACK**
` <>`__14-33: This is a great example of where intuition is misleading or just plain wrong. The reason that there are lesser amounts of plankton at lower latitudes is just that the quantities very near the surface (where CZCS detects water plus plankton only to very shallow depths) are lessened, for at least two reasons. One is that at higher temperatures, water is less dense and less viscous. This impedes the “swimming” ability of the plankton who then seek out denser water lower down. The other reason is that Sun angles are higher in low latitudes and the rays can penetrate deeper. So, the plankton needn’t live right at the surface where the water tends to be more turbulent from wave action.**BACK**
` <>`__14-34: Think of the gyres as having tails. In the upper image, look for an eddy just below the islands. Its “tail” is curving down and to the right of its center, a motion achieved by clockwise rotation. The reverse curvature is the case in the lower image. `BACK <Sect14_13.html#14-34>`__
` <>`__14-35: You need to look at several key criteria for fish abundance. All depend on availability of food. Chlorophyll concentration can be traced with SeaWIFS. It, or appropriate NOAA satellites will also give relevant SST (sea surface temperatures). One can also use temperature or color to chart the location and fluctuation of major oceanic currents such as the Gulf Stream, whose warmer waters promote life (but some currents, such as the California current, are cooler waters and thus less suitable to fish enrichment). Satellites whose sensors show wave action help to warn the fishermen of waters where fishing might be impeded or even dangerous. `BACK <Sect14_13.html#14-35>`__
` <>`__14-36: This is an example of multi-year ice. The darker blocks of ice enclosed by lighter are older. Many of those blocks in turn contain even smaller pieces. The older ice broke up into individual floes, then new freezing took place, embedding the earlier ice. Now that ice sheet itself is in process of breaking apart. `BACK <Sect14_14.html#14-36>`__
` <>`__14-37: Clockwise. How’s that for a short answer! But, why: Clockwise associates with warmer water. These ice swirls occur when warm water spirals to the surface and cools rapidly until it freezes. `BACK <Sect14_14.html#14-37>`__
` <>`__14-38: In December it is “summer” in the Southern Hemisphere. Greenland is the other great ice-covered area. **BACK**
` <>`__14-39: The area of 1975 coverage is at least twice that of 1977. The snow pack was probably between two and three times as thick. So the volume should be somwhere between four and six times greater. `BACK <Sect14_15.html#14-39>`__
` <>`__14-40: The GOES-8 image shows that the storm extended much further south. The snow line marks the boundary where, to the north, the air was cold enough for only snow and ice to fall; to the south, rain. `BACK <Sect14_15.html#14-40>`__
` <>`__14-41: Both the radar images were taken after the flood on the river itself had peaked and then subsided, but floodwaters remain in the surrounding countryside, covering more than in 1973. St. Louis is protected by levees and is also higher than farmlands; water rose up to the Arch. `BACK <Sect14_16.html#14-41>`__