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16-1: The giveaway is at the top and near top. Part of the Arabian Peninsula appears in medium brown. The Horn of Africa is also visible but much of Africa is masked by the dark green of tropical vegetation. So, Africa is present and a little bit of western Asia. BACK

16-2: There is a temperature limit to the occurrence/survival of life. In the magmas/lavas of an active volcano, life will be absent. BACK

16-3: The list is long. Here are some samples: Introduction of noxious gases into the atmosphere; Increase in atmospheric carbon dioxide; Alteration of the natural ozone layer in the upper atmosphere; Possible acceleration of ice sheet melting, causing sea level rise; Deforestation; Destruction of range and grazing lands; Pollution of Streams; Extinction of biotic species. BACK

16-4: Pinatubo lies at about 17° N latitude, well within the "horse latitudes" dominated by the trade winds. This sub-equatorial wind circulation systems kept the ash confined to these low latitudes. BACK

16-5: In the right center is a long, narrow black pattern; there are several other such patterns around the volcano. These are all "lahars" - mudflows of volcanic ash caused by heavy rains sweeping this material into streams. The one that enlarged to double its size results from rain wash that brought the ash to lower elevations and redeposited it. The red at the bottom is not ash. BACK

16-6: The introduction of carbon dioxide is seasonal in magnitude. Much less is added during the northern hemisphere winters, so there is a downturn in the plot, making this a cyclic phenomenon. All three curves steadily increase, roughly in accord with increasing human population and also further industrialization. It is difficult to explain these increases by known natural factors, so by default the environmentalists who voice dire warnings about Man's degradation of the global natural state have rather convincing evidence. BACK

16-7: There is not a steady decrease in ozone from 1979 to 1992. In fact, there are somewhat non-systematic variations from year to year. Two major minima occur in 1986 and 1992. But there are rises after years of decreased ozone content. This tends to blunt the arguments of those who portend catastrophe in the protective ozone layer. Other, natural factors may be partly responsible for the fluctuations. Obviously, a longer period of observations is necessary to verify any general downward trend. BACK

16-8: About threefold or 300% in the five year period between 1982 and 1987. BACK

16-9: Physical Geography and, to a lesser extent, Environmental Science or Ecology. BACK

16-10: Right now, those in the seconds to minutes time scale and those whose changes take centuries or longer. But, that can change. In principle, geostationary satellites, particularly if equipped with improved telescopes, can monitor very short term changes. And, looking well ahead into the future, the satellite-based data now being archived will someday become greatly relevant to those evaluating long-term trends in the Earth's environment. BACK

16-11: Energy, climate, biogeochemistry, and Man's activities. BACK

16-12: This published diagram perhaps is overgeneralized to keep it simple. The arrow from the CO2 box goes to the ocean but seems to be directed at zooplankton when, in fact, phytoplankton are the principal intakers of that gas. A bit misleading; the draftsman intended it to simply enter the ocean. The SO3 and NO3 box seems to end in the atmosphere but these two gases can be returned to Earth by reaction with water to make sulphuric and nitric acids (acid rain). There are several other shortcomings. BACK

16-13: The principal source is the burning of hydrocarbons (extracted mainly as petroleum and natural gas); the main sink is the deep ocean. Not shown is carbon already locked up in sedimentary carbonates (mostly limestones) in the Earth's crust; this is a minor source since most is buried and not actively contributing to the cycle except where it is being weathered at the surface. BACK

16-14: That player perhaps should reader "payer", namely, Congress which appropriates the funds. To a lesser extent the executive branch plays an important role also, in deciding on what programs to sponsor and push through. Each year around budget time, the agencies must do a "hard sell" on their continuing participation in the programs that involve the U.S. in environmental monitoring from space and particularly the Mission to Planet Earth. Budget cuts in recent years have somewhat tapered the original plans for this venture. BACK

16-15: The "culprit" is the Global Data and Information System (referred to later as EOSDIS). The problem is simply that never before has so much data (more than three terabytes or 3 x 1012 or three trillion bytes of computer-compatible data) been received on a daily basis and the computer power to handle this through-put must be both grandiose and efficient beyond any experience to date. The data come from the multiple numbers of sensors that will be on several satellites that eventually will be in orbit simultaneously. Difficulties in getting that facility ready have slowed the launch dates of the primary satellites supporting MTPE. BACK

16-16: Most of the data will be connected to quantities needed for environmental assessment. Thus, the sensors should be able to image the surface of land and sea and identify land cover classes; determine plant types, biomass, and stress state; measure a range of atmospheric properties such as temperature, pressure, wind direction, water content, chemical composition; gather data on sea surface temperature, chlorophyll content, wave and current movements; monitor water distribution (inventory), and the like. Thus, EOS really is an amalgamation of sensors that each are somewhat specialized and have flown before on their own satellites but are now to operate in consort together so that disparate data are now collected simultaneously over the same target while orbiting to provide global coverage. BACK

16-17: In case you missed their identification at the bottom of the table, SNR stands for Signal to Noise Ratio (appropriate to reflectance measurements) and NE deltaT stands for Noise-Equivalent Temperature difference (pertinent to thermal measurements). Each is a measure of quality of output or, more technically, the sensitivity of the instrument detectors. There is always some noise in the system due to a variety of causes that contributes to the minimal value of the signal. These two measures specify the minimum values above the background noise that the instrument detectors can discriminate as the signal coming from the target of interest. BACK

16-18: MODIS is primarily a meteorological and oceanographic satellite.BACK

16-19: Those who are interested principally in land phenomena. BACK

16-20: Spread the load out even further - to other receiving and processing centers. This is the gist of the Regional Applications Center (RAC) concept first developed in the Goddard's Applied Information Sciences Branch (Code 935) and now being managed by the Stennis Space Center in Mississippi. About 10 such centers are currently operational. Each regional center has its own antenna dish and will be able to process data received right at its own site. If enough of these are established and funded, the EOSDIS will have notably reduced daily demands. BACK

16-21: The partitioning of solar energy among the physical, chemical, and biological entities that make up the Earth's ecosystems. BACK