Arid climates

Goats, the animal of choice in areas of harsh climates and limited food supply, are particularly suited to warm and sometimes arid climates. 

When drying catde hides in tropical arid climates, the hides are scraped clean of desh, then stretched on racks, and dried slowly in the shade. An apphcation of an insecticide may be used. This method is slow, labor intensive, and unreHable for heavy hides. The system is only used in mral tropical areas and is not appHcable to modem commercial catde hide production (3). 

Numerous theories exist as to how the Chilean deposits formed and survived. It has been postulated that the unique nitrate-rich caUche deposits of northern Chile owe their existence to an environment favorable to accumulation and preservation of the deposits, rather than to any unusual source of the saline materials (2). The essential conditions are an extremely arid climate similar to that of the Atacama desert in the 1990s, slow accumulation during the late Tertiary and Quaternary periods, and a paucity of nitrate-utilizing plants and soil microorganisms. 

A pressure filter is a plate-and-frame press which operates on an intermittent time cycle. Drier cakes are generally attainable from a filter press. Sludge drying beds are usually used for smaller sludge volumes, which drain and dry rapidly. Thein appHcation is usually restricted to the more arid climates. 

Air is the source of six industrial gases, N2, O2. Ne, Ar, Kr and Xe. As the mass of the earth s atmosphere is approximately 5 X 10 million tonnes, the supply is unlimited and the annual industrial production, though vast, is insignificant by comparison. The composition of air at low altitudes is remarkably constant, the main variable component being water vapour which ranges from 4% by volume in tropical jungles to very low values in cold or arid climates. Other minor local variations result from volcanism or human activity. The main invariant part of the air has the following composition (% by volume, bp in parentheses) ... 

Calcium—In general, calcium (as CaCOs) below 800 ppm should not result in calcium sulfate scale. In arid climates, however, the critical level may be much lower. For calcium carbonate scaling tendencies, calculate the Langelier Saturation Index or the Ryznar Stability Index. 

Sulfates—If calcium exceeds 800 ppm, sulfates should be limited to 800 ppm, less in arid climates, to prevent scale. Otherwise, a sulfate level up to 5,000 ppm is acceptable. 

Water resources decision making in many areas, particularly arid and semi-arid climates such as the American West, depends on interannual to decadal variations in surface water availability. In addition to more predictable seasonal differences, runoff tends to exhibit long-term trends alternating between flood and drought periods. Figure 6-10 shows historical wet and dry periods based on streamflow records for 50 world rivers. For the most part, these periods are consistent on a regional basis, though they appear to alternate on a hemispheric scale. 

Runoff sensitivity, particularly in arid and semi-arid climates, is largely a result of sensitivity in soil moisture response. If rainfall amount and frequency decrease, more soil moisture is lost to evapotranspiration, creating a soil moisture deficit that must be replaced before surface runoff or significant ground-water flow returns. The converse also tends to... 

The principal variation of the undisturbed groundwater table over a series of years is shown in Figure 36. This natural variation is mainly climate dependent. Most important is the precipitation and under what season the precipitation occurs. Normally, most of the recharge take place under non growing seasons in west European climate zones. In arid climate zones the recharge take place more occasionally and then combined with temporary cold and rainy conditions. 

Ankeny, M.D., Coons, L.M., Majumdar, N., Kelsey, J., and Miller, M., Performance and cost considerations for landfill caps in semi-arid climates, in Landfill Capping in the Semi-Arid West Problems, Perspectives, and Solutions, Reynolds, T.D. and Morris, R.C., Eds, Environmental Science and Research Foundation, Idaho Falls, ID, 1997. 

Jacquiet, P, Cabaret, J., Thiam, E. and Cheikh, D. (1998). Host range and the maintenance of Haemonchus spp. in an adverse arid climate . International Journal for Parasitology, 28(2), 253-261. 

The topography of the Ebro River basin determines a Mediterranean climate with continental characteristics in most of the river basin as well as a semi-arid climate in the center of the depression. At the western extreme of the basin (Pyrenees and Iberian mountains), there is an oceanic climate. The central part of the basin is isolated from the oceanic influence because of the surrounding mountains. This results in the increase of the continentality of the climate and the drastic decrease of the rainfall. In the central part of the river basin (Zaragoza, Alcaniz, and Lleida urban areas), aridity is the main climatic characteristic. 

Compared to the Moon, meteorites have a greater chance to survive impact on Mars because of its atmosphere. Compared to Earth, the current extremely arid climate on Mars lets meteorites... 

BIOGEOCHEMICAL CYCLING OF ELEMENTS AND POLLUTANTS EXPOSURE IN SEMI-ARID AND ARID CLIMATIC ZONE... 

These barriers are of great importance in exposure pathways for all considered ecosystems placed in semi-arid and arid climate zones. 

Persistence Persists up to one day in moderate climates shorter persistence in dry, arid climates may last up to one week in snowy conditions... 

The order Aridisol is, as its name suggests, typical of arid climate conditions and found in the southwest deserts. The Aridisol for this project is of the Sagehill series and was collected from Gilliam County, Oregon. The soil is an alkaline coarse-grained soil with free CaC03. It has low infiltration rates and capacities. 

The formation of substantial evaporite deposits requires two conditions (1) some mechanism by which salt ion concentrations are kept at supersaturated levels, and (2) a steady resupply of salt ions. The hydrogeologic setting that is most likely to meet these two criteria are shallow-water embayments located in arid climates where sea level is relatively stable and terrestrial runoff is very low or absent. 

Shallow-water embayments provide a mechanism to isolate seawater so that evaporation can raise salt ion concentrations. Arid climates are required to ensure that the rate of water loss from evaporation exceeds the rate of water supply by rainfell, groundwater seeps, or river runoff. Seawater can be resupplied continuously via a type of antiestuar-ine circulation as illustrated in Figure 17.2 or episodically as a result of sea level change, plate tectonics, or very high tides and storm surges. 

Schematic longitudinal profile through a semi-isolated basin located in a hot, arid climate and separated from the open sea by a narrow portal. The sill depth, although shallow, is still great enough to permit some two-way flow of surface water. The lines show inferred seawater density (g/cm ) and the arrows show current directions. The pattern of evaporite deposition is based on the relationships between brine density and precipitate composition as shown in Figure 17.1, assuming that salt particles accumulate on the seafloor through the process of pelagic sedimentation. Source-. From Scruton, P. C. (1953). American Association of Petroleum Geologists Bulletin, 37, 2498-2512.

Between 80 Ma and 50 Ma, the Namib rocks were eroded to a smooth peneplain (the Namib Unconformity). Namib Group Tertiary and Quaternary sedimentary debris was deposited in east-west to southwest trending paleochannels incised into Karibib marbles and schists on that Cretaceous age unconformity. From mid Tertiary to present, the central Namib region has maintained profoundly arid climatic conditions for the last 50 or more million years. Uplift initiated the post African erosion surface that filled valleys and channels with poorly sorted angular... 

It is well known that dogs track better in humid air. Rodents find buried seeds better in wet soil. This is important in arid climates. After rains, yellow pine chipmunks, Tamias amoenus, and deer mice, Peromyscus maniculatus found experimentally buried seeds of Jeffrey pine, Pinus jeffreyi, and antelope bitterbrush, Purshia tridentata, better than in diy soil. The recovered number of seeds increased 27- and 15-fold, respectively. In wet soil, seeds take up water rapidly and emanate volatile organic compounds that the rodents exploit. By extension, variations in humidity in arid environments may have profound effects on olfaction-dependent behaviors such as finding food, social interactions, preying, and predator avoidance (Vander Wall 1998). 

Rodent species differ in their ability to smell buried seeds those from arid climates perform better than species from mesic climates. Specifically, Panamint kangaroo rats, Dipodomys panamintinus, from arid and semiarid areas of the Great Basin Desert in North America were the only species that found deep caches... 

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