Geography Final
Air mass is a large volume of air in the lower part of the earth atmosphere – troposphere, with horizontal dimensions of hundreds or thousands of miles and vertical dimensions of a few kilometers. It is characterized by thermal uniformity and certain liquid water content. The source regions of the air masses formation are areas where the air descends and then extends horizontally. This display corresponds to the anticyclone system. Anticyclones are more inactive than cyclones, so the formation of the air masses usually happens in the quasi-stationary anticyclones. Air masses are classified according to the region of their formation, depending on location in one of the latitude zones. According to geographical division, the air masses can be divided into Arctic or Antarctic, temperate, tropical, and equatorial air masses. These air masses can be also subdivided into oceanic and continental types.
Front is a transition region between two different air masses; it can be warm or cold, stationary or occlusive. Warm front is an atmospheric air mass, moving towards the colder air. Warm air mass necessarily comes to the region after the warm front. As the warm front approaches, the pressure begins to fall, the clouds thicken, and abundant precipitations fall. In winter, the low stratus clouds appear during the passage of the front, temperature and humidity rise slowly, and the wind increases. After the passage of the front, the wind direction changes, the pressure drop stops, the clouds dissipate, and the precipitations cease. Cold front is an atmospheric air mass, moving in the direction below the warm air mass. In the summer, the precipitations, thunders, and squalls are usually observed before the passage of the cold front. Cold air comes and pushes the warm air: there is advection of cold, and then the cold air mass comes to the region after the cold front. The wind turns to the right; this direction turn is more significant and severe in case of a cold front. The wind speed increases and the pressure grows slowly. When the cold front has passed, the pressure begins to rise rapidly.
Storm is any adverse weather conditions with strong wind. If the wind speed of the storm is over 60 miles, it is given its own name. Storms can be classified according to the place of their formation: tropical storm, subtropical storm, hurricane (the Atlantic Ocean), typhoon (the Pacific Ocean). Thunderstorm is an atmospheric phenomenon, in which electric discharges (lightning, followed by the thunder) appear in the clouds or between the clouds. As a rule, the thunder forms in the powerful cumulus clouds and is associated with heavy rain, hail, and strong wind. Thunderstorm refers to one of the most dangerous for people natural phenomenon: the number of registered deaths causes serious concerns. Tornado is an atmospheric vortex that forms in cumulus clouds and spreads down to the surface of the earth in a form of cloud sleeve of tens or hundreds of meters. The vortex that forms on the sea is called a waterspout while the one that forms on the land is called a tornado. Atmospheric vortex is called a thrombus. Tornadoes can appear in many shapes and sizes. Most tornadoes occur in the form of a narrow cone with a small cloud of debris near the ground. Tornadoes can create a wall of rain or dust. These vortexes are especially dangerous as even experienced meteorologists cannot predict them. Hurricane is an atmospheric phenomenon with the low pressure in the center. It is often coupled with storm wind speed in contrast to extra-tropical cyclones. About 80 tropical cyclones are observed in the world annually. The formation of this type of cyclone requires a high water temperature. The intensity of tropical cyclones is much bigger than the extra-tropical cyclones.
Climate is a relatively constant weather regime with regular atmospheric processes; it forms in the area as a result of the influence of solar radiation, atmospheric circulation, and other physical phenomena. There are four main types of climate: continental, oceanic, climate of the western coast, and climate of the eastern coast. These climates can be also subdivided into equatorial, tropical monsoon, tropical monsoon climate in the plateau, tropical dry, the Mediterranean, subtropical continental, subtropical monsoon, temperate maritime, moderate continental, temperate continental, temperate monsoon, subarctic, sub Antarctic, polar, arctic and Antarctic climates.
Vegetation is a set phytocenosis of a certain area or the whole Earth. Vegetation is characterized by species composition and quantity of species and particular combination of representatives from different plant taxa and environmental links between them. Hydrophytes are plants, which grow in fresh, salt, brackish water, or water surface. Mesophytes, on the other hand, are land plants that are adapted to living in the environment with less or more moist soil. There are a lot of representatives of this type of plants such as bent grass, timothy, a chamomile, a clover, a goldenrod, a lily of the valley, a lungwort; some kinds of trees: beech, lilac, filbert. Xerophytes are plants that habit dry regions; they can endure the long drought. These species are a typical flora of deserts or semi-deserts; they usually grow on the coasts and in the sand dunes. Annual plant is a plant, a life cycle of which ends in one growing season and includes maturation, flowering, and death. The representatives of these plants are pea, cauliflower, and fennel. Many annual plants are used for decorative purposes, because of their bright color and beautiful flowers. Perennial plant, on the other hand, is a plant that lives for more than two years. Perennials adapt to soils, poor resources easier than the annuals. This adaptation is caused by better-developed root system, which can penetrate deeper into the soil to gain access to water and other nutrients. Climax vegetation is the greenery that evolve in a given climatic conditions on a certain territory, in the lack of serious disruption over a long time. A perfect example of climax vegetation is the tropical evergreen forests, temperate forests, tundra, savanna, and grasslands. Succession is serial, irreversible, and natural change of a biocenosis (phytocenosis, microbial community) in the specific area of the environment in a certain time period.
Biome is a complex ecosystem of one climatic zone. Terrestrial biome is classified by type of vegetation: polar desert, tundra, taiga, broadleaf forests, steppes, subtropical rain forests, Mediterranean biomes, monsoon forests, arid deserts, xerophyte shrubs, southern steppes, semiarid desert, savanna, savanna with woody vegetation, subtropical forest, tropical rain forest, alpine tundra, and mountain forest. Types of forests: there can be coniferous (spruce, pine, fir), broad-leaved (oak, linden, elm), small-leaved (birch, alder, aspen), or bottomland forest (different kinds of willows, poplars, black alder). Types of deserts: there are sand, loessial, loamy, clayed, rocky, and saline deserts. Types of grasslands: there are continental, dry meadow, lowland, and alpine grasslands. Types of steppes: there are mountain, grassy, real xerophytes, feather-grass, and moist steppe.
There is no uniform soil classification today. All soils are usually classified on the basis of their special characteristics or area. According to 1938 USDA soil taxonomy, all soils are divided into zonal and azonal types. Zonal soils are mineral soils, developed in autonomous conditions that cover extensive areas with typical conditions of soil formation. Azonal soils are soils spread on a small area in a certain region and characterized by diversity in morphology, soil properties, and conditions of formation with zonal soils. This type includes peaty, volcanic, and floodplain soils. Soil horizon is one of several homogeneous soil layers, constituting the soil profile and differing in morphology, composition, and properties.
Plate tectonics theory is the modern geological theory of the lithosphere movement, according to which the crust of earth consists of lithosphere plates that move in relation to each other. Pangaea is the name given by Alfred Wegener to the protocontinent that emerged in the Paleozoic era. Laurasia is the northern of the two continents that were formed as a result of the dissolution of the protocontinent Pangaea in the Mesozoic era. The parts of it are modern Eurasia and North America. Gondwanaland is the southern of the two continents that emerged as the result of dissolution of the protocontinent Pangaea. It included modern South America, Africa, Antarctica, Australia, and tectonic blocks of Hindustan and Arabia.
The Earth has its unique inner structure. Barysphere is the inner part of the earth, including the core and intermediate sheath or mantle. Sometimes, it is considered the only core of the Earth. Moho is the lower boundary of the Earth crust where the speed of seismic waves increases abruptly. Asthenosphere is the top plastic layer of the upper mantle of the planet. Lithosphere is the hard shell of the Earth that consists of the crust and the upper mantle. Mantle is a part of the Earth, located below the crust and above the core. The mantle is the big part of the Earth. The inner core is the deepest geosphere of the Earth with a radius of about 1220 km. It is in the solid state. The outer core is a liquid layer (2266 km). It consists of iron and nickel. The core is located above the solid inner core and below its mantel. Sial is the top layer of the Earth crust consisting of silica and aluminum. Sima is the lower layer of the Earth crust consisting of magnesium silicate minerals. Granite is the acidic magmatic irruptive rock, which is a common part of the continental Earth crust. Basalt is the basic effusive rock, which is the most common of all kainotype rocks. Plate boundaries are divided into three groups: divergent (when new crust is created in the form of two or more plates), convergent (when a mountain range is created due to the push of an oceanic plate), and transform plate boundaries (when two plates slides in a horizontal position). A hot spot can emerge only on the edge of a plate tectonic. Subduction can happen if two tectonic plates meet to sink one another.
Volcanoes are geological formation on the surface of the Earth crust, where magma comes to the surface, forming lava and volcanic gases. They are classified by the form: shield, stratovolcano, and cinder cone volcanoes. The shield volcanoes are situated in Hawaii and Iceland; the stratovolcanoes are in Papua –New Guinea; the cinder cone volcanoes are in Argentina. Caldera is extensive cirque bolson with steep walls and relatively flat bottom of the volcanic origin. Lava is the hot fluid or viscous melt of rocks, mainly consisting of silica. It differs in composition, color, temperature, and impurities (for instance, carbonate, silicic, and basaltic).
Earthquakes are vibrations of the Earth surface caused by natural causes or artificial processes. Epicenter is the perpendicular projection of the underground (underwater) center to the surface of the Earth. Seismic waves are waves of energy that travel through the Earth in a process producing low-frequency acoustic energy (earthquake, explosion). Seismograph is special sensing equipment, which is used to detect or record all types of seismic waves.
