How do you think water or moisture determines the geomorphology of tropical area?
Weathering is a natural process involving the decomposition of rocks and minerals into smaller particles through physical, chemical, and biological means. It plays a very indispensable role in reshaping the Earth's surface and as a source of soil. There are mainly three types of weathering: physicalRead more
Weathering is a natural process involving the decomposition of rocks and minerals into smaller particles through physical, chemical, and biological means. It plays a very indispensable role in reshaping the Earth’s surface and as a source of soil.
There are mainly three types of weathering: physical or mechanical, chemical, and biological.
Physical Weathering: Also known as mechanical weathering, it is the breakdown of rocks into smaller pieces without bringing about chemical changes. The main involved processes include:
Freeze-thaw cycles: Water infiltrates into the fissures of rocks, freezes, expands, and finally causes the rock to break apart.
Exfoliation: Pressure release brings about peeling away of the outer layers from rocks; it mostly happens in a dome-shaped manner.
Abadian: Wind, water, or ice carry particles that rub against rock surfaces, wearing them away.
Weathering by Chemical Methods: It is the process by which the minerals in rocks are changed by chemical reactions with water, air, or other chemicals. The major processes here include:
Hydration: Water molecules are incorporated into the mineral structure; they enlarge it and, therefore, weaken it.
Hydrolysis: Minerals combine with water to produce new minerals that are softer, more susceptible to be further broken down—for instance, the breakdown of feldspar into clay.
Oxidation: Oxygen combines with minerals, heavily the ones containing iron; as a result, rusting occurs and, therefore weakening of that rock, for example, iron turning to iron oxide.
Carbonation: Carbon dioxide, which is dissolved in water, forms carbonic acid by reacting with water. Carbonic acid reacts with the minerals, mainly calcite in limestone, that has the capacity to dissolve them.
Biological Weathering: Organisms play a role in the weathering process of rocks, both physically and chemically. Trends of note include :
Root expansion: Plant roots expand in rock cracks and apply pressure to them, eventually breaking the rock. Growth of Lichen and Moss: These organisms produce acids which in turn etch, or chemically wear down, the surface of the rock.
Different forms of weathering have different effects on rocks. Physical weathering increases surface area for chemical reactions, thereby increasing chemical weathering. Chemical weathering of rocks changes their mineral composition, so enhancing their possibility of being broken physically. Biological weathering breaks them further by both mechanical and chemical methods. All these processes combine to constantly change the face of the Earth.
(i) The Mediterranean climatic regions are found in the western parts of the continents within the latitudinal zone of 30°-45° in both hemispheres. The Sub-Tropical High-Pressure Belts extending between 30°-35° latitudes are characterized by dry trade winds during the summer season and anti-cyclonic conditions. This belt extends up to 40° latitudes in the Northern hemisphere at the time of summer solstice and in the Southern hemisphere at the time of winter solstice. Thus, the western parts of the continents within the zone of 30°-40° latitudes do not receive rainfall during the summer season. On the other hand, the Sub-Tropical Belt shifts towards the Equator at the time of winter solstice in the Northern hemisphere and at the time of summer solstice in the Southern hemisphere. Consequently, the zone is characterized by the Westerlies, which lead to precipitation during the winter season. The Mediterranean type of climate is thus characterized by dry summers and wet winters. (ii) The regions lying between 60°-70° latitudes are characterized by two types of winds in a year. With the northward migration of the sun at the time of summer solstice, the Polar Easterlies are weakened because the Westerlies extend over these areas due to the northward shifting of Sub-Polar Low-Pressure Belts. The situation is reversed at the time of winter solstice when there is southward migration of the sun. The Polar Easterlies are re-established between 60°-70°N because of the shifting of the belt of the Westerlies southward. Consequently, it creates a climate characterized by wet summers through the Westerlies and associated cyclones and dry winters due to Polar Easterlies. (iii) Monsoon climate is also the result of the shifting of pressure and wind belts. Due to the northward migration of the sun in the Northern hemisphere at the time of summer solstice, the North Inter-Tropical Convergence Zone (NITCZ) is extended up to 30°N latitude over the Indian subcontinent, Southeast Asia, and parts of Africa. Thus, the Equatorial Westerlies are also extended over the aforesaid regions, which become the southwest or summer monsoons. These southwest monsoon winds bring much rain because they come from over the ocean and are associated with tropical cyclones. The NITCZ is withdrawn from the Indian subcontinent and Southeast Asia because of the southward shifting of pressure and wind belts due to the southward migration of the sun at the time of winter solstice. Thus, north-east trades are re-established which leads to the north-east or winter monsoons. Since they come from over the lands, they are dry.
Model Answer Introduction Oceanic salinity refers to the concentration of salt in seawater, which varies across different regions of the world's oceans due to several factors. The average salinity is about 35 parts per thousand. Understanding these variations is crucial, as they have significant impRead more
Model Answer
Introduction
Oceanic salinity refers to the concentration of salt in seawater, which varies across different regions of the world’s oceans due to several factors. The average salinity is about 35 parts per thousand. Understanding these variations is crucial, as they have significant impacts on ocean circulation, marine ecosystems, and climate patterns.
Body
Reasons for Oceanic Salinity Variations
Multi-Dimensional Effects of Oceanic Salinity Variations
Conclusion
The variations in oceanic salinity have profound implications, influencing ocean circulation, climate patterns, and marine biodiversity. Understanding these factors is critical for predicting and managing the impacts of climate change on marine ecosystems and human communities.
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