Geography and Astronomy
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Geography and Astronomy Notebook: Preliminary Factual Sheet Created: 1/27/2017 11:57 PM Updated: 5/28/2018 2:47 PM Author: Siya Rasik URL: http://www.insightsonindia.com/2017/04/24/insights-daily-current-affairs-24-april-2017/ 2017 Drainage Patterns The streams within a drainage basin form certain patterns, depending on the slope of land, underlying rock structure as well as the climatic conditions of the area. These are dendritic, trellis, rectangular, and radial patterns. Dentritic Pattern The dendritic pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree, thus the name dendritic. Trellis Pattern A river joined by its tributaries, at approximately right angles, develops a trellis pattern. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other. Rock structures of variable resistance, Folded topography A rectangular drainage pattern develops on a strongly jointed rocky terrain. The radial pattern develops when streams flow in different directions from a central peak or dome like structure. A combination of several patterns may be found in the same drainage basin The oldest oceanic crust is about 260 million years old. This sounds old, but is actually very young compared to the oldest continental rocks, which are 4 billion years old. Gyre circulation: Three forces cause the circulation of a gyre: Global wind patterns – Wind drags on the ocean surface, causing water to move in the direction the wind is blowing. Earth’s rotation – The Earth’s rotation deflects, or changes the direction of, these wind-driven currents. This deflection is a part of the Coriolis effect. Earth’s landmasses – Earth’s continents and other landmasses (such as islands) also influence the creation of ocean gyres. The massive South Pacific Gyre, for instance, includes hundreds of kilometers of open ocean. In contrast, the northern Indian Ocean Gyre is a much smaller ocean gyre. The Ocean Conveyor Belt: The movement of the world’s major ocean gyres helps drive the “ocean conveyor belt.” The ocean conveyor belt circulates ocean water around the entire planet. Also known as thermohaline circulation, the ocean conveyor belt is essential for regulating temperature, salinity and nutrient flow throughout the ocean. Garbage Patches: Ocean gyres circle large areas of stationary, calm water. Debris drifts into these areas and, due to the region’s lack of movement, can accumulate for years. These regions are called garbage patches. The Indian Ocean, North Atlantic Ocean, and North Pacific Ocean all have significant garbage patches. Despite the decline in total fertility rates (TFR) countrywide, 12 States continue to have TFR above 2.1 children per woman, known as replacement-level fertility. However, when the TFR declines, the drop does not stop at 2.1, as seen in Kerala (1.6), Tamil Nadu (1.7) and Karnataka (1.8). This leads to faster changes in the population structure characterised by a reduction in the proportion of young people and an increase in the proportion of the elderly “Replacement level fertility” is the total fertility rate—the average number of children born per woman—at which a population replaces itself from one generation to the next, without migration. Most of the current and future demographic potential is locked in the northern States, and largely located in Bihar, Jharkhand, Madhya Pradesh, Rajasthan, and Uttar Pradesh… The proportion of the elderly started increasing in the southern States several years ago. Now, the phenomenon has extended to the western, extreme northern and eastern States. Dam and a barrage: Both refer to impervious barriers; while water in the case of a dam is made to flow through specially designed spillways, in the case of a barrage it is allowed to overflow What is a weir? It is an impervious barrier constructed across a river to raise the water level on the upstream side. The water is raised up to the required height and the water then flows over the weir. What is a dam? It is a high impervious barrier constructed across a river valley to form a deep storage reservoir. The surplus water is not allowed to flow over the dam, but it flows through the spillways provided at some level built into the dam. In a weir the water overflows the weir. What is a barrage? It is a weir that has adjustable gates installed over top of it, to allow different water surface heights at different times. The water level is adjusted by operating the adjustable gates. Hypoxic zones are areas in the ocean of such low oxygen concentration that animal life suffocates and dies, and as a result are sometimes called “dead zones.” Hypoxic zones can occur naturally, but scientists are concerned about the areas created or enhanced by human activity. There are many physical, chemical, and biological factors that combine to create dead zones, but nutrient pollution is the primary cause of those zones created by humans. The Changthang plateau, where the the Changpa nomads reside, is in Ladakh, Jammu and Kashmir. ( High altitude cold desert) Home to the goats with the silken coat, Changthang in Ladakh shows howpeople live in harmony withnature in a cold desert Changthangi, or pashmina goats, retreating to lower altitudes during winter PORTS Entre ports are collection centres where the goods are brought from different countries for export. Ports of Call are the ports which originally developed as calling points on main sea routes where ships used to anchor for refuelling, watering and taking food items. Packet stations are exclusively concerned with the transportation of passengers and mail across water bodies covering short distances. These stations occur in pairs located in such a way that they face each other across the water body. Troposphere is the hottest part of the atmosphere because it is heated by the Earth’s surface. It is the nearest atmospheric layer of earth’s surface. Loam is soil composed mostly of sand (particle size > 63 µm), silt (particle size > 2 µm), and a smaller amount of clay (particle size < 2 µm). By weight, its mineral composition is about 40–40–20% concentration of sand-silt-clay, respectively. Clay type soil, organic content, and soil structure influence soil water retention. The maximum amount of water that a given soil can retain is called field capacity, whereas a soil so dry that plants cannot liberate the remaining moisture from the soil particles is said to be at wilting point. Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. Capillaries are most effective in Loam Textured soil. The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating based on a hurricane's sustained wind speed. This scale estimates potential property damage. Hurricanes reaching Category 3 and higher are considered major hurricanes because of their potential for significant loss of life and damage. Category 1 and 2 storms are still dangerous, however, and require preventative measures. In the western North Pacific, the term "super typhoon" is used for tropical cyclones with sustained winds exceeding 150 mph. Category Sustained Winds Types of Damage Due to Hurricane Winds Very dangerous winds will produce some damage: Well-constructed frame homes 74-95 mph could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees 1 64-82 kt will snap and shallowly rooted trees may be toppled. Extensive damage to power lines 119-153 km/h and poles likely will result in power outages that could last a few to several days. Extremely dangerous winds will cause extensive damage: Well-constructed frame 96-110 mph homes could sustain major roof and siding damage. Many shallowly rooted trees will 2 83-95 kt be snapped or uprooted and block numerous roads. Near-total power loss is expected 154-177 km/h with outages that could last from several days to weeks. Devastating damage will occur: Well-built framed homes may incur major damage or 111-129 mph removal of roof decking and gable ends. Many trees will be snapped or uprooted, 3 96-112 kt blocking numerous roads. Electricity and water will be unavailable for several days to (major) 178-208 km/h weeks after the storm passes. Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees 130-156 mph 4 will be snapped or uprooted and power poles downed. Fallen trees and power poles 113-136 kt (major) will isolate residential areas. Power outages will last weeks to possibly months. Most of 209-251 km/h the area will be uninhabitable for weeks or months. Catastrophic damage will occur: A high percentage of framed homes will be 157 mph or higher 5 destroyed, with total roof failure and wall collapse. Fallen trees and power poles will 137 kt or higher (major) isolate residential areas. Power outages will last for weeks to possibly months. Most of 252 km/h or higher the area will be uninhabitable for weeks or months. El - Nino phenomena adversely affext six out of ten Indian summer phenomena. El Nino cycle (usually a 3-5 year oscillation of sea surface temperatures). TRIBES STATE TRIBES Andh, Sadhu Andh, Bhagata, Bhil, Chenchus (Chenchawar), Gadabas, Gond, Goundu, Jatapus, Andhra Pradesh Kammara, Kattunayakan, Kolawar, Kolam, Konda, Manna Dhora, Pardhan, Rona, Savaras, Dabba Yerukula, Nakkala, Dhulia, Thoti, Sugalis. Apatanis, Abor, Dafla, Galong, Momba, Sherdukpen, Arunachal Pradesh