Geography

Cyclones are also termed atmospheric disturbances. When the velocity of winds increases to such an extent that they attain strong force, a cyclonic storm is formed. Cyclones are the centres of low pressure. They are surrounded by closed isobars having increasing pressure outward. The wind circulation is from outside towards the central low pressure. They … Read more

Anticyclones are centres of high pressure.They are surrounded by closed isobars having decreasing pressure outward.  The circulation is from central high pressure towards the periphery in such a way that air blows outwards in a clockwise direction in the Northern hemisphere and anticlockwise direction in the southern hemisphere. Due to Coriolis force, blowing winds are … Read more

. It is an inclined zone along which two opposing air masses having contrasting characteristics in terms of air temperature humidity density pressure converged together.  An extensive transitional zone between two converging air masses is called a frontal zone. The frontal zone is inclined at a low angle to the Earth’s surface. It is also … Read more

Air mass is a large body of air having little horizontal variation in temperature and moisture.The air masses have a relatively uniform distribution of vertical gradients in their physical properties like temperature, pressure, and humidity. Air masses are formed in very particular surface and atmospheric conditions which are found only in a few areas of … Read more

Cyclonic rain occurs due to the convergence of extensive air masses. When two contrasting air masses like cold polar air mass and warm westerly air mass coming from opposite directions converge along a line a front is formed. The warm wind is lifted upward along this front where the cold air being heavier settles down. … Read more

Permanent winds are also called invariable or planetary wind systems because they blow over larger areas of the earth. They blow in the same direction throughout the year. Trade Winds These flow from subtropical high-pressure belts to equatorial low-pressure belts in both hemispheres north and south. These are known as Northeast trade winds in the … Read more

. These winds change their directions with the seasonal changes or periodically. Monsoon Winds A monsoon wind is a seasonal wind found especially in Asia that reverses direction between summer and winter and often brings heavy rains. The Asiatic monsoon is the result of the interaction of both the planetary wind system and regional factors, … Read more

India lost a large proportion of cotton growing area to Pakistan during partition. However, its acreage has increased considerably during the last 50 years. Cotton is a tropical or sub-tropical crop grown in semi-arid areas of the country (mainly in the Deccan Plateau).  Hard-frost is injurious to cotton cultivation and it requires at least 210 … Read more

Solar storms are caused by the release of magnetic energy called solar winds from the sunspots. These storms result from variations in the solar wind that cause major changes in the currents, plasmas, and fields in Earth’s magnetosphere.  Solar Storms happen when Sun emits large bursts of energy in the form of solar flares and … Read more

Lattitude In the previous article, we have studied that the angle of incidence of sun’s rays goes on decreasing from the equator towards the poles. Higher the angle of incidence, higher is the temperature. Similarly, lower the angle of incidence, lower is the temperature. This is why the temperature is higher near the tropical regions … Read more

The phenomenon in which temperature increases with increasing altitude temporarily and locally under certain conditions is known as inversion of temperature. Inversion is usually of short duration but quite common nonetheless. Long winter night, clear sky, dry air and absence of winds leads to quick radiation of heat from the earth’s surface, as well as … Read more

  As we all know, the sun is the primary source of energy for the earth. The sun radiates its energy in all directions into space in short wavelengths, which is known as solar radiation. The earth’s surface receives only a part of this radiated energy (2 units out of 1,00,00,00,000 units of energy radiated … Read more

To the north and south of the equator, there are two westward-moving currents, i.e., the North and the South Equatorial Currents. Between these two, there is the counter equatorial current which moves from west to east. The South Equatorial Current bifurcates into two branches near the Cape De Sao Roque in Brazil and its northern … Read more

The major movements of the ocean waters can be classified into three. They are: Waves Tides Ocean Currents Waves and the ocean currents are horizontal movements of ocean waters while the tide is a kind of vertical movement of the ocean water. Waves Waves are nothing but the oscillatory movements that result in the rise … Read more

Difference in density As we all know, the density of sea water varies from place to place according to its temperature and proportion of salinity. The density increases with an increase in salinity and decreases with a decrease in salinity. But when the temperature increases, density decreases and when the temperature decreases density increases. This … Read more

The mountains, on the basis of their mode of formation, can be classified as: Fold Mountains Mountain ranges mainly consisting of uplifted folded sedimentary rocks are called Fold Mountains. They are formed due to the force of compression arising from the endogenic or internal forces. Synclines (trough) and anticlines (crest) are part of Fold Mountains. … Read more

Coral reefs harbour the highest biodiversity of any ecosystem globally and directly support over 500 million people worldwide, mostly in poor countries. They are among the most threatened ecosystems on Earth, largely due to unprecedented global warming and climate changes, combined with growing local pressures. A spike of 1–2°C in ocean temperatures sustained over several … Read more

Pediplains When the high relief structures in deserts are reduced to low featureless plains by the activities of wind, they are called as Pediplains. Deflation Hollows Deflation is the removal of loose particles from the ground by the action of wind. When deflation causes a shallow depression by persistent movements of wind, they are called … Read more

Soil erosion: Among the agents, water is considered as the main cause of soil erosion. Main agents of soil erosion are (1) Water, (2) Wind, (3) Waves and (4) Glaciers Removal of the top layer of soil by various means, which include both natural events and human activities, is called as soil erosion. Decline of … Read more

. Physical or mechanical weathering processes depend on some applied forces. Unloading and Expansion Removal of overlying rock load because of continued erosion causes vertical pressure release. Thus, the upper layers of the remaining rock expand to produce disintegration of rock masses. Fractures will develop roughly parallel to the ground surface. In areas of curved … Read more

Chemical weathering can be due to solution, carbonation, hydration or oxidation/reduction. Solution When something is dissolved in water or acids, the water or acid with dissolved content is called a solution. This process involves the removal of solids in solution and depends upon the solubility of a mineral in water or weak acids. When coming … Read more

Marine heatwaves are periods of extremely high temperatures in the ocean.  This phenomenon causes ocean temperatures to be extremely warm for an extended period that can have significant impacts on marine ecosystems and industries.?  These can occur in summer or winter. The most common drivers of marine heatwaves include: Ocean currents can build up areas … Read more

Major characteristics of Alluvial Soils are as follows: They are immature and have weak profiles due to their recent origin. Most of the soil is sandy and clayey soils are not uncommon. They vary from loamy to sandy-loam in drier regions and clayey loam towards the delta. Pebbly and gravelly soils are rare. Kankar (calcareous … Read more

The earthquake which originates in the lithosphere propagates different seismic waves or earthquake waves. Earthquake waves are basically of two types – body waves and surface waves. Body waves They are generated due to the release of energy at the focus and moves in all directions traveling through the body of the earth. Hence, the … Read more

Seismometers are the instruments which are used to measure the motion of the ground, which including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources. A Seismograph is also another term used to mean seismometer though it is more applicable to the older instruments. The recorded graphical output from a seismometer/seismograph … Read more

Volcanoes are classified on the basis of nature of eruption and the form developed at the surface. Shield Volcanoes  They are far and wider. They extend to great height as well as distance. They are the largest of all volcanoes in the world as the lava flows to a far distance. The Hawaiian volcanoes are … Read more

They have an immense influence on local and regional weather conditions.  There is a close relationship between the intensity of temperate cyclones and jet streams. Severe storms occur when Jet streams interfere with surface wind systems.  They also help in giving a relatively clear picture of the occurrence of the events of El Nino and … Read more

There has been a significant increase in agricultural output and improvement in technology during the last fifty years. Production and yield of many crops such as rice and wheat has increased at an impressive rate. Among the other crops, the production of sugarcane, oilseeds and cotton has also increased appreciably. India ranked first in the … Read more

. The Pesticide Management Bill, 2020 was introduced in Rajya Sabha by the Minister of Agriculture and Farmers Welfare, Mr. Narendra Singh Tomar, on March 23, 2020.  It seeks to regulate the manufacture, import, sale, storage, distribution, use, and disposal of pesticides, in order to ensure the availability of safe pesticides and minimise the risk … Read more