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Highlighting the differences between aridity and drought, discuss the multi-dimensional impact of droughts.
According to the Aridity Anomaly Outlook Index for July, issued by the India Meteorological Department (IMD) this year, at least 85% of districts faced arid conditions across India. Also, around 21.06 percent of India was facing drought-like conditions, according to the Drought Early Warning System.Read more
According to the Aridity Anomaly Outlook Index for July, issued by the India Meteorological Department (IMD) this year, at least 85% of districts faced arid conditions across India. Also, around 21.06 percent of India was facing drought-like conditions, according to the Drought Early Warning System. Aridity is defined, in meteorology and climatology, as the degree to which a climate lacks effective, life-promoting moisture. Drought is a period of abnormally dry weather sufficiently long enough to cause a serious hydrological imbalance.
The differences between the two include:
Multi-dimensional impacts of droughts are the following:
- Water supply: During droughts, communities may have limited access to water for household use, including drinking, cooking, cleaning, etc. Further, it affects transportation and power generation.
- Agriculture: Droughts affect livestock and crops thereby having a devastating effect on farming and food production, which contributes to food price instability. In countries already facing food insecurity, cost spikes can lead to social unrest, migration, and famine.
- Energy: Droughts can raise concerns about the reliability of electricity production from plants that require cooling water to maintain safe operations. Hydroelectric power may also become unavailable during droughts. Further, when heat waves coincide with droughts, electricity demands can grow, compounding stress on the grid.
- Public health: Reduced flows in rivers and streams due to droughts can lead to a concentration of pollutants, thereby threatening the quality of water used for drinking and recreation. Also, drought-fuelled wildfires can expose nearby communities to smoke and pollutants, which can exacerbate chronic respiratory illnesses.
- Social impacts: Due to frequent droughts, there can be outmigration of the population from drought-affected areas leading to greater indebtedness, alienation from land and livestock assets, malnutrition, starvation, etc. There needs to be regular monitoring of droughts in states by setting up Drought Monitoring Centres (DMCs), which will be staffed by a multi-disciplinary team of meteorologists, hydrologists, and agriculture scientists. Also, state governments and businesses need to identify their vulnerability to droughts and improve resilience by practicing and promoting water conservation and enhancing water efficiency.
See lessExplain the phenomenon behind the shifting of wind belts. Also, illustrate its impact on the climate of a region.
The relative position of the Earth with respect to the sun changes within a year due to Earth's revolution. Further, due to the inclination of the Earth on its axis, there are differences in the heating of the continents and oceans, and as a result, the pressure conditions in January and July vary gRead more
The relative position of the Earth with respect to the sun changes within a year due to Earth’s revolution. Further, due to the inclination of the Earth on its axis, there are differences in the heating of the continents and oceans, and as a result, the pressure conditions in January and July vary greatly. This consequently results in the shifting of the wind belts.
Shifting of pressure and wind belts:
These seasonal changes in the relative positions of the wind belts introduce the following typical climatic conditions:
(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.
See lessJet streams play an important role in altering the climate of India and the world. Discuss with examples.
Jet streams are strong fast meandering narrow currents flowing in the upper troposphere. These are geostrophic westerly winds, which are developed when air masses of different temperatures meet. They usually extend from 20 degrees latitude to the poles in both hemispheres. Jet streams play a signifiRead more
Jet streams are strong fast meandering narrow currents flowing in the upper troposphere. These are geostrophic westerly winds, which are developed when air masses of different temperatures meet. They usually extend from 20 degrees latitude to the poles in both hemispheres.
Jet streams play a significant role in altering the global and regional climate.
Further, the position of the jet stream also plays a crucial role in determining the strength and duration of El Nino and La Nina.
See lessWhat is a climate tipping point, and why is it considered a critical concern in the context of climate change?
A climate tipping point refers to a critical threshold in the Earth's climate system. Crossing this threshold can lead to significant and often irreversible changes in the climate, ecosystem, or both. These changes can happen relatively quickly once the tipping point is passed, even if the initial dRead more
A climate tipping point refers to a critical threshold in the Earth’s climate system. Crossing this threshold can lead to significant and often irreversible changes in the climate, ecosystem, or both. These changes can happen relatively quickly once the tipping point is passed, even if the initial drivers pushing towards it are small or slow.
Climate tipping points are considered important because they can trigger cascading effects that amplify global warming and environmental disruption. For example, the melting of polar ice caps can accelerate as warmer temperatures reduce the reflective surface area (albedo effect), which in turn leads to more absorption of solar radiation and further warming. These feedback loops can create a domino effect that exacerbates climate change impacts beyond human control.
Understanding and identifying these tipping points is crucial for climate science and policy-making. It helps in setting more effective targets for greenhouse gas emissions reductions and conservation efforts to prevent or mitigate irreversible environmental changes.
See lessElaborate on the process of air mass formation while also providing a general classification of air masses.
Air mass formation occurs when a large body of air remains over a specific region for an extended period, taking on the characteristics of that region. This process involves: 1. Solar heating: The sun heats the Earth's surface, warming the air closest to the ground. 2. Expansion and rise: Warm air eRead more
Air mass formation occurs when a large body of air remains over a specific region for an extended period, taking on the characteristics of that region. This process involves:
1. Solar heating: The sun heats the Earth’s surface, warming the air closest to the ground.
2. Expansion and rise: Warm air expands and rises, creating an area of low pressure near the ground.
3. Replacement: Cooler air moves in to replace the risen air, creating a circulation pattern.
4. Cooling and sinking: As the air rises, it cools, eventually sinking back to the ground, creating a high-pressure system.
5. Homogenization: The air is mixed and homogenized, taking on the characteristics of the region.
Classification of air masses is based on their temperature and humidity properties, which are influenced by the region they form over. The main types of air masses are:
– Polar (P): Formed over polar regions, characterized by cold temperatures and low humidity.
– Tropical (T): Formed over tropical regions, characterized by warm temperatures and high humidity.
– Continental (c): Formed over land, characterized by low humidity and temperature extremes.
– Maritime (m): Formed over oceans, characterized by high humidity and moderate temperatures.
These air masses can be further classified as:
– Arctic (A): Extremely cold and dry, formed over Arctic regions.
– Antarctic (AA): Extremely cold and dry, formed over Antarctica.
– Equatorial (E): Very warm and humid, formed near the equator.
These classifications help understand the characteristics of air masses and their impact on weather patterns.
See lessBring out the differences in the formation and role of ozone in the troposphere and stratosphere. Also, discuss the various strategies to reduce the impact of tropospheric ozone.
Ozone (03) is a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth's upper atmosphere (stratosphere) and lower atmosphere oxygen (troposphere). Depending on where it is in the atmosphere, ozone affects life on Earth in either goodRead more
Ozone (03) is a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth’s upper atmosphere (stratosphere) and lower atmosphere oxygen (troposphere). Depending on where it is in the atmosphere, ozone affects life on Earth in either good or bad ways. Formation of tropospheric and stratospheric ozone Tropospheric or ground-level ozone is formed primarily from photochemical reactions between two major classes of air pollutants, volatile organic compounds (VOCs) and nitrogen oxides (NOx). NOx and VOC break apart in the presence of intense sunlight and recombine into new structures, creating ozone. It is created by human activities as emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapor, and chemical solvents are some of the major sources of NOx and VOC. On the other hand, stratospheric ozone is formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (02). Solar ultraviolet radiation breaks apart one oxygen molecule (02) to produce two oxygen atoms (20) and each of these highly reactive atoms combines with an oxygen molecule to produce an ozone molecule (03). These reactions occur continually whenever solar ultraviolet radiation is present in the stratosphere. Role of tropospheric and stratospheric ozone The tropospheric ozone or bad ozone can trigger a variety of health problems including chest pain, coughing, and throat irritation. It is also a major component of urban smog, which can worsen bronchitis and emphysema, trigger asthma, and permanently damage lung tissue. Further, bad ozone also damages vegetation and ecosystems as it leads to reduced agricultural crop and commercial forest yields, reduced growth and survivability of tree seedlings, and increased susceptibility to diseases, pests, and other stresses such as harsh weather. Whereas, the stratospheric ozone absorbs a portion of UV (Ultra Violet) light called UVB from the sun, preventing it from reaching the planet’s surface. Thus, it protects from many harmful effects, including skin cancers, cataracts, and harm to some crops and marine life. But this good ozone is gradually being destroyed by man-made chemicals referred to as ozone-depleting substances (ODS), including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), etc.
Strategies to prevent the formation of tropospheric ozone.
The Government has further taken initiatives such as the National Clean Air Programme (NCAP), Graded Response Action Plan (GRAP), etc. to check ozone pollution and improve air quality. There is a need for the effective implementation of multi-faceted programs to cut NOx and VOC emissions from vehicles, industrial facilities, and electric utilities. Voluntary programs may also be started to encourage the communities to adopt practices, such as carpooling, to reduce harmful emissions.
See lessGive an account of Global Atmospheric Circulation.
Answer: The Earth is surrounded by a thin layer of air called the atmosphere. The air in the atmosphere moves in response to differences in temperature at the equator (warm) and the poles (cold). This movement of air is called global atmospheric circulation. The movement of air across the planet occRead more
Answer: The Earth is surrounded by a thin layer of air called the atmosphere. The air in the atmosphere moves in response to differences in temperature at the equator (warm) and the poles (cold). This movement of air is called global atmospheric circulation. The movement of air across the planet occurs in a specific pattern that is dependent on:
The whole system is driven by the equator, which is the hottest part of the Earth. Air rises at the equator, leading to the creation of low pressure and rainfall. When the air reaches the edge of the troposphere (tropopause), it cannot go any further and so it travels to the north and south. The air becomes colder and denser, and falls, creating high pressure and dry conditions at around 30° north and south of the equator. Large cells of air are created in this way. The following are the 3 major cells:
Ferrel Cell: This lies in between the Polar and Hadley cells, and is a little more complicated. Put simply, it is the net effect of air motions from all the storms or ‘depressions’ that occur in the mid-latitudes. Air sinks in the sub-tropics and rises around 60-70°. In this region, westerly surface winds occur. These cells drive airflow, atmospheric pressure, and rainfall. The rising and sinking of air cause high and low pressure at the surface, respectively. The large-scale winds of the atmosphere initiate large and slow-moving currents of the ocean. Oceans in turn provide input of energy and water vapour into the air. These interactions take place rather slowly over a large part of the ocean.
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