Category: Geography Notes PPT

Tropical Storm occurs in the Earth’s Ocean Basins where tropical cyclones are found. They are precisely centered in the North Atlantic, Northeast and Central Pacific, Northwest and Southwest Pacific, and also in Indian. Tropical storms are quite similar to intense and mature tropical cyclones. These cyclones possess horizontal dimensions of about 160 km (which is around 100 miles). 

We will further know in detail about the tropical storms. Also, we will enlighten on Tropical Weather. 

Tropical Storm

A tropical storm is a storm that has an organized center and has low pressure which originates over the warm tropical oceans. The surface winds maximize their range from 63 to 118 km (that is 39 to 73 miles) on a per-hour basis. These kinds of storms represent the intermediate stage which is between the organized tropical depressions which are loosely formed and other intense tropical cyclones which are known as hurricanes or typhoons, they are named differently in different parts of the globe. 

The winds are the highest at the surface area but decrease with the increasing altitude. These winds typically attain the approximate intensity of about 30–50 km (that is 20–30 miles) which is away from the center of the circulation. 

Tropical Weather 

Two reasons why tropical weather is different from the weather in higher latitudes. The reason is here, the sun shines directly on the tropics rather than shining directly on the higher latitudes. They shine directly at least on an average over a year, this makes the tropics very warm compared to the higher latitude regions. Another reason is, the vertical direction, while one stands on the earth’s surface, is perpendicular to the Earth’s axis of rotation at its equator. The axis of rotation and the vertical are the same at the pole, this causes the rotation of the earth to influence the atmospheric circulation more intently at higher latitudes than at the lower latitudes. 

For these above-mentioned factors, clouds and rainstorms occur in the tropics more spontaneously than compared to that in the higher latitudes. In these, they are more tightly controlled by the larger-scale forces in the atmosphere. For these differences, the clouds and rain are very difficult to forecast in the tropics than at the higher latitudes. On the other hand, the temperature can be easily forecasted in the tropics, as it doesn’t differ much.

Heat, Moisture, Clouds, and Rain

With higher temperatures, more water vapour gets collected in the air without the process of condensing. When the sun shines strongly on the tropic regions mainly on the warm oceans they have an effectively infinite amount of water that evaporates into the open air. This is the time when the overlying atmosphere becomes humid.

Temperature and pressure both drop very quickly with the increasing altitude, this happens in the tropical regions as elsewhere on the Earth. If the warm air is lighter than the air surrounding it, this will expand and cool. Thus, it will cause water vapour in it to condense into these tiny liquid droplets and this forms a cloud. The latent heat of the condensation warms the air, this causes the air to become warmer, which further allows the air to updraft and rise. After enough water condenses, then the cloud droplets can become large enough to fall as rain.

Sometimes the tropical shower ends quite quickly when the rain evaporates. The evaporating rain cools the air which is located near the surface, the warm air rises into a new cloud. Also, the cooling effect with the weight of the rain itself can create a downdraft which will be enough to create turbulence which then turns and lifts the nearby warm, making the air humid, making a new updraft. This process then well feeds on itself to produce a large complex of storms that maintains the rainy weather over a couple of days. 

More on Tropical Storms

The tropical storms act as precursors for the more intense tropical cyclones, which occur more often. The yearly average tropical storms that occur in the various ocean basins are as follows:

• North Atlantic 

• North Eastern Pacific 

• North Western Pacific 

• Northern Indian 

• South Western Indian 

• Australian. 

In all the ocean basins, roughly around 45 percent of the tropical storms continue to intensify their motion to minimal tropical-cyclone strength or greater.

The above image depicts the data of the number of tropical cyclones and tropical storms that occur around the globe. 

There are a number of factors that might result in the failure of a tropical storm to continue to intensify a particular area. In some cases, the storm also moves into a region where the large-scale environment will not favor further growth. The sea surface temperature is quite low, the middle atmosphere is also too dry, or the winds which are blowing at the upper levels are too high to support the continued vertical development of the storm. 

In oceanography, water mass is defined as the body of water with a common formation history and also has physical properties distinct from the surrounding water. The physical properties of water mass include salinity, temperature, isotopic ratios, and other physical properties which are conservation flow tracers (Flow tracer is any fluid property used to track direction, magnitude, flows, and circular patterns). Water mass is also recognized through its non-conservative flow tracers such as intricate, silicate, oxygen, and phosphate. 

Water masses are categorized not only based on their respective tracers but also by their locations in the World’s ocean. Water masses are also categorized based on their vertical position so that there are deep water mass, intermediate water mass, and surface water mass.

Water Mass Formation

Water masses are formed as a result of different climatic conditions and effects in specific regions. When ice is formed in a cold climate like Antarctica, the cold temperatures separate the molecular bond of water causing it to become less dense. However, the ice becomes less dense than water when water increases its volume by 9% when frozen.  This in turn makes the water less saline.  The salinity of the water makes the water freeze at a lower temperature than freshwater. Freshwater freezes at an average of 28.4°F whereas saline water freezes at an average of 32°F. 

Atomic Mass of Water 

The Atomic mass ( mₐ or m) is the mass of an atom. The atomic mass is often represented in the non – SI unit dalton ( da or u), where 1 dalton is defined as the 1/12 mass of a single carbon atom, at rest. Water (H₂O) contains 2 hydrogen atoms and 1 oxygen atom. This implies that the atomic mass of water is 18.02 amu. This is because

The atomic mass of Hydrogen: 1.00784 amu  2 = 2.01568

The atomic mass of Oxygen = 15.999 amu

Therefore, the atomic mass of water = 2.01568 + 15.999 = 18.015 amu

Molecular Mass of Water

The molecular mass of any substance is defined as the sum of atomic masses of all the atoms present in each molecule of a given substance. It is measured in Daltons (Da or u). Molecular mass is calculated by adding up the atomic masses of all the atoms present in each molecule of a given substance. For example, if we need to calculate the molecular mass of water, H₂O, we need to add the atomic mass of hydrogen 2 times and atomic mass of nitrogen one time:

 

Therefore, the water molecular mass is 18.015 u.

Relative Molecular Mass 

Relative molecular mass (Mr.) is defined as the sum of the relative atomic mass (Ar.) of each atom present in the given molecule. 

How to Find Relative Molecular Mass?

1. Determine the molecular formula of a given molecule.

2. Determine the number of atoms of each element present in the given molecule. 

3. Determine the relative atomic mass of each element.

4. Multiply the number of atoms of each element with the relative atomic mass.

5. Add the total values to get the relative molecular mass.

Relative Molecular Mass of Water

Step 1: Determining the molecular formula of water 

Step 2:  Determining the number of atoms of each element in the molecule.

Step 3: Determining the relative atomic mass of each element.

• Ar of hydrogen is 1 

• Ar of oxygen is 16 

Step 4: Multiplying the number of atoms of each element with the relative atomic mass.

2 H = 2 1 = 2 

1 O = 1 16 = 16 

Step 5: Adding the total values to get the relative molecular mass

2 + 16 = 18

Hence, the relative molecular mass (Mr.) of water is 18.

Mass of One Mole of Water

The mass of one mole of any substance is equivalent to that substance’s atomic molecular mass in grams. For example, the mean molecular weight of water is 18.015 amu. Hence, the mass of one mole of water is 18.015 grams.

Did You Know?

• The first scientists to introduce atomic mass were John Dalton and John Berzelius.

• Molar mass is the mass of a substance that consists of 6.022×10²³ atoms.

• The unit of molar mass is gram per mole, abbreviated as g/mol.

• The Antarctic water bottom is a very important water mass. The Antarctic water bottom is the remaining portion when sea ice is being formed. It is extremely cold but not quite freezing so that water moves down along the ocean floor.  

As fossil energy supplies dwindle, the development of alternative energy sources has become a necessity. Simultaneously, global energy demand is increasingly rising, placing the planet on the brink of a global energy crisis. Furthermore, the widespread use of traditional energy sources pollutes the atmosphere and leads to global warming. Wind and other renewable energy sources, on the other hand, are feasible and clean alternatives to fossil fuels. Wind is one of the most cost-effective and efficient renewable energy sources because of its low operating costs and broad availability. One of the fastest-growing clean energy technologies is wind power. Globally, consumption is growing, partially due to lower prices.

According to IRENA’s latest statistics, global installed wind-generation capacity onshore and offshore has increased by nearly 75 times in the last two decades, from 7.5 gigawatts (GW) in 1997 to 564 GW in 2018. Wind energy production more than doubled between 2009 and 2013, accounting for 16 per cent of all renewable energy generation in 2016. Wind speeds are high in many parts of the world, but the best locations for producing wind power are often remote. Offshore wind power has a lot of promise.

What is wind energy?

Wind power is a type of energy conversion in which turbines transform wind kinetic energy into mechanical or electrical energy that may be utilized as commercial wind turbines generate electricity by harnessing rotational energy to power a generator. They are composed of a blade or rotor and an enclosure known as a nacelle, which houses a drive train atop a tall tower. The biggest turbines can generate 4.8–9.5 megawatts of electricity, with rotor diameters that can exceed 162 meters (531 feet), and are mounted to towers that may reach 240 meters (787 feet).

Wind energy is the most established and mature renewable energy source. It creates electricity by using the kinetic energy created by the influence of air currents. It is a clean and renewable energy source that decreases greenhouse gas emissions and protects the environment. 

Wind turbines

Wind power has been utilized since antiquity to propel sail-powered vessels or to power mill gear that moves mill blades. Wind turbines have been used to generate electricity since the early twentieth century. The wind propels a propeller, which turns the rotor of a generator, which generates power, via a mechanical system. Wind turbines are frequently clustered together in wind farms to maximize energy efficiency and reduce environmental impact. The machines have a twenty-year lifetime.

Wind energy, also known as wind power, is generated by employing a wind turbine, which is a device that harnesses the strength of the wind to generate electricity. The wind blows the turbine’s blades, which are linked to a rotor that further rotates a generator. Wind turbines are classified into two types: horizontal-axis wind turbines (HAWTs) and vertical-axis wind turbines (VAWTs) (VAWTs). The most prevalent form of the wind turbine is the HAWT. They often feature two or three long, thin blades, similar to an airplane propeller. The blades are oriented to face straight towards the wind. VAWTs feature shorter, broader curved blades that resemble electric mixer beaters.

Individual wind turbines may generate 100 kilowatts of power, which is enough to power a house. Small wind turbines are also employed in locations such as water pumping facilities. Wind turbines that are slightly bigger perch on towers that can reach 80 meters (260 feet) in height and have rotor blades that can reach 40 meters (130 feet) in length.  Wind turbines with rotor blades that are more than 162 meters (531 feet) long can be seen sitting on towers that rise 240 meters (787 feet) tall. 

Uses of wind energy

Some of the uses of wind energy are mentioned below.

Once created, power can be utilized, linked to the electrical grid, or stored for later use.

Working principle of a turbine

Wind turbines operate on a simple principle: rather than using energy to create wind (like a fan does), wind turbines utilize the wind to create power. Wind moves a turbine’s propeller-like blades around a rotor, which spins a generator, which generates energy.

The wind is a type of solar energy created by three simultaneous events:

The words “wind energy” and “wind power” both refer to the act of harnessing wind energy to create mechanical power or electricity. This mechanical power can be employed for specific activities (such as grinding grain or pumping water), or it can be converted into energy via a generator.

Small wind turbines are commonly employed in scattered applications. Single tiny wind turbines with a capacity of fewer than 100 kilowatts are primarily utilized for residential, agricultural, and small commercial and industrial uses.

Alluvium is a loose soil, or sediment, not fused into a rock, formed by erosion, reshaped by water in some form, and redeposited in a riverside setting or by a river. This is suitably represented by the name Alluvium meaning “to wash against”. In simple terms, the soil or sediment deposited or redeposited by continuous erosion from water (for example of a running river) and solidifying but not completely fused into a rock is generally called Alluvium. It is typically made up of many various materials which include fine particles such as silt, clay and large sand and gravel particles. When such alluvium is over time deposited and solidified or lithified, into a rock, it is called an alluvial deposit.

Characteristics of the Alluvium

Alluvium occurs in deposits of a variety of landforms. The recent alluvium or the new alluvium is deposited on all level floodplains which are near to a stream or a river. Whereas the older alluvium is found on alluvial terrace landforms which are higher than any of the river-associated floodplains and are not subject to frequent erosion or washing away due to flooding. An important point to note is that sediment forms and deposits in a perennial river system are not typically referred to as alluvial. Thus, if any of the sediment formations can be credited to another very well-described geological event, then it is not referred to as alluvial. 

As is clear from the alluvium meaning – “wash against” in Latin, alluvium is the subaerial deposition of sediments due to river currents in the flood plains. The typical composition of alluvium or alluvial soil includes clays, silts, sands, gravels and occasional cobbles. Many times the composition is a mixture of all these particles along with some organic matter. This type of deposition of a landform is poorly sorted and the variations in particle shape are of different degrees. But in very general forms they all are rounded to some extent. 

Alluvium is associated with all the channels where water is present or was present in the past. The term “alluvial channels” based on alluvium is a very general term for all the channels that derive their deposition or form in some part because of flowing water irrespective of their time duration i.e. either perennial or short-lived. A variety of landforms are associated with alluvium which includes alluvial fans, braided channels, deltas, meander cutoffs, levees, point bars and terraces.

The soil of alluvium landforms is generally rich in potash and poor in phosphorus. The colour of the alluvial soils varies from light grey to ash grey. The shades depend on different factors namely, the texture of the materials and the time taken for attaining certain maturity after deposition. Due to various factors such as their location around the floodplains and the deposited particles with organic matter and mineral content, alluvial soils are one of the highly used soils for cultivation.

How Old or New is Alluvium?

Alluvium is the most recent form of a deposition. Geologically it comes in the Quaternary, which is the most recent of the three periods of the geologic Cenozoic era of the most recent Phanerozoic Eon. It is mostly referred to as the “cover” simply because it covers or hides the underlying lithified rock under it. 

Most of the sediments that are present in a given basin, but are not lithified into rocks are typically lumped together as alluvium. Depending on the time passed from their deposition, the alluvium is categorized into two types: Khadar and Bangar. They are explained below:

• Khadar: The new alluvium is known as Khadar. It is formed by the deposition brought by the annual floods in a given flood plain. It contains the newly deposited fine silts which aid in enriching the soil. 

• Bhangar: As the new alluvium is known as Khadar, the old alluvium is known as Bhangar. It is a system of older deposition which are found away from the flood plains and were probably deposited by flowing water in the past.

Both the Khadar and Bhangar contain calcareous concretions (called Kankars). In India, both types of Alluvium are found in the upper and middle Ganga plain. Some of the alluvium is also found in the Brahmaputra valley. In the composition of the alluvium, the sand content decreases while one goes from west to east. 

Alluvium is also distributed in different parts of the world. For example, the alluvium of the Pliocene age occurs in parts of Idaho. Alluvium from the late Miocene age is found in the valley of San Joaquin River, California. An example of alluvium deposition is shown in the given picture:

The Alluvium Conclusion 

From the given article it is quite clear that Alluvium is a type of geological deposition (yet to be lithified into a rock) of sands, silts and other particles including organic matter by flowing water. It is rich in minerals such as potash and is widely used for cultivation. 

An Equinox is an astronomical phenomenon that occurs twice a year, once in the spring and once in the fall, when the Earth’s axis is turned neither away from nor towards the Sun. The inclination of the Earth (with respect to the Sun) is 0° at Equinoxes, and the day and night are almost equal in length on Equinox day, i.e. 12 hours. 

Equinoxes occur every year on the 20th or 21st of March and the 22nd or 23rd of September, and all days have the same duration of day and night. In the Northern Hemisphere, March Equinox is known as Vernal Equinox and Spring Equinox, while it is known as Autumnal Equinox and Fall Equinox in the Southern Hemisphere. In other words, it is springtime in the United Kingdom, the United States, Canada, Russia, India, and China on March Equinox, while it is autumn in Australia, Argentina, Chile, New Zealand, and South Africa.

Equinoxes are preferably referred to as March Equinox (Northern Equinox) and September Equinox (Southern Equinox).  

This only occurs twice a year, on the spring and autumn equinoxes. This means that on these days, the day period is the same (12 hours) at all points on the earth’s surface (except right at each pole, where it will be about to change from permanent light to dark, or vice versa). In several parts of the world, especially in the northern hemisphere, the autumnal equinox marks the start of autumn. This is the first day of spring in the southern hemisphere.

 

Types of Equinoxes

Equinoxes are classified into two groups. The equinoxes in March and September are each assigned their own names.

Spring Equinox

The Spring Equinox is the first day of spring. The Spring Equinox happens as the sun reaches the equator from the southern to the northern hemisphere, marking the start of the spring season. The North Pole continues to lean back against the sun. The day and night are nearly similar in time. Spring Equinox is near 20 March.

Autumn Equinox

The Autumn Equinox occurs as the sun reaches the equator from the northern to the southern hemisphere, marking the beginning of the autumn season. The North Pole tilts away from the sun. The day and night are nearly similar in time. The autumnal equinox is near September 22nd.

Equinox and Culture

For thousands of years, equinoxes have been a part of many cultures and rituals. Equinoxes, for example, signifies the start of important days such as the new year. Planting and harvesting seasons are determined by the equinoxes. Both equinoxes are designated as national holidays in Japan as a day to honor ancestors. During the equinox, the Hindu temple Angkor Wat in Cambodia is said to be constructed in such a way that the sun rises directly above its central temple. Between 1113 and 1150, the temple was founded. There are many examples of this in various religious and cultural cultures.

Fun Facts

• Equinoxes do not always occur on the same day each year.

• Saturn has equinoxes as well, but they only happen every 15 years because it takes about 30 years for Saturn to orbit the Sun.

• Equinoxes generally occur about 6 hours later each year, with a jump of a day (backward) on leap years.

• The Mid-Autumn Festival, also known as the Moon Festival, is held in China to mark the autumnal equinox.

Canyon geography is very simple. A canyon is a huge valley, with tremendously deep, steep sides and perhaps a river flowing along the bottom. The term “Canyon” is derived from the Spanish word cañon, which implies “pipe” or “tube”. The word “gorge” is also most commonly used to refer to “canyon,” but a gorge is relatively steeper and narrower than a canyon almost always. That said gorges and canyons are almost similar except for steepness and narrowness.

 

How are Canyons Formed?

The natural processes of weathering and erosion, the movement of rivers, and activity in tectonic creates canyons. Canyons are most commonly developed by erosion.

 

Have you ever thought how old the Canyons would be? Any guesses, you might think it is around a few months or some years. Not exactly! Canyons have been formed long back millions of years. Canyons are formed with erosion. This happens when the land has started to be worn away within the time due to some sort of force, this might be bodies of water or due to the impact of weather. In terms of Canyons, the river is the primary player that is responsible for creating erosion. Rivers start carving within the land with the flowing water, and the land is worn away and then Canyons formation happens in millions of years. 

 

You must have heard of a Grand Canyons that is available in the United States (western part). This canyon is tremendous so it earns the tag of its grand shape. The size of these Canyons is measured as 250 miles long and a mile deep. It has been formed after millions of years via the famous Colorado River. Similarly, Colca Canyons in Peru, and from Tibet to China Yarlung Tsangpo Canyons is famous for its deep and grand area. The next type of Canyons formation is due to the rifts that occur between the peaks of two mountains. We can give an example of the Himalayas and Alps rocky mountains. In such a situation, a stream or river helps in chalking out a split between two mountains that are towering. And, when Canyons are formed with this process then they are known as box canyons. 

 

What is the Real Role of Weathering in Canyon Formation? 

By this time you are aware of the term erosion so weathering is another word for erosion. And, erosions can be of varied types including win, freezing water, flowing water, and thawing water. This is associated with varied factors such as you collect a few stones on a bach that are powerful and large waves. The shape of these stones is well-rounded. Have you ever thought about how they got this round shape? Similarly, you can notice some sand particles having pointed edges now you are getting that weathering is also there in the sand. So, these are examples of water and wind erosion. With such erosion, they have got jagged edges. 

 

These are a few popular examples, you can explore Geography for more such examples. 

 

Canyon Landform

A canyon is a deep valley that is also narrow and cut by a river through rock. Canyons differ in size from narrow cuts to mega trenches. They consist of very steep sides and maybe thousands of feet deep. Smaller valleys of identical appearance are known as gorges. Over thousands of years, a river’s flowing water erodes or wears down rocks and soil to create a valley. The largest and most popular canyons have had slit through dry areas by swift streams sustained by rain or melting snow from wetter areas. The walls remain rough and steep since there is little rainfall or surface water to wear them off. An example is the Grand Canyon, in the U.S. state of Arizona.

 

Weathering and Erosion

Weathering and erosion also lead to the creation of canyons. In the winter season, water seeps into cracks in the rock and then this water. As this water freezes, it enlarges and converts into ice. Ice compels the cracks to get bigger and bigger, eroding bits of stone in the process. During short, heavy rainfalls, water gushes down the cracks, wearing off even more rocks and stone. As more rocks fragment and fall, the canyon grows wider at the top than at the bottom.

 

When this process takes place in soft rock, like the sandstone, it can result in the formation of slot canyons. Slot canyons are observed to be very deep and narrow. At times, a slot canyon can even be less than a meter (3 feet) wide, but hundreds of meters deep. Slot canyons can be threatening since their sides are generally very smooth and difficult to climb.

 

Canyon Ledges

Some canyons with hard, underlying rock may grow ledges and cliffs after crumbling their softer, surface rock. These ledges have the appearance of giant steps.

 

It is in fact quite amazing to know that sometimes an entire civilization can develop on and around these canyon ledges. Native US nations, such as the Sinagua and the Hopi created cliff dwellings. Cliff dwellings look like apartment-style shelters that accommodated hundreds of people. The shaded, lofted canyon ledges in Walnut Canyon and Canyon de Chelly, in Arizona, rendered protection from antagonist locales and the burning desert sun.

 

Box Canyons

Hard-rock canyons open at one end are known as box canyons. The Navajo and Hopi people usually used box canyons as natural corrals for sheep and cattle. They simply established a gate on the open side of the box canyon and closed it when the animals were inside.

 

Limestone is a kind of hard rock that is most commonly found in canyons. Sometimes, limestone erodes and develops caves underneath the earth. As the ceilings of these caves crumble, canyons form. The Yorkshire Dales, a region in northern England, is an assemblage of canyons and river valleys developed by limestone cave collapses.

 

Grand Canyon Geology

The Grand Canyon is one of America’s treasure troves and a World Heritage Site of UNESCO. In the Grand Canyon, there are clear horizontal layers of different rocks that are themselves a telltale of when, where, and how they have been deposited, long before the canyon was even carved. The Law of Superposition implies that sediment is accumulated in layers in order, with the youngest rocks on the top, while the oldest rocks on the bottom just the way sand piles up in an hourglass.

 

Conclusion 

Thus, this was all about canyons. For the ease of the student’s definition, ways of canyon formation and their different types have been explained thoroughly. The topic is really interesting if it is studied from scratch and understood with examples. Here, the best tip for the students who are preparing it for examination is that they should prepare their own notes along with this so that their practice starts right from the time of learning. And, once they are versed with the historical background then it is going to be easy for them to learn and remember the concepts.