Physical Geography (UPSC) (Part-II)

The annual range of temperature is higher in the enclosed seas than in the open sea.
The Atlantic Ocean records relatively higher annual range of temperature than the Pacific Ocean.

Since the Northern hemisphere has more landmass as compared to the Southern hemisphere, the annual range of temperature will be greater in northern hemisphere.

Planetary albedo refers to the reflectivity of an entire planet, while terrestrial albedo pertains to the reflectivity of individual surface types like water bodies, forests, and snow-covered areas.
• Planetary Albedo: It would consider the average reflectivity of the entire planet, thus including land masses, water bodies, and atmosphere. This is kind of a composite for the global reflectivity.
• Terrestrial Albedo: This would mean the albedo related to Earth’s surface, considering variations of reflective properties of different landscapes like deserts, forests, oceans, and ice.
• Urban Albedo: This refers to the reflectivity of urban setups, which is usually lower due to the dark materials used, such as asphalt and concrete. The albedo of the urban areas has huge disparities depending on the building material used and planning of the city, usually between 15–20%.

For India, China, UK and USA, the correct sequence of the Median age of their population is
India China < USA < UK

Mars
Mars, the first planet discovered outside Earth’s orbit, is known as the “Red Planet” due to its reddish appearance, caused by iron oxide (rust). It takes 687 days to complete one revolution around the Sun.
Mars has two small natural satellites, Phobos and Deimos, with Deimos being the smallest satellite in the universe. The highest point on Mars is Olympus Mons, the tallest volcano in the solar system.
India’s ISRO launched Mangalyaan (Mars Orbiter Mission) on November 5, 2013, and it successfully entered Mars’ orbit on September 24, 2014. India became the first nation to reach Mars on its first attempt.
Jupiter
Jupiter is the largest planet in the solar system, 1300 Earths could fit inside it. It rotates rapidly on its axis and is surrounded by faint rings. Jupiter takes 11.9 years to complete one revolution around the Sun and has 92 known satellites. Ganymede, the largest of them, is also the biggest satellite in the solar system. The planet’s atmospheric pressure is 10 million times higher than Earth’s. Jupiter’s Great Red Spot is a continuous high-pressure storm, creating asymmetric storms on the planet.
Saturn
Saturn is considered the most beautiful planet in the Solar System and is the second-largest after Jupiter. It takes 29.5 years to complete one revolution around the Sun and has a yellowish appearance. Saturn is famous for its four stunning rings, which are not visible to the naked eye. It has 147 natural satellites, with Titan being the largest, nearly the size of Mercury. Saturn is the least dense planet in the solar system, with a density lower than water, meaning it would float if placed in a large enough water body.
Uranus
Uranus was discovered in 1791 by William Herschel. It is the third-largest planet in the solar system and is named after the Greek god of the sky.
Uranus takes 84 years to complete one revolution around the Sun and, like Venus, it rotates from East to West. Its bluish-green color is due to the presence of methane in its atmosphere. Through a telescope, it appears greenish. Uranus has five rings named Alpha, Beta, Gamma, Delta, and Epsilon and 27 known satellites.

The extremely hot and dense center of our planet is known as the Earth's core. The Gutenberg discontinuity signals the end of the mantle and the commencement of Earth's liquid outer core.

Volume: The core accounts for 33% of the Earth's mass and 16 percent of the Earth's volume.
Composition: Unlike the mineral-rich mantle and crust, it is made almost entirely of metal - iron (Fe) and nickel (Ni) hence, sometimes called Nife layer.
Siderophiles, the elements that dissolve in iron (gold, platinum, cobalt, etc) are also found in the core.
The core contains 90% of the earth's sulfur.
The other elements speculated to be the parts of the core are oxygen and silicon.
Two layers: The core is further divided into two layers - inner core and outer core. The Lehmann discontinuity or the Bullen discontinuity is the boundary separating these regions.

• Approximately 69 percent of Earth’s freshwater is locked away in the form of ice in glaciers and polar ice caps.
• Another 30 percent of Earth’s freshwater is under the surface in the form of groundwater.

That leaves only about one percent of Earth’s freshwater readily available for human use.
Unfortunately, the available surface freshwater is not equally distributed throughout the world.

• Brazil, Russia, Canada, Indonesia, China, Colombia, and the United States have most of the world’s surface freshwater resources.
• As a result, approximately one-fifth of the world’s population lives in water-scarce areas.

This lack of water affects people’s access to clean, usable water, as well as the economic development and geopolitics of different areas.

The tropical rainforests receive annual precipitation amounts of 60 to 160 inches. (152 to 406 cm). Some rainforests in the world experiences annual rainfall amounts of almost 400 inches.

The impact of El-Nino Modoki includes:

• Zonal Gradients – This phenomenon results in anomalous two-cell Walker Circulation over the tropical Pacific, with a wet region in the central Pacific.
• Central Pacific Storms – El-Nino Modoki will increase storm frequency in the Central Pacific and the potential for landfall along the Gulf Coast and Central America.
• Cyclones – Compared to the general phenomenon, the Arabian Sea experiences more cyclones during pre and post-monsoon seasons. Conversely, the Bay of Bengal experiences more cyclones during the pre-monsoon and post-monsoon periods.

Natural surfaces have varying albedos; for example, snow has a high albedo (0.8–0.9), while forests and oceans have low albedos (0.1–0.2).

• Albedo of Snow and Ice: These surfaces are highly reflective, generally in the order of 80–90%, meaning most of the sunlight gets reflected and helps in keeping polar and glacial regions cool.
• Water Albedo: Water bodies have a low albedo, 5–10%, but vary with the angle of incoming sunlight.
• Forest Albedo: The vegetated areas have a relatively low albedo, about 10–20%, and hence absorb more of the incident sunlight required for photosynthesis.
• Desert Albedo: These regions have moderate albedos, ranging from about 30–40%, consisting of light-colored sandy surfaces in arid and semi-arid regions.