Problem 14 - A Complete Resource Book in Chemistry for JEE Main

Question

The point of temperature inversion between troposphere and ionosphere is called (a) mesopause (b) stratopause (c) ionopause (d) tropopause

Step-by-Step Solution

Answer

The point of temperature inversion between the troposphere and ionosphere is called the tropopause (d).

Step 1: Understanding Atmospheric Layers

To solve the problem, it's crucial to know the layers of the atmosphere. The atmosphere is divided into several layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Each has distinct characteristics and temperature gradients. A temperature inversion occurs at the boundaries between these layers.

Step 2: Identifying Key Features of Layers

The troposphere is the lowest atmospheric layer where weather occurs; it ends at the tropopause, the boundary above which the temperature inversion begins. The stratosphere follows and is known for a temperature increase due to ozone. The next layer, the mesosphere, ends at the mesopause, a point of another inversion. Beyond that are the thermosphere and then the ionosphere, which is part of the thermosphere.

Step 3: Locating the Inversion Point

The given exercise is about finding the inversion point between the troposphere and ionosphere. The launch of the temperature inversion starts directly above the troposphere, at the tropopause. This is the boundary where the temperature stops decreasing with altitude and starts increasing in the stratosphere.

Step 4: Matching with Provided Options

Reviewing our findings, we see that the tropopause is the temperature inversion point between the troposphere and the next layer, which gradually leads towards the ionosphere. Among the options, (d) tropopause matches our understanding as the correct inversion point.

Key Concepts

Temperature Inversion

In the atmosphere, a temperature inversion is a fascinating phenomenon where the normal temperature pattern—usually a decrease in temperature with an increase in altitude—is reversed. This means higher layers are warmer than the cooler layers below. Typically, in the troposphere, temperatures drop as you go upwards. However, during an inversion, this pattern flips:

• Inversions can trap pollutants close to the ground, affecting air quality.
• Seen often during calm nights when the ground cools down rapidly, causing the air near the ground to be colder than the air above.
• They play significant roles in weather formation and can lead to atmospheric phenomena like fog.

Temperature inversions occur at various atmospheric boundaries like the tropopause, stratopause, or mesopause. Recognizing these can help in understanding weather patterns and climatic conditions.

Troposphere

The troposphere is the lowest layer of Earth's atmosphere, starting at the surface and extending up to around 8 to 15 kilometers, depending on your location. This is where all the weather we experience happens!

• Contains most of the atmosphere's mass, despite being the thinnest layer.
• The air in the troposphere is in a constant state of mixing due to weather systems, leading to the changeable weather we witness daily.
• Temperatures in this layer generally decrease with elevation.

The top boundary of the troposphere is the tropopause, which serves as a barrier to prevent mixing with the stratosphere. The understanding of this layer is crucial since it is directly related to weather conditions and climate patterns.

Tropopause

The tropopause is the transitional boundary that separates the troposphere from the stratosphere. It is one of the layers where a temperature inversion occurs. This means:

• Above the tropopause, in the stratosphere, temperature increases with altitude due to the absorption of solar radiation by the ozone layer.
• It varies in height depending on latitude and season, being higher at the equator and lower at the poles.

The presence of the tropopause confines most weather events, like thunderstorms, within the troposphere. Its identification was key in the original exercise since it marks the start of the temperature inversion leading into the stratosphere.

Stratosphere

Above the tropopause lies the stratosphere, extending up to about 50 kilometers above Earth. Contrary to the troposphere:

• Temperature in the stratosphere increases with altitude.
• This increase is due to ultraviolet (UV) radiation from the sun being absorbed by the ozone layer, which heats this part of the atmosphere.
• This layer is more stable with little mixing, which is why jets often fly here to avoid turbulence.

The understanding of the stratosphere is crucial for comprehending how Earth's radiative balance works and how man-made issues such as ozone depletion affect our planet. The stratosphere serves as a buffer zone protecting life on Earth by blocking and absorbing the sun's harmful UV rays.