Consider the following statements.
a. The temperature of the troposphere generally decreases with increasing altitude.
b. The troposphere is heated not by absorption of incoming short wave solar radiation but by transfer of heat from the earth's surface.
Now state whether :
Both the statements are correct and second is the correct explanation of the first
Detailed Solution on Troposphere Temperature and Heating
This question explores the characteristics of the Earth's troposphere, specifically focusing on temperature variations with altitude and the primary mechanism responsible for heating this atmospheric layer.
Analysis of Statement A: Temperature Decrease with Altitude
Statement A posits that the temperature of the troposphere generally decreases as altitude increases. This is a fundamental characteristic of the troposphere, the lowest layer of Earth's atmosphere, where almost all weather phenomena occur.
The average rate at which temperature decreases with an increase in altitude in the troposphere is known as the environmental lapse rate. This rate is approximately $6.5 \ ^\circ C$ per kilometer ($3.6 \ ^\circ F$ per 1000 feet) on average, although it can vary depending on location, time, and weather conditions.
Therefore, Statement A is correct.
Analysis of Statement B: Troposphere Heating Mechanism
Statement B suggests that the troposphere is primarily heated by heat transfer from the Earth's surface, rather than directly by absorbing incoming solar radiation. This statement accurately describes the main heating process for the troposphere.
- Incoming solar radiation (mostly shortwave) passes through the atmosphere.
- The Earth's surface absorbs a significant portion of this solar energy, converting it into heat.
- The warmed Earth's surface then heats the air layer directly above it through conduction (direct contact) and infrared radiation (longwave).
- This heat is subsequently distributed further into the atmosphere via convection currents (rising warm air and sinking cool air).
While the atmosphere does absorb some solar radiation (e.g., ozone absorption in the stratosphere), the dominant heating source for the surface-level air in the troposphere is the Earth itself.
Therefore, Statement B is correct.
Connecting the Statements: Explanation of Lapse Rate
Statement B provides the direct reason for the observation in Statement A. Because the primary heat source for the troposphere is the Earth's surface, the air is warmest near the ground. As altitude increases, the air is further away from this heat source, leading to a decrease in temperature.
The process described in Statement B (surface heating) directly causes the temperature profile described in Statement A (temperature decreasing with altitude). Hence, the second statement serves as a correct explanation for the first.
Conclusion
Both statements are factually correct descriptions of the troposphere's thermal properties. Furthermore, the heating mechanism described in the second statement is the fundamental reason for the temperature gradient explained in the first statement.
Conclusion: Both statements are correct, and the second is the correct explanation of the first.
Important Questions from Climatology
Consider the following statements about anticyclones :
1. Anticyclones are high pressure systems.
2. Air in the centre of the system must be subsiding.
3. Anticyclones are characterized by converging winds.
How many of the above statements is/are correct?
- Snow, sleet and hail are the forms of
- Nisarga, Gati, Nivar, Tauktae and Yaas are names of
Which one of the following is the correct sequence of layers as we move from the Earth’s surface upwards?
Which one of the following is a cold local wind?
