Which one of the following statements about temperature is correct?

The troposphere is the lowest layer of the atmosphere where temperature generally decreases with increasing altitude [1]. This phenomenon is known as the normal lapse rate, which averages approximately 6.4°C to 6.5°C per kilometer [1]. While some sources cite 6.5°C as the standard environmental lapse rate, others specifically define the normal lapse rate as 6.4°C per km [1]. In contrast, the stratosphere is characterized by a temperature inversion where temperatures remain constant for a short distance before increasing with height due to the absorption of ultraviolet radiation by the ozone layer [2]. Therefore, statements suggesting temperature decreases or remains entirely constant throughout the stratosphere are incorrect, as is the claim that temperature increases with height in the troposphere [2]. Option 4 accurately reflects the standard lapse rate observed in the troposphere [1].

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Structure of the Atmosphere > p. 7
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Stratosphere (12 to 50 km) > p. 275