1.1, in the lowest 10 km of the earth’s atmosphere, the air temperature generally decreases with altitude. The rate of this temperature change with altitude, the “lapse rate,” is by definition the negative of the change in temperature with altitude, i.e., −dT/dz.

air—commonly referred to as the normal, or environmental, lapse rate—is highly variable, being affected by radiation, convection, and condensation; it averages about 6.5 °C per kilometre (18.8 °F per mile) in the lower atmosphere (troposphere).

The environmental lapse rate (ELR), is the rate of decrease of temperature with altitude in the stationary atmosphere at a given time and location. For example, there can be an inversion layer in which the temperature increases with altitude.

To calculate the lapse rate initial temperature and the initial height and the final height, let final altitude will be equal to the 12 km C and final temperature = -54 degrees C. hence the lapse rate will equal to the -5.5 C/km, that increase with each km rise in altitude, temperature will drop by 5.5 degrees C.

There are three types of lapse rates that are used to express the rate of temperature change with a change in altitude, namely the dry adiabatic lapse rate, the wet adiabatic lapse rate and the environmental lapse rate.

The dry adiabatic lapse rate is approximately a 5.5 degree Fahrenheit change in temperature for every 1000 feet of vertical movement. The moist adiabatic lapse rate, on the other hand, is the rate at which a saturated parcel of air warms or cools when it moves vertically.

Definition. The Lapse Rate is the rate at which temperature changes with height in the Atmosphere. Lapse rate nomenclature is inversely related to the change itself: if the lapse rate is positive, the temperature decreases with height; conversely if negative, the temperature increases with height.

The temperature decreases with height. The temperature lapse rate in an atmosphere is the rate of decrease of temperature with height; that is to say, it is −dT/dz.

A super-adiabatic lapse rate occurs when the temperature decreases with height at a rate of greater than 10 degrees Celsius per kilometer. A super-adiabatic lapse rate is usually caused by intense solar heating at the surface.

The MALR (Moist Adiabatic Lapse Rate) is also called the wet or saturated adiabatic lapse rate. It is the temperature trajectory a parcel of saturated air takes. The wet adiabatic lapse rate varies from about 4 C/km to nearly 9.8 C/km. The slope of the wet adiabats depend on the moisture content of the air.

Our atmosphere is divided into various layers. In the troposphere, the temperature decreases with an increase in height. It increases by 1°C for every 165 m. This is called the normal lapse rate of temperature.

In troposphere, with increase in height, the density of air decreases and the temperature also starts falling. For every 165 metres, there occurs a 1 oC fall in temperature and this is known as the normal lapse rate of temperature.

Normal Lapse Rate of Temperature: The decrease in Temperature is known as normal lapse rate, which is calculated as an average decrease of 1°C for every 166 metres altitude gained. The lapse rate works mainly in the troposphere which results in various types of weather and climatic changes affecting the life on earth.