# Lapse Rate and Humidity: Temperature Inversion and Pattern of Lapse Rate

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## Lapse Rate and Temperature Inversion

### Temperature Lapse Rate

Decrease of temperature with height

### Environmental Lapse Rate

Decrease of temperature at any given place and time

### Temperature Inversion

Increase of temperature with height

## Pattern of Lapse Rate

If air temperature at heights h1 and h2 are T1 and T2 respectively, the lapse rate is given by

## Adiabatic Lapse Rate

Decrease of temperature of air parcel with increase in height when no heat is exchanged with the surrounding

## Atmospheric Stability Condition

### Stable

Environmental Lapse rate < Dry-adiabatic lapse rate

Sub Adiabatic condition

### Conditionally Stable

Wet-adiabatic lapse rate<Environmental Lapse rate < Dry-adiabatic lapse rate

### Unstable

Environmental Lapse rate > Dry-adiabatic lapse rate

Super Adiabatic condition

Humidity - Amount of water vapour in given volume of air.

Expressed in terms of g/m

^{3}, g/cm^{3}, mg/cm^{3}.Mixing Ratio - Ratio of weight of water vapour to the weight of per unit volume of dry air.

Saturation Mixing Ratio - Concentration of maximum of water vapour in a dry air to certain volume and mass.

Relation between humidity, mixing ratio and saturation mixing ratio

## Sounding Instruments

Radiosonde: Measures temperature, pressure and relative humidity of air.

Rawinsonde: Measures wind speed and direction along with temperature, pressure and relative humidity.

## Multiple Choice Questions

1. For which among the following, lapse rate is negative?

Temperature inversion

Increase of temperature with height

Decrease of temperature with height

Both a and b

Answer: d

2.Which among the following is the wet-adiabatic lapse rate?

6°C/km

6.5°C/km

9.8°C/km

7°C/km

Answer: a

3. When environmental lapse rate is less than dry adiabatic lapse rate, the atmosphere is

Stable

Unstable

Conditionally stable

Both b and c

Answer: a

4. The relative humidity and the saturation mixing ratio of a given environmental condition is 0.4 and 0.05 g/kg respectively. What is the mixing ratio?

0.1 g/kg

0.2 g/kg

0.3 g/kg

0.4 g/kg

Answer: b

5. Which instrument measures wind speed and direction along with temperature, pressure and relative humidity?

Radiosonde

Hygrometer

Psychrometer

Rawinsonde

Answer: d

#Lapse Rate and Humidity

#UGC NTA NET

#Lapse rate and temperature inversion

#Pattern of lapse rate

#Adiabatic Lapse rate

#Atmospheric stability

#Humidity

#mixing ratio

#saturation mixing ratio

-Mayank