Water in the Atmosphere

Overview

Water vapor is the most variable and influential component of the atmosphere. This chapter covers the phases of moisture—from humidity and cloud formation to the various types of precipitation.

Learning Objectives

Define Absolute, Specific, and Relative humidity
Explain the processes of condensation and evaporation
Classify clouds based on their physical appearance and height
Assess the different mechanisms of precipitation

Key Concepts

Relative Humidity

The ratio of actual moisture in the air to its total capacity at a given temperature. It dictates when condensation (dew/rain) will occur.

Mechanism of Rainfall

Includes Convectional (heating), Orographic (mountain barrier), and Cyclonic (frontal contact).

Key Terms

Dew PointOrographic RainNimbusSublimationCumulus

Examples

Cherrapunji’s Rainfall

A classic example of intense Orographic rainfall caused by the Khasi hills.

Quick Check

What is 'Specific Humidity'?
How do clouds form?