Introduction

Clouds are one of the forms of condensation. There are different types of clouds. These are high altitude clouds, mid-altitude clouds, low altitude clouds, and vertical clouds. The stratus cloud is a low-altitude cloud. The following is a description of the stratus cloud and the difference between the stratus cloud and cumulus clouds. 

A collection of tiny water droplets or snow particles floating in the atmosphere together is called a cloud. Water vapor condenses in the earth’s atmosphere forming clouds. When these clouds are heavy enough, they fall on the earth in the form of rain. 

As the light water vapor gradually rises to the surface, it comes in contact with excess cooling and becomes saturated. The temperature of this saturated air below the dew point, condensation causes excess water vapor to condense into tiny water particles and snow particles. All these tiny water particles and snow particles floating in the sky, sheltering dust particles, coal, etc. floating in the air. This is how clouds are created. 

In 1803, British meteorologist Luke Howard was the first to classify clouds. Clouds are currently divided into three main categories based on their height. Stratus cloud is a type of low cloud that is located at an altitude of less than 2 km (1) & (3). 

Stratus cloud

Meaning

The word stratus comes from the Latin word, “stratro”, which means, “layer”.

Definition

A gray or white cloud that looks like a fog, covers the whole sky like a sheet and is arranged in layers. This type of cloud is called a stratus cloud. They are one type of low-altitude cloud. It is formed from 0 to 1,200 feet. 

These clouds are opaque because their thickness is so high. It is formed when a sheet of cool air passes under a sheet of moist warm air and takes the form of strata of clouds. When these two types of clouds are intermingled with each other and condensation starts subsequently. Therefore the warm air-cooled and formed stratus clouds (3).

Interesting facts about stratus clouds

1. Stratus clouds are white or gray in color. 

2. These types of clouds form near the surface so they look a lot like mist or fog.

3. It formed in stable and calm conditions.

4. Clouds of this class are closest to the earth’s surface. 

5. They are arranged in layers so they are called stratus clouds. 

6. These horizontally wide gray clouds cover the entire sky. 

7. Stratus clouds are those clouds that formed from the surface to 1,200 feet in the atmosphere.

8. This type of cloud is formed when fog rises near the ground or when the deep fog clears the bottom. 

9. It is mainly found in the troposphere. 

10. They can sometimes cause light rain. 

11. The symbolic name of this cloud is St.

12. It is mainly formed over the oceans (2) & (3).

Importance

• It is thin, gray or white, sheet-like clouds with low altitude covering the whole sky, so it is responsible for drizzle or snow but not much precipitation. It has not had adequate water droplets so not much precipitation occurs from this cloud.
• These clouds have dense layers. When this cloud is present in the sky, the sunlight does not reach the surface properly. It protects us from the harmful rays of the Sun and also protects us from the heat in the summer season.
• It absorbs heat emitted from the earth’s surface and cools and warms the atmosphere.
• At night it acts as a blanket on the surface of the earth and therefore keeps us from getting too cold (3).

Formation of stratus clouds

Stratus clouds form in stable weather conditions when gentle breezes cool down. It is formed when a sheet of cool air passes under a sheet of moist warm air and takes the form of strata of clouds. When these two types of clouds are mixed with each other, then condensation starts. In this way, the warm air-cooled and formed stratus clouds.

After formation, it looks like featureless gray or white sheets of cloud composed of water droplets and falls down onto the surface as a mist or fog. Sometimes snow or drizzle is created from stratus clouds (1). 

Difference between cumulus and stratus clouds (1) & (3)

	Stratus clouds	Cumulus clouds
Appearance	Like white and gray color layered sheets.	White color fluffy cotton and are isolated from each other.
Formation	Formed due to low-level convergence and upper-level divergence.	Due to atmospheric convection
Density	Stratus clouds are dense and thick. It brings steady rain and snow. It is layered horizontally in a stratus shape.	Cumulus clouds are more cellular and have rounded tops and flat bottoms vertically floating in the sky.
Altitude	Low-altitude clouds.	Multi-level clouds or vertical clouds.
Convection currents	No convection currents in stratus clouds	Cumulus clouds have convection currents.
Weather indication	Stratus clouds can cause drizzles.	Whereas this cloud represents the clear weather.

Q & A

1. Cumulus and stratus clouds belong to which group of clouds?

Clouds are basically divided by the height of altitude level in the troposphere. There are various types of clouds like-high altitude, middle altitude, and low altitude clouds.

Stratus clouds fall under low-level altitude clouds and cumulus clouds fall under multi-level clouds (3).

2. Which type of weather does the stratus cloud bring?

Stratus clouds bring a little bit of precipitation because of their thin characteristics. Due to its thinness, it cannot form many clouds that are responsible for bringing much precipitation. Sometimes snow or drizzle is formed from stratus clouds (1).

3. How to stratus cloud form?

Stratus clouds form in calm weather conditions. It is formed when cool air passes under moist warm air and takes the form of layers of clouds. When these cool air and moist warm air are mixed with each other then condensation starts. In this way, the warm air-cooled and formed a stratus cloud (3).

4. Cumulus and stratus clouds belong to which cloud group?

Cumulus clouds belong to vertical clouds or multi-level clouds.

Stratus clouds belong to low clouds (3).

5. How are stratus clouds formed?

Mainly stratus clouds are formed in calm weather. When gentle breezes increase cool, humid air on cool land or sea surface, then these clouds are formed (1). 

Reference

1. Savindra Singh. Climatology. Pravalika Publications, Allahabad. Chapter 2: Origin, composition, and structure of the atmosphere. Page No: 20.

Written By: Manisha Bharati