Introduction

There are different types of clouds. Clouds are one of the forms of condensation. These are high-altitude clouds, mid-altitude clouds, low-altitude clouds, and vertical clouds. Nimbus is a type of cloud. The following is a description of what a nimbus cloud is.

A cloud is an aerosol composed of tiny liquid droplets of visible mass, ice crystals, planetary particles, or other particles of similar space. On Earth, clouds form as a result of the saturation of air when it cools to its dew point or when enough moisture from the surrounding environment causes the dew point to reach ambient temperature.

Nimbus is a type of cloud that can have a direct impact on Earth’s climate change. They can reflect incoming rays from the sun which contributes to cooling. So these clouds play a great role in the weather. What are nimbus clouds and their importance are discussed below (1).

Definition and Characteristics of Nimbus Clouds

Definition

A dark, gray, and featureless layer of cloud which is thick enough to block out the sun and the type of cloud that produces continuous rain, is called nimbus cloud (4).

Characteristics

• The Nimbus clouds are dark clouds. The literal meaning is precipitation is falling from the cloud.
• They are formed at an altitude of 500 to 5000 m.
• These clouds can moderate or low-intensity rainfall.
• The amount of rainfall from such clouds is much higher as it rains for a long period of time.
• Meteorological symbol for this cloud is Ni-st.
• Also called rain cloud, causes lightning, thunderstorms, or hail.
• They are dense clouds and can block the sun’s rays too.
• Usually seen in mid-latitudes (2).

Formation and Types of Nimbus Clouds

Formation

1. Nimbus clouds form when the air cools and this results in the condensation of water vapor which forms invisible and visible clouds or ice droplets.

2. These clouds form through the depth and density of an altostratus cloud.

3. It often forms along warm or occluding fronts.

4. Nimbus clouds extend through the lower and middle altitudes of the troposphere bringing rain to the earth’s surface.

5. It is usually a low-base cloud.

6. Sometimes when an altostratus cloud is thick, it descends to lower altitudes and becomes a nimbostratus cloud (3).

Types

There are two types of nimbus clouds. These are cumulonimbus and nimbostratus (5).

Cumulonimbus

One type of cloud that can produce hail, thunderstorms, and lightning is known as a cumulonimbus cloud.

Characteristics

• Cumulonimbus clouds are multi-level clouds.
• Comes with thunderstorms and lightning and heavy rainfall.
• They cover the entire sky.
• Are white and fluffy, with gray in color.
• Clouds of this class are very deep, dense, black, and huge in size.
• These clouds spread eastward due to the influence of westerly winds in the upper winds.
• These clouds look like a dome with a flat shape at the top and a flat shape at the bottom of the cloud.
• Cumulonimbus clouds are white, gray, and black.
• These types of clouds are usually lightning clouds.
• Natural disasters including hailstorms, tornadoes tend to be these clouds

Nimbostratus

A type of cloud which are dark and low-level clouds accompanied by light to moderate rain is called a nimbostratus cloud.

Characteristics

• It is a type of low-altitude cloud.
• The Nimbostratus cloud is located below the stratocumulus clouds.
• The color of the nimbus clouds is dense and black.
• These clouds cause continuous light to moderate rainfall.
• The amount of rainfall from such clouds is much higher as it rains for a long period of time.
• The symbol for this cloud is Ni-st.
• These types of clouds never cause lightning, thunderstorms, or hail.
• Nimbostratus cloud is called the rain cloud.
• This cloud is so dense that the sun cannot be seen if there is this cloud in the sky (1) & (2).

Physical Properties and Structure of Nimbus Clouds

Physical properties

• Nimbus clouds are arranged in layers like sea waves across one side of the blue sky during the rainy season.
• These clouds are so thick that the sun cannot be seen.
• There is no lightning in this cloud.
• When these clouds accumulate in the sky, which means there is a lot of rain and hail.
• The color of this cloud is dark gray or black.
• When this cloud accumulates in the sky, there is a lot of rain, so this cloud is called a rain cloud.
• Clouds of this class are located below the stratocumulus clouds.
• Nimbus clouds are shapeless and have hairy layers in many cases.
• These clouds are typically 2000 to 4000 m thick (2).

Structure

Nimbus clouds are very thick. It extends vertically through several kilometers of the atmosphere. It looks flat and gray. When this cloud is in the sky, it looks like a big blanket of clouds across the entire sky. These clouds occur at altitudes between 2km and 4 km in Polar Regions, between 2 km and 7 km in temperate regions, and between 2 km and 8 km in tropical regions. It is dark, gray, featureless layers of cloud, thick (3).

Role and Significance of Nimbus Clouds in Weather Patterns

• Nimbus clouds are clouds that form temperatures in the atmosphere.
• When such clouds accumulate in the sky, it rains with thunderstorms.
• These clouds block out the sun.
• It produces persistent rain.
• The nimbus clouds are often connected with frontal systems provided by mid-latitude cyclones.
• These clouds are also an essential part of the water cycle (1).

Precipitation Associated with Nimbus Clouds

Nimbus clouds are often connected by continuous moderate rain or snow and cover most of the sky. These clouds often bring precipitation that can last for several hours until the associated front passes (1).

Life Cycle and Duration of Nimbus Clouds

Nimbus clouds complete their life cycle through three stages. These are the developing stage, the mature stage, and the dissipation stage. They usually cover the entire sky. Sometimes it found high altitudes in the atmosphere. These clouds are seen at an altitude of about 3000 m in the middle level of the troposphere. Nimbus clouds often bring precipitation that can last for several hours until the associated passes through the front (1).

Nimbus Clouds and Severe Weather Phenomena

They cause some type of bad weather phenomena. It produced lightning and other dangerous weather conditions like tornadoes, hazardous winds, and large hailstones. Nimbus cloud means rain clouds. That is, if these clouds are seen in the sky, it should be understood that the weather is changing in a while, that is there is rain or hail (1).

Observing and Identifying Nimbus Clouds

Nimbus clouds are dark, gray, thick, and featureless clouds. When these clouds accumulate in the sky, it blocks out the sun. These clouds mainly produce rain or hail. This is the identification of nimbus clouds (1).

Q&A

1. What Nimbus cloud means?

A Nimbus cloud means a large gray cloud that brings heavy rain.

2. What are 3 facts about Nimbus clouds?

• Nimbus clouds are clouds that produce precipitation.
• These types of clouds usually cause heavy rainfall with thunderstorms.
• It is usually formed at lower altitudes.

3. Do nimbus clouds mean rain?

Yes, it means heavy rain.

4. How high is a Nimbus cloud?

These clouds are found at an altitude of 2400 meters.

5. What do nimbus clouds look like

The Nimbus cloud looks like a dark, gray, thick, and featureless layer of cloud.

6. Is Nimbus a type of cloud?

Yes, it is a type of rain cloud.

Written By: Manisha Bharati

Reference

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