The phenomenon where cool, dense air sits under a layer of lighter warmer air is known as a

Options

A. temperature inversion
B. heat island
C. heat sink
D. Milankovitch cycle

Answer

**Step-by-Step Solution:**

1. **Understanding the Phenomenon**: The question describes a situation where cool, dense air is trapped beneath a layer of warmer air. This is a common atmospheric condition.

2. **Identifying the Term**: The term that describes this phenomenon is "temperature inversion." In a temperature inversion, the normal temperature gradient of the atmosphere is reversed, with cooler air at the surface and warmer air above.

3. **Location of Temperature Inversion**: Temperature inversions typically occur in the troposphere, which is the lowest layer of Earth's atmosphere. This layer is where most weather events occur.

4. **Examples of Temperature Inversion**: One of the notable effects of temperature inversion is the occurrence of freezing rain. This happens when warmer air aloft causes precipitation to fall as rain, which then freezes upon contact with the colder surface below.

5. **Eliminating Other Options**:
- **Heat Island**: This refers to urban areas that experience higher temperatures than their rural surroundings due to human activities and infrastructure.
- **Heat Sink**: This term describes a region that absorbs and retains heat, but it does not specifically refer to the layering of warm and cool air.
- **Milankovitch Cycle**: This relates to the Earth's orbital changes and does not pertain to air temperature layers.

6. **Conclusion**: Based on the definitions and explanations provided, the correct answer to the question is "temperature inversion."

**Final Answer**: The phenomenon where cool, dense air sits under a layer of lighter warmer air is known as **temperature inversion**.

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