TAG: GS-3: DISASTER MANAGEMENT
CONTEXT: The recent flooding in southern and eastern Spain was caused mainly by a weather phenomenon known as DANA (Depresión Aislada en Niveles Altos) or “cold drop”.
EXPLANATION:
What is DANA?
- DANA, also known as “cold drop” in Spanish, stands for “isolated depression at high altitudes.”
- Known as “gota fría” or “cold drop,” DANA is an annual phenomenon caused by cold air descending over the warm Mediterranean Sea, leading to atmospheric instability.
- This instability causes warm, moist air over the sea to rise quickly, forming dense cumulonimbus clouds that release heavy rainfall.
- It is a weather phenomenon that occurs when a pocket of cold air descends over the warmer waters of the Mediterranean Sea. This collision of cold and warm air creates atmospheric instability, causing rapid formation of dense cumulonimbus clouds.
How it Forms?
- Related to the polar jet stream, which separates cold polar air from warm tropical air.
- When a pocket of cold air detaches from this jet stream and meets warmer air over the Mediterranean, DANA forms, often bringing intense rain.
Impact of Climate Change on DANA
- Warmer Air Holds More Moisture: With global warming, warmer air can retain more moisture, leading to heavier rainfall events.
- Mediterranean Sea Temperatures: Sea surface temperatures have risen, with the Mediterranean recording its highest-ever temperature in August, adding to the severity of DANA.
Increasing Intensity of DANA:
- Traditionally, cold drops are common in Spain during autumn and spring.
- DANA events are now more frequent, intense, and geographically widespread.
- Rising global temperatures mean warmer air retains more moisture, contributing to intense rainfall.
- Increased Mediterranean Sea surface temperatures exacerbate this; in August, the sea reached its highest recorded temperature.
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