More on Winter Heat Waves in Europe
- Extreme Warm Spell:
- There were several parts of Europe where temperatures surged to summer or springtime levels, with temperatures rising by 10 to 20 degrees Celsius above normal.
- At least seven countries recorded their hottest January weather ever. These included Poland, Denmark, the Czech Republic, the Netherlands, Belarus, Lithuania and Latvia.
- Climatologists said that the continent is experiencing an extreme warm spell because of the formation of a heat dome over the region.
What is a Heat Dome?
- A heat dome occurs when an area of high-pressure traps warm air over a region, just like a lid on a pot, for an extended period of time.
- The high-pressure forces air to sink and once it reaches the ground, it gets compressed and becomes even warmer and drier, further raising the temperature of the area.
- Heat domes generally stay for a few days but sometimes they can extend up to weeks, which might cause deadly heat waves.
- They are more likely to form during La Niña years, when waters are cool in the eastern Pacific and warm in the western Pacific, creating vast areas of sweltering.
Causes of Formation of Heat Dome
- Jet stream blocking: Jet streams are narrow bands of strong wind in the upper levels of the atmosphere that generally blow from west to east all across the globe.
- Change in Ocean Temperature: The phenomenon begins when there is a strong change (or gradient) in ocean temperatures.
- In the process known as convection, the gradient causes more warm air, heated by the ocean surface, to rise over the ocean surface.
- As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward land, where it sinks, resulting in heat domes.
- Climate change and heat domes: Researchers say that climate change may be making heat domes more intense and longer.
- They suggest with the rising temperatures, it is expected that the jet stream will become more wavy and will have larger deviations, causing more frequent extreme heat events.