PINEAPPLE EXPRESS PHENOMENON
1. Context
2. About Pineapple Express
- The Pineapple Express is a well-known atmospheric river which brings moisture from the tropical Pacific, near Hawaii, to the West Coast of the United States and Canada. It is a specific example of a common atmospheric phenomenon that resembles a conveyor belt for moisture.
- These rivers in the sky occur often on the West Coast but can happen in other locations, including the eastern United States, where they often channel moisture from the Caribbean. And they carry a lot of moisture -enough water vapor to equal or sometimes exceed the average flow of the Mississippi River at the point where it flows into the Gulf of Mexico.
- When this moisture begins to interact with land, it can fall as rain or snow. Often, as is the case lately in California, the precipitation is abundant because these atmospheric rivers provide a continuous flow of moisture.
- Although atmospheric rivers come in different shapes and sizes, for one to be a “true Pineapple Express,” location matters.
- The tail end, where the moisture is pulled into the atmosphere, must start near Hawaii. Then the river must stretch continuously through the atmosphere to the U.S. West Coast.
3. The Science behind atmospheric rivers
4. What happens as a Result?
- Whether an atmospheric river is a Pineapple Express or not, the result is something like a conveyor belt for precipitation.
- When the rivers are particularly strong or come back-to-back in what are called “atmospheric river families” the effects can be serious, like the extensive flooding that California is experiencing now.
-
The polar vortex is a vast region of low pressure and cold air that circulates around the Earth's polar areas. It has two variations: the tropospheric polar vortex and the stratospheric polar vortex.
-
The tropospheric polar vortex forms in the lower atmosphere, extending from the Earth’s surface to around 10 to 15 kilometers. This region is where most weather events occur.
-
The stratospheric polar vortex is found at altitudes between 15 to 50 kilometers. Unlike the tropospheric vortex, this one disappears in the summer and reaches its peak strength during autumn.
-
Santa Ana winds are a regular feature of California’s climate, typically occurring from October to January. These winds form when high pressure builds over the Great Basin, situated between the Rocky Mountains and the Sierra Nevada, while a low-pressure system develops off California's coast.
-
The pressure difference generates powerful winds that move from the inland deserts of the Basin toward Southern California's eastern and northern areas, ultimately heading toward the Pacific Ocean.
-
As these winds descend the mountains, they compress, warm up, and lose humidity — sometimes dropping to less than 10%
For Prelims
| For Prelims: The Pineapple Express, The atmospheric rivers, Mississippi River, Gulf of Mexico and Hawaii Islands. |
|
Previous Year Questions
1.The formation of ozone hole in the Antarctic region has been a cause of concern. What could be the reason for the formation of this hole? (2011) (a) Presence of prominent tropospheric turbulence; and inflow of chlorofluorocarbons (b) Presence of prominent polar front and stratospheric clouds; and inflow of chlorofluorocarbons (c) Absence of polar front and stratospheric clouds; and inflow of methane and chlorofluorocarbons (d) Increased temperature at polar region due to global warming Mains
1.How do the melting of the Arctic ice and glaciers of the Antarctic differently affect the weather patterns and human activities on the Earth? Explain. (2021) 2.Why is India taking keen interest in resources of Arctic region? (2018) 3.How does the cryosphere affect global climate? (2017) |
