What’s the Pineapple Categorical?

Animation of an AR event in January 2017 (Credit: NOAA/ESRL/PSD)

This animation from NOAA’s Earth System Analysis Laboratory reveals an atmospheric river occasion in January 2017. Atmospheric rivers are comparatively slim areas within the ambiance which can be chargeable for many of the horizontal transport of water vapor outdoors of the tropics.


Atmospheric rivers are slim areas within the ambiance that transport a lot of the moisture from the tropics to northern latitudes. Atmospheric rivers are a part of the Earth’s ocean water cycle, and are tied carefully to each water provide and flood dangers.

A widely known instance of a robust atmospheric river known as the “Pineapple Categorical” as a result of moisture builds up within the tropical Pacific round Hawaii and may wallop the U.S. and Canada’s West Coasts with heavy rainfall and snow.

Prevailing winds cross over heat bands of tropical water vapor to type this “river,” which travels throughout the Pacific as a part of the worldwide conveyor belt. When it reaches the west coast, the Pineapple Categorical can dump as a lot as 5 inches of rain on California in someday. 

Atmospheric rivers are available all styles and sizes, however those who comprise the biggest quantities of water vapor and the strongest winds are chargeable for excessive rainfall and subsequent flooding. These occasions can have an effect on the complete west coast of North America, usually disrupting journey and damaging property within the course of.

After all, not all atmospheric rivers are disruptive. Many are weak and supply useful rain or high-elevation snow that present essential inputs to the water provides of western communities.


How does sea ice have an effect on world local weather?

sea ice in the Arctic Ocean

Sea ice within the Arctic Ocean. Whereas sea ice exists primarily within the polar areas, it influences the worldwide local weather.


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Sea ice additionally impacts the motion of ocean waters. The ocean is salty and when sea ice varieties, a lot of the salt is pushed into the ocean water beneath the ice, though some salt could grow to be trapped in small pockets between ice crystals. Water beneath sea ice has a better focus of salt and is denser than the encompassing ocean water, so it sinks and strikes from the floor. On this manner, sea ice contributes to the circulation of the worldwide ocean conveyor belt. Chilly, dense polar water descends from the floor and circulates alongside the ocean backside towards the equator, whereas heat water from mid-depth to the floor travels from the equator towards the poles.

Sea ice is frozen water that varieties, expands, and melts within the ocean. It’s totally different from icebergs, glaciers, ice sheets, and ice cabinets, which originate on land. For probably the most half, sea ice expands throughout winter months and melts throughout summer time months, however in sure areas, some sea ice stays year-round. About 15 p.c of the world’s oceans are lined by sea ice throughout a part of the 12 months.

Whereas sea ice exists primarily within the polar areas, it influences the worldwide local weather. The intense floor of sea ice displays numerous daylight out into the ambiance and, importantly, again into area. As a result of this photo voltaic power “bounces again” and isn’t absorbed into the ocean, temperatures nearer the poles stay cool relative to the equator.

When warming temperatures steadily soften sea ice over time, fewer vivid surfaces can be found to mirror daylight again into the ambiance. Extra photo voltaic power is absorbed on the floor and ocean temperatures rise. This begins a cycle of warming and melting. Hotter water temperatures delay ice development within the fall and winter, and the ice melts quicker the next spring, exposing darkish ocean waters for an extended interval the next summer time.

Adjustments within the quantity of sea ice can disrupt regular ocean circulation, thereby resulting in adjustments in world local weather.  Even a small enhance in temperature can result in better warming over time, making the polar areas probably the most delicate areas to local weather change on Earth.

The place is Earth’s Largest Waterfall?

infographic showing the world's largest waterfall

Within the Denmark Strait, southward-flowing frigid water from the Nordic Seas meets hotter water from the Irminger Sea. The chilly, dense water rapidly sinks beneath the hotter water and flows over the large drop within the ocean ground, making a downward move estimated over 123 million cubic toes per second. Obtain Infographic | Infographic Textual content


Rivers flowing over Earth’s gorges create waterfalls which might be pure wonders, drawing hundreds of thousands of holiday makers to their breathtaking magnificence, grandeur, and energy. However no waterfall is bigger or extra highly effective than those who lie beneath the ocean, cascading over immense cataracts hidden from our view.

Certainly, the world’s largest waterfall lies beneath the Denmark Strait, which separates Iceland and Greenland. On the backside of the strait are a collection of cataracts that start 2,000 toes beneath the strait’s floor and plunge to a depth of 10,000 toes on the southern tip of Greenland—practically a two-mile drop.

However how can there be waterfalls within the ocean? It’s as a result of chilly water is denser than heat water, and within the Denmark Strait, southward-flowing frigid water from the Nordic Seas meets hotter water from the Irminger Sea. The chilly, dense water rapidly sinks beneath the hotter water and flows over the large drop within the ocean ground, making a downward move estimated at nicely over 123 million cubic toes per second. As a result of it flows beneath the ocean floor, nonetheless, the huge turbulence of the Denmark Strait goes utterly undetected with out the help of scientific devices.

Infographic Textual content

The world’s largest waterfall is within the ocean

This infographic illustrates how a big underwater cataract (waterfall) naturally kinds beneath the waves throughout the Denmark Strait. A map within the higher proper of the graphic reveals the placement of Denmark Strait, between Greenland and Iceland.

Hotter floor waters move northward. These hotter waters steadily lose warmth to the environment and sink. Denser, chilly water flows southward in a deep present alongside the ocean ground over an undersea ridge within the Strait. The peak of the Denmark Strait cataract is roughly 11,500 toes. By comparability, the biggest waterfall on land is 3,212 toes.

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The world’s oceans transfer in what known as the Meridional Overturning Circulation, extra generally known as the worldwide conveyor belt. The conveyor belt circles the globe, transporting warmth and water and serving to to stabilize world local weather. It’s also a significant part of the worldwide ocean nutrient and carbon dioxide cycles. Heat floor waters are depleted of vitamins and carbon dioxide, however are re-enriched as they journey via the belt of colder, nutrient-rich water in deeper and backside layers. The ocean’s meals chain depends upon this combination, which helps the expansion of phytoplankton, seaweed, and life itself.


Final up to date: 02/26/21
Writer: NOAA
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