Freshwater strengthens ocean storms, say scientists

Areas of the world's oceans, saturated with fresh water, were huge overclocking settings for hurricanes, the strength of which can increase to 50% at the intersection of these areas, climate scientists say in a paper published in the journal Proceedings of the National Academy of Sciences.

"Sixty percent of the world's population lives on the land, which are in the range of a tropical cyclone. Hurricane" Nargis "killed more than 138,000 people in Myanmar in 2008. We can predict which path will move cyclones, but we need to better understand then what power they gain, to protect them from their destructive force, "- said the head of oceanographers Kartik joker (Karthik Balaguru) at Pacific Northwest National Laboratory in Richland (USA).

Joker and his colleagues studied the history of the formation and disappearance of the hurricane "Omar" that raged in the Caribbean Sea in October 2008. He was awarded a 4 star rating ("great") on the Saffir-Simpson scale — at the peak of its development in hurricane winds reached 215 kilometers per hour.

Oceanographers have traced the evolution of the hurricane on the data collected from the system of floating probes "Argo" (Global Monitoring Earth's oceans) and climate satellites in orbit. The researchers used this information to calculate the water temperature at the surface of a "step" of the hurricane.

As the scientists explain, tropical cyclones are actively engaged with near-surface layers of the ocean. In the initial stages of the hurricane warm water acts as a source of energy, which powers the hurricane, and at the end — it absorbs residues. This is due to the fact that the movement of the cyclone on the water causes it to "mixing" — warm subsurface water replaced the cold depths.

The authors analyzed the density and other properties of the water on the way, "Omar" and found something strange — in some parts of the water do not mix. Warm subsurface water could not sink to the depths because of the so-called barrier layer — a sufficiently thick layer of fresh or salt water below. Because of this, these areas accounted for the most powerful bursts of activity hurricane.

Joker and his colleagues tested their findings by analyzing the data in a similar way to other storms in the Earth's oceans in 1998-2007. It turned out that hurricanes crossed the thick barrier layers on the way its temperature lowered to 36% less than their normal "brothers." If you look at it another way, a layer of fresh water has increased the power of hurricanes by 50%.

The researchers believe that their work will help to better predict the consequences of Oceanology occurrence of hurricanes. However, this would require to map the distribution of barrier layers in the ocean, the authors conclude the article.

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