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  • NASA scientists have performed the first multi-year study

  • using satellite data to measure the 3-D distribution of dust

  • that travels from the Sahara Desert to the Amazon rainforest.

  • The Sahara is the world's largest desert.

  • At more than 3 million square miles,

  • it's almost the size of the continental United States.

  • Each year, Saharan dust is lifted from the ground,

  • and transported by winds on a 3000-mile journey

  • across the Atlantic Ocean.

  • A portion of the dust collects in the Amazon basin

  • the largest rainforest on the planet.

  • Although dust particles are small,

  • no larger than around a tenth of the width of a human hair,

  • they form massive plumes that can be seen from space.

  • NASA's CALIPSO satellite was launched in 2006

  • to study the vertical structure of clouds and particles

  • in Earth's atmosphere.

  • CALIPSO observations from 2007 through 2013

  • show that on average,

  • 182 million tons of dust leaves Africa each year.

  • Of this amount, about 27 million tons

  • is deposited in the Amazon basin.

  • Sahara dust contains phosphorus,

  • which is an important nutrient for plants.

  • In the tropic region, the phosphorus is quite limited.

  • So it's important to estimate how much dust

  • from the desert is transported to the Amazon.

  • The study shows Saharan dust adds phosphorous to the soils

  • that help compensate for losses

  • due to surface runoff and floods.

  • However, the amount of dust transported to the Amazon

  • changes from year to year.

  • According to the study, this variation is closely associated

  • with changes in rainfall in the Sahel,

  • a belt of semi-arid land just south of the Sahara.

  • When the Sahel was dry, the dust transport to the Amazon

  • in the next year would increase.

  • When it was wet,

  • dust transport would decrease.

  • Using satellites to get a clear picture of dust is important

  • for understanding, and eventually using computers to model

  • where that dust will go,

  • now and in future climate scenarios.

NASA scientists have performed the first multi-year study

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NASA|衛星がサハラ砂漠の塵を3Dでアマゾンまで追跡 (NASA | Satellite Tracks Saharan Dust to Amazon in 3-D)

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    serena   に公開 2021 年 01 月 14 日
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