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Thunderstorms have a significant effect on the formation of ozone.Nitrogen oxide is produced as a result of lightning; this in turnyields ozone at altitudes of 10 kilometres. Strong updraughts inthunderstorms also transport emissions from the ground into theupper atmosphere. But how significant is this effect - compared toaviation, for example? Researchers at the German Aerospace Center, in collaboration withthe US National Center for Atmospheric Research (NCAR), NASA andother partners, are studying such questions. To this end, they willbe conducting measurement flights in the United States untilmid-June. The researchers are looking to increase the existing bodyof data and gain a better understanding of the processes that takeplace in thunderstorms. "Thunderstorms are like vacuum cleaners," explains Heidi Huntrieserfrom the DLR Institute of Atmospheric Physics. The DLR projectleader is supervising the measurement flights in the United States. "Thunderstorms suck air up from the ground, sometimes at speedssurpassing 100 kilometres per hour, and carry it to an altitude ofabout 10 kilometres, to what is known as the 'anvil region'. Thisis the mushroom-shaped layer high above the storm, where the aircan only flow horizontally and hardly upwards at all." If polluted air, such as that from vehicle emissions on the ground,is transported to this region, the chemistry of these emissions isaltered by the low temperatures, differing humidity and moreintense solar radiation there; they take much longer to break down,and the production of ozone is increased. "At these altitudes,nitrogen oxide can produce up to 10 times as much ozone as on theground," says Huntrieser. Huntrieser and her project partners intend to use the measurementsto increase the existing data pool. "Previous measurements lead to the conclusion that global aviationproduces about one teragram of nitrogen oxide per year, butthunderstorms are responsible for about five times as much. Allnitrogen oxide sources jointly contribute about 50 teragrams ofnitrogen oxide to the atmosphere each year, so thunderstorms areresponsible for about 10 percent," explains Huntrieser. A teragramis 10 to the power of 12. New model simulations show that thunderstorms exert a greatinfluence on ozone. "These were somewhat surprising results," saysHuntrieser. "Now we need more measurement data to confirm this." Use of three research aircraft Three research aircraft are being used for the mission: the DLRFalcon research aircraft will take measurements at an altitude of10 kilometres, while the American HIAPER research aircraft willtake measurements at up to 15 kilometres. A DC-8, a much largeraircraft, will mainly operate at lower altitudes. "Our ambitiousgoal is for all the aircraft to operate simultaneously at differentaltitudes in the vicinity of thunderstorms. It would be a first,"says Huntrieser. Influence exerted by different types of lightning Besides the transportation processes from the ground to the upperatmosphere, the studies will focus on the influence exerted bydifferent types of lightning. There are relatively short lightningbolts a few kilometres long, and some that stretch horizontallyover a distance of 100 kilometres or more. The formation of lightning also depends on the type of storm;previous measurements over Europe indicate that storms with largeamounts of hail and frozen rain that occur at mid-latitudes cancontain relatively more and sometimes longer lightning bolts. By comparison, measurements in tropical storms in Brazil indicatefewer ice particles, more cloud droplets and many - but shorter -lightning bolts. Previous measurements also indicate that lessnitrogen oxide per lightning bolt is produced in storms withshorter lightning bolts than in those with longer lightning bolts.Due to the varied climatic conditions in the United States, theresearchers can investigate both types of storms. Over Alabama there are storms with less ice, and over Coloradothere are those with more frozen rain and hail. Oklahoma is knownfor its violent storms, also known as supercells, which can alsotrigger tornadoes. The research flights are very challenging, but not dangerous forthe occupants: "We are not flying directly into the storms. Thatwould be much too dangerous because of the strong turbulence, riskof ice formation, lightning strike and the high wind speeds. Our measurements are being taken in the calmer anvil region,"explains Huntrieser. The robust Falcon is ideal for this. The DLRpilots have already carried out numerous similar measurements withthe research aircraft over Europe, Brazil, Australia and Africa. The researchers are also breaking some new ground with theirmeasurement flights. Between 12 and 48 hours after the storm hasdissipated, the scientists are planning to carry out measurementflights inside the storm's residual air mass and determine, forexample, how much ozone has been produced and how the chemicalcomposition has changed as a result of the storm. We are high quality suppliers, our products such as Digital Counting Scales Manufacturer , Electronic Precision Balance Manufacturer for oversee buyer. To know more, please visits Electronic Precision Balance.
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