甘肃省沙尘暴现象 英语ppt

2Whatissandstorm?ThereasonforsandstormDamageandpreventionOutlineWhatissandstorm?Sandstormisameteorologicalphenomenoncommonlyfoundinaridandsemi-aridregions.Itisresultedfromconvectioncurrentscreatedbyintensiveheatingoftheground.Thesecurrentscancreatewindupto120km/handAppearasasolidwallofdustasmuchas1,525mhighwhichblowoveralongdistance.Sandstormisakindofclimatichazard.ItwasfoundinareaslikeSaharaDesertinNorthAfrica,CentralAustralia,SouthwestofUSA,CentralAsiaandNorthwestChina.TheactualityinGansuProvince1.Timedistributionfeatures2.SpacedistributionfeaturesThesandstormrateinthefourseasonsayearinGansuprovinceRate(%)WinterSpringSummerAutumnMinqin18.7741.4929.779.96Zhangye17.5948.0425.259.10Dunhuang14.640.8725.598.91Jiuquan12.6355.7921.799.79Yumen4.5351.5222.0611.89Wuwei17.5063.6413.645.22Gansu18.5454.3019.717.45Timedistributionfeatures1.Maximuminspring2.Minimuminautumn3.ThenumberinsummerislargerthanitinwinterTheaveragedaysdistributionofsandstormcontourmapinGansuProvinceSpacedistributionfeatures1.Thenumberoftimesisdecreasingfromnortheasttosouthwest2.MaximuminMinqinThereasonofsandstorminGansuProvince1.Thespecialgeographicpositionandlandform2.Thewarmanddryweatherconditioninspringandtheconstantlymovingcoldwindstowardeastandsouth3.Changingtheland-coverartificiallyThespecialgeographicpositionandlandformThewarmanddryweatherconditioninspringandtheconstantlymovingcoldwindstowardeastandsouth1.DryweatheristhemostfundamentalnaturalenvironmentalfactorsofsandstormoccurrenceinGansuProvince2.StrongwindisthedynamicfactorofsandstorminGansuProvinceChangingtheland-coverartificially1.Overgrazing2.Excessivelandreclamation3.Excessivefirewood4.ImproperuseofwaterresourceOvergrazingExtensivegrazingwayvegetationdeteriorationBaregroundFormanewsandresourceExcessivelandreclamationIncreaseinpopulationIncreaseofpressureonlandUncoveredlandAnewsandresourceExcessivefirewoodOvercuttingIncreasingairspeedFormanewsandresourceSandstormImproperuseofwaterresourceWaterreducingOverusingwaterVegetationdeathAnewsandresourceandincreasingwindspeedTheaffectofsandstorm1.strongwind2.sandburial3.soildrifting4.airpollutionStrongwindSandburialSoildriftingAirpollutionMeasures1)Protecttheenvironment2)Protectthevegetation3)Developmentofenvironmentalprotectioninfrastructure4)Controllingpopulationquantity,improvingpopulationqualityOvercome:1.Insisttoreturnfarmlandtoforestsandanimalbreedinggroundstopastures2.Havereducedtheincidencerateofsandstorm3.HaveestablishedsomeprotectionandrelevantpoliciesSometipsWhensandstormcoming:1)Lessgoout,closeyourwindowwell2)Keepindoorhaverelativehumidityandclean3)Ensuresufficientsleep,drinkmorewater,andwashyourhandsfrequently4)WearamaskInordertoweallhaveabeautifulenvironmenttolive,pleaseprotectourenvironment.Becauseit’sourduty.