基于TRMM衛(wèi)星對(duì)強(qiáng)對(duì)流天氣中閃電活動(dòng)、雷達(dá)反射率及冰散射的研究.pdf

1、蘭州大學(xué)碩士學(xué)位論文基于TRMM衛(wèi)星對(duì)強(qiáng)對(duì)流天氣中閃電活動(dòng)、雷達(dá)反射率及冰散射的研究姓名：楊美榮申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：大氣科學(xué)大氣物理與大氣環(huán)境學(xué)指導(dǎo)教師：郄秀書袁鐵20100501英文摘要AbstractTheelectricalactivityinthunderstormsiscloselyrelatedtoicecrystal，graupel，supercooledwaterandconvectiveupdraft，andcon

2、sequentlylightningdatacangivesomeinformationaboutthemicrophysicalanddynamicprocessinthunderstormsTheTropicalRainfallMeasuringMission(TgMM)satellitecanprovidesynchronousobservationsonlightningactivityradarreflectivityandi

3、cescattering，providinganopportunitytostudytherelationshipsbetweenlightningactivityandmicrophysicalanddynamicparametersinsevereweathersInthisthesis，thedatafromtheprecipitationradar(PR)，lightningimagingsensor(LIS)andpassiv

4、emicrowaveimaging(TMI)havebeenusedtOinvestigatethecharacteristicsoflightningactivity，radarreflectivityandicescatteringin46tropicalcyclonesoverthenorthwestempacificand9squalllinesOVerChina，furtherlyanalyzetherelationships

5、betweentheoccurrenceoflightningflashes，andradarreflectivityandicescatteringTheconclusionsarepresentedasfollowing：Firstly，lightningflashesaremorelikelytooccurintheweakerperiodsoftropicalcyclones，comparingwiththestrongerpe

6、riodsTherearedifferentspatialdistributionsoflightningactivityinthedifferentintenseperiodsoftropicalcyclonesThelargestflashdensityoccursineyewallregionduringtropicalstorm，severetyphoonandsuperseveretyphoonperiods，whileitO

7、CCUrsinouterrainbandregionduringotherperiodsAsawhole，theprecipitationsystemsintropicalcyclonesaredominatedbystratiformrain，andtheicescatteringsignatureisweakerGiventhesameradarreflectivity，lightningflashesaremorelikelyto

8、occurduringtyphoonandseveretropicalstormperiods，butalargerthresholdofradarreflectivityisneededinsupertyphoonperiodsSecondly，theanalysisonthetropicalcycloneswhoseintensityreachtheleveloftyphoonshowsthatthereisapeal(ofligh

9、tningdensityineyewallregions，andthelargestradarreflectivityandstrongesticescatteringalsoappearineyewallregionsGiventhesameheightandcumulativefrequencythereflectivityineyewallregionsis25dBZlargerthanthatintheotherregionsF