Abstract
wrine oundry lyer simultion nd verifition during fyfwiEilot using xgwp model es fe xtionl gentre for wedium nge ether porestingD sxe fuildingD wusm fhvn gomplexD vodi odD xew helhiD sndi emilX swtidnmrwfFgovFin

e glol spetrl model @VHvIVA tht is opertionl t xgwp is utilized to study the struture of the mrine oundry lyer over the fy of fengl during the fyfwiEilot periodF he vertil profiles of vrious meteorologil prmeters within the oundry lyer re studied nd verified ginst the ville oservtionsF he diurnl vrition of vrious surfe fields re lso studiedF he impt of nonElol losure sheme for the oundry lyer prmeteristion is seen in simultion of the flow pttern s well s on the oundry lyer struture over the oeni regionF IF sntrodution enlysis of the mrine oundry lyer struture nd the ir se intertion proesses re ruil nd very importnt in understnding the generl flow pttern over the sndin suontinent inluding the genesis of lows nd depressionsF st remins then essentil tht the oundry lyer struture s simulted y the numeril models should e reprodued in the most relisti mnnerF he mrine oundry lyer plys key role in the tmospheri energy exhnge proE essesF es distinguished from most lnd surfesD open se nd oen surfes re hrterized y remrkle temporl nd sptil homogeneity of tempertureF his is primrily due to the lrge het pity nd effiient mixing proesses in the upper oeni mixed lyerF husD over muh of the oenD the surfe het flux does not ply lrge role in determining the oundry lyer strutureF yservE tionl vlidtion of oundry lyer theoryD detils of oundry lyer struture rely hevily on dt whih is reltively sprse nd espeilly rre in the se of mrine oundry lyerF pew oservtionl studies re ville on the mrine oundry lyer over the sndin yenF fyfwi offered n opportunity to explore the struture of the mrine oundry lyer nd its evolution over the fy of fenglF PF ynopti onditions he ilot experiment ws rried out on ord y gr unyF he ship left wormugo on PQrd ytoer IWWVD moved towrds south lmost prllel to the west ost of sndi up to S xD nd then turned estwrdsF he first sttionry @driftingA time series sttion ws t U x VU i for two dys @ytoer QHthD QIstAD the seond time series sttion ws t IH x VU i for two dys @Pnd EE Qrd xovemerAF huring the period for whih the ilot dt ws otined @Ist nd Qrd xovemer IWWVAD sher zone ws seen over south fy of fengl on Ist xovemer in whih low pressure formed on Pnd xovemer in southwest fy off rilnkEsouth milndu ostF his low pressure persisted over the sme re till Tth xovemer nd eme less mrked on Uth xovemerF he operE tionl model t xgwp @yiA ws run with the initil ondition of Ist xovemer IWWV nd the forests of three dys were otinedF imilr foreE sts were lso otined with the xgwp model hving different prmeteristion sheme for the oundry lyer vizF nonElol losure sheme @xvgAF he flow pttern s well s the preipittion pttern were otined nd ompred with the oservtionl nlysis using oth the shemesF he profiles of temE perture nd humidity s otined from gr uny ueywordsF wrine oundry lyerY prmeteristionY fyfwiY nonElol losureY glol modelF roF sndin edF iF @irth lnetF iFAD IHWD xoF PD tune PHHHD ppF PVSEEPWP # rinted in sndi PVS were lso ompred with those otined from oth the modelsF ine the differene etween oth the models lies in the prmeteristion sheme of the oundry lyer onlyD the impt of the different shemes for the oundry lyer ould redily e identifiedF QF hesription of the shemes QXI fv prmeteristion sheme of xgwp model e short desription of the modelD whih is run on n opertionl sis t xgwpD is given in fsu et l @IWWWAF he stndrd fv prmeteristion uses firstEorder losure pproximtion wherey the turuE lent fluxes re orrelted to the men vertil grE dients through the eddy diffusivitiesF hese eddy diffusivities re stility dependent @depending upon the ulk ihrdson numerA nd re determined through mixing length onsidertionsF st is ssumed tht the mixing length l vries s kz @k eing the von krmn onstnt nd z the height ove the groundA lose to the groundD ut pprohes onstnt vlue ! PSH m t greter heightsF husD the eddy diffusiE vities re determined throughX u l P jdvadzjY where l is the mixing length given y l kzaI kza!X rereD is set of semiEempiril stility funtions dependent upon the ulk ihrdson numer D nd ! is the limiting mixing lengthF QXP rmeteristion using the non lol losure sheme here re ertin limittions of the mixing length theory @tull IWVRA the most importnt eing its iniE lity to represent relistilly mixing in the onveE tive oundry lyer involving the ounter grdient fluxes99 @ roen nd whrt IWVTY rong nd n IWVWAF yne of the lterntives is to go to higher order losure pprohes ut they were omputtionlly more expensiveF woreoverD eyotte @IWWTA showed tht these shemes were in the stritest sense lol diffusion shemes nd hd strong tendeny to underentrin in the presene of strong pping inversionF eently n lterntive pproh hs een suggestedD the so lled nonElol u losure whih is omputtionlly effiient nd hs the pility to represent lrge eddy turulene within well mixed oundry lyerF his sheme @rong nd n IWVWY roen nd whrt IWVTA hs een widely tested for generl irultion models s well s numeril predition models with further generliztion nd reformultion @roltslg et l IWWHAF sn the present studyD the sheme tht is used is fter rong nd n @IWVWAD where the turulene diffusion equtions for prognosti vriles g Y uY vY qY q re expressed y a t a z u a z À where u is the eddy diffusivity oeffiient nd is orretion to the lol grdient tht inorportes the ontriution of the lrge sle eddies to the totl fluxF he diffusivity oeffiient in the mixed lyer is given y u m kw s zI À zah p where p is the profile shpe exponentD w s is the mixed lyer veloity sleD h is the fv height nd k is the von krmn onstntF he fv height is given y
where i is the ritil ulk ihrdson numerD h is the horizontl wind speed t hD v is the virtul potentil temperture t the lowest model level v h is the virtul potentil temperture t h nd s is the pproprite surfe tempertureF por the free tmoE sphereD howeverD the lol u pproh is utilizedF
RF esults
pigures I@AD @A nd @A show the flow pttern s seen in the nlysis nd dy P forests from yi nd xvg respetively vlid for Qrd xovemer IWWVF es mentioned in the previous setion low pressure re hd formed round VU i IH x on Pnd xovemer whih persisted till Tth xovemerF es seen oth yi nd xvg were le to predit the irultion over fy of fengl @round VU i IH xA lthough yi showed intense irultion ompred to nlysis whih shows only shered zoneF foth the models show two losed irultions over the fy s well s over the erin e unlike the nlysis whih showed n extended sher zone over the erin eF sn generl oth the models show similr flow ptterns for ll the forest dysF pigure P @AEE@A shows the oserved nlysed rinfll @witr et l IWWUA nd PREE RV hour umulted preipittion vlid for Qrd xovemer IWWV with yi nd xvg respetivelyF sn generl it is seen tht yi shows more rinfll over southest fy whih is not oservedF his my e due to the ft tht yi enhnes the flow pttern over the fy s ws seen in figure IF xvg on the other hnd shows resonle mount of rinfll over the fyF he rinfll over southern peninsul is however etter simulted in yi ompred to xvg lthough the oserved rinfll is higher @out three timesAF he rinfll pth in the djoining prt of north ri vnk hs not een shown y either modelsF pigures QEES show the vrious profiles in the oundry lyer t VU i IH x t four different time intervls orresponding to dtes Ist nd Qrd xovemer IWWVF PVT wti fsu pigure IF qeogrphil distriution of VSH h wind vetors ms ÀI nd geopotentil heights @mA over the monsoon region for Qrd xovemer IWWV @A erifying nlysisY @A RV hr forest y yiY @A RV hr forest y xvgF wrine oundry lyer simultion nd verifition PVU he profiles of humidity nd tempertures s simuE lted y the model with the initil ondition of Ist xovemer IWWV vlid for different forest hours re ompred with the oservtionsF huring the period of omprisonD it ws noted tht Ist xovemer ws loudy nd riny ompred to Qrd xovemer whih ws reltively ler dyF he temperture profile in figure Q whih is vlid for Ist xovemer IWWW t HUHH hours suggests tht the mixed lyer depth is reltively shllower nd extends up to IHHH mF he mximum wind speed is round IH ms ÀI nd the humidity is quite highF st is seen tht lthough the profiles of the humidity re ompring well with the oservtions till out VWH hD the mgnitudes re smller y oth the modelsF foth the models re unle to simulte the higher vlues of humidity ove VWH hF he profiles otined from oth xvg nd yi re omprle with eh other exept for the diffusivity pigure PF qeogrphil distriution of umulted RVEEUP hrD preipittion in mGdy for Qrd xovemer IWWV over the sndin region nd djoining res @minF ontour I mA shded res represent preipittion`I mF @A enlysed rinfll from sxe nd rin gugeY @A RV hr forest y yiY @A RV hr forest y xvgF profile whih shows higher vlues for yi t the lower levelsF pigure R shows similr profiles vlid for Qrd xovemer HUHH hrsF his dy ws ler dy whih gets refleted in the temperture profile tht shows mixing till higher levelF he wind speeds re lso higherF roweverD the wind speed simulted y xvg is lower ompred to yiF he mgnitude of the humidity simulted y oth the models re higher ompred to the oservtions ove RHH metersF he humidity generted y xvg t lower levels is higher @A rition of drg oeffiient with IH m wind y yiY @dA rition of drg oeffiient with IH m wind y xvgY @eA UP hr forest of moisture fluxY @f A UP hr forest of sensile het fluxY EEEEE yiY E E E E xvgF wrine oundry lyer simultion nd verifition PWI ompred to yi till out SHH metersD ove whih the reverse is trueF his is pprent from the profiles of diffusivity whih shows higher vlues t lower levels y xvg inditing effiient trnsport of humidity from the lower levels to the higher levelsF pigure S @AEE@fA shows the diurnl vrition of ounE dry lyer heightD surfe pressureD het nd moisture fluxes long with vrition of drg oeffiients with IH m winds using oth xvg nd yiF ine yi does not expliitly resolve the oundry lyer heightD the sme is produed only y xvgF st is seen tht the oundry lyer height vries etween WSH m nd IRHH mF pigure S@A shows the surfe pressure y yi nd xvg whih shows drop in the sme round IQHH hrs of Ist xovemerF his my e ttriuted to the rinfll tht ourred round tht timeF he vrition y yi nd xvg is lmost the sme in mgnitudeF pigures S@ A nd @dA show the vrition of drg oeffiients with the winds t IH m y yi nd xvgF foth the models show similr vrition s well s similr vluesF es pointed out y ery @IWVVA the dependene of the drg oeffiients on IH is wek in the trnsition regime of wind speeds less thn UXS ms ÀI PXS` IH`U XSF es seen from the figuresD the wind speed t IH m never exeed UXS ms ÀI F st is lso seen tht there is weker dependene of the drg oeffiients on IH F he vlues re lso omprE le to those otined in the moderte rnge of wind speeds @urus IWUPA whih is nerly onstnt nd is round IXP Â IH ÀQ F qrrtt @IWWRA lso shows similr vritions s well s vlues within this wind speed rngeF pigures S@eAEE@fA show the diurnl vrition of moisture nd het flux respetively y oth the modelsF sn generlD oth the models show high vlues of moisture flux ISH À IUH m ÀP whih eventully is redued fter the rinfllF fy nd lrge xvg shows higher vlues of the flux ompred to yiF he sensile het fluxes s expeted re very smll nd the vritions y oth the models re similr nd omprleF SF gonlusions imultion of the mrine oundry lyer is otined over the fy of fengl using two different shemes of the oundry lyer for the fyfwiEilot periodF huring the sid periodD oth the flow pttern s well s the preipittion pttern were simulted resonE ly well y oth the modelsF yi however hd tendeny to enhne the irultion over the fy nd the orresponding preipittion pthF he flow ptterns y nd lrge ompred resonly with the verifying nlysisF es fr s the profiles in the oundry lyer were onernedD the two situtions of tmospheri onditions vizF loudy during Ist xovemer nd the ler dy for Qrd xovemer were rought out y the models from the temperture profilesF elthough the temperture profiles ompred resonly well with the oserved oneD the humidity profiles were under predited for Ist xovemer nd over predited for Qrd xovemer whih ws ler dyF inds simulted y the xvg for the ler dy re lmost onstnt with height nd re less y out P ms ÀI ompred to yiF he diffusivity profiles y oth the models show differenes in the lower levelsF he differenes in the simultion y the two models ould e ttriuted to these differenes in the diffusiE vity profiles whih re minly responsile for the disE triution of the prmeters in the vertilF rition of surfe prmeters y oth the models shows similr hrteristisF he moisture flux in generl is higher nd sensile het flux is lower s simulted y xvg ompred to yiF he oundry lyer depth whih vries etween WHH nd IRHH m is simulted y xvg whih seemed to e in generl greement with oservtions @fhtD personl ommunitionAF he vrition of drg oeffiients is lso t pr with generl oservtions nd oth the models simulted similr feturesF yverllD sed on the simultion of Ist xovemer IWWVD it ws seen tht y nd lrgeD oth xvg nd yi performed in similr mnnerF roweverD yi hd overestimted the irultion s well s the preipittion pttern ompred to xvg s well s the verifying nlysis nd oservtionsF sn this respetD xvg hd slight edge over yiF he surfe prmeter simultions did not show muh vrition using yi nd xvg exept for the fluxesF he moisture fluxes simulted y xvg were more relistiF purther studies re on to ssess the impt of two different shemes for fv on the simultion of the mrine oundry lyer strutureF eknowledgement he uthor is grteful to the red of eserh hivision nd red of xgwp for the enourgement nd the support provided during the present workF eferenes ery IWVV sntF qeophysF eriesD RPD ppF QHU eyotte u IWWT foundryEvyer weteorolF IQIEEIUS fsu wtiD mn D wohnty g nd jgopl i xD IWWW eqiyr QQEESS fht q D personl ommunition qrrtt t IWWR he tmospheri oundry lyerD ppF QIT roltslg e e wD foville f eD fruijn t p nd n r v IWWH wonF ether evF ISTIEEISUS rong nd n r v IWVW wonF ether evF IUPTEEIUSH urus i f IWUP etmosphereEyen sntertion @yxford niversity ressA witr e uD fohr e u nd jn hD IWWU sntF tF glimtolF IHVQEEIHWP tull fD IWVR tF etmosF iF QQSIEEQQTU roen s nd whrt v IWVT foundryEvyer weteorolF IPWEEIRV

{'paper_id': '56064219', 'title': 'Marine boundary layer simulation and verification during BOBMEX-Pilot using NCMRWF model', 's2_url': 'https://api.semanticscholar.org/CorpusID:56064219', 'source': 'S2ORC'}