A comparison of Lagrangian dispersion models coupled to a meteorological model for high stack air pollution forecast

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1 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press A comparson of Lagrangan dsperson models copled o a meeorologcal model for hgh sack ar pollon forecas E. Penabad V. Pere-Mñr J.A. Soo J.J. Casares J.L. Bermde 3 F.L. Ldg 4 Grop of Non-Lnear Physcs Unversy of Sanago de Composela Span. Dep. of Chemcal Engneerng Unversy of Sanago de Composela Span. e-mal: asoo@sc.es 3 As Pones Poer Plan Endesa Span 4 Dep. of Cvl and Envronmenal Engneerng Sanford Unversy USA Absrac Snce 994 operaonal ar pollon forecas s ronely appled a he As Pones coal-fred poer plan h a 35-m sack n order o preven local fmgaon epsodes. Over he las en years several mprovemens n he nmercal models ere done o oban more accrae ar pollon forecass on a daly bass. In hs ork a comparson of he resls obaned for dfferen perods sng o dfferen lagrangan dsperson models Adapve Pff Model APM and Lagrangan Parcle Model LPM s presened. Boh models n dfferen ays ere copled o he same non-hydrosac meeorologcal predcon model Advanced Regonal Predcon Sysem ARPS adaped o hs envronmen. From he resls obaned can be seen ha boh models can reprodce he locaon of he man plme mpacs measred n he area. Hoever LPM mpacs are sally farher and shorer n me han APM mpacs n agreemen h feld daa.

2 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press Inrodcon In he desgn and developmen of a forecasng ar pollon conrol sysem FAPS Soo e al. [] based n meeorologcal and dsperson models accrae resls of hese nmercal models are a crcal sse specally drng complex convecve condons. In hs case even hogh he applcaon of a hgh resolon non-hydrosac meeorologcal model can provde an accrae esmaon of he mean varables nd emperare rblence parameers appled n dfferen dsperson models ll offer sgnfcan dfferen resls. In hs ork a comparson of he resls of o Lagrangan dsperson models Lagrangan Parcle Model LPM and Adapve Pff Model APM copled o a non-hydrosac meeorologcal model Advanced Regonal Predcon Sysem ARPS s done drng a complex ar pollon epsode h srong nd shear n he doman of a coal-fred poer plan. Meeorologcal Model The Advanced Regonal Predcon Sysem ARPS s a comprehensve regonal o sormscale amospherc modelng / predcon sysem developed a he Cener for Analyss and Predcon of Sorms CAPS a he Unversy of Oklahoma [3]. ARPS has been ndergong real-me predcon ess a he synopc level hrogh sorm scales n he pas several years over he connenal Uned Saes as ell as n par of Asa. For he las o years ARPS has also esed as an operaonal nmercal eaher predcon model for regonal eaher forecas n Galca NW of he Iberan Pennsla [4].. PBL parameeraon The srface layer physcs ARPS calclaons allo he evalaon of srface drag coeffcens. Ths s done n an sably dependen ay accordng o blk chardson nmber vales. Some modfcaons have been nrodced n he orgnal ARPS model n order o oban from hose drag coeffcens he bondary layer parameers [5]: frcon emperare θ* and frcon velocy * and hen Monn-Obkhov lengh L and frcon hmdy q*. Once hs parameers are knon nder nsable condons PBL hegh s comped by sng a prognosc eqaon proposed by Pelke & Mahrer [6]. On he oher hand an exponenal varaon n me oards an eqlbrm hegh [7] s appled n sable condons. Modelng of he dsperson of ar pollans n he PBL reqres an accrae esmaon of he sandard devaons of velocy flcaons σ v σ hch are calclaed sng he esmaed vale of. In hs ork expressons compled by Pelke [5] from Hanna [8] have been appled h modfcaons on σ formlaon for convecve condons proposed by Ryall & Maryon [9]. Ths

3 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press scheme has already been mplemened n parcle dsperson models sch as FLEXPART []. Fnally expressons for σ v and σ are obaned * 3 * 3 * Unsable condons - L v σ σ a > < C C C C v v l..3 - Sable condons.58 * σ σ b 3 Dsperson models 3. Lagrangan parcle model The Lagrangan parcle model LPM [] releases for each eraon a nmber n of fcos parcles from he sack hle he oal nmber of parcles n he hole doman does no exceed a maxmm nmber of 3 parcles hch sascally represen he rblen ranspor and smlae he pollans plme groh. The locaon of a sngle parcle sng a follong-erran coordnae sysem s defned by ] [ ] [ p x x here represens he mean vale of horonal and vercal componens of he Lagrangan parcle velocy; 3p s he plme rse conrbon as n APM [5 6]. The rblen flcaon s represened by and s esmaon follos a sascal approach as he Mone-Carlo models here s a semrandom componen obaned by he manplaon of random nmbers sng a Markov process frs-order aocorrelaon process

4 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press R 3 3 here R are he aocorrelaons of he componens and are he componens of a prely random vecor h ero-mean normal dsrbon. Usng hs approach he moon of a parcle s no affeced by he poson of oher parcles. For he esmaon of plme groh R can be relaed o he Lagrangan rblence me scale by R exp- /T L here hs Lagrangan me scale T L s esmaed for each componen as follos - Unsable condons T T L v L.5 σ v. σ L.59 σ 5.5 exp σ <. > L <. < L >. 4a - Sable and neral condons T L v λm V.β v v β v mn.6 V σ v 4b here λ m s he peak avelengh n he rblen specra V s he parcle mean velocy and β s he rao beeen Lagrangan and Eleran me scales. 3. Adapve pff model APM Soo e al. [] s a ne verson of he model based n he Lagrangan adapve pff Ldg e al. [3]. Ths verson ses he same ype of adapve Gassan pff o descrbe he plme groh ha allos a non-symmerc vercal concenraon dsrbon sng 5 pff ceners. In APM ne approaches for plme rse and plme groh esmaon ere nclded. For he esmaon of plme groh Draxler [4] expressons ere appled sng he sandard devaons of velocy flcaons esmaed by ARPS: σ and σ θ obaned from σ and σ v. The se of hese expressons s dependable on he amospherc sably so he poenal lapse rae esmaed by ARPS as appled a each pff locaon.

5 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press 4 Resls and dscsson The man crren applcaon of ARPSLPM and ARPSAPM models s he forecasng of he SO plme dsperson from As Pones Poer Plan over a rads of. Ths area s locaed n he Norhes of Span fgre and s characered by seep hlls and sea nles bahed by he Alanc Ocean h he poer plan n he cener. The op of he regon s Serra do Xsral 36 asl-m. Ths area has been modeled n a 35x35 grd cenered n he Poer Plan locaon h an horonal spacng of m and h 33 vercal sreched levels reachng p o 5 m. Tme sep has been se o s excep for APM ha as se o 6 s. Meeorologcal and Lagrangan dsperson models ere rn o esmae he SO concenraon specally grond level concenraon arond he poer plan. A real-me meeorologcal and ar qaly monorng neork see fgre h one 8 m meeorologcal oer egh m oers and 7 SO glc remoe saons provdes measremens connosly o he poer plan. For comparson of boh Lagrangan models a convecve ar pollon epsode drng Jne s as chosen n order o evalae he models response o nd shear h severe changes n nd drecon a dfferen levels. Pollans sensors Poer Plan Meeorologcal Toer Fgre : As Pones Poer Plan ar qaly monorng neork.

6 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press F-Fraga Redonda Saon F5-Bemanes Saon Srface Wnd Velocy m /s 5 5 Srface Wnd Velocy m /s Srface Wnd Drecon F-Fraga Redonda Saon Srface Wnd Dre con F5-Bemanes Saon Srface Tem perare ºC F-Fraga Redonda Saon Srface Tem perare ºC F5-Bemanes Saon Fgre : Comparson of srface nd velocy nd drecon and emperare esmaed by ARPS lne and measred dos a o locaons F F5 along he pollans plme raecory on Jne s. a b Hegh asl-km 5 5 Hegh asl-m Poenal T emperare K Poenal Temperare K Fgre 3: Poenal emperare profle a esmaed by ARPS lne and measred ransonde do lne a Z on Jne s. b Deal of esmaed lne and measred do lne profles p o m.

7 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press Jne s corresponds o a saon h srong hgh pressre cenered n he Alanc Ocean arond he Wes of Ireland; here s also a relave lo cenered n he Iberan Pennsla. Ths mples moderae norheasern srface nds n he area nder sdy and a sgnfcan convecve crclaon. Esmaed srface emperare fgre s n a good agreemen h daa n boh saons F and F5 h only some relevan dfferences n drnal heang and nocrnal coolng. The agreemen n nd drecon predcon s very hgh h maxmm dfferences arond 5º. Wnd velocy s also n a good agreemen h measremens h a slgh overesmaon specally on model sarp. On fgre 3a he model reprodces qe ell he behavor of poenal emperare n he pper layers compared o ransonde measremens; near he srface fgre 3b alhogh some dfferences can be noced n he srcre of boh esmaed and observed profles a he layers here he ranspor of he plme akes place abo 6-8 agl-m he amospherc sably n boh model resls and observed daa s he same. Alhogh boh dsperson models se he same plme rse eqaons dfferen me seps may case qe dfferen plme cenerlne hegh predcon as s shon on concenraon vercal profles fgre 4. Boh models reprodce n dfferen ays he vercal groh of he plme: LPM shos a ell defned plme h only grea dsperson n he cenral hors of he day nder nsable condons hle APM gves a greaer vercal dsperson. Ths may case more localed and nense mpacs from LPM resls han hose from APM. Besdes de o he hgher plme esmaed by APM drng he las hors of he day hs model reprodces a eak sohesern ranspor n he pper layers of he plme follong he convecve crclaon. SO glc remoe saons n he sohesern par of he doman namely Fs saons deeced relevan levels of glc n Jne s. In order o compare he relave mpacs esmaed and observed a relave grond level concenraon rglc as defned for each saon ha s he rao beeen he esmaed or measred glc and he maxmm measred glc along hs day. Wh hs approach fgre 5 shos ha saons locaed abo -5 km F F6 from he poer plan measred perssen SO glc vales drng ngh me and he cenral hors of dayme and a maxmm peak n he afernoon; meanhle farher saons F5 F4 more han km donnd he poer plan deeced me-locaed mpacs. From he analyss of LPM and APM resls boh esmaed rglc levels are smlar o measred on he farhes Fs saons F5 F4 drng he afernoon and evenng and qe smlar o he observed rglc levels on F6 n he afernoon. In addon APM resls sho an mpac n F arond 6: LST ha as reprodced by APM b no by LPM becase s plme groh s loer so he plme reaches o grond farher han he APM plme. Ths agreemen corresponds manly o convecve condons and srong nd shear. Hoever perssen rglc measred drng ngh me s no represened by he models. In general boh models esmae he epsodc mpac of he pollans plme drng hs day herefore boh are operaonally sefl for ar pollon

8 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press prevenon. Hoever APM prodces more perssen plme mpacs han LPM hch s more n agreemen h he rreglar mpacs measred drng dayme; b LPM fals n he plme mpacs observed n he F saon as he closes saon o he poer plan among he affeced. 5 Conclsons In hs ork o dfferen Lagrangan dsperson models LPM and APM have been copled o he same non-hydrosac meeorologcal model ARPS n order o forecas sngle plme ranspor arond a poer plan. The vercal plme groh srcres are dfferen for boh models: LPM shos a narroer plme hle APM esmaes a more spread one. LPM 8: LST 6: LST : LST 8 km km 8 km km 8 km km Hegh agl-m 8 Hegh agl-m 8 Hegh agl-m 8 a SO Concenraon µg/m3 8: LST SO Concenraon µg/m3 APM 6: LST SO Concenraon µg/m3 : LST km km km km km km Hegh agl-m 5 Hegh agl-m 5 Hegh agl-m 5 b SO Concenraon µg/m SO Concenraon µg/m3 5 5 SO Concenraon µg/m3 Fgre 4: SO concenraon profles esmaed by LPM a and APM b a dfferen me on Jne s a 3 and km donnd he poer plan.

9 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press SO relave glc F6-Fraga do Eme Saon SO relave glc F4-Taboada Saon SO relave glc F-Fraga Redonda Saon SO relave glc F5-Bemanes Saon Fgre 5: SO relave grond level concenraon rglc respec o he maxmm measred glc on Jne s : Measred do lne esmaed by APM dashed lne and esmaed by LPM connos lne over for locaons here SO glc as deeced. Esmaon of SO rglc concenraons shos ha LPM mpacs are sally farher han APM mpacs and shorer n me b drng he dayme mpac perods LPM esmaons are more n agreemen o measremens han APM esmaed mpacs. Acknoledgemens Ths ork as sppored by Xna de Galca and Endesa nder research proec PGIDTTIC5E. E. Penabad ork as sppored by a research PhD gran of Xna de Galca. References [] Soo J.A. Pére-Mñr V. decasro M. Soo M.J. Casares J.J. Lcas T.. Forecasng and dagnosc analyss of plme ranspor arond a poer plan. Jornal of Appled Meeorology 37 pp [] Xe M. Droegemeer K.K. Wong V. The Advanced Regonal Predcon Sysem ARPS A ml-scale nonhydrosac amospherc smlaon and

10 Ar Pollon X C.A. Brebba J.F. Marín-Dqe eds. WIT Press predcon model. Par I: Model Dynamcs and Verfcaon. Meeorology and Amospherc Physcs 75 pp [3] Xe M. Droegemeer K.K. Wong V. Shapro A. Breser K. Carr F. Weber D. L Y. & Wang D. The Advanced Regonal Predcon Sysem ARPS A ml-scale nonhydrosac amospherc smlaon and predcon model. Par I: Model physcs and applcaons. Meeorology and Amospherc Physcs 76 pp [4] Balsero C.F. Soo M.J. Pére-Mñr V. Xe M. & Breser K. Operaonal Nmercal Weaher Forecas n Galcan Regon Span by sng a Non-hydrosac Nmercal Model 6h EGS General Assembly Nce France. [5] Pelke R.A. Mesoscale Meeorologcal Modelng Academc Press: Ne York 984. [6] Pelke R.A. & Mahrer Y. Technqe o represen he heaed-planeary bondary layer n mesoscale models h coarse vercal resolon. Jornal of Amospherc Scences 3 pp [7] Sll R.B.. An Inrodcon o Bondary Layer Meeorology Kler: Dordrech 99. [8] Hanna S.R. Trblen dffson: Chmneys and coolng oers. Engneerng Meeorology ed. E. Plae Elsever Ne York pp [9] Ryall D.B. & Maryon R.H.. Valdaon of he UK Me Offce s NAME model agans he ETEX daase. ETEX Symposm on Long-Range Amospherc Transpor Model Verfcaon and Emergency Response ed. K. Nodop Eropean Comsson EUR 7346 pp [] Sohl A. & Seber P. The FLEXPART Parcle Dsperson Model v. 4.. [] Soo M.J. Soo J.A. Pére-Mñr V. Casares J.J.& Bermúde J.L A comparson of operaonal Lagrangan parcle and adapve pff models for plme dsperson forecasng. Amos. Envron. 35 pp [] Soo J.A. decasro M. Ldg F.L. Casares J.J. & Bermúde J.L. Operaonal evalaon of an mproved adapve pff model APM appled o he complex erran arond he As Pones Poer Plan n Norhesern Span. h Jon Conference on he Applcaons of Ar Pollon Meeorology h he A&WMA Amercan Meeorologcal Socey Long Beach CA pp [3] Ldg F.L. Salvador R. & Bornsen R. An adapve volme plme model. Amos. Envron. 3 pp [4] Draxler R.R. Deermnaon of amospherc dffson parameer. Amos. Env. pp [5] Benne M. Son S. & Gardner D.R.C. An analyss of ldar measremens of boyan plme rse and dsperson a fve poer saons. Amos. Env. 6 pp [6] Zhang X. & Ghonem A. A compaonal model for he rse and dsperson of nd-blon boyancy-drven plmes. II. Lnearly srafed amosphere Amos. Env. 8 pp