Investigation of the dispersion of air pollutants by the RePLaT model

Transcription

1 Invesigaion of he disersion of air olluans by he RePLaT model Tímea Haszra haimi.web.ele.hu MTA ELTE Theoreical Physics Research Grou, Budaes, Hungary HARMO Seember 2014, Varna, Bulgaria

2 Lagrangian disersion models ghos aricles (comuaional aricles) real aricles oin-like aricles wih arificial, ime-deenden mass (e.g. m = 1 kg) mass decreases exonenially due o deosiion: m / = C m rajecory is deermined by he amosheric flows + in some models mean seling/erminal velociy e.g.: FLEXPART, HYSPLIT aricles wih fixed, realisic size and densiy (e.g. r = 1 μm, ρ = 2000 kg/m 3 ) rajecory is deermined by he amosheric flows + erminal velociy of individual aricles e.g. for fas redicion of volcanic ash disersion no we deosiion e.g.: PUFF, VAFTAD

3 RePLaT model 1 (Real Paricle Lagrangian Trajecory model) a Lagrangian model racking real aerosol aricles he aricles have fixed, realisic size (e.g. r = 1 10 μm) and densiy (e.g. ρ = 2000 kg/m 3 ) equaion of moion Newon s equaion advecion urbulen diffusion dr d v wermn ξ r r ρ, ρ ν v, v g ξ n werm aricle osiion aricle radius densiy of aricle, air kinemaic viscosiy of air velociy of aricle, air graviaional acceleraion noise urbulen diffusion uni vecor oining uwards 2 2 r g 9 erminal velociy Sokes law (aerosol aricles, r 10 μm) 1 Haszra, T. and Tél, T. (2013) Nonlin. Proc. Geohys. 20(5),

4 RePLaT model (Real Paricle Lagrangian Trajecory model) we deosiion random rocess: a aricle is caured by a raindro wih a cerain r,rain robabiliy r = r rain, ρ = ρ rain r rain and r,rain deend on reciiaion inensiy

5 RePLaT model (Real Paricle Lagrangian Trajecory model) we deosiion based on he Eulerian aroach: 1 dm d m(δ) m(0) m(δ) m(0) kwm ex( kwδ) in 1 ex( kwδ) ou m mass k w scavenging coefficien a aricle is caured by a raindro wih robabiliy r,rain = 1 ex( k w Δ) k w, r rain : deend on P reciiaion inensiy werm 8 3 rain rrain g Cd quadraic drag force r = r rain, ρ = ρ rain w erm w erm

6 RePLaT model (Real Paricle Lagrangian Trajecory model) meeorological daa in λ, φ, coordinaes (e.g. ERA Inerim daabase, Euroean Cenre for Medium-Range Weaher Forecass) equaion of moion: λ, φ, inerolaion: bicubic sline in horizonal linear in ime and verical numerical soluion: Euler mehod

7 Equaion of moion R R R v R R u 24 ) ( ) ( ) ( 24 ) ( ) ( 24 cos ) ( ) ( erm E E 2 2 E E cos R R y x R [ 0.5; 0.5] uniform disribuion random number R E Earh s radius x, y consan horizonal urb. diff z verical urb. diff. (Monin Obukhov similariy heory) advecion urbulen diffusion

8 Eyjafjallajökull simulaion (May 8 19, 2010) wind seed r = 1 μm, ρ = 2000 kg/m 3 n = aricles simulaion: adv., urb. diff., no we de. [hpa] h://

9 Eyjafjallajökull simulaion (May 8 19, 2010) comarison: simulaion and saellie measuremen volcanic ash [h://

10 Fukushima simulaion (March 10 30, 2011) emission [Sohl e al., 2012] [hpa] aerosol-bound 137 Cs isooe r = 0.2 μm, ρ = 1900 kg/m 3 n = 10 6 aricles simulaion: advecion urb. diff. we deosiion deosiion field [kbq/m 2 ]

11 Fukushima simulaion (March 10 30, 2011) comarison: measuremen and simulaion arrival imes coincide reasonably well 133 Xe: simulaions were able o reroduce he measured concenraions 137 Cs: someimes overesimaions uncerainies: esimaed emission daa coarse resoluion of he meeorological daa (6h) heavy reciiaion evens smoohed ou arameerizaions 137 Cs 133 Xe

12 Uncerainies in he disersion forecass inu daa for he disersion model emission daa meeorological daa ensemble forecass uncerainies associaed o he disersion model rocesses aken ino accoun, arameerizaions numerical aroximaions chaoic advecion of olluans [Aref, 1984] (sensiiviy o he iniial condiions, irregular moion, comlex srucures)

13 Imac of he meeorological daa General overview 50 erurbed + 1 unerubed member (CF) + HRES ρ = 2000 kg/m 3, r = 1, 2,, 10 μm aerosol aricles simulaions: advecion no urb. diff. no we de. 3D aricle disribuion afer 2.5 days high-resoluion (deerminisic) r = 1 μm ensemble members r = 4 μm iniial condiions: (March 12, 2011) n 0 = Δλ Δφ = 1º 1º,

14 Imac of he meeorological daa Tyes of olluan clouds for r = 1 μm [hpa]

15 Imac of he meeorological daa Horizonal disribuion for r = 1 and 10 μm Colored conours indicae he ercenage of he ensemble disersion simulaions ha redic a concenraion above a hreshold Black: he same by using he HRES forecas ensemble olluan clouds exand o a 5 10 imes larger area han ha of he HRES forecas r = 1 μm air column r = 10 μm deosiion field

16 Imac of he meeorological daa Cener of mass for r = 1 μm for aricles in ensemble disersion members ha blue: remain in air red: deosied radius: roorional o he sandard deviaion of aricles around he cener of mass km imac of using erurbed forecass 3375 km HRES imac of using forecass wih differen resoluion 750 km Haszra, T., Lagzi, I., Tél, T. (2013): Disersion of aerosol aricles in he free amoshere using ensemble forecass. Nonlin. Proc. Geohys. 20(5) Haszra, T., Horányi, A. (2014): Some asecs of he imac of meeorological forecas uncerainies on environmenal disersion redicion. Időjárás (acceed)

17 Summary and Oulook RePLaT Lagrangian disersion model fuure work: RePLaT should be imroved by addiional facors (e.g. more deailed descriion of he we deosiion) he simulaions carried ou by he RePLaT model agree reasonably well wih observaions effec of uncerainies in he meeorological daa on he disersion calculaion, and is deendence on he aricle size ensemble olluan clouds exand o a larger area han ha of he HRES forecas risk assessmen where and when does he concenraion exceed a cerain hreshold wih wha robabiliy? Noe: i is only one of he error sources! i would be useful o ake ino accoun oher uncerainy sources