Large scale facilities

Transcription

1 The Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, is part f the Department f Envirnmental Engineering, f Demcritus University f Thrace in Greece. The labratry clsely cllabrates with ther Atmspheric Physics and Meterlgy Departments in the cuntry and in Eurpe via natinal, internatinal and EU funded prgrammes. Scientific aims The determinatin f atmspheric pllutin levels in cities and rural envirnments The determinatin f trans-bundary atmspheric pllutin lads The relatin f greenhuse gases t glbal and lcal climatlgy The determinatin f the ptical and chemical prperties aersl and their relatin t direct and indirect climate frcing The study f Indr Air Quality (IAQ) prblems and the effect f indr atmspheric pllutants n wrks f art and human health The mdelling & management f IAQ The study f ccupatinal safety and health issues and industrial hygiene prblems Bigechemistry Remte sensing Large scale facilities I. The labratry has instrumented and perates the nly Greek aircraft fr airbrne research, assciated als with the Eurpean Fleet fr Airbrne Research, with the characteristics AEROFOTO-DUTH ( II. It perates the 125 m flux twer at the ld Vice f America statin (VOCALS), N E, determining fluxes f Greenhuse Gases and Mercury. III. A reginal facility fr High Reslutin magnetic sectr GC-MS with reslving pwer >60,000. Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 1

2 IV. MS/MS. A reginal facility fr high reslutin ION CHROMATOGRAPHY-UHPLC- V. A Reginal facility fr high energy, wavelength dispersive XRF (99 elements). The flux twer The main scpe f the Instrumented 125 m flux twer is t determine: 1. Mmentum, Sensible Heat, Latent Heat, CO2, CH4 and H2O fluxes utilizing the eddy-cvariance methd and 2. Mmentum, Sensible Heat, Latent Heat, Hg, CO2, and H2O fluxes utilizing the gradient and variance methds. 3. The energy balance clsure and its variatins fr site next t the sea taking int accunt a wide range f parameters. 4. Prvide a lng term mnitr f carbn dixide, methane and mercury and a hst f meterlgical parameters like sunlight intensity, wind speed & directin, humidity, temperature and pressure. Site Equipment fr the flux measurements The twer is equipped with the fllwing state f the art instruments: Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 2

3 A 3-D Snic Anemmeter, CSAT3 (Campbell sci.) with 10Hz sampling rate and a fine wire thermcuple fr sensible heat flux measurements. A Cavity Ring-Dwn Spectrscpy (CRDS) Picarr Analyzer with 10Hz sampling rate fr the greenhuse gases CO2, CH4 and H2O. A Gaseus Hg analyser with detectin limit f 5ng/m-3, Tekran 2537 b. A data-lgger CR3000 Campbell sci. 1 net radimeter CNR4 Kipp and Znen fr incming and utging shrt and lng wav radiatin. Fur humidity and temperature prbes HC2-S, Rtrnic ag., with their radiatin shields. A wind sentry anemmeter AND three RM Yung 3-Cup Anemmeters and. A labratry made analyzer f CO 2 Methdlgy Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 3

4 Direct eddy cvariance. The data are subjected t despiking by cmputing the mean and standard deviatin fr a series f mving windws f varius lengths, (Vickers and Mahrt,1997). Any pint which is mre than 3.5std frm the windw mean is replaced by linear interplatin. If the cnsecutive spikes are mre than three, they are cnsidered as missing values. Since steady state cnditins must be taken int accunt, the data are flagged when they fail t pass the respective test f Fken and Wichura (1996). They are als tested fr skewness and kurtsis (Vickers and Mahrt, 1997). T ensure that the data crrespnd t turbulent develpment, their integral turbulent characteristics are cmpared t mdel nes based n the flux variance similarity, (Fken, 2008). Lag crrelatin analysis is als perfrmed fr the specific humidity and temperature fr their crrelatin with vertical velcity. T fix the rientatin f crdinate frame fr the snic anemmeter wind measurements, bth the 2-d crdinate rtatin and the planar fit methd (Wilzcak et al., 2001) were applied separately t investigate the influence f the methds t the results. The pst prcessing includes the determinatin f fluctuatins and the separatin f the turbulent signals frm trends r lw frequency cmpnents impsed either by instrumental drift r as a result f changes in meterlgical cnditins. The appraches used (Mncrieff et al, 2004) are, time averaging and remval f a standard r a mving mean, detrending by subtracting the trend frm each averaging perid using the least square methd, filtering the datasets with a recursive filter r a cmbinatin f prefiltering with a lw Butterwrth filter and time averaging. The cmparisn f the results leads t the mst suitable technique fr each case study. Crrectins fr buyancy fluxes accrding t Sctanus et al. (1983) were als applied, while give tests determine the mre suitable averaging perid. Spectra crrectins are thence cnsidered fr estimating flux lsses in the high frequency range. In rder t estimate the surce areas fr the cnvective flux measurements varius ftprint mdels are applied like the Eulerian analytical mdel suggested by Hrst and Weil (1992) and the ftprint mdel f Hsieh et al. (2000). Mdified Bwen Rati Methd. Data crrespnding t frictin velcity belw the limit f 0.07m/s are excluded. Gradient methd based n Mnin Obukhv similarity thery is als applied fr calculating turbulent heat fluxes, mmentum and scalar fluxes frm the slw respnse measurements taken at fur levels n the twer. The iterative methd was used after impsing the crrectin functin fr stability cnditins. Bulk apprach. Calculating turbulent heat fluxes, mmentum and scalar fluxes frm the slw respnse measurements taken at 2 levels n the twer. Flux variance methd based n pwer law and crrelatin methds t estimate scalar fluxes and sensible heat fluxes under free cnvectin cnditins. Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 4

5 Sme results fr 5 days f measurements. Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 5

6 References Fken T Specifics f the Near-Surface Turbulence. In: Micrmeterlgy: Springer Berlin Heidelberg, Fken, T., Wichura, B., Tls fr quality assessment f surface-based flux measurements. Agric. Fr. Meterl. 78: Hrst TW, Weil JC Ftprint estimatin fr scalar flux measurements in the atmspheric surface layer.. Bundary-Layer Meterlgy, 59: 279±96 Hsieh Cheng-I, Katul G, Chi Tze wen An apprximate analytical mdel fr ftprint estimatin f scalar fluxes in thermally stratified atmspheric flws. Advances in Water Resurces, 23: Mncrieff J, Clement R, Finnigan J, Meyers T Averaging, Detrending, and Filtering f Eddy Cvariance Time Series. In: Handbk f Micrmeterlgy, Vl. 29, (Lee X, Massman W, Law B, eds):springer Netherlands, Schtanus P, Nieuwstadt FTM, de Bruin HAR Temperature measurement with a snic anemmeter and its applicatin t heat and misture flux. Bundary-Layer Meterlgy, 26: Vickers D, Mahrt L Quality Cntrl and Flux Sampling Prblems fr Twer and Aircraft Data. Jurnal f Atmspheric and Oceanic Technlgy 14: Wilczak J, Oncley S, Stage S Snic Anemmeter Tilt Crrectin Algrithms. Bundary-Layer Meterlgy, 99: Labratry f Atmspheric Pllutin and f Pllutin Cntrl Engineering f Atmspheric Pllutants, Department f Envirnmental Engineering, Demcritus University f Thrace. Page 6