Emeis, S.

Schäfer, K.

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Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisRemote sensing of meteorological conditionsat airports for air quality issuesStefan Emeis, Klaus SchäferInstitute for Meteorology and Climate Research –Atmospheric Environmental Research (IMK-IFU)Forschungszentrum Karlsruhe GmbHKreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, Germanystefan.emeis@imk.fzk.deECATS, Spring School & Research Colloquium, 13 March 2007, MMU ManchesterForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisRemote sensing:basicsandinstrumentationTypical frequency bands for remote sensing of the atmosphereaerosol rain turbu-lenceLIDAR/CeilometerRADARRASSSODARlog10 wave length λlog10 frequency νlog10 wave length λlog10 frequency ν17   16   15    14    13    12    11    10     9     8      7   6      5     41 THz              1 GHz     1 MHz1 nm              1 µm              1 mm               1 m     1 km - 9    - 8    - 7   - 6   - 5    - 4   - 3   - 2    - 1     0      1     2      3      4      55     4      3      2     1      0     -11 KHz              1 Hz1 mm               1 m                1 km - 3   - 2    - 1     0      1      2      3     Wind-profilerFTIR MWR106 cm-1 1 cm-1 10-6 cm-17     6      5      4      3     2      1      0    - 1    - 2   - 3   - 4   - 5    - 6    - 7log10 wave numberelectro-magneticacousticModified from Fig. 8.1 in „Meteorologie in Stichworten“, Borntraeger, Berlin Stuttgart 2000 stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisAcoustic Remote sensing:backscatter at thermal fluctuations and gradients(and large snow flakes)in the atmosphereForschungszentrum Karlsruhein der Helmholtz-Gemeinschaftheighttime  emit receivemonostatic SODAR: measuring principles© Scintec, TübingenEmission of sound wavesinto three directions:in order to measure all threecomponents of the wind(horizontal and vertical)deduction: sound travel time         =  heightbackscatter intensity =  turbulenceDoppler-shift =  wind speedstefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisLarge SODARof IMK-IFU(METEK DSDR3x7)frequency:   1500 Hzrange:          1300 mresolution:        20 mlowestrange gate: ca. 60 msize of instrument:height:        4 mwidth:          1,50 mlength:       10 mweight:        8 tReitebuch, O. und S. Emeis, 1998: SODAR-measurements for atmospheric research and environmental monitoring. Meteorologische Zeitschrift, N. F., 7, 11-14. stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeismobile trailer (container) withbuilt-in minisodar anddata acquisition of IMK-IFUAerovironment AV4000minisodarrange:                      200 m frequency:           4500 Hzvertical resolution:      5 mtemporal resolution: 10 minphased-array SODARForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisOptical Remote sensing:backscatter at aerosol particles,insects, water droplets, ice, and snow(fog and clouds are opaque)in the atmosphere11Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisCeilometer/LIDAR measuring principledetection: travel time of signal      = heightbackscatter intensity    = particle size and number distributionDoppler-shift                 = cannot be analyzed from ceilometer datafrom LIDAR: velocity component in line of sight heighttime  emit receivestefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisceilometerabout 1 m in sizenormally mounted verticallyemits radiation at 0.9 µm (eyesafe)stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisDifference between acoustic and optical remote sensingacoustic remote sensing:SODAR  seesthermal structure of atmospheric boundary layerwind and turbulence profilesoptical remote sensing:ceilometer seesaerosol content of atmospheric boundary layer(often this follows the thermal structure of the boundary layer but not always, advection and secondary formation of aerosols has influence, too)Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisExamples:Mixing-layer heightWind and turbulence profilesLow-level jetsForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisMixing-layer heightheight underneath which the atmosphere is usually well mixedand pollutants are distributed rapidlyForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisResults of MLH retrieval during simultaneous operation partly agree and partly complement each otherComparison of SODAR measurements with data from a Wind-Temperature-RADAR (RASS) of IMK-ASF and a ceilometer of Vaisala (backscatter at 0.9 µm) for 09 May 2002Emeis, S., Chr. Münkel, S. Vogt, W.J. Müller, K. Schäfer, 2004: Atmospheric boundary-layer structure from simultaneous SODAR, RASS, and ceilometer measurements. Atmos. Environ., 38, 273-286. stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisSODAR measurement programme for Charles de Gaulle Airport (Paris):∆t = 30 min, ∆z = 20 m, zmin = 40 m, zmax =   800 mused variables for the determination of MLHacoustic backscatter intensity Rz in dB, σw in m/scriteria for diagnosing MLH:criterion 1 (top of turbulent layer)Rz < 88 dB ∧ Rz+1 < 86 db ∧ Rz+2 < 84 dBcriterion 2 (surface-based or lifted inversion)Rz > 105 dB ∧ σw < 0,3 m/s ∨ dR/dzz+1 < 0 ∧ dR/dzz-1 > 0 ∧ σw < 0,7 m/sEmeis, S., M. Türk, 2004: Frequency distributions of the mixing height over an urban area from SODAR data. Meteorol. Z., 13, 361-367.Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisWeekly variation of mixing-layer height (CDG)clear diurnal cycleof MLHlow values in themorning hours(100 – 200 m)high values in theafternoon(above the rangeof the instrument> 800 m)stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisWeekly variation of mixing-layer height (CDG)clear diurnal cycleof MLHlow values in themorning hours(100 – 200 m)high values in theafternoon(above the rangeof the instrument> 800 m)stefan.emeis@imk.fzk.deForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisDiurnal variation of mixing-layer height from SODAR and Ceilometer data (Budapest)SBL SBLCBLFree troposphereRL RLSBL:stable boundarylayer (usually atnight and in winter)CBL:convective bound-ary layer (usuallyat daytime due tostrong insolation)RL:residual layer(usually at night-time)Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeiswind and turbulence profilesForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisExample from ameasurement campaignatParis CDG airportinJune/July 2005The sodar has beenat position “6”S1S4S2S3Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof wind speed uCDGJune/July 2005S2: influenced bythe airport(lower windspeed overrough surface)S4: rural profiles(higher windspeed oversmooth surface)S2S4Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof wind speed uJune/July 2005CDGall datatypical difference between daytimeand nighttimeprofiles (smallgradient at daytime,large one atnighttime)daynightForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof σw(variance of verticalwind speed, a measure for turbulence)S2: influenced bythe airport(higher turbu-lence overrough surface)S4: rural profiles(lower turbu-lence oversmooth surface)S4S2Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof σw(variance ofvertical wind speed)CDGall datatypical difference between daytimeand nighttimeprofiles (high atdaytime, low atnighttime)daynightForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof turbulenceintensity (u / σw)CDGS2: influenced bythe airport(higher turbu-lence overrough surface)S4: rural profiles(lower turbu-lence oversmooth surface)S4 S2Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof turbulenceintensity (u / σw)CDGall datatypical difference between daytimeand nighttimeprofiles (high atdaytime, low atnighttime)daynightForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisLow-level jets (LLJ)maxima of horizontal wind speed a few hundred metresabove the ground, associated with large vertical wind speed and direction gradientsusually form after sun set and disappear at sun rise appear only in clear nights (no or only few clouds)when a synoptic surface pressure gradient is presentForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof wind speedoverview23-30 June 2005CDGLLJ especiallyon June 26 to 28at 150 to 300 mheight abovegroundLLJForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeis19vertical profilesof wind speedselected 30 minaverages26 June 2005CDGLLJ between200 and 325 mabove groundleads to strongvertical windshearLLJneutral logarithmicwind profileForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisvertical profilesof wind direction26 June 2005CDGselected profiles(same as before)30 min averagesshowing verticalwind directiongradientsLLJForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisweather map showinga typical weather situation for LLJ at Paris CDGsurface pressure00 GMT26 June 2005Paris CDG lies at theedge of a high pressuresystem (leading toclear skies) withnoticeable horizontalsurface pressure gradientForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisTypical weather conditions for the formation of nocturnal low-level jets (LLJ):- clear skies- dry air masses (low thermal radiation from the atmosphere back to the ground)- non-vanishing synoptic pressure gradient- low to medium synoptic wind speedsPhysical mechanism:- rapid thermal cooling of the surface after sun set leads to the formation of acool stable surface layer with low turbulence- missing turbulence leads to a decoupling of the layer above the surface layerfrom the frictional influence of the ground on the atmospheric flow- vanishing frictional influence leads to an acceleration of wind speed in thedecoupled layer- during the night: inertial oscillation (turning of wind direction of LLJ)- next morning: destruction of the phenomenon due to thermal mixing from belowForschungszentrum KarlsruheTechnik und UmweltNocturnal low-level jet  (LLJ) and turning of wind direction with heightday2002Dr. S. Emeis, IMK-IFUnightwell-mixedboundarylayerstablesurface layerTHPRCTHP CfrictionalforceForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisfurther eamples:surface pressure00 GMT22, 27, 28 June,10 July 2005(nights with LLJat Paris CDG)Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeistemperaturedew pointwindinversionvertical structureof the lowertroposphereradiosonde soundingsin Trappes00 GMT for heights below3000 m26, 27, 28 June,10 July 2005(nights with LLJat Paris CDG)Forschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan Emeisstatistical evaluationof sodar windmeasurementswind speedfrequency distributionwith heightJune/July 2005CDG240 m160 m100 mLLJ40 mForschungszentrum Karlsruhein der Helmholtz-GemeinschaftIMK-IFU, Stefan EmeisThank you for your attentionLet’s take off …Source: Stadt Stuttgart / www.lfu.baden-wuerttemberg.de

Remote sensing of meteorological conditions at airports for air quality issues

https://publikationen.bibliothek.kit.edu/230070772/3815186

Remote sensing of meteorological conditions at airports for air quality issues

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