Borsdorff, T.

Camy-Peyret, C.

Sussmann, R.

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Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsOutline• Zugspitze/Garmisch Instrumentation• Interference errors and micro window selection• Zugspitze FTIR profile retrieval• Strategy for validation of FTIR total columns by sondes• Optimized FTIR total column retrieval and its validation• Summary and Outlook iResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsIFUGarmisch, 734 mFTIRGPSRadio sondesZugspitze, 2964 mLIDARIFUIFUGPSFTIRIFUIn situIn situLIDARUVUVIMK-IFU Working Group „Variability and Trends“ScientistsR. Sussmann H.E. ScheelT. Trickl H. Vogelmann EngineersH. GiehlM. Rettinger PhD studentsT. Borsdorff F. ForsterTriple NDACC Primary Station: FTIR, Aerosol, UV.Permanent Ground-Truthing FacilityZugspitze/Garmisch according to the WMO requirements.MAPS,CRISTA,MOPITT, SAGE, GOME,AIRS,SCIAMACHY,ACE, IASI,CALIPSO, OCO, TCCON,GOSAT, …Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsIFUGarmisch, 734 mFTIRGPSRadio sondesZugspitze, 2964 mLIDARIFUIFUGPSFTIRIFUIn situIn situZugspitze/Garmisch instrumentation for water vaporcolumns/profilesResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsIFUGarmisch 734 mFTIRZugspitze2964 mIFUFTIRIFUH2O columns and profiles“Differential FTIR”with Zugspitze: H2O columns and profilesGarmisch operational since 2004typ. 130-140 measurementdays per yearZugspitze operational since 1995typ. 130-140 measurementdays per yearResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements2057.80 2057.85 2057.900.000.850.900.951.001.051.10normalized intensitywave number [cm-1] CO2 O3 solar  CO  total2069.62 2069.64 2069.66 2069.68 2069.700.000.850.900.951.001.051.10normalized intensitywave number [cm-1] CO2 O3 solar  CO  total2157.50 2158.00 2158.50 2159.000.000.200.400.600.801.001.201.401.60normalized intensitywave number [cm-1] CO2 H2O O3 solar  N2O CO  totalExample CO retrieval:interfering speciesO3, N2O, CO2, H2OInterference erros and micro window selection: Interference errors (I)Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements2.96446810121416182022240 5 10 15 20 25 stdv of true CO variability  CO smoothing error  CO - O3 interf. error CO - H2O interf. error  CO - N2O interf. error × 10 CO - CO2 interf. error × 10stdv of smoothing and interference errors [%]altitude [km]Interference erros and micro window selection: Interference errors (II)ExampleCO retrievaltaken from:Sussmann, R. and Borsdorff, T: Technical note: Interference errors in infrared remote sounding of the atmosphere, Atmos. Chem. Phys., 7, 3537-3557, 2007.Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements839,6 839,8 840,0 840,2 840,40,70,80,91,0 Measured spectrum Calculated spectrum Relative IntensityWave number  (1/cm)-0,020,000,02  Residual849,0 849,2 849,4 849,6 849,8 850,0 850,20,60,70,80,91,0 Measured spectrum Calculated spectrum Relative IntensityWave number  (1/cm)-0,020,000,02 Residual852,0 852,2 852,4 852,6 852,8 853,00,50,60,70,80,91,0 Measured spectrum Calculated spectrum Relative IntensityWave number  (1/cm)-0,020,000,02 Residual010-010R10, R14water linesZugspitze FTIR water vapor profile retrieval: Interference-free micro windows010-010R11water line010-010R10, R13, R16water linesHITRAN2000Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements0.73424681012140.000 0.005 0.010 0.015 0.020volume mixing ratioaltitude [km]Garmisch radio sonde profilesZugspitze FTIR water vapor profile retrieval: A priori information used (I)AIRS validation campaign19 Aug 2002  - 17 Nov 2002Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements0.734 2 4 6 8 10 12 140.7342468101214altitude [km]altitude [km]- 0- 0.05- 0.10- 0.15- 0.20- 0.25- 0.30- 0.35- 0.40- 0.440.73424681012140 10 20 30 40 50 60 70standard deviation of H2O variability [%]altitude [km]water vapor covarianceVMRUnit: covariances of VMR-layer scaling factorsZugspitze FTIR water vapor profile retrieval: A priori information used (II)water vapor variability (stdv)Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements2.964468101214-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0averaging kernelaltitude [km]1 mm water vapor columnZugspitze FTIR water vapor profile retrieval: Averaging kernelsdofs ≈ 3 (snr ≈100)dofs-1-layers: 3 - 4 km4 - 7 km7 – 15 kmResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurements2.9644681012141618202224260 20 40 60 80 100 120 140 160 180 10 mm water vapor column 1 mm water vapor column stdv of true water vapor variabilitysmoothing error [%]altitude [km]Zugspitze FTIR water vapor profile retrieval: Smoothing error⇒ Smoothing error/altituderange does not dependupon absolute column levelResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsZugspitze FTIR water vapor profile retrieval: Retrieved profile versus sonde2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondeH2O volume mixing ratio [ppm]altitude [km]snr = 155.938column = 2.98 mm2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondesnr = 174.032column = 1.51 mmH2O volume mixing ratio [ppm]altitude [km]2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondesnr = 126.952column = 2.17 mmH2O volume mixing ratio [ppm]altitude [km]2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondesnr = 179.151column = 1.36 mmH2O volume mixing ratio [ppm]altitude [km]2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondesnr = 154.527column = 2.22 mmH2O volume mixing ratio [ppm]altitude [km]2.96446810121416182022240 500 1000 1500 2000 FTIR radio sondesnr = 163.892column = 1.85 mmH2O volume mixing ratio [ppm]altitude [km]⇒ profile retrieval works fine, given high quality spectra (snr > 120)and dry days (< 3 mm)Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsStrategy for validation of FTIR total water vapor columns by sondes: Tobin-SondesSonde 1 launched 1h before overpassSonde 2 launched 5 min before overpassVaisala RS 80-30 G sondesTOTEX-800-g balloons2 x Digicora III (Marvin 21, SPS220G)TOBIN-Inter-/Extrapolation between both soundings:qTobin(z, top) = qsonde(z, t0) + (dq(z)/dt) (top – t0)Tobin, D., W. Feltz, B. Knuteson, H. Revercomb, “ARM T/q Best Estimate Profiles for AIRS validation”, 1 March 2000AIRS validation campaign19 Aug 2002  - 17 Nov 2002Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsStrategy for validation of FTIR total water vapor columns by sondes: Tobin-SondesResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsStrategy for validation of FTIR total water vapor columns by sondes: Tobin-SondesResearch Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementsColumnsaboveZugspitze, 2964 m2-h-meanvaluesintegrated Tobin-profiles⇒ FTIR is one of the  most accurate techniques to quantify columnar water vapor0 1 2 3 4 5 6 7 8012345678Y = A + B * XParameter    Value                  Error------------------------------------------------------------------A                0.00727      0.12393B              1.01153      0.03263------------------------------------------------------------------R           R-Square           SD           Bias          N------------------------------------------------------------------0.98824     0.97662     0.27622     0.04646     25 ------------------------------------------------------------------ Linear Fit Upper 95% Confidence Limit Lower 95% Confidence LimitTotal Water Column from FTIR (mm)Total Water Column from Radio Sondes (mm)Optimized FTIR total water vapor column retrieval and its validationunit: [mm]Research Center Karlsruhe IMK-IFU, Garmisch-Partenkirchen, Ralf SussmannWater vapor retrieval from Zugspitze FTIR measurementstaken from:Morland, J., Deuber, B., Feist, D. G., Martin, L., Nyeki, S., Kämpfer, N., Mätzler, C., Jeannet, P., and Vuilleumier, L.: TheSTARTWAVE atmospheric water database, Atmos. Chem. Phys., 6, 2039-2056, 2006.FTIR Zugspitze - SondeSussmann, Borsdorff, Camy-Peyret, Atmos. Chem. Phys.,  to be publishedOptimized FTIR total water vapor column retrieval and its validationIMK-IFU, Research Center Karlsruhe, Garmisch-Partenkirchen, Ralf SussmannEPS/MetOp validation at Ground-Truthing Center Zugspitze/GarmischWater vapor retr eval from Zugspitze FTIR measurementSummary• found interference-free micro-window set• profile retrieval• OE with climatological a priori covariance from sondes:dofs ≈ 3, i.e., layers 3 - 4 km, 4 - 7 km, 7 – 15 km• smooting error/altitude range does not depend on absolutewater column• FTIR profiles reproduce sonde fine struture well, given highquality spectra (snr > 120) and dry days (< 3 mm)• FTIR is the most accurate technique for total columns (?): validation against sondes (Tobin): R2 = 0.98, slope = 1.01, stdv < 0.3 mm, intercept < 0.01 mm, bias < 0.05 mm Outlook• validation against lidar / synergetic combination with lidar• investigate “differential FTIR“ (Garmisch – Zugspitze column)

Water vapor retrieval from Zugspitze FTIR measurements

https://publikationen.bibliothek.kit.edu/230072239/3815252

Water vapor retrieval from Zugspitze FTIR measurements

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