Natalia Kouremeti, Julian Gröbner, Ricco Soder, Pascal Schlatter, Patrik Langer Marek Smid, Geiland Porrovechio Meelis-Mait Sildoja, Saulius Nevas

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1 Natalia Kouremeti, Julian Gröbner, Ricco Soder, Pascal Schlatter, Patrik Langer Marek Smid, Geiland Porrovechio Meelis-Mait Sildoja, Saulius Nevas ATMOZ Workshop 01.Jun 2017 El-Arenosillo

2 Objectives of the new Direct Irradiance Spectroradiometer Retrieval of total column of Ozone CCD based Spectrometer High resolution (better than 0.3 nm FWHM) over the UV-Vis range Oversampling more than 3 pixels within the FWHM High Sensitivity & Signal to Noise Ratio in UV Absolute Stability - AOD

3 Optical Design Czerny-Turner design Optical Elements Off -Axis Parabolic Mirror FL 125mm & 30 o (40x40mm) Grating 1800 lines/mm (44x44mm) Custom made Spherical Mirror FL 110mm (65x50mm) Entrance Slit Detector Length 60x1000 μm mm Rotation Min Wavelength (nm) Maximum Wavelength (nm) Imaged Wavelengths (nm) linear step nm/pixel FWHM (nm) Pixels within the FWHM UV ± Vis ± Vis (O 4 & H 2 O) to NIR (O 2 ) to Maximum to 0.70 Up to 100

4 ATMOZ Spectroradiometer: ERMIS Detector: Hamamatsu cooled to -20 o C - 3 stage cooling S OS4 2048x256 pixels S OS4 2048x506 pixels Spherical Mirror: FL 110mm FL 100mm Grating : 1800 lines/mm Off -Axis Parabolic Mirror FL 125mm & 30 o Entrance Slit: 60x1000 μm

5 ATMOZ SPECTRORADIOMETER: ERMIS Telescope - FOV ~1 o Optical Fiber Spectrometer Casing & Electronics filled with N 2 and pressurized to 1.5 bars to avoid condensation on the detector and deterioration of the optical components Converging & Focusing Lenses 2 Filter Wheels ND filters Spectral Filters 400nm UV340 UG11

6 ERMIS Characterization Line Spread Functions ATLAS System Wavelength Calibration In range Stray Light Contribution Direct irradiance Calibration ERMIS current version Five Selected Position Of the Grating covering the spectral range nm

7 LSF LSF ERMIS Line Spread Functions - GP1: nm pixel pixel

8 FWHM (nm) ERMIS Line Spread Functions 0.3 GP#1 : nm GP#2 : nm GP#3 : nm GP#4 : nm GP#5 : nm wavelength (nm)

9 Signal (cpms) Direct Irradiance Test Scan 10 1 O HCHO NO 2 H 2 O O wavelength (nm)

10 ERMIS Deployment ATMOZ campaign September - October 2016, Izaña Tenerife Davos PMOD/WRC March - May 2017 El Arenosillo RBCC-E XII now Ozone Retrieval Method QDOAS algorithm - BIRA Izaña Dataset Spectral Range nm ETS : env03_cosi_kittpeak_thullier O 3 cross section : Bass & Paur Davos Dataset Spectral Range nm ETS : Kuruz O 3 cross section : Bremen 228K

11 Distribution (%) Ozone (DU) ATMOZ campaign ERMIS Version September - October 2016, Izana Tenerife ERMIS QASUME Day of Year Normal Distribution Fit = DU =2.748 DU O 3 Difference (DU) [ERMIS - QASUME]

12 Distribution (%) Retrival Residuals (%) Ozone (DU) Davos ERMIS Version DAVOS Period : 15-Mar to 20-Apr Day Of Year Normal Distribution Fit = DU 25 =4.880 DU 10 Izana 9 Davos O 3 Difference (DU) [ERMIS - Brewer] ozone air mass

13 Ratio to mean Ratio to mean Ratio to median STD(%) Signal (cpms) pixel Absolute 2 & Wavelength Stability ULS2 - PTB pixel wavelength(nm) pixel : : : : : : : : :59 14: : pixel : : : pixel

14 Future Work Improve of the absolute stability Ozone Retrieval Temperature Calibration Retrievals in the Visible Hardware modifications Telescope Increase the Sensitivity of ERMIS Stability of wavelength

15 Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos, Switzerland ERMIS

16 Ratio ERMIS/QASUME Comparison to QASUME wavelength (nm)

17 Comparison to QASUME QASUME

18 Line Spread Functions measurement on

19 Signal (cpms) LSF First Version Problems Back reflection from the detector Reflections on the walls for wavelengths longer than 394 nm OUT OF RANGE STRAY LIGHT - Low pass Filter 400nm pixel pixel

20 The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union

21 Ratio to mean of 100mean Comparison to QASUME Brige Temp. ( o C)

22 Ratio to End Of Day Scan Brige Temp. ( o C)

23 Vertical Pixels Vertical Alignment ATLAS Wavelength Scan Horizontal Pixels

24 Out of Range Stray Light Contribution (%) Stray Light Corrected Signal (counds) Stray Light Correction (%) ERMIS fit fit + 20 px fit + 40 px fit + 60 px fit + 80 px fit px fit px data- Single Gaussian fit data- Best Gausian fit pixel Theoritical STRLC measurement clear wavelength(nm) Wavelength(nm)

25 Response Ratio Uncertainty in Response (%, 1sigma) Response Function (Counts/[W.m -2.nm -1 ]) Calibration ERMIS Calibration Lamp: F323,Distrance = mm wavelength (nm) Repetability (std/mean)/sqrt(n)) Distance ( 5mm for 100 th percentile) Smoothing Irradiance - PTD Total Wavelength (nm) Wavelength (nm)

26 Direct Iradiance (W/nm/m2) Direct Iradiance (cpms) Direct Irradiance nm - 10-Sep SZA(deg) SZA wavelength (nm)

27 Ratio of Signal (cpms) ITi/ITj Signal (counts) Signal (cpms) Blooming Effect x IT(ms) pixel 2.8 Pixel - IT(ms) 200 ms / 100 ms ms / 200 ms ms / 300 ms 500 ms / 400 ms ms / 500 ms ms / 600 ms 800 ms / 700 ms ms / 800 ms ms / 900 ms 1st pixel 1.4 2nd pixel Cumulative Raw Signal (counts) x 10 7

28 Comparison to QASUME QASUME

29 Comparison to QASUME QASUME

30 Comparison to QASUME QASUME

31 Comparison to QASUME QASUME

32 Comparison to QASUME QASUME

33 Comparison to QASUME QASUME

34 Comparison to QASUME QASUME

35 Ratio ERMIS/QASUME Comparison to QASUME wavelength (nm)

36 Comparison to QASUME nm 1nm 330 nm 1nm 340 nm 1nm 349 nm 1nm 370 nm 1nm 390 nm 1nm

37 Comparison to QASUME QASUME

38 Ozone (UG11,BB, no stray light, single spec retrieval ) Comparison to QASUME (BB )