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Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 The airborne research platform of the FU Berlin: Overview of measurements taken during the BBC.

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Presentation on theme: "Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 The airborne research platform of the FU Berlin: Overview of measurements taken during the BBC."— Presentation transcript:

1 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 The airborne research platform of the FU Berlin: Overview of measurements taken during the BBC campaign and presentation of first products and analysis Marc Schröder, Thomas Ruhtz, Eyk Bösche, Jürgen Fischer Institut für Weltraumwissenschaften Freie Universität Berlin Germany

2 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Table of contents Overview of measurements Calibration BBC casi data catalog casi cloudmask Statistical characterisation of clouds

3 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Overview of measurements Instrument casi FUBISS classic HDRAD FUBISS extended HMR, G12 MIDAC Description Compact airborne spectrographic imager, nadir radiances (vis) FUB integrated spectrographic sys- tem (radiances): 1 nadir,1 zenith (vis), 1nadir (highvis), 1 nadir (NIR) Radiometer from the University of Heidelberg, 4 visible channels Irradiances (vis), nadir, zenith Flight attitude (20 Hz), GPS (10 Hz) Fourierspectrometer (5-17  m) Status ok ok, except for NIR ok no HMR since , GPS ok no Amount 54 G 2 G 9 M 4 G 0.5 G 1 G

4 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Calibration examplary results for FUBISS vis nadir absolute calibrationspectral calibration

5 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Calibration: Spectral comparison Hintergrund Radiative smoothing (Bounded) cascade models Multifraktalität data taken from the leg04 time: utctime: utc

6 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Calibration: Time series comparison data taken from the leg04 wavelength: 753 nm

7 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 BBC casi data catalog Hintergrund Radiative smoothing (Bounded) cascade models Multifraktalität

8 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 BBC casi data catalog: Track overview start time stop time section length leg01 leg02 leg03 leg04 09:30:48 10:31:17 10km length: 28.69km / sections: 2 length: 30.22km / sections: 3 length: 29.27km / sections: 2 length: 57.11km / sections: 5 Date: Leg: 02

9 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 BBC casi data catalog: Images 34.2° altitude swath top of image correspondes to geograhpic north casi

10 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask: Algorithm development casi nadir radiances, one received over cloud, the other over meadow, normalised to the respective radiance at 780 nm define ratio: r = L(490 nm) / L(780 nm) find thresholds: cloud if r  r T and cloud if L(490 nm)  L T (490 nm)

11 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask development: Thresholds histograms of casi nadir radiances at 490 nm and the ratio r, data from , leg5 thresholds: r T = 0.5 and L T (490 nm) = 60 Wm -2 sr -1  m -1

12 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask development: Cloud shadow on clouds white: cloudmask with previous condition only 2nd condition: r T  1.35 and L T (490 nm)  35 Wm -2 sr -1  m -1 gray: advanced cloudmas- king technique pm, leg2

13 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask: Results I data from pm, leg6

14 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask: Results II data from , leg7

15 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 casi cloudmask: Results III data from , leg1

16 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Power spectra Definition: Scale invariance: stationarity if stationary incre- ments if E(k) ~ |F(k)| 2 E(k) ~ k -   < 1 1 <  < m  =2.52  =1.37 data from , leg3 cloud fraction b = 0.97

17 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Structure function analysis 1)  (r;x) =  (x+r) -  (x) =  i+r -  i with i=1,...,N-r and N=L/l 2) ~ (r/L)  (q) with q  0 Results for H(q) =  (q) / q small scales r: H(q=1) = 0.47 large scales r: H(q=1) = 0.22

18 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 small scales r: C(q=1) = 0.11 large scales r: C(q=1) = 0.07 Singulare measures 1)  (1;x) =  (x+1) -  (x) =  i+1 -  i with i=1,2,...,N-1 and N=L/l 2)  (1;x) = |  (1;x)| / with = 1/(N-1)  |  (1;x)| 3)  (r;x) = 1/r   (r;x) 4) ~ (r/L) -K(q) with q  0 Results for C(q) = K(q) / (q-1) and C(q=1) = K´(q) | q=1

19 Marc Schröder et al., FUB BBC Workshop, Leipzig, 05.´02 Summary calibrated level 1b data for casi and FUBISS highvis, shortly available: FUBISS vis (nadir, zenith) delivered level 0b data to the IUP BBC casi data catalog, available for each day casi cloudmask, partly processed statistical characterisation of clouds: to be completed for days with high cloud fraction


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