OMI Daily Instrument Configuration Timeline and Telemetry Plots for 2004-08-10 (DOY 223)


Other Available Daily Reports for 2004-08-10:


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Instrument Configurations

The graph below shows the types of measurements that were performed as a function of the orbit phase (on the horizontal axis). Each orbit starts and ends at the spacecraft midnight. The EOS-Aura satellite dayside covers the orbit phase range 0.18 - 0.82. The eclipse covers orbit phase ranges 0 - 0.18 and 0.82 - 1. The graph shows four types of information in vertical direction per orbit, from top to bottom:

  • Binning factor: twelve (12), global (8), spatial (4), two (2), unbinned (1).
  • Dark mode: dark, light.
  • Measurement zone: none, tropical, mid-latitude, arctic, ozone hole.
  • Measurement class: none, Earth, sun, dark, LED, White Light Source (WLS).

The various types of information in the graph are colour-coded, as explained in the legenda below the graph. The orbit numbers are given on the left hand side of the graph. No colour indicates that at these orbit phases no OMI measurements were performed.



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CCD Temperatures

The CCD temperatures are measured close to the CCD detectors on the detector modules (DM) of the instrument. Since the detector modules are actively thermally stabilised, the CCD temperatures typically vary less than 20 mK over one day.


UV   VIS
 
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Optical Bench Temperature

The plot below shows the Optical Bench (OPB) temperature of the instrument. The shown temperature is the average of the four OPB temperature sensors as calculated by the Level 0-1B data processor. This average temperature is used for various correction steps in the Level 0-1B data processor. The temperature typically shows variations over an orbit of about 0.3 K peak-peak and about 0.1 K over one day.



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ELU Video-Channel Board Temperatures

The plot below shows the temperature of the Video Channel printed circuit boards (PCB) of the Electronics and Logic Unit (ELU). Each channel in the instrument (UV and Visible) has a corresponding video board in the ELU. The video channel boards are used for driving the CCD, collecting / sampling the data from the CCD and for post-processing of the measured data. Since the ELU is not thermally stabilised, the ELU video channel PCB temperatures will typically vary in the order of 0.4 K peak-peak over an orbit and about 0.3 K over one day.


UV   VIS
 
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ELU AUX Board Temperature

The plot below shows the temperature of the Auxiliary (AUX) printed circuit board (PCB) of the Electronics and Logic Unit (ELU). The AUX PCB is used for driving CCD and Optical Bench (OPB) heaters, driving the instrument's LED and White Light Source (WLS) calibration sources and for collecting analog telemetry. Since the ELU is not thermally stabilised, the ELU AUX PCB temperature will typically vary in the order of 0.4 K peak-peak over an orbit and about 0.3 K over one day.



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Electronics Offset

The plot below shows the instrument electronic offset for the UV and Visible channels. The electronic offset consists of two components. The first component is a CCD bias voltage that is introduced in the read-out of the CCD detectors. The second component is an artificial offset that is introducted by the Electronics and Logic Unit (ELU) just before sampling to avoid underflows in the analog-to-digital conversion.

Since the first component is subject to variable electronic gains, the total electronics offset is different for each of the electronic gains in the instrument. Therefore, the offset is plotted per gain code. Gain code 0 corresponds to a gain of approximately 10x, gain code 1 to a gain of 40x, gain code 2 to a gain of 1x and gain code 3 to a gain of 4x.

The electronics offset in this plot is derived from the data in the read-out register (ROR) of the CCD by the Level 0-1B data processor. Since the offset varies over the orbit, the measured offset is also used to correct the measurement data in the L0-1B data processor. Several measurement types do not use all four different electronic gains. As a result, plot data for some of the electronic gains may not be available.


UV   VIS
 
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Spectral Calibration

The plots below show the spectral instrument stability for this day for the radiance measurements for the UV1, UV2 and VIS channels. For each radiance measurement a spectral calibration is performed for the central row. In this fit the wavelength of each pixel in one row (viewing direction) is expanded in polynomial coefficients as a function of column number on the CCD detectors. The 0th order coefficient of this polynomial fit is shown in the plots for the central nadir viewing direction (row 14 for UV1, row 29 for UV2 and VIS). This coefficient provides a view on the spectral instrument stability during the day.





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