Changes between Version 103 and Version 104 of ticket/370/TicketDetails


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Timestamp:
Feb 4, 2020 12:29:55 PM (21 months ago)
Author:
Jin Lee
Comment:

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  • ticket/370/TicketDetails

    v103 v104  
    130130
    131131My thoughts on the benefit of higher UM and PFM resolutions,
    132    * Higher UM resolution will be able to resolve smaller scales. CX background is then at a higher resolution (more spatial variability). This will lead to more accurate CX columns. Better forward modeling. So the background and observation would be closer. Analysis would fit observations more closely. But on the other hand, CX background will have greater spatial variability and this may move model away from observations, which will resulting in analysis being away from observations. Which effect dominates?
     132   * Higher UM resolution will be able to resolve smaller scales. CX background is then at a higher resolution (more spatial variability). This will lead to more accurate CX columns and hence forward modeling. So the background and observation would be closer. Analysis would fit observations more closely. But on the other hand, CX background will have greater spatial variability and this may move model away from observations, which will resulting in analysis being away from observations. Which effect dominates?
    133133   * Improved PFM resolution will lead to improved evolution of increments. With everything being equal this will lead to improved forward model , which leads to .... Result is a better fit to observation.
    134134
    135 The suites have fixed thinning distance regardless of UM and PFM resolutions used. There are 3 rounds of thinning: after checking of preprocess flags (!ThinCall 1), before 1DVar (!ThinCall 2) and stationlist thinning. At the last stage the thinning distance is usually quite large: ~100 km. This is bigger than satellite footprint size and PFM resolution (for N320). My thoughts,
     135In short higher UM and PFM resolutions will enable the analysis to better use observations. Q. Is this born out by experiment?
     136
     137My thoughts on thinning of satellite observations,
     138   * The suites have fixed thinning distance regardless of UM and PFM resolutions used. There are 3 rounds of thinning: after checking of preprocess flags (!ThinCall 1), before 1DVar (!ThinCall 2) and stationlist thinning. At the last stage the thinning distance is usually quite large: ~100 km. This is bigger than satellite footprint size and PFM resolution (for N320).
    136139   * A new obtype is thinned independently of other obtypes so the new obtype will be used, albeit thinned
    137140