air quality assessment & management
Reference and User Manual
AirWare   On-line Reference Manual
  Release Level 6.2
  Release Date 2013 09
  Revision Level 1.0
Last modified on:   Sunday, 8-Sep-13 19:21 CEST

Dust entrainment: sensitivity analysis

The dust entrainment (emission) scenario pages leads to a page designed for sensitivity analysis.

The page shows the first emission matrix from the current scenario together with the scenario parameters available for calibration;

The location specific parameters can here be edited (temporary changes) to explore the effect on the emission model. The parameters accessible for calibration/sensitivity analysis include:

  • Wind threshold factor for
    • coarse, medium, heavy soil fraction;
  • soil moisture threshold in percent (%);
  • a multiplier that defines the slope of the linear threshold function between the threshold (maximum soil moisture for erosion) and zero soil moisture;
  • wind multiplier that scales the average hourly wind;
  • wind exponent, defines the non-linear erosion strength as a function of wind speed above the threshold;
  • Weibull function cutoff: as an exponential function, Weibull is open; the cutoff limits the consideration of speeds above average wind (in any given cell) times the cutoff value;
  • Weibull shape parameter (see also: Dust model basics)
  • a calibration factor, that works as a simple multiplier on the model output designed to correct bias.

Under the configuration box there are

  • a domain selector;
  • and input data visualization selector;

    Under the map window, the interface offers:

    • a tape deck to select any given hour within the scenario;
    • a set of buttons that trigger:
      • model re-runs;
      • a histogram of matrix values for the current hour;
      • thumbnails over 24 hours for the individual hourly values of the emission matrix;

    Clicking on any arbitrary location on the map, a pop-up window with the input data including the Weibull function generated wind speed distribution is shown.

    Sensitivity analysis by inputs and process:

    The next set of choices defines the configuration for a model re-run.

    Concepts/values include:

    • soil fractions for
      • coarse soils
      • medium soils
      • heavy (fine) soils
    • soil moisture
    • vegetation index
    • slope, aspect
    • wind speed

    It allows to toggle on/off individual processes of the model, ignore them, or set their value to a user defined constant, so that the contribution of individual processes can be isolated.

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