Exercise #14




  • Problem #1 - All the previous dust simulations were done assuming no gravitational settling. Rerun the last dust simulation, the one with the corrected emission factors, with deposition and evaluate changes.

  • Hint - Assume a particle density of 4.0 g/cc with a diameter of 2.5 µm and a shape factor of 1.0

  • Solution - The scatter diagram and statistical results with deposition should be compared with the previous no deposition scatter and statistical results.

  • Problem #2 - Using the output from problem #1, display the concentration contours with the sampling data and county boundaries.

  • Hint - From the concentration display menu optimize the map scale by forcing the map center and radius, define a map background with county boundaries, adjust the contour intervals to clarify the graphic, and select the measured data file.

  • Solution - These options result in this graphic, although many other combinations will also produce satisfactory results.

  • Problem #3 - On 21 June 2020 (15 March 2021) around 1200 UTC, the GOES satellite captured an image of Saharan dust crossing the Atlantic Ocean (Gobi dust passing Beijing). Configure and run HYSPLIT to create the model equivalent of this image.

  • Hint - Start the simulation about a week before. The 15th of June (12th of March) would be a good starting point if using the weekly GDAS meteorological data files. Create a global concentration grid with snapshot output with sufficient vertical extent to capture the satellite view. The meteorology files are not provided and need to be downloaded. Part of the exercise is to determine the correct file.

  • Solution - There should be a good correspondence between the satellite image (image) and the model graphic (graphic).