Here we present an example of how we compare HYSPLIT trajectories with a smoke plume from a southern California wildfire. The Shekell fire was a Santa Ana wind driven wildfire (see discussion page) near the town of Moorpark and consumed over 9,700 acres by December 4th. This was a good example since the smoke plume was confined to a narrow area and was lofted over the ocean that made it easier to discriminate from the land surface. We use a visible satellite image from MODIS-Aqua at 12:25 pm Pacific time. The RGB visible image was converted to 256 level gray scale and modified to enhanced the plume over the ocean.

HYSPLIT was run in the backward mode out to 48-hours with the 40-km EDAS meteorological model. Three starting heights were chosen: 500, 1000 and 2000 meters since the plume height was not known. These are shown as the colored dots in the map below. The fire location is shown as an orange area in the map.

While the 1000 and 2000 meter trajectories deviated substantially from the plume center, the 500 meter starting height followed the plume faithfully with the trajectory coming to within 24 km of the fire. We ran another 500 m back trajectory (red squares) from a point further downwind in the plume and the model predicted the path to coincide with the fire location. The second model run at 500 m also encountered higher wind speed based on the distance between each hourly end point.