48 hour Trajectory Forecast for high VIIRS AOT
The trajectory forecast animation plots latest available daily VIIRS aerosol optical thickness AOT (in blue-red rainbow color), an animated ~48 hour air parcel trajectory forecast (in magenta-white colors), and the 3hr accumulated precipitation (in yellow).
VIIRS derived aerosol optical thichness (AOT)
VIIRS AOT used for these plot is based on the VIIRS aerosol product and is from the VIIRS sensors aboard the Suomi-NPP (S-NPP) satellite. S-NPP has an ascending orbit and a 1:30pm equatorial overpass time. The predicted and actual overpass time for a given day can be found at http://www.ssec.wisc.edu/datacenter/npp/. VIIRS AOT is plotted on a scale of 0.0 to 1.0 with AOT greater than 1.0 shown as dark red.
Forward air parcel trajectory forecast
The high VIIRS AOT regions are used to initialize starting locations for forecast trajectories. The high VIIRS AOT values are determined by calculating mean AOT values on a 40 km x 40 km grid.
The trajectories are initialized at the high AOT value locations at 50mb, 100mb, 150mb, and 200 mb above the surface level. The initialization points for the trajectories are colored to the AOT scale and the most recent day of VIIRS data remains on the plot.
The air parcel trajectories model is run using the 12Z NOAA (National Oceanic and Atmospheric Administration) /NCEP(National Center for Environmental Prediction) NAM (North American Mesoscale Model) forecast data providing a ~48hr forecast via trajectories. The pressure levels of the trajectories are plotted in mb and colored to a magenta-white scale. The most recent 12 hours of the 48 hour forward trajectories are plotted at each frame of the animation. The 850mb wind field vectors are plotted to show wind direction and speed.
The forecast trajectory animation details the potential vertical movement of high aerosol loads in the troposphere. The darker colors on trajectory pressure scale are limited to the 1000-800 mb pressure levels to help distinguish trajectories moving within the boundary layer. As the forecast trajectories progress in time, darker color trajectories indicate a flow of air towards the surface, and a potential similar movement of the aerosols, captured by the high AOT. White color trajectories indicate a upward movement in the air flow.
3-hour accumulated precipitation
The 3 hour accumulated precipitation in these plots is from the NAM forecast model (NOAA/NCEP). Areas where 3 hour accumulated precipitation is greater than 2kg/m2 are shaded yellow and can be used to determine rain out or potential for wet deposition in areas of high aerosol loading.