Description: Root Mean Square Error (RMSE) is a measure of the difference between model forecasts and observations. Mean Error (i.e., Bias) is a measure of the average difference between model forecasts and observations. The closer that a point is to a value of 0.0, the more accurate the 12Z forecasts of particulate matter of fine particles with diameters that are ≤2.5 micrometers (PM2.5) were over the western contiguous U.S. during the last 31 days at that particular forecast hour. Forecast hours are shown along the x-axis. The black line represents the raw AQM forecast while the red line represents the bias-corrected AQM forecast. The solid line is the RMSE and the dashed line is the Mean Error.



Description: Similar to the first image, except for the central contiguous U.S. during the last 31 days.



Description: Similar to the first image, except for the eastern contiguous U.S. during the last 31 days.



Description: Similar to the first image, except for the southern contiguous U.S. during the last 31 days.