The CIMSS automated cloud-drift wind system uses a loop of 3 consecutive infra-red window channel images to track the motion of clouds.
In the first step of the process, suitable targets are identified and they are assigned heights via several methods. Targets are selected based on brightness temperature gradients and an analysis of the spatial coherence of the scene. Height assignment takes advantage of the information provided by the water-vapor absorption band.
As a second step, an auto-correlation technique is employed to search subsequent images for each target's pattern. Initial vectors result when the patterns were successfully found in all 3 images.
Finally, an automated quality control algorithm removes questional vectors and adjusts the heights of others to produce the final product. A wealth of information is used in this process, including differences in the first and second vector pairs for each target, comparisons with surrounding vectors and the background provided by an operational forecast model.
The CIMSS automated water-vapor motion wind system uses a loop of 3 consecutive water-vapor absorption channel images to track motion in the mid to upper atmosphere.
In the first step of the process, suitable targets are identified based on horizontal gradients and they are assigned heights based on cold sampling of the surrounding water-vapor brightness temperatures.
As a second step, an auto-correlation technique is employed to search subsequent images for each target's pattern. Initial vectors result when the patterns were successfully found in all 3 images.
Finally, an automated quality control algorithm removes questional vectors and adjusts the heights of others to produce the final product. A wealth of information is used in this process, including differences in the first and second vector pairs for each target, comparisons with surrounding vectors and the background provided by an operational forecast model.
