Moisture transport axes are lines of pronounced maximum vertically integrated moisture transport. In the mid-latitudes, these lines generally correspond to atmospheric rivers, warm conveyor belts and/or feeder air streams. Structurally similar features occur also at lower latitudes in association with monsoons and topographically steered flow. At higher latitudes, moisture transport axes mark polar atmospheric rivers or warm-air intrusions.

In this update a bug in the detection algorithm is fixed that can lead to small-scale zigzag patterns in the axis lines. At the input resolution used here (0.5°), these zigzags are generally imperceptible. The updated dataset further includes files containing the distance to the closest moisture transport axis. This information is very useful for constructing time average occurrence maps.