What is the direction definition of vertical wind speed for a CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH? For example, does a negative value mean upward or downward?

The CSAT3A, CSAT3AH, CSAT3B, and CSAT3BH use a right-handed Cartesian coordinate system. If someone is standing in front of the sonic anemometer looking from the transducer array to the block, that person is looking down the positive x-axis. Based on this orientation, the positive y-axis is to the left, and the positive z-axis is vertical.