zonal flow The winds that blow in a mainly west-to-east or east-to-west direction, and particularly to the main, broad airstreams of the general or large-scale atmospheric circulation (e.g. the zonal westerly winds of middle latitudes). The zonal (or circulation) index is a conventional measurement indicating the strength of the west-to-east airflow over middle latitudes.

zonal flow The winds that blow in a mainly west-to-east or east-to-west direction, and particularly to the main, broad airstreams of the general or large-scale atmospheric circulation (e.g. the zonal westerly winds of middle latitudes). The zonal (or circulation) index is a conventional measurement indicating the strength of the west-to-east airflow over middle latitudes.