The surface of maximum wind as an alternative to the isobaric surface for wind climatology

Abstract

The surface of maximum wind (SMW) is introduced as an analysis frame for climate studies of fast upper tropospheric winds. As defined here, the vertical domain for the SMW includes the troposphere above 500 hPa and upper tropospheric jet streams that may protrude into the lower stratosphere. We use NCEP‐NCAR Reanalysis data for summers 1958–2004 in the vicinity of the tropical easterly jet (TEJ) to show how the spatial and temporal variability of the SMW relate to jet stream cores and the tropopause. We then compare the SMW climatology of the TEJ to an isobaric climatology of the TEJ, demonstrating that the SMW climatology reveals descent and slowing of the TEJ over the period of record, whereas the isobaric climatology provides only an overestimate of the TEJ slowing trend.