Jet stream activity detected as wavelike disturbances at mid-latitude ionosphericF region heights

Summary Wavelike disturbances with periods of 12 to 15 minutes detected at ionosphericF region heights by radio techniques are investigated. These disturbances in an otherwise quiet ionosphere are attributed to the presence of active wind patterns associated with the jet stream at the height of the tropopause. The active flow patterns on the tropopause weather maps indicate horizontal wind shear, the direction of flow parallel to the isolines of constant speed. Conversely, the ionospheric activity diminishes when the contours of constant wind speed swing perpendicular to the direction of flow.At times the wind patterns meander across the United States from west to east essentially unchanged. On such occasions the ionospheric activity attributed to these winds appears over a given station for 5 or 6 days, and then disappears. At other times less stable wind patterns are seen to break apart within a matter of hours and the ionospheric activity appears in correspondingly short gusts. For both cases, the ionospheric activity may be thought of as localized, in terms of global circulation, exhibiting a strong longitudinal dependence.Initial work sponsored by the Institute for Telecommunication Sciences of the Environmental Science Services Administration, Boulder, Colorado.