Comment

Abstract

An examination of ion concentration data from the AE-E, AE-C, and DE-2 spacecraft did not detect the small-comet influx into the upper atmosphere predicted by Frank et al. (1986). It is suggested that either the proposed cometary flux is overestimated by over an order of magnitude, or that the ionospheric signature used is not presently defined properly. In a reply, Frank et al. describe a more direct method for identifying the mechanisms participating in the interaction of the cometary water cloud with the ionosphere: examining DE-1 spacecraft images of the earth's UV afterglow for a crossing of a transient decrease, or atmospheric hole, with the DE-2 spacecraft, and verifying if the ionospheric signature identified with this crossing is noted at other times in the quiet atmosphere. A possible signature of the passage of the cometary water cloud through the ionosphere is identified, and a mode for this interaction is indicated.