Rotational characteristics of coronal holes

From May 1972 to October 1973, daily measures were obtained of EUV coronal hole areas appearing at the central meridian. Autocorrelation of these coronal hole area time series provide synodic rotation periods which indicate an almost rigid rotation by such features for lag length as short as one rotation. The rotation periods of coronal holes at high latitudes best compare with inferred interplanetary field rotation periods. (Auth.)