CORONAL STREAMER BELT ASYMMETRIES AND SEASONAL SOLAR-WIND VARIATIONS DEDUCED FROM WIND AND ULYSSES DATA

Solar wind measurements from Wind during March 1995 are combined with those from Ulysses' fast latitude scan to construct a map of the strea mer belt. On the timescale of coronal change, the map is nearly a snap shot view of solar wind speed contours threaded by the trace of the he liospheric current sheet (HCS) in the +/-30 degrees heliolatitude rang e. The combined set of HCS crossings agrees remarkably well with the n eutral line on the corresponding classical source surface map. The neu tral line is displaced slightly southward, with latitudinal excursions ranging from -22 degrees to +17 degrees. In contrast, a line running through the locus of minimum speed, although following the general tre nd of the neutral line, is confined to lower latitudes and displaced s lightly northward, ranging from -4 degrees to +13 degrees. The separat ion between the minimum speed locus and the neutral line marking the H CS was unexpected. Possible interplanetary and solar origins are discu ssed. The deduced asymmetries as well as coronal change between Decemb er and March were responsible for solar wind variations at Earth that mimicked the previously reported seasonal variation in Wind data and w ould have masked it had the observations been taken during September e quinox.