Distribution with colatitude θ of the computed solar wind speed v at 1 AU and the coronal expansion factor f_c of the flow tube intersecting the Earth orbit at θ. The model result incorporating (neglecting) the field line shape, called Case C (S), is given by the solid (dashed) line. They are obtained by varying the flow tube alone but keeping all other parameters unchanged. Cases C and S both take the radial variation of the magnetic field strength into account, and differ from each other only in that Case C considers the field line shape whereas Case S neglects it. The blue continuous curve gives the daily averaged speed measurements by Ulysses during the first half of its latitude scan from Sep. 12, 1994 to Mar. 4, 1995. As for f_c, it is taken to have the value of f at a heliocentric distance of 1.7 R_⊙.