Using the DE 2 electric field data from 191 dawn-dusk passes, we have sought parameters that distinguish between the various polar ionospheric convection patterns for northward IMF. The passes were divided into the daytime and nighttime sectors, and categorized the convection into three convection patterns for each sector by focusing on flow having a horizontal scale of >150 km. The three daytime sector patterns are convection of reverse polarity, i.e., sunward at the highest latitudes and antisunward on both sides of the sunward flow region, irregular convection having multiple sunward and antisunward flow regions, and convection having a single antisunward flow region at the highest latitude, which is similar to the pattern for southward IMF. The IMF clock (BY/BZ) angle, the Earth's dipole tilt angle, and the IMF BX/BZ angle measured from the dipole axis are the parameters that cause the difference in the three convection patterns. In the nighttime sector three similar convection patterns are identified. The occurrence of these patterns is controlled by the IMF clock angle. Thus, the convection pattern for northward IMF is very sensitive to the direction of the IMF. The magnetospheric sources for the convection patterns are discussed. ¿ American Geophysical Union 1996