Fig. 3. The time-mean streamfunction field (psi) and non-divergent wind field for 15 March-15 April 1996 at (a) the 150-hPa level and (b) the surface. The contour interval in (a) is 3 x106 m2 s-1 and in (b) is 2 x106 m2 s-1; negative contours are dashed. The wind vectors are linearly scaled relative to the arrows shown at the lower right. Units are m s-1. The total vector wind field is given by the sum of the nondivergent and divergent winds (see Fig. 4). The shading shows regions where outgoing longwave radiation (OLR) is 230 W m-2.