begin a = addfile("atmos2.nc","r") ; Read in first time step u = a->U(0,15,:,:) ; and 15th level of v = a->V(0,15,:,:) ; atmospheric data. t = a->T(0,15,:,:) wks = gsn_open_wks("png", "stream1h") ; Open "stream1h.png" png file. gsn_define_colormap(wks,"wgne15") ; Change color map res = True ; Plot options desired. res@gsnPolarNH = True ; Specify the hemisphere res@mpMinLatF = 60 ; Minimum lat to plot res@mpFillOn = False ; Turn off map fill res@cnFillOn = True ; Turn on contour fill. res@gsnSpreadColorEnd = -3 ; except for last 2 colors. res@stArrowLengthF = 0.008 ; Default is dynamic res@stLengthCheckCount = 5 ; default is 35 res@stArrowStride = 1 ; Default is 2 res@stLineStartStride = 1 ; default is 2 res@stMinArrowSpacingF = 0.03 ; Default is 0.0 res@stStepSizeF = 0.001 ; default is dynamic res@stMinDistanceF = 0.03 ; Distance between lines res@stMinLineSpacingF = 0.005 ; Because this is ice data that has a gap in the tropics, we need to ; explicitly pass the range of the data to plot. Since we are coloring ; the contours, this range should also match the MinLatF above, since the ; range for the colors is chosen over the full data passed, and not the ; map limits. ; plot = gsn_csm_streamline_contour_map_polar(wks,u({60:90},:), \ v({60:90},:), \ t({60:90},:),res) end