请问绘制ACONC结果时为什么报错？

Jackeylove

DataDir1 = "/data1/loucx/CMAQ1/data/cctm/"
flist1 = systemfunc("ls "+DataDir1+"ACONC.*_d03")
Sfile1 = addfiles(flist1, "r")
ListSetType (Sfile1, "join")
isop=Sfile1[:]->ISOP
wrffile=addfile("/data1/loucx/Build_WRF/DATA/WRF/wrfout_d03_2020-07-01_00:00:00","r")
lat2d=wrffile->XLAT(0,3:185,3:185)
lon2d=wrffile->XLONG(0,3:185,3:185)
nlat=dimsizes(lat2d(:,0))
nlon=dimsizes(lon2d(0,:))
Isop=dim_avg_n(isop(:,:,0,:,:),0)*1000  ;Dimensions and sizes:[24] x [183] x [183]
do k=0,1;23
  ISop=Isop(k,:,:)
  hour=k+8
wks  = gsn_open_wks ("x11", "day-average-isop"+hour+":00")
gsn_define_colormap(wks,"WhBlGrYeRe")
。。。绘图相关设置就不放了
res@cnLevelSelectionMode = "ManualLevels"
res@cnMinLevelValF =0
res@cnMaxLevelValF =3
res@cnLevelSpacingF =0.02
res@lbBoxLinesOn = False
plot=gsn_csm_contour_map(wks,ISop,res);;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;在这里报错的
shp1="/data1/loucx/Build_WRF/cnmap/cnhimap.shp"
lnres1        = True
lnres1@gsLineColor      ="black"
lnres1@gsLineThicknessF = 1         ; 2x thickness  ---2 to 3.5
shp = gsn_add_shapefile_polylines(wks,plot,shp1,lnres1)

这里是错误：check_for_y_lat_coord: Warning: Data either does not contain a valid latitude coordinate array or doesn't contain one at all.(0)        A valid latitude coordinate array should have a 'units' attribute equal to one of the following values:
(0)            'degrees_north' 'degrees-north' 'degree_north' 'degrees north' 'degrees_N' 'Degrees_north' 'degree_N' 'degreeN' 'degreesN' 'deg north'