nc=netcdf('trmm_precipitation.nc');
time=nc{'time'}(:);
precip=permute(perm(nc{'precipitation'}(1:end,:,:)),[2 1 3]);
lon=-180:0.25:180-0.25;
lat=-50:0.25:50-0.25;
[lat,lon]=meshgrid(lat,lon);
grd.lon=lon; grd.lat=lat; grd.mask=lat*0+1;

pmean=mean(precip,3);
pmean(pmean < 0)=nan;
clf
pcolorjw(grd.lon, grd.lat, pmean); hold on
world_coast('color','k','linewidth',2);
world_coastp('color','k','linewidth',2);
colormap(getpmap(7)); 
caxis([0 .45]);colorbar 'h'
print -dpng -r300 trmm_mean_precip.png