source: lmdz_wrf/trunk/tools/wmo_0509.code @ 1949

reference:http://artefacts.ceda.ac.uk/badc_datadocs/surface/code.html
short_description:High cloud type
WMOcode:0509
long_description:Clouds of genera Cirrus, Cirrocumulus and Cirrostratus.           
codeTYPE:S
@: Values
/=cirrus, cirrocumulus & cirrostratus invisible owing to darkness, fog, blowing dust or sand, or other phenomena, or more often because of the presence of a continuous layer of lower clouds
0=no cirrus, cirrocumulus or cirrostratus clouds
1=cirrus in the form of filaments, strands or hooks, not progressively invading the sky.
2=dense cirrus, in patches or entangled sheaves, which usually do not increase & sometimes seem to be the remains of the upper part of a cumulonimbus; or cirrus with sproutings in the form of small turrets; or cirrus having the appearance of cumuliform tufts
3=dense cirrus, often in the form of an anvil, being the remains of the upper part of cumulonimbus
4=cirrus in the form of hooks, filaments, or both, progressively invading the sky; they generally become denser as a whole.
5=cirrus (often in bands converging towards 1 point or 2 opposite points of the horizon) and cirrostratus, or cirrostratus alone;in either case, they are progressively invading the sky, and generally growing denser as a whole, but the continuous veil does not reach 45 degrees above the horizon.
6=cirrus (often in bands converging towards 1 point or 2 opposite points of the horizon) and cirrostratus, or cirrostratus alone;in either case, they are progressively invading the sky, and generally growing denser as a whole; the continuous veil extends more than 45 degrees above the horizon, without the sky being totally covered.
7=veil of cirrostratus covering the celestial dome
8=cirrostratus not progressively invading the sky and not completely covering the celestial dome.
9=cirrocumulus alone, or cirrocumulus accompanied by cirrus or cirrostratus, or both, but cirrocumulus is predominant