Products/Data - CONUS Cloud Products
CONUS cloud products are available hourly from CIMSS. These products are derived using real time data from the GOES 10 (western US + Pacific Ocean) and GOES 12 (eastern US + Atlantic Ocean) imager and sounder instruments. Cloud product datasets derived using GOES imager data have a 4 km spatial resolution, and those derived using sounder data have a 10 km spatial resolution. The following are included in each CONUS cloud datafile:
- Cloud amount (%)
- Cloud-top pressure (mb)
- Cloud-top temperature (K)
All cloud products are derived using a multi-spectral approach. Cloud/no cloud determination is made based on a series of multi-spectral threshold tests. Once this is determined, total cloud amount is calculated by dividing the number of cloudy pixels by the total number of pixels. Cloud top pressure is determined using the CO2 slicing technique for the GOES sounder products, as well as for the GOES-12 imager. Cloud top pressure is not presently derived from GOES-10 imager data, because the necessary bands are not present (on GOES-12, the 12.0 µm channel was replaced by a 13.3 µm channel, allowing for the 13.3/11 CO2 ratio technique to be used.) Cloud top temperature is subsequently derived by comparing cloud top pressure to a first guess atmospheric profile. In the case of clear fields of view, the reported temperature is the calculated skin temperature based on GOES radiances.
Separate products are available for the GOES sounder and imager instruments. The two instruments have the following technical specifications:
1.GOES Imager Characteristics
| Channel Number | 1 (visible) | 2(NIR) | 3 (Water Vapor) | 4 (IR 1) | 5 (IR 2) | 6 (IR 3) |
|---|---|---|---|---|---|---|
| Wavelength Range (µm) |
0.55 – 0.75 | 3.80 – 4.0 | 6.50 – 7.0 | 10.2 – 11.2 | 11.5 – 12.5 | 12.9 – 13.7 |
| GOES-12 FOV (nadir) |
1 km | 4 km | 4 km | 4 km | n/a | 8 km |
| GOES-10 FOV (nadir) |
1 km | 4 km | 8 km | 4 km | 4 km | n/a |
2.GOES Sounder Characteristics
| Channel Number | Longwave IR | Mediumwave IR | NIR | Visible |
|---|---|---|---|---|
| Number of bands | 7 | 5 | 6 | 1 |
| Wavelength Range (µm) |
12.02 – 14.71 | 6.51 - 11.03 | 3.74 – 4.57 | 0.70 only |
FTP site for data: ftp://ftp.ssec.wisc.edu/asap/products/conus_clouds/