To access the images for 1997 go to:

	Monthly average shortwave downward flux at the surface
	Monthly average downward photosynthetically active radiation at the surface
	Monthly average shortwave upward flux at top of atmosphere
	Monthly average surface albedo
	Monthly average snow coverage

Provided are month by month comparisons of the above parameters as obtained from:

• GCIP/GAPP V2.1 at 1/8th deg.
• GCIP/GAPP V2.0 at 1/2 deg.
• GCIP/GAPP V1.0 (Current NOAA/NESDIS operational version which started in January 1996 and continues, and is provided at:here)
• The  ISCCP DX data, using GEWEX/SRB algorithm
• The ISCCP D1 data, using GEWEX/SRB algorithm

A comparison of relevant snow products is also provided, using data from:

• GCIP/GAPP V2.1 at 1/8th deg

• GCIP/GAPP v2.0 at 1/2 deg

• The Air Force Snow Product as used in NOAA/NESDIS operational version till 1999

• NOAA/NESDIS Interactive Multi-sensor Snow and Ice Mapping System (IMS) product, as available since February 1997. 

There was a problem with the snow information used originally with the NOAA/NESDIS operational product (came from Air Force). Note the gaps during February, March and April, which affected all derived surface parameters.  This product was replaced with the IMS product in December 1999.  During snow free months, the agreement between the various parameters is good, in particular, the downwelling SW. 

Please note:

The ISCCP products, both D1 and DX use sampled data, one pixel every 30 km.  In the D1 case, the pixels are gridded to 2.5 deg at GISS, and in the DX case, the gridding of the raw DX data to 0.5 deg is done at the University of Maryland.  Both the operational GCIP/GAPP product as well as the reprocessed one, use 4 km pixels.