NCEP Stage II Multi-Sensor Precipitation Analysis

Old vs. New Comparison

On 10 Jul 2001, the NCEP Stage II (aka Stage IV) hourly precipitation analysis became operational.  The old Stage II analysis continued on to provide users with a transition period, and was discontinued on 31 Jul 2002.   The new Stage II replaced the old in the long-term archive on 1 Jan 2002.

Major differences between the old and the new Stage II analyses are listed below:

1. Data Availability:

 Old Analysis New Analysis Produced During 1 May 1996 – 31 Jul 2002 10 Jul 2001- 1-week Archive N/A /pub/gcp/precip/stage2/yyyymmdd 6-month Archive N/A /pub/gcp/precip/mpe.arch/stage2/ Long-term Archive May 1996 – Dec 2001 Jan 2002 - http://www.joss.ucar.edu/cgi-bin//codiac/dss?21.006

1. Grids for the 4km analyses:

 Old Analysis New Analysis Projection Polar stereographic Dimension 1160 x 880 1121 x 881 Lower left point (1,1) = (22.7736N,120.376W) (1,1) = (23,117N,119.023W) Upper left point (1,880) = (52.613N,136.394W) (1,881) = ( 53.509,134.039W) Lower right point (1160,1) = (19.810N,80.802W) (1121,1) = ( 19.805, 80.750W) Upper right point (1160,880) = (45.619N,60.079W) (1121,881) = ( 45.619, 59.959W) Pole Point (I,J) = (441,1601) (I,J)=(400.5,1600.5) y-axis Parallel to 105W Resolution 4.7625 km at 60N

1. Grids for the 15km analyses (simply a 3x3 mapping from the 4km grid).

 Old Analysis New Analysis Dimension 386 x 293 373 x 293 Lower left point (1,1) = (22.813N,120.351W) (1,1) = (23,156N,118.996W) Upper left point (1,293) = (52.564N,136.264W) (1,293) = ( 53.421,133.876W) Lower right point (386,1) = (19.876N,80.877W) (373,1) = ( 19.870, 80.825W) Upper right point (386,293) = (45.646N,60.277W) (373,293) = ( 45.618, 60.197W) Pole Point (I,J) = (147.323,534) (I,J)=(133.81,533.83) y-axis Parallel to 105W Resolution 14.2875 km at 60N

1. Naming convention (date stamp in italics denotes the ending time of the accumulation period).  15km files are not saved in the long-term archive.