This is an analysis still under development. The final version may be
different from what is available here.
These data were developed at CICS/ESSIC. This file briefly describes the
analysis and tells how to read the data. Questions or comments about the
data should be addressed to Tom.Smith@noaa.gov. Constructive feedback
about the analysis, its uses and limitations, and suggestions for
improvements are also welcome.
Data: historical reconstructed precipitation anomalies. The reconstruction
is computed using statistics based on GPCP data from 1979-2008. The 2.5-deg
reconstruction is monthly, 1901-2008. Historical data used include GPCC
gauge estimates, the Compo et al. reanalysis of the 20th Century (R20C)
estimates for high latitudes only, and correlated data including SST and
SLP. The reconstruction is computed in three steps as follows:
(1) A CCA analysis is computed using annual average SST and SLP anomalies
to specify annual average precipitation anomalies.
(2) A set of annual-global EOFs of GPCP anomalies is used to analyze the
annual averages. Weights for the first 9 EOFs are computed by fitting
data to the set of modes. Input data include GPCC annual gauge anomalies
wherever they are available. Over oceans the CCA annual anomalies are
used. At high latitudes, poleward of 45 degrees latitude, the Compo et al.
reanalysis of the 20th Century (R20C)anomalies are also used where gauges
are not available.
(3) A set of 20 monthly increment EOFs is used to compute anomaly increments
from the annual average. EOF weights are computed by fitting monthly
GPCC anomaly increments wherever they are available. The R20C anomaly
increments are used poleward of 45 degrees latitude where no gauges are
available.
The climatology (12 months) and the reconstruction (1296 months) are
included here. Data are written out into ascii files. The spatial
grid and the code used to write the data are included below.
Grid: 2.5-deg latitude by longitude. The 144 longitudes are centered on
1.25E (i=1) to 358.75E (i=144). The 72 latitudes are centered on 88.75S
(j=1) to 88.75N (j=72).
c 67 1 2 3 4 5 6 7 2
c* Writes out the monthly 2.5-d data, 1901-2008. The grid is centered
c* on 1.25E-358.75E by 88.75S-88.75N. Data and climatology and recons.
c
parameter(im=144,jm=72,iyr1=1901,iyr2=2008,ntm=12*(iyr2+1-iyr1))
real a2(im,jm)
character fm*11,st*3
data fm/'unformatted'/, st/'old'/
c
c* Output files:
open(51,file='data/ascii.clim25.anom.dat')
open(52,file='data/ascii.recp25.anom.dat')
c
c* Input files:
open(21,status=st,form=fm,file='data/pre25.clim.1979.2008.dat')
open(22,status=st,form=fm,file='data/rec.mon.1901.2008.dat')
c
do mon=1,12
read(21) a2
do i=1,im
write(51,81) (a2(i,j),j=1,jm)
end do
end do
close(21)
close(51)
c* Get the data.
do nt=1,ntm
read(22) a2
do i=1,im
write(52,81) (a2(i,j),j=1,jm)
end do
end do
c
stop
81 format(200f7.2)
end