One column was added on the left side on Nov,30, 2016. This is for the update thru Feb 2016.

We use the homogenized NCDC CD data (operational) and K=15 for both T and P

End 2016 update

One column was added on the left side on Sept,23, 2015. This is for the update thru Feb 2015. There was no update in 2014!

We use the homogenized NCDC CD data (operational) and K=15 for both T and P

End 2015 update



Three columns were added on the left side on April 19 2013

The third from the left is a regular annual update

The second from the left is a regular annual update plus a change to homogenized data (hmgz) which NCDC is anticipated to release soon

The column on the left is a regular annual update plus a change to homogenized data (hmgz) plus a change to K=15 for temperature as advocated by Wilks(2013)

end 2013 update



2011 and 2012:

For your perusal I have placed updated (untampered) OCN on a web page:

http://www.cpc.ncep.noaa.gov/products/people/wd51hd/index.html

then click on left menu OCN-81-10.

Shown is the last 10 (T), 15(P) years averaged minus a 30 year climatology for each of 12 seasons.

Units are st.dev., i.e. 40 is 40% of the local standard deviation.

Data is 102 'super'CDs.

You will find all maps wrt current 81-2010 normals. The column on the right shows the difference in the (1981-2010) and (1971-2000),climos, in physical units, C X 100 for Temp and mm/month X 10 for Precip.



What is shown in column (1) and (2) is untampered OCN, i.e. no skill mask applied

and no damping.



The untampered OCN shown here differs from what is operationally used only in the following ways:

-) operationally we have a skill mask, i.e. where a-priori correlation is less than 0.3 no forecast is shown. The a-priori skill is determined from 1962 up the moment of issuance.

-) the amplitude of the operational OCN is reduced by a factor that relates to the a-priori skill so as to minimize RMS error.

-) We update these set of 12 display maps only once a year with final CD data, while operational OCN is up-to-date with (prelim) data thru last month.

OTHER COMMENTS:

-) Operational OCN can be found under item 32 of long lead briefing package:90-day tools

-) Related use of OCN can be consulted in trendadjusted ENSO composites at http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ENSO/total.html

-) Other Related use of OCN, on an EOF by EOF basis, can be found under item 19 of long lead briefing package: E-OCN developed by Peitao Peng

-) Long Lead briefing package, see: http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing/index.pri.html

Reference: J. Huang, H. M. van den Dool and A. G. Barnston, 1996: Long-Lead Seasonal Temperature Prediction Using Optimal Climate Normals. J. Climate., 9, 809-817.