Recent and planed NCEP climate modeling activities Hua-Lu Pan EMC/NCEP

EMC is considering the following upgrades to the operational CFS 1.Reducing the 8-lag in the initial condition to a 1-day lag. 2.Introducing 2 new members at higher resolution (T126L64) out to 60 days only. These 2 members would initiate from the same initial condition as the operational two T62L64 members. Both these upgrades would aim to improve upon the week 3-6 / monthly forecast leads.

NAO – PNA SKILL CFS Operational T62L64 Forecasts MAR2005 – FEB IC at Day 1-7 of each of the 24 months Forecast lead times 1-45 days

Negative skewness in observations

Daily skill scores Averaged over 14 forecasts per month after forecast lead time of 8 days

Studies to prepare for a monthly forecast suite (week3 to week6) Four-times daily T126 version of the CFS, Runs are made to 60 days in length, Daily runs of the hindcasts, The test period is The period of the runs are : 7 May – 15 July and 7 Nov – 15 Jan.

Daily

Month-1 Correlation Scores NAO33.0 % PNA21.3 %

Impact of Coupling

Pattern correlation for Persistence Summer Winter

Pattern Correlation for initialization dates from May to June 2002 June 6 th -9 th The Predictability Barrier 6-9 June: MJO maximum activity crosses “the Maritime Continent”

March 2005 – Feb 2007 Week 1 Week 3 Week 4 Monthly Week 2 Longitude

March 2005 – Feb 2007 Week 1 Week 2 Week 3 Week 4 Monthly 0.55 = mean ac of daily forecasts in week 1 range Initial Month

Suru Saha and Hua-Lu Pan, EMC/NCEP With Input from Stephen Lord, Mark Iredell, Shrinivas Moorthi, David Behringer, Ken Mitchell, Bob Kistler, Huug van den Dool and others Design of the 30-year NCEP CFSRR T382L64 Global Reanalysis and T126L64 Seasonal Reforecast Project ( )

4 Simultaneous Streams Jan 1978 – Sep years Oct 1985 – Sep years Oct 1992 – Sep years Oct 1999 – Sep years 2-year overlap for ocean and land spin ups Total of 36 years of Reanalysis NCEP CFSRRSLIDE - 1

Atmospheric T382L64 (GSI) Analysis at 0,6,12 and 18Z Ocean and Sea Ice Analysis (GODAS) at 0,6,12 and 18Z From each of the 4 cycles, a 9-hour coupled guess forecast (GFS at T382L64) is made with hourly coupling to the ocean (MOM4 at 1/4 o equatorial, 1/2 o global) Land (GLDAS) Analysis with Noah at 0Z Coupled 2-day forecast from initial conditions from every cycle, or coupled 5-day forecast from every 0Z cycle (starting every year from 1 Jan 00Z) is made with the T382L64 GFS with hourly coupling to the ocean (MOM4 at 1/4 o equatorial, 1/2 o global) for sanity check. ONE DAY OF REANALYSIS NCEP CFSRRSLIDE - 3

1 year T126L64 coupled forecast ( GFS + MOM4 + Noah ) CFS REFORECASTS 1 Jan 0Z2 Jan 6Z3 Jan 12Z4 Jan 18Z6 Jan 0Z Coupled one-year forecast from initial conditions 30 hours apart is made for 2 initial months (April and October) with the T126L64 GFS with hourly coupling to the ocean (MOM4 at 1/4 o equatorial, 1/2 o global). Total number of forecasts = 28 x 2 x 30 = 1680 For each cycle, there will be approximately 7 members per month, with a total of 210 members over a 30-year period. This ensures stable calibration for forecasts originating from each cycle, for a given initial month NCEP CFSRRSLIDE - 4

Example : Skill Estimation for the Initial Month of February In real time operational prediction, the latest members would be used. For instance, the earliest forecasts release for CPC would be the 15 th of the month. Therefore, all members up to the 9 th of the month would be used since operations would run in near real time. For skill estimation, the following 16 members would be used for February starts (going backwards) : Feb 8 18z, Feb 7 12z, Feb 6 06z, Feb 5 00z, Feb 3 18z ……Jan 21 00z This includes 4 days of 4 different cycles (Jan 21 0z – Feb 8 18z), smoothly separated by 30 hours. This is in contrast to the present system, where we use 15 members from Jan 9 00z – Feb 3 00z, in 5- day chunks. NCEP CFSRRSLIDE - 5 CFS REFORECASTS