Seamless prediction systems prove potential for skillful Arctic sea-ice forecasts far beyond weather time scales
IUP Seminar Bremen, May 4th, 2018 Lorenzo Zampieri Alfred Wegener Institute
Seamless prediction systems prove potential for skillful Arctic - - PowerPoint PPT Presentation
Seamless prediction systems prove potential for skillful Arctic sea-ice forecasts far beyond weather time scales IUP Seminar Bremen, May 4 th , 2018 Lorenzo Zampieri Alfred Wegener Institute Outlook Predictability and ensemble forecasting
Seamless prediction systems prove potential for skillful Arctic sea-ice forecasts far beyond weather time scales
IUP Seminar Bremen, May 4th, 2018 Lorenzo Zampieri Alfred Wegener Institute
Outlook Predictability and ensemble forecasting Research Motivation The S2S Prediction Project Verification metrics Predictive skills Dynamical models vs Climatology
A simple set of equations… !" !# = −&" + &( !" !# = −") + *" − ( !) !# = "( − +)
Lo Lorenz, E. N. (1963) De Dete termi rministic no nonp nper eriodic fl flow.
…with an interesting solution
J.
Sling ngo an and T.
Ensemble Forecasting
J.
Sling ngo an and T.
Im Images from the YOPP PP Pr Promotional Video
Im Images from the YOPP PP Pr Promotional Video
The S2S timescale
Im Image from the S2S Pr Promotional Video
The S2S Database
forecast centers
sea-ice concentration
UK Met Office ECMWF KMA CMA Météo France NCEP
The sea-ice edge position
Sea-ice edge Observation Sea-ice edge Model
Integrated Ice Edge Error IIEE = " + $
The Spatial Probability Score Ensemble sea-ice forecasts Probabilistic verification metric required
Spatial Probability Score !"! = $
%
('( − '*), -% Spatial Probability Skill Score !"!! = . − !"! !"!/012
Ensemble Forecasting
J.
Sling ngo an and T.
Ensemble S2S sea-ice forecasts
UKMO ECMWF KMA CMA MF NCEP
Verification against satellite observations through the SPS Forecast SPS compared with the climatological CSPS Assessment of the forecast predictive skills Evaluation of the forecast errors and biases
Skills of S2S forecast systems
Lead Time [Days] 10 20 30 40 50 60 0.25 0.75 1 SPS [106km2] 0.5
ECMWF UKMO KMA NCEP CMA (out of range) MF ECMWF Pres. Climatology
Lead Time [Days] 10 20 30 40 50 60
0.5 1 SPSS
Results averaged over 12 years
Forecasting the 2007 minimum
NCEP Day 30 - 2007.09.15 MF Day 30 - 2007.09.13 CMA Day 30 - 2007.09.15 ECMWF Pres. Day 30 - 2007.09.16 ECMWF Day 30 - 2007.09.15 KMA Day 30 - 2007.09.15 UKMO Day 30 - 2007.09.15
Sea Ice Probability
15% sic OSI-SAF Climatology 2007.09.16
The CSPS seasonal cycle
Jan 01 Apr 01 Jul 01 Oct 01 Jan 01 0.25 0.5 0.75 1 CSPS [106km2]
Jan 01 Apr 01 Jul 01 Oct 01 Jan 01 20 40 60 80 100 100 80 60 40 20 ME [%] AEE [%]
Jan 01 Apr 01 Jul 01 Oct 01 Jan 01 20 40 60 80 100 100 80 60 40 20 U [%] O [%]
Skills of the climatological forecasts based on the previous 10 years of observations 15/09/2007 forecast is based on: 15/09/1996, 15/09/1997, … , 15/09/2006
ECMWF & UKMO
−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 −2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 −2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20Initial
−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20SPSS AEE and ME O and U ECMWF UKMO
CMA & Météo France
ECMWF Pres.
100SPSS AEE and ME O and U CMA MF
Initial
−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20Improvements in ECMWF system
−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 −2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 −2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20Initial
−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20 Jan 01 Mar 01 May 01 Jul 01 Sep 01 Nov 01 Jan 01 20 40 60 80 100 100 80 60 40 20SPSS AEE and ME O and U ECMWF
ECMWF Pres.
Target Time
N E W ! O L D !
Improvements in ECMWF system
Conclusions
forecast systems
relevant model biases affect the forecasts