Ben Kirtman, Director, Cooperative Institute for Marine & Atmospheric Studies, University of Miami, Rosentiel School for Marine and Atmospheric Science UCAR Congressional Briefing - April 2018

1. The Role of the Oceans in Seamless Prediction from Days to Seasons:
DISCOVERING CLUES THAT STRENGTHEN SUBSEASONAL TO SEASONAL PREDICTION
Hosted by the University Corporation for Atmospheric Research • April 24, 2018
Ben Kirtman, University of Miami - RSMAS

2. THE OCEANS & FORECASTING • 2018
Role of the Ocean in S2S Prediction
v Ocean Memory – Ocean Evolution Below the
Surface
v Air-Sea Interactions – Exchange of Heat,
Moisture and Momentum
v Both are Essential for S2S Prediction (and Even
for Weather)

3. THE OCEANS & FORECASTING • 2018
Evolution of the 1997-98 El Niño Event
Warm Sub-Surface Temperature (Deeper
Thermocline) Anomaly is the Precursor of
the Coming Warm Event – Why We Can
Predict

4. THE OCEANS & FORECASTING • 2018

5. THE OCEANS & FORECASTING • 2018

6. THE OCEANS & FORECASTING • 2018

7. THE OCEANS & FORECASTING • 2018
Mature Warm Event
The Precursor of the Coming Cold Event

8. THE OCEANS & FORECASTING • 2018

9. THE OCEANS & FORECASTING • 2018

10. THE OCEANS & FORECASTING • 2018

11. THE OCEANS & FORECASTING • 2018
Importance of Air-Sea Interactions: Heat Exchange
0
0.5
-0.5
a b cObservations
With Fine
Structure
Currents
Without Fine
Structure
Currents

12. THE OCEANS & FORECASTING • 2018
SST:
Without
Fine
Structure
Currents
SST: Observations
12
Importance of Air-Sea Interactions

13. THE OCEANS & FORECASTING • 2018
SST: Observational
Estimate
13
Importance of Air-Sea Interactions
SST: With
Fine
Structure
Currents

14. THE OCEANS & FORECASTING • 2018
Rainfall: With and Without
Fine Structure Currents
Rainfall: Observational
Estimate
14
Importance of Air-Sea Interactions

15. THE OCEANS & FORECASTING • 2018
Importance of Air-Sea Interaction: Sub-Seasonal Predictability
FIG. 4. Time–lon diagrams of equatorial (10°S–10°N) precipitation anomalies (mm dayϪ1
) averaged over the 10 events for (a) the
coupled expts, (b) the Perfect SST expts, (c) the Fcst SST expts, (d) the Persisted SSTA expts, (e) the Monthly SST expts, and (f) the
Clim SST expts.
FIG. 4. Time–lon diagrams of equatorial (10°S–10°N) precipitation anomalies (mm dayϪ1
) averaged over the 10 events for (a) the
coupled expts, (b) the Perfect SST expts, (c) the Fcst SST expts, (d) the Persisted SSTA expts, (e) the Monthly SST expts, and (f) the
Clim SST expts.
15 NOVEMBER 2008 PEGION AND KIRTMAN 5879
“Observations” “Forecast” with Air-Sea Interaction “Forecast” without Air-Sea Interactions

16. THE OCEANS & FORECASTING • 2018
25
26
26
26
28
03
25
52
27
27
29
29
0°N 0°N
120°E 140°E
20°N
120°E 140°E
2 24.5 25 25.5 26 26.5 27 27.5 28 28.5 29 29.5 30 30.5 31 31.5 40
Sea-surface temperature (°C)
20°N
120°E 140°E
120°E 140°E
c TC Neoguri, uncoupled d TC Neoguri, coupled
Best
track
Best
track
(starting d
Novembe
using the
model, (b)
using the
model, (c)
(starting d
2014) usin
uncoupled
and (d) TC
using the
model, wi
observatio
valid at 00
Novembe
00 UTC on
2014, resp
ECMWF Newsletter No. 154 – Winter 2017/18 METEOROLOG
880
900
920
940
960
980
1000
0
200
400
600
800
1000
1200
0
200
400
600
800
1000
1200
4 Nov 2013 6 Nov 8 Nov 10 Nov 12 Nov 4 Nov 2013 6 Nov 8 Nov 10 Nov 12 Nov
4 Jul 2014 6 Jul 8 Jul 10 Jul 12 Jul 4 Jul 2014 6 Jul 8 Jul 10 Jul 12 Jul
880
900
920
940
960
980
1000
a TC Haiyan, surface heat flux b TC Haiyan, central pressure
c TC Neoguri, surface heat flux d TC Neoguri, central pressure
Netsurfaceheatflux(W/m2
)
Centralmeansea-levelpressure(hPa)Centralmeansea-levelpressure(hPa)
Netsurfaceheatflux(W/m2
)
Coupled Uncoupled ‘Best track’
a TC Haiyan, uncoupled b TC Haiyan, coupled
Figure 2 The plots show HRES forecasts of (a) net (sensible + latent) surface heat flux for TC Haiyan, (b) central pressure for TC Haiyan, (c) n
surface heat flux for TC Neoguri, and (d) central pressure for TC Neoguri.‘Best track’estimates for central pressure are also shown.
Hurricane Prediction: Tropical Cyclone Neoguri
Without Air-Sea Interactions With Air-Sea Interactions
Air-Sea Heat Exchange Intensity

17. THE OCEANS & FORECASTING • 2018
Role of the Ocean in S2S Prediction
v Ocean Memory – Ocean Evolution Below the
Surface
v Air-Sea Interactions – Exchange of Heat,
Moisture and Momentum
v Both are Essential for S2S Prediction (and Even
for Weather)