260 likes | 361 Views
SEECOF-10 Forecasts for DJF. Christian Viel Météo-France. Outline. Ocean analysis Ocean forecasts General Circulation forecasts Impacts (T, RR) Summary. Oceanic analysis SST Oct. 2013. Ocean analysis. From MERCATOR, reference GLORYS 1992-2009. August. September. October. time.
E N D
SEECOF-10Forecasts for DJF Christian Viel Météo-France
Outline • Ocean analysis • Ocean forecasts • General Circulation forecasts • Impacts (T, RR) • Summary
OceanicanalysisSSTOct. 2013 Ocean analysis From MERCATOR, reference GLORYS 1992-2009
August September October time Ocean analysis Equatorial Pacific Equatorial Indian Equatorial Atlantic Kelvin waves
Ocean analysis Weak SST anomalies in equatorial regions : • Atlantic : ~neutral • Pacific : weak positive anomaly in the western part, becoming neutral in the eastern part (warming) ENSO phase : neutral • Indian : west neutral, east positive IOD still negative (but now ~0) Niño3.4
Outline Ocean analysis Ocean forecasts General Circulation forecasts Impacts (T, RR) Summary
Ocean forecasts Météo France SST forecasts ECMWF
Ocean forecasts - Atlantic Northern tropical Atlantic (TNA) :
Ocean forecasts Tropics : • Pacific : weak positive anomaly around the Warm Pool; ENSO neutral • Indian : IOD ~0 • Atlantic : warmer than normal conditions in Northern sub-tropics
Previous oceanic conditions to winter weather regimes SST Composites of November (standardized anomalies) vs winter regimeoccurrences in DJF(MF model) Lower Tercile NAO- NAO+ Upper Tercile Lower Tercile Blocking Atlantic ridge UpperTercile (significance threshold 70 %)
Outline Ocean analysis Ocean forecasts General Circulation forecasts Impacts (T, RR) Summary
Tropical response and forcing - DJF Upper troposphere circulation fields (200 hPa) + - Shaded areas : velocity potential anomalies (divergent circulation anomalies) green <-> upward motion anomaly pink <-> downward motion anomaly + - Isolines : stream function anomalies (rotational circulation anomalies) blue lines <-> cyclonic (in NH) red lines <-> anticyclonic (in NH) + -
General Circulation forecasts - DJF • Relatively good consistency in tropical response to SST forcing • But no trace of teleconnection from tropics to NH mid-latitude limited predictability related to tropical forcing
Outline Ocean analysis Ocean forecasts General Circulation forecasts Impacts (T, RR) Summary
Temperature probabilities : DJF Skill (1987-2001)
Precipitation probabilities : DJF Skill (1987-2001) outer-quintile categories Skill (1987-2001)
Summary for DJF • - close to normal conditions in equatorial waveguides , despite of • warming of SST anomalies over the central part of Equatorial Pacific ENSO : neutral conditions • - limited predictability over mid-latitudes (Europe) • - some signal (for T) over the Mediterranean basin : slightly enhanced probabilities of warmer than normal conditions .
Temperature and rainfall scenarios for Europe : DJF T RR Skill (1987-2001) Not yet available Not yet available http://elaboration.seasonal.meteo.fr
Previous oceanic conditions to winter weather regimes SST Composites of November (standardized anomalies) vs winter regimeoccurrences in DJF(MF model) Lower Tercile NAO- NAO+ Upper Tercile Lower Tercile Blocking Atlantic ridge UpperTercile (significance threshold 70 %)