Environment Canada Monthly and Seasonal Forecasting Systems Hai Lin Meteorological Research Division Environment Canada

Current EC Seasonal+monthly Forecasting System Main features: Multi-model ensemble approach 4 AGCMs: GEM-CLIM, SEF, GCM2 and GCM3 10 members for each model, lagged initial conditions 2-tier system Persistent SST anomaly 4-month integration 1st month  monthly forecast Seasonal forecasting system has been replaced on December 1, 2011 To assess the contribution of moisture and convections to LFV, especially the MJO. Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability. Implication to the MJO

Next EC Seasonal and Monthly Forecasting Systems 2 separate systems Monthly system based on GEPS, expected to be in operation in early 2012 Seasonal system uses 2 coupled models (1-tier system), expected in operation December 2011 To assess the contribution of moisture and convections to LFV, especially the MJO. Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability. Implication to the MJO

Monthly System Two components 1) Real time forecasting system GEPS based Two components 1) Real time forecasting system 2) Hindcast (model climate and statistics) 4

Real time forecasting system Extend GEPS to 32 days once a week (00Z Thursday) Persistent SST anomaly added to time-evolving SST climatology GEM 4.4, 0.6x0.6L40 Perturbed physics 21 members, ensemble Kalman Filter 5

Hindcasts To generate GEPS model climatology For the same date, past 15 years 4 members each year, 60 members for each date Use 3 weeks centered at the date of the current Thursday, total of 180 members Can be done any time before the real time forecasting, when the computer is available 6

Proposed products Forecast products of weekly average T2m and PR over Canada Ensemble mean anomaly maps Probability maps for above, below and near normal 7

Evaluation Summer (July and August) Winter (January and February) Summer (July and August) Past three years (24 forecasts for each season) Correlation skill for ensemble mean 500 hPa geopotential height and T2m Categorical forecast score for T2m and PR The following maps are based on previous GEPS version GEM3.2.8 0.9x0.9L28 8

Correlation skill Winter Z500 30-day average 9

Correlation skill Winter T2m 30-day average 10

for categorical forecasts Percent Correct for categorical forecasts Winter T2m 30-day average 11

for categorical forecasts Percent Correct for categorical forecasts Winter PR 30-day average 12

for categorical forecasts 10-day average T2m Over Canada Percent Correct for categorical forecasts 13

New Seasonal System AGCM3 (T63L31) -> CanCM3 2-coupled models (CCCma models) AGCM3 (T63L31) -> CanCM3 AGCM4 (T63L35) -> CanCM4 coupled with CanOM4 (1.41°× 0.94° / L40) ocean model 1-tier system 10 members for each model 1-12 month forecast issued every month 14