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Long-Range Forecasts Long-Range Forecasting products issued by NEACC

SL-AV model description

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Name of the GPCMoscow, HMC RF
When was the current long-range forecast system implemented?October 2004 / New forecast ensemble construction (described below) implemented in September 2007
Is it a Tier-2 forecast system?Yes
Atmospheric Model ResolutionSemi-Lagrangian, 1.125 lat x 1.40625 lon/L28
Source of atmospheric initial conditionsNCEP Reanalysis 2 (hindcast) / HMC data assimilation system (forecast)
Source of ocean initial conditionsReynolds-Smith OI
If Tier-2, what is the source of SST predictions?Persisted SST anomaly
Hindcast Period1979-2003
Ensemble size for the hindcasts10
How is the hindcast ensemble configured?2 per day (5 last days of the month prior to current, 12 hr. steps. For example, hindcast for JJA: from 00 hr. 26th аApr. to 12 hr. 30th аApr with 12 hour step)
Ensemble size for the forecast10
How is the forecast ensemble configured?Original and perturbed (breeding of fast growing modes) analysis fields from the date 2 days prior to current month (For example, for JJA it is 12 hr. 28thа April)
Length of forecasts4 months (seasonal/three month forecast with one month lead time)
Data formatGRIB1
What is the latest date seasonal anomalies for the next month/season become available?SSTs are taken 3 days before the forecast period.
How are the forecast anomalies constructed?Forecast minus model 25 yr. climatology from hindcasts