The newest
model ensemble forecasts from the IPCC are still predicting 0.2 C per decade increase (a little less than Hansen's 1988 Scenario B.)
Not exact matches
I am inclined to stay on the southwestern side of the
model guidance, given the rather consistent
forecasts of the ECMWF and its
ensemble.
In addition to running the
models at the highest resolution possible to obtain the most accurate
forecasts, scientists also conduct something called
ensemble models, which allow them to determine the accuracy and consistency of their prediction.
Hargreaves, J.C., J.D. Annan, N.R. Edwards, and R. Marsh, 2004: An efficient climate
forecasting method using an intermediate complexity Earth System
Model and the
ensemble Kalman filter.
All
forecasted SST series were pooled and for each calendar year the
forecasted nest abundances is the
model average for the
ensemble of 200 simulations, essentially, deterministic
models within a stochastic shell [59].
p.s. To compare to Vahrenholt's
forecast, here's a comparison of earlier
model projections of global temperature for the IPCC (prediction with the CMIP3
model ensemble used in the 4th IPCC assessment report, published in 2007) with the actual changes in temperature (the four colored curves).
The use of «
ensemble forecasting» (# 15 and # 23) presupposes that the number of tweakable parameters significantly exceeds that required for fitting the
model.
If you are unfamiliar with
ensemble weather
forecast systems, see my previous posts How should we interpret an
ensemble of
models?
These small alterations are taken into account in climate
models, with the average of all
models (i.e. an
ensemble forecast, a term you should know well as a former meteorologist), scientists (like those at the IPCC) can arrive at a sensible estimate of what we are likely to experience in the future.
There is significant uncertainty in the
forecast; Zhang and Lindsay point out that the standard deviation in the
model ensemble is high in this area (Figure 2b).
Such
ensembles could provide a misleading estimate of
forecast uncertainty because they do not systematically explore
modelling uncertainty (Allen et al., 2002; Allen and Stainforth, 2002).
A new assimilation system (CERA) has been developed to simultaneously ingest atmospheric and ocean observations in the coupled Earth system
model used for ECMWF's
ensemble forecasts.
Since 2013 the
ensemble forecasts have coupled the atmosphere - wave - ocean
model from the start of the
forecast.
Since November 2014 the
ensemble forecasts have been run with 0.25 degree horizontal resolution with the sea ice
model active.
Unlike the ENSO and IOD SST
forecasts, the seasonal outlooks are based on the last three weeks of
forecasts, i.e. five separate
model runs combining to make a 165 - member
ensemble, as this was shown to give higher skill.
The NEMO
model provides the dynamic ocean
model used in the
ensemble prediction system and the seasonal
forecast system (S4).
The
ensemble and seasonal
forecast systems use a coupled atmosphere - ocean
model, which includes a simulation of the general circulation of the ocean and the associated coupled feedback processes that exist.
Careful calibration and judicious combination of
ensembles of
forecasts from different
models into a larger
ensemble can give higher skill than that from any single
model.
Many numerical weather prediction centers now use coupled ocean - atmosphere
models to produce
ensemble forecasts on the subseasonal time scale.
The current operational
ensemble forecast systems
model sea ice dynamically using the LIM2
model within NEMO ocean
model to represent the dynamic and thermodynamic evolution of sea ice within the coupled
forecast system.
Wood, A. W., A. Kumar, and D. P. Lettenmaier, 2005: A retrospective assessment of National Centers for Environmental Prediction climate
model — based
ensemble hydrologic
forecasting in the western United States.
A retrospective assessment of National Centers for Environmental Prediction climate
model — based
ensemble hydrologic
forecasting in the western United States
When
ensemble spread is small and the
forecast solutions are consistent within multiple
model runs, forecasters perceive more confidence in the
forecast in general.
Centralized archives of
ensemble model forecast data, from many international centers, are used to enable extensive data sharing and research.
AER scientists have developed techniques to process an
ensemble of over fifty tropical cyclone track
forecasts from all leading US and international hurricane
modeling centers.
[17] When the
models within a multi-model
ensemble are adjusted for their various biases, this process is known as «superensemble
forecasting».
His research activities revolve around tropical cyclone simulations and prediction
models, 3D and 4D variational analysis schemes,
ensemble forecasting techniques and coupling of mesoscale Numerical Weather Prediction (NWP)
models to Atmospheric Transport and Dispersion (ADT)
models.
In contrast, the updated
ensemble forecast from a coupled ice - ocean
model submitted by Zhang (Figure 3) still shows the September ice edge further north than in 2009.
An
ensemble of 24
forecasts were made to provide estimates of mean and
model variability.
This is consistent with both the June and July (Figure 3)
ensemble predictions from a coupled ice - ocean
model submitted by Zhang, which show considerably more ice in the East Siberian Sea compared to 2009, and it is consistent with the June statistical
forecasts submitted by Tivy, which also predict a greater ice area than in 2009 and above - normal ice concentrations along the coasts.
§ It can even be useful in a
forecast ensemble to include variations in the
model formulation if the structure of the long - time attractor manifests in limited - time integrations relative to the initial - state influence (27)...
Climate
model forecasts for the Niño3.4 Index, from the North American Multi-
Model Ensemble (NMME).
Zhang and Lindsay, 4.4, + / - 0.4,
Model These results are obtained from a numerical
ensemble seasonal
forecasting system.
Wang, 5.0 (± 0.27),
Modeling A projected September Arctic sea ice extent of 5.0 million km2 is based on a NCEP
ensemble mean CFSv2
forecast initialized from the NCEP Climate
Forecast System Reanalysis (CFSR) that assimilates observed sea ice concentrations and other atmospheric and oceanic observations.
Wu and Grumbine, 5.06 (± 0.58),
Modeling The projected Arctic minimum sea ice extent from the NCEP CFSv2
model with revised CFSv2 May - June - July ICs using 92 - member
ensemble forecast is 5.06 million km2 with a SD of 0.58 million km2.
GFDL NOAA (Msadek et al.), 4.82 (4.33 - 5.23),
Modeling Our prediction for the September - averaged Arctic sea ice extent is 4.82 million square kilometers, with an uncertainty range going between 4.33 and 5.23 million km2 Our estimate is based on the GFDL CM2.1
ensemble forecast system in which both the ocean and atmosphere are initialized on August 1 using a coupled data assimilation system.
There is significant uncertainty in the
forecast; Zhang and Lindsay point out that the standard deviation in the
model ensemble is high in this area (Figure 2, right).
The
ensemble prediction from the PIOMAS
model submitted by Zhang and Lindsay shows a mostly - open Northwest Passage (Figure 2, left) and their
forecast is for an open Northwest Passage in September.
El Niño
forecast, IRI
ensemble: leading climate
models show El Niño during summer 2014 Compared to last month's
forecast the IRI climate
model ensemble shows a somewhat faster development of a positive ENSO state and clear indications of El Niño... Continue reading →
Likewise, to properly represent internal variability, the full
model ensemble spread must be used in a comparison against the observations, as is well known from
ensemble weather
forecasting (e.g., Raftery et al., 2005).
Our projected Arctic sea ice extent from the NCEP CFSv2
model with June 2013 revised - initial condition using 30 - member
ensemble forecast is (surprisingly increased to) 4.7 million square kilometers with a standard deviation of 0.4 million square kilometers.
Where precision is an issue (e.g., in a climate
forecast), only simulation
ensembles made across systematically designed
model families allow an estimate of the level of relevant irreducible imprecision... In each of these
model —
ensemble comparison studies, there are important but difficult questions: How well selected are the
models for their plausibility?
Examples include the
forecasting of tropical cyclone tracks, heavy rainfall, strong winds, and flood prediction through coupling hydrological
models to
ensembles.
CAS = Commission for Atmospheric Sciences CMDP = Climate Metrics and Diagnostic Panel CMIP = Coupled
Model Intercomparison Project DAOS = Working Group on Data Assimilation and Observing Systems GASS = Global Atmospheric System Studies panel GEWEX = Global Energy and Water Cycle Experiment GLASS = Global Land - Atmosphere System Studies panel GOV = Global Ocean Data Assimilation Experiment (GODAE) Ocean View JWGFVR = Joint Working Group on
Forecast Verification Research MJO - TF = Madden - Julian Oscillation Task Force PDEF = Working Group on Predictability, Dynamics and
Ensemble Forecasting PPP = Polar Prediction Project QPF = Quantitative precipitation
forecast S2S = Subseasonal to Seasonal Prediction Project SPARC = Stratospheric Processes and their Role in Climate TC = Tropical cyclone WCRP = World Climate Research Programme WCRP Grand Science Challenges • Climate Extremes • Clouds, Circulation and Climate Sensitivity • Melting Ice and Global Consequences • Regional Sea - Ice Change and Coastal Impacts • Water Availability WCRP JSC = Joint Scientific Committee WGCM = Working Group on Coupled
Modelling WGSIP = Working Group on Subseasonal to Interdecadal Prediction WWRP = World Weather Research Programme YOPP = Year of Polar Prediction
Our prediction is based on the GFDL - FLOR
ensemble forecast system, which is a fully - coupled atmosphere - land - ocean - sea ice
model initialized using a coupled data assimilation system.
Wang, 6.31 (5.84 - 6.78),
Modeling The projected Arctic sea ice extent from CPC based on NCEP
ensemble mean CFSv2
forecast is 6.31 × 106 km2 with an estimated error of ± 0.47 × 106 km2.
Other factors that will affect the
forecast skill of a realistically initialized CESM include
ensemble size, internal
model biases, initialization method, and the low resolution adopted here.
Applying the framework of Delworth and Manabe (1988) to the more complex CESM system, we compare simple red noise null hypothesis
models for soil moisture variations at various depth levels with an
ensemble of perfect
model forecasts conducted with the CESM.
They also recommend usage of different independently devised
models to produce
ensemble forecasts, for better comparison and quicker
model improvements.
The correct action to take in this case is to REMOVE the
model from the
ensemble of GCMs used to study or
forecast the climate until it is fixed (which may be «forever».