For
forecast models these errors can be overcome by continually inserting new vertical component of vorticity observational data every 6 hours, thus reducing the error that has spread upward from the erroneous boundary layer.
Not exact matches
Vlieghe told the committee: «I'm never confident of any
forecast, and I think the big thing that we risk missing here is that every time there is what we call a
forecast error — which means the outturn is different from the central projection — to think that «Well if only we'd had a better
model we wouldn't have made that
forecast error.»
Since the average
error in a 2 - day
forecast is about 90 miles, it is important to remember that the
models may still have additional shifts, and one must pay attention to the NHC cone of uncertainty.
Obviously, any
model will have a margin of
error and I will be exploring that when I publish my final
forecast on Tuesday.
This is because clouds have more - complex microphysics than the open sky, so even small
errors in the
models can cascade into large uncertainties in the
forecast.
Forecasts without systematic
errors: climate
models, such as the
model MPI - ESM LR of the Max Planck Institute for Meteorology, predict a significant increase in temperature by the end of this century, especially at the Earth's poles.
In summary the projections of the IPCC — Met office
models and all the impact studies (especially the Stern report) which derive from them are based on specifically structurally flawed and inherently useless
models.They deserve no place in any serious discussion of future climate trends and represent an enormous waste of time and money.As a basis for public policy their
forecasts are grossly in
error and therefore worse than useless.For further discussion and an estimate of the coming cooling see http://climatesense-norpag.blogspot.com
Scientists at Lawrence Livermore National Laboratory within the Atmospheric, Earth, and Energy Division, along with collaborators from the U.K. Met Office and other
modeling centers around the world, organized an international multi-
model intercomparison project, name CAUSES (Clouds Above the United States and
Errors at the Surface), to identify possible causes for the large warm surface air temperature bias seen in many weather
forecast and climate
model simulations.
For NWP
forecasts,
model error is not usually so dominant that a reforecast set is needed but for the subseasonal to seasonal range
model error is too large to be ignored.
That study concluded that any difference between
model forecasts and atmospheric climate data is probably due to
errors in the data.
Drift analysis is however necessary for climate predictions given the non-stationarity of the systematic
error along the
forecast time as the
model evolves from the initial condition space to the
model climate.
In fact, most uncertainties in the alarmist pseudo-science are internal contradictions and consequences of its shoddy practices: cherry picking data, making conclusions based on statistically insignificant observations, declaring trends based on variations that are within
error margins, relying on computer
models that contradict principles of the information theory, forging
forecasts for unreasonably long time periods, etc..
[23]
Forecasts at long leads will inevitably not be particularly sharp (have particularly high resolution), for the inevitable (albeit usually small)
errors in the initial condition will grow with increasing
forecast lead until the expected difference between two
model states is as large as the difference between two random states from the
forecast model's climatology.
no
model should be used for anything of importance before it has demonstrated what criteria it has been able to accurately
forecast, within what margin of
error over what timeframe.»
When there are only unproven
models with very large margins of
error claimed as acceptable initially after the
models are run I am skeptical of the
models abilities to accurately
forecast future conditions.
[6] David Orrell argues that the major contributor to weather
forecast error is
model error, with sensitivity to initial conditions playing a relatively small role.
Traditionally numerical weather prediction has advanced progressively by improving single, «deterministic»
forecasts with an increasing
model accuracy and decreasing initial condition
errors.
The
model's systematic bias,
forecast RMS
errors, and anomaly correlation skill are estimated based on its historical
forecasts for 1982 - 2011.
Our tests of
forecast accuracy over the period from 1851 to 1975 found that for
forecasts for 91 to 100 years ahead, the
models used by the IPCC had
errors that were more than 12 times larger than
errors from our «no - trend»
model....
When modelers show what criteria each of their
models are designed to
forecast over what timescales, and within what margin of
error, AND their
models have shown a track record of reasonably accurately matching observed conditions; then I will believe the
model that has demonstrated such performance is worthy of consideration for formation of government policy.
Just as weather
forecasts are useful for a week or so until too many
errors accumulate — it may just be possible to build a climate
model that is useful for seasonal to decadal
forecasting.
My argument is pretty simple, when you put in reasonable values for GHG, TSI forcing (aerosols too if you want), your
model forecasts a warming in the 1910 to 1945 period so low that the high end of the
forecast is below the low end of the observation
error, i.e. the
model fails.
In the case of the
models discussed here, the
errors are so large that the
models are useless for long - term
forecasting.
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.
Since becoming operational in 1995, the GFDL hurricane
model has played a major role in improving hurricane prediction, resulting in a significant reduction in track
forecast error.
The GFDL hurricane
model had the most reliable track guidance and smallest track
forecast errors through 3 days lead time and was near the top of the pack at 4 - and 5 - day lead time.
Decadal climate prediction is immature, and uncertainties in future forcings,
model responses to forcings, or initialisation shocks could easily cause large
errors in
forecasts.
The figure above compares the average track
forecast errors in the Atlantic Ocean basin during the past six hurricane seasons for the most reliable computer
models available to the National Hurricane Center during this period.
In addition to the fact that «for the predictions through the spring season in the growth phase of El Niño events, the prediction
errors induced by both initial
errors and
model errors tend to have a prominent season - dependent evolution and yield a prominent spring predictability barrier (SPB)» Duan et al., 2012, it is important to note that even after the SPB passes, our ENSO
forecasting skills are abysmal, i.e.:
Achieving that minimum goal, however, offers absolutely no assurance any generally sensible
model result offers a go - ahead with confidence to project changes of only a few degrees surface temperature over a future century when
forecast error of the
model is neither known nor knowable.
With no a priori knowledge of the
forecast models, we suggest a simple memory kernel that reduces both the timescale
error (eτ) and the scaling
error (eζ).
And the
error in the boundary layer approximation in the Canadian
model destroyed the
forecast in a matter of hours.
Using the statistical structure of temporal correlations in fluctuations for generated and
forecast power time series, we quantify two types of
forecast error: a timescale
error (eτ) that quantifies deviations between the high frequency components of the
forecast and generated time series, and a scaling
error (eζ) that quantifies the degree to which the
models fail to predict temporal correlations in the fluctuations for generated power.
Improved budgeting and
forecasting processes significantly reducing existing
modeling errors and turnaround by one week.