Sentences with phrase «hindcasts of»

This post will show that hindcasts of historically recent global air temperature trends also have no physical meaning.

This late - 1970s reversal in sea ice trends was not captured by the hindcasts of the recent CMIP5 climate models used for the latest IPCC reports, which suggests that current climate models are still quite poor at modelling past sea ice trends.»

In An Initial Look At The Hindcasts Of The NCAR CCSM4 Coupled Climate Model Bob Tisdale explores hindcasts vs observations:

With respect to confidence in the future based on hindcasts of the past, I would only say that even with The Perfect Model (tm) the hindcasts can only be as good as the data they are given.

The lack of any actual survey, let alone comparison of Callendar's model out of sample with hindcasts of more recent GCMs, as Steve has done, means we owe Nick our gratitude for highlighting the inadequacies of AR4 WG1 in this area.

As noted above, most earlier hindcasts of 20th century climate as well as current IPCC AR4 runs [Miller et al., 2006; Knutson et al., 2006] do not reproduce the observed trends over recent decades in the AO component of the circulation, and thus do not capture the intensification of warming trends that has been observed over Northern Europe and Asia.

Your statement that «Thus it is natural to look at the real world and see whether there is evidence that it behaves in the same way (and it appears to, since model hindcasts of past changes match observations very well)» seems to indicate that you think there will be no changes in ocean circulation or land use trends, nor any subsequent changes in cloud responses thereto or other atmospheric circulation.

[Response: First off, he is confusing models that include the carbon cycle with those that have been used in hindcasts of the 20th Century and are the basis of the detection and attribution of current climate change.

Thus it is natural to look at the real world and see whether there is evidence that it behaves in the same way (and it appears to, since model hindcasts of past changes match observations very well).

Your statement that «Thus it is natural to look at the real world and see whether there is evidence that it behaves in the same way (and it appears to, since model hindcasts of past changes match observations very well)» seems to indicate that you think there will be no changes in ocean circulation or land use trends, nor any subsequent changes in cloud responses thereto or other atmospheric circulation.

31, Alan Millar: The hindcast of the models, against the temperature record from 1900 to 2000, is indeed very impressive.

Surely the hindcast of the models should show periods of time where the climate signal is moving away, up and down, from the climate and weather signal?

I'm not really that familiar with the efforts that have been made to validate the hindcast of global climate models, BUT if they are skillful with respect to the number of degrees of freedom they use and predict, then they are skillful.

Ding, Hui, Richard J. Greatbatch, Mojib Latif, Wonsun Park, Rüdiger Gerdes, 2013: Hindcast of the 1976/77 and 1998/99 climate shifts in the pacific.

Another, more interesting, reason is that it can help invalidate models (or give them at best some limited validity) by letting them run for hindcast of the actual situation.

In fact, my model is a hindcast of the data, not a simple fitting of the data.

It is assumed that a successful hindcast of temperature changes over the 20th century increases our confidence in projections of future warming.

Where CO2 is relevant is in explaining much of growth in crop yields — I have just done a test using a quadratic function on CO2, temperature, and rainfall which produces an amazingly accurate hindcast of wheat yields in Moree NSW 1965 - 1999 using just those 3 variables.

Not exact matches

«This study takes advantage of more than 25 years of observations and detailed model hindcasts to comprehensively demonstrate that these early predictions were right.»

However, marine scientists, under the auspices of the GEOMAR Helmholtz Centre for Ocean Research Kiel, recently managed to successfully hindcast climate shifts in the Pacific.

No - one is claiming that «prediction» of the cooling counts as a major success for the models, since it was hindcast, not predicted.

Some studies have attempted to estimate the statistical relationship between temperature and global sea level seen in the period for which tide gauge records exist (the last 2 - 3 centuries) and then, using geological reconstructions of past temperature changes, extrapolate backward («hindcast») past sea - level changes.

I understand the argument that past projections are based on estimated future forcings which can change, but this amounts to the same things as tuning hindcasts and declaring matching a hindcast to observations as a validation of your model.

The fact that the hindcasts with their method perform worse than a standard IPCC scenario, the number of failed previous cooling predictions, the negative skill in the Gulf Stream and deep - water formation regions... should these not have cautioned them against going to the media to forecast a pause in global warming?

All the GCMS do a decent job of the hindcast, yet diverge in the forecast.

While I grant you that the large gap in the late 90s is of huge concern, isn't that same concern warranted with the large continuous gap from actual in the IPCC hindcast from 1965 to 1985?

Part of the uncertainty in the attribution is of course how realistic the «noise» in the models is — and that can be assessed by looking at hindcasts, paleo - climate etc..

Of course you should have posted the models hindcasts for the whole of the 20th century and then you would see the excellent short to medium term correlation between model output ant global temperature recorOf course you should have posted the models hindcasts for the whole of the 20th century and then you would see the excellent short to medium term correlation between model output ant global temperature recorof the 20th century and then you would see the excellent short to medium term correlation between model output ant global temperature record.

I should point out that in the ClimatePrediction models used, the first two of their three phases were hindcast, control phases using pre-industrial CO2 levels.

This is of course one big reason why climate science has focussed on this particular metric — because the models can do a reliable and credible (validated through hindcasting recent and paleo climates) job at it!

Decadal hindcast simulations of Arctic Ocean sea ice thickness made by a modern dynamic - thermodynamic sea ice model and forced independently by both the ERA - 40 and NCEP / NCAR reanalysis data sets are compared for the first time.

What we really want is to see some simple comparison of temperature data since 1988 with projections circa 1988 beyond 2010 and hindcasts from 1988 with current (2010) understanding beyond 2010.

Both previous hindcasts showing cooling of the model were wrong.

That is, they added in an a trend of 4 degrees / 41 years = 0.0975 deg / year, comparable to the 0.093 deg / year seen in the hindcast.

Nobody has figured out a useful model with the correct formulas, its a huge challenge, might be impossible, so hindcasting is never going to even get to a useful stage at current state of knowledge.

This can involve «perfect model» experiments (where you test to see whether you can predict the evolution of a model simulation given only what we know about the real world), or hindcasts (as used by K08), and only where there is demonstrated skill is there any point in making a prediction for the real world.

The performance of models using a climate sensitivity range of from 1.0 to 5.0 is essentially equal in hindcasting.

[Response: I don't recall having made any such statement, but regardless, the proof of the pudding is in the hindcasting.

Gavin: are you truly satisfied with the quality of the model results (especially hindcast)?

In either case, LES can also be driven by weather hindcasts, and the simulation results can be evaluated against the wealth of observations that are now available, observations both from space and from the ground.

In the end, one need not know with a high degree of accuracy the intricacies of the climate's variability to show an increased warming trend: 3 Furthermore, there are no models that exist that are able to match recent observed warming without taking rising CO2 levels into account, i.e. if radiative forcings from CO2 aren't taken into account, then models don't match hindcasting.

This hindcast uses two time - varying inputs: 10 - meter wind vectors from the atmospheric model NAVGEM (Navy Global Environmental Model, Hogan et al. 2014) run at the Fleet Numerical Meteorology and Oceanography Center (FNMOC), and analyses of ice concentrations (also produced at FNMOC) from passive microwave radiometer data (SSM / I).

It is the average long - wave cloud forcing error derived from comparing against observations, 20 years of hindcasts made by 26 CMIP5 models.

The last is essentially circular reasoning, which has demonstrated no skill to hindcast and can not predict future states beyond a limited frame of reference (i.e. scientific domain).

Adding the actual data over those 10 years to readjust the model led to a new prediction of 1.9 C which again correctly hindcasts to known results.

Climate model simulations confirm that an Ice Age can indeed be started in this way, while simple conceptual models have been used to successfully «hindcast» the onset of past glaciations based on the orbital changes.

Using new data from CryoSat - 2 validated with in situ data, they generate estimates of ice volume for the winters of 2010/11 and 2011/12 and compare these data with current estimates from the University of Washington team of sea ice hindcasts (PIOMAS) and earlier (2003 — 8) estimates from the ICESat mission.

As I have noted from time to time, these interactions are frequently used to tune hindcasts so that a better representation of the past response of the Earth's climate systems is obtained.

In a cross-validation hindcast, the model (PHENOM) is able to explain 63 % of the variance in onset date for grid cells containing at least 50 % mixed and boreal forest.

Is this a case where some of the natural oscillations are (were) not emergent in the modeling results... even in a hindcast situation?