Sentences with phrase «does model sensitivity»

[27] Sokolov, A P (2005): Does model sensitivity to changes in CO2 provide a measure of sensitivity to other forcings?

Not exact matches

Through responding with sensitivity and positive discipline, where we've modeled to our kids how to resolve conflict, we don't have to do nearly as much policing as some parents as our kids are just behaving the way we've taught them.

The reason, it seems, has to do with Mexico City's unusual sensitivity to earthquakes and the efforts it has made to compensate, which could serve as a model for preparedness in the developing world.

A 2000 - year transient climate simulation with the Community Climate System Model shows the same temperature sensitivity to changes in insolation as does our proxy reconstruction, supporting the inference that this long - term trend was caused by the steady orbitally driven reduction in summer insolation.

Isaac Held, a National Oceanic and Atmospheric Administration climate scientist, said he agreed with the researchers about the «the importance of getting the ice - liquid ratio in mixed - phase clouds right,» but he doesn't agree that global climate models generally underestimate climate sensitivity.

Hence the NH / SH ratio does not make a good quantitative test of modeled sensitivity in my opinion.

Hi, I don't mean to turn this into yet another sceptic thread, but I've read in another site that there apparently are doubts about current models assuming that climate sensitivity is constant.

The climate sensitivity is an output of complex models (it is not decided ahead of time) and it doesn't help as much with the details of the response (i.e. regional patterns or changes in variance), but it's still quite useful for many broad brush responses.

does fit the temperature trend to an acceptable level, if one should reduce the sensitivity for CO2 / aerosols far enough... Current models also can reproduce other transitions (LGM - Holocene) with a reasonable accuracy, but this is mainly in periods where there is a huge overlap between temperature (as initiator) and CO2 / CH4 levels (as feedback).

For large animals, like hippo and buffalo, their sensitivity to change — especially with predictions of more frequent and prolonged drought — means they don't do well in any of the future scenarios modelled by the park's scientific teams.

Therefore, I wouldn't attach much credence, if any, to a modelling study that didn't explore the range of possibilities arising from such uncertainty in parameter values, and particularly in the value of something as crucial as the climate sensitivity parameter, as in this example.

This paper suggests that models with sensitivity around 4ºC did the best, though they didn't give a formal estimation of the range of uncertainty.

In addition, the authors do not account for uncertainties in the simple model whose sensitivity is fitted.

Given that clouds are known to be the primary source of uncertainty in climate sensitivity, how much confidence can you place in a study based on a model that doesn't even attempt to simulate clouds?

A combination of circumstances makes model - based sensitivity estimates of distant times and different climates hard to do, but at least we are getting a good education about it.

So, the key thing in evaluating climate sensitivity is to use the LGM as a test of how well the models are doing clouds, using the LGM, and then see what happens in the same model when you project to the future.

This formulation highlights a couple of important issues — that the observational data doesn't need to be direct (and the more complex the model, the wider range of possible constraints there are) and that the relationship between the observations and the sensitivity needs to be demonstrated (rather than simply assumed).

In the response by raypierre - I agree about the problems with simple energy balance model and its lack of spatial representation, but it's tough to fault the authors for the lack of cloud detail, since the science is not up to the task of solving that problem (and doing so would be outside the scope of the paper; very few paleoclimate papers that tackle the sensitivity issue do much with clouds).

To explore the possibility that frailty (which is associated with both low cholesterol and death28 29) could confound these results, we did a sensitivity analysis adjusting our Cox models (table 4 ⇑) for two known markers of frailty (changes in body weight and changes in systolic blood pressure).28 29 30 These adjustments did not materially change the effect estimates, which remained significant in both groups.

These models all suggest potentially serious limitations for this kind of study: UVic does not simulate the atmospheric feedbacks that determine climate sensitivity in more realistic models, but rather fixes the atmospheric part of the climate sensitivity as a prescribed model parameter (surface albedo, however, is internally computed).

By scaling spatio - temporal patterns of response up or down, this technique takes account of gross model errors in climate sensitivity and net aerosol forcing but does not fully account for modelling uncertainty in the patterns of temperature response to uncertain forcings.

Research performed on human males with androgen insensitivity syndrome compared to the classical sexual development models which were created from research on rats, indicates that the rat model does not account for the sensitivity of the hypothalamal - hypophyseal - gonadal axis with fluctuations in hormonal levels, namely androgens and estrogens.7

Briggs and Domingue found strong evidence of these illogical results when using the L.A. Times model, especially for reading outcomes: «Because our sensitivity test did show this sort of backwards prediction, we can conclude that estimates of teacher effectiveness in LAUSD are a biased proxy for teacher quality.»

The most unfortunate thing is that the somewhat clumsy press - release obscured the true message, which is that physics alone does not rule out high sensitivities, even if you impose the requirement that the model match the present annual mean climate.

This is hypothesized to result from fresh water input into the Northern Hemisphere (although it is worth noting that the transient simulations of this sort fix the magnitude of the freshwater perturbation, so this doesn't necessarily mean that the model has the correct sensitivity to freshwater input).

You may feel you didn't criticize the Stainforth et al paper, but you did misunderstand it in one crucial respect, in that you said explicitly that our «the most important result... is that by far most of the models had climate sensitivities between 2ºC and 4ºC, giving additional support to the widely accepted range.»

Winton, M. (2011), Do Climate Models Underestimate the Sensitivity of Northern Hemisphere Sea Ice Cover?

The standard climate sensitivity and climate model do not in - clude effects of «slow» climate feedbacks such as change in ice sheet size.

Re # 7 — If you go through the cp.net paper in the link above, you would find that the value (not «more valuable») in the thousands of runs is in exploring the parameter space, and finding out that high - sensitivity models aren't just a «one - off» that you can happily throw out when you do an ensemble of 5 to 50 or whatever.

Model results don't depend critically on resolution — the climate sensitivity of the models is not a function of this in any obvious way, and the patterns of warming seen in coarse resolution models from the 1980s are very similar to those from AR4 or the upcoming AR5 (~ 50 times more horizontal grid points).

Even the admirable Revkin doesn't get it quite right: On horizontal surfaces, observations and modeling show a role for melting in both the baseline ablation and the sensitivity of ablation to precipitation and temperature; melting is the dominant ablation mechanism on vertical ice cliffs; and though Kaser et al find «no evidence» about rising temperatures, it is only because the in situ studies don't cover a long enough period to detect trends.

My experience is that most groups do not «precisely» tune their models to 20th Century trends or climate sensitivity, but given this example and the Hourdin results, more clarity on exactly what is done (whether explicitly or implicitly) is needed.

However, a model that yields a sensitivity less than 2 is very unlikely to yield insight into the climate because it simply doesn't look like Earth.

If the model says that an 11C sensitivity may be possible, he does not want the public to be told.

This kind of forecast doesn't depend too much on the models at all — it is mainly related to the climate sensitivity which can be constrained independently of the models (i.e. via paleo - climate data), moderated by the thermal inertia of the oceans and assuming the (very likely) continuation of CO2 emissions at present or accelerated rates.

Of course, these evaluations rely on the models being able to mimic the sensitivity of the real climate system and assume that paleoclimatic reconstructions of the temperature do adequately describe the past climate variations.

[Response: I looked into what you could change in the model that would have done better (there is no such thing as a RIGHT / WRONG distinction — only gradations of skill), and I estimated that a model with a sensitivity of ~ 3 deg C / 2xCO2 give the observed forcings would have had higher skill.

The model almost certainly does not have perfect natural variability or sensitivity to anthropogenic forcing.

This formulation highlights a couple of important issues — that the observational data doesn't need to be direct (and the more complex the model, the wider range of possible constraints there are) and that the relationship between the observations and the sensitivity needs to be demonstrated (rather than simply assumed).

They do the calculations in a somewhat different way, but it appears to be a sound analysis, and I particularly like the thorough testing of the sensitivity to the various parameters used in the statistical model.

So, small (a degree or so) variations in the global mean don't impact the global sensitivity in either toy models, single GCMs or the multi-model ensemble.

I haven't seen anything that very strongly supports the IRIS idea, but I do concur with one idea buried in the paper: that the parameterization of fractional cloud cover in GCM's is not based on very clear physical principles, and could operate in many different ways — some of which, I think, could make climate sensitivity considerably greater than the midrange model of the current crop.

The fact that even model versions with very high climate sensitivities pass their test does not show that the real world could have such high climate sensitivity; it merely shows that the test they use is not very selective.

This paper suggests that models with sensitivity around 4ºC did the best, though they didn't give a formal estimation of the range of uncertainty.

If I knew the transient sensitivity of this model (which I don't), I could have scaled against that.

Additionally, there is little evidence that the rate of conversion of cloud water to rain actually changes with temperature, although Mauritsen and Stevens show that incorporating the iris into the model does improve the model's simulations of some aspects of the climate system (even though it doesn't change climate sensitivity much).

So even though El Nià ± o may serve as an analogue for some aspects of the influence of the weakening Walker circulation on climate, it does not serve as a dynamical analogue nor is the sensitivity to model details the same.

CO2's effectiveness per ppm does decrease as you go to higher concentrations (which is why we discuss the sensitivity to 2xCO2 rather than per 100 ppm for instance), but this is very well understood and has been incorporated into the models from the beginning.

The climate sensitivity is an output of complex models (it is not decided ahead of time) and it doesn't help as much with the details of the response (i.e. regional patterns or changes in variance), but it's still quite useful for many broad brush responses.

does fit the temperature trend to an acceptable level, if one should reduce the sensitivity for CO2 / aerosols far enough... Current models also can reproduce other transitions (LGM - Holocene) with a reasonable accuracy, but this is mainly in periods where there is a huge overlap between temperature (as initiator) and CO2 / CH4 levels (as feedback).