Sentences with phrase «with emergent constraints»

As with all emergent constraints, this means it can be difficult to use natural variations to constrain the climate response of clouds.

Not exact matches

Personally, I'm doubtful that emergent constraint approaches generally tell one much about the relationship to the real world of aspects of model behaviour other than those which are closely related to the comparison with observations.

Caldwell regarded a proposed emergent constraint as not credible if it lacks an identifiable physical mechanism; is not robust to change of model ensemble; or if its correlation with ECS is not due to its proposed physical mechanism.

Keeping only models with enough structural differences often reduces the reliability of identified emergent constraints.

Given that there is no strong a priori knowledge about any linear relationship — this is why it is an «emergent» constraint — it seems inadvisable to make one's statistical inference strongly dependent on models that are not consistent with the data at hand.

One way to illustrate this is to look at the data Florent Brient and I analyzed in another emergent - constraint paper, which used fluctuations in TOA energy fluxes in marine tropical low - cloud (TLC) regions and their correlation with ECS (Brient and Schneider 2016, see blog post).

Regarding the emergent constraint used in Brient & Schneider (2016), it is noteworthy that if the models are weighted by reference to their consistency with the data, regression of ECS on TLC reflection variability explains almost none of the intermodel ECS variation — the R - squared is negligible.

Is there anything to object to in this work, leaving aside issues with the whole emergent constraint approach?

You could go further and talk about tuning to «emergent constraints» for climate sensitivity, observational metrics that are correlated with climate sensitivity when looking across model ensembles.

Personally, I'm doubtful that emergent constraint approaches generally tell one much about the relationship to the real world of aspects of model behaviour other than those which are closely related to the comparison with observations.

Another question is — if an «emergent constraint» emerges from simulation that correlates with temperature, could / should not this constraint / correlation be tested against high quality historic instrumental data?

It seems doubtful that emergent constraints will be able to provide a useful, reliable constraint on real - world ECS unless and until GCMs are demonstrably able to simulate the climate system — ocean as well as atmosphere — with much greater fidelity, including as to SST warming patterns under multidecadal greenhouse gas driven warming.

It is interesting that Tapio Schneider, the joint author of the Brient Alb paper, with considerable mathematical / statistical abilities, advocates caution regarding emergent constraint studies.

[1] An emergent constraint on ECS is a quantitative measure of an aspect of GCMs» behaviour (a metric) that is well correlated with ECS values in an ensemble of GCMs and can be compared with observations, enabling the derivation of a narrower (constrained) range of GCM ECS values that correspond to GCMs whose metrics are statistically - consistent with the observations.

The Zhai methods have more shortcomings than those used by Brient & Schneider for their very similar emergent constraint, and the radical difference for four CMIP5 models in the two studies» assessment of consistency with the observational constraint from seasonal variations is a major concern.

Caldwell regarded a proposed emergent constraint as not credible if it lacks an identifiable physical mechanism; is not robust to change of model ensemble; or if its correlation with ECS is not due to its proposed physical mechanism.

The Brient Alb and Zhai emergent constraints are very similar; they both involve the variation of low cloud SW reflection with SST.