Sentences with phrase «modeling positive water vapor feedback»

And I wanted to add that a key factor for both angstrom and koch low - balling the importance of C02 concentration was not just that they didn't fully envision conditions where energy radiates away, but that they weren't modeling positive water vapor feedback (the magnitude of which but not the existence is still being hashed out).

Not exact matches

«By comparing the response of clouds and water vapor to ENSO forcing in nature with that in AMIP simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate of the strength of the negative cloud albedo feedback and (2) an overestimate of the positive feedback from the greenhouse effect of water vapor.

In addition, it now appears that water vapor feedback, while still positive and robust, is likely to be weaker than previously estimated by the models.

It appears to me that the new «scientific evidence» is suggesting that water vapor feedback is not as strong as had been estimated by the models previously and that net cloud feedback may be neutral to slightly negative, rather than strongly positive, as predicted previously by the models.

Niche Modelling concludes from the Leviticus data that net total global radiative feedback from water vapor, etc. is negative, rather than strongly positive, as estimated by the models cited in IPCC AR4.

manacker December 19, 2012 at 8:00 pm said:» It appears to me that the new «scientific evidence» is suggesting that water vapor feedback is not as strong as had been estimated by the models previously and that net cloud feedback may be neutral to slightly negative, rather than strongly positive, as predicted previously by the models»

«Height - resolved measurements of specific humidity (q) and relative humidity (RH) are obtained from NASA's satellite - borne Atmospheric Infrared Sounder (AIRS)... The water - vapor feedback implied by these observations is strongly positive, with an average magnitude of λ q = 2.04 W / m2 / K, similar to that simulated by climate models.»

Quoting Dr Roy Spencer: «One of the most robust feedback relationships across the IPCC climate models is that those models with the strongest positive water vapor feedback have the strongest negative lapse rate feedback (which is what the «hot spot» would represent).

Pinatubo was particularly good for this, because as Soden et al 2002 showed, the GCMs of the day not only accurately modeled the atmospheric drying after the eruption, but also demonstrated that a positive water vapor feedback was required to explain the MSU - measured lower troposphere temperatures.

Without a strong positive feedback from water vapor (as assumed in the models), Human - made climate forcing becomes insignificant.

b) The models all assume that stratospheric water vapor would increase with increasing CO2 (the famous «positive feedback»), but it has actually decreased, providing negative feedback instead.

It only becomes significant in the models by assuming that water vapor concentration increases in response to the slight warming produced by CO2 increases and therefore constitutes a powerful positive feedback effect which triples the effect of CO2 by itself.

1 Positive 1.1 Carbon cycle feedbacks 1.1.1 Arctic methane release 1.1.1.1 Methane release from melting permafrost peat bogs 1.1.1.2 Methane release from hydrates 1.1.2 Abrupt increases in atmospheric methane 1.1.3 Decomposition 1.1.4 Peat decomposition 1.1.5 Rainforest drying 1.1.6 Forest fires 1.1.7 Desertification 1.1.8 CO2 in the oceans 1.1.9 Modelling results 1.1.9.1 Implications for climate policy 1.2 Cloud feedback 1.3 Gas release 1.4 Ice - albedo feedback 1.5 Water vapor feedback 2 Negative 2.1 Carbon cycle 2.1.1 Le Chatelier's principle 2.1.2 Chemical weathering 2.1.3 Net Primary Productivity 2.2 Lapse rate 2.3 Blackbody radiation

But I am not about to buy in on the AGW premise of IPCC, which is based on a mean ECS value of 3.2 C (with a «fat tail»), which is in turn based on net positive feedback from clouds and a water vapor feedback based on essentially maintaining constant relative humidity with warming, all of which is solely based on model predictions and not on empirical evidence.

It's my understanding that NVAP data shows as atmospheric CO2 increases, water vapor decreases; exactly opposite what climate models predict because they assume water vapor is a net positive feedback; more wv, more warming, more wv, more warming.....

They concluded that the «water - vapor feedback implied by these observations is strongly positive» and «similar to that simulated by climate models.»

``... underestimating the negative feedback from cloud albedo and overestimating the positive feedback from the greenhouse effect of water vapor over the tropical Pacific during ENSO is a prevalent problem of climate models.

The funny thing is that contrary to the models the amount of water vapor in the air has gone down since 1950 so how in the world is this positive feedback thingy supposed to work anyway.

There is nothing in the climate models that says that the positive feedbacks such as the water vapor feedback and the ice albedo feedback, etc. operate only for CO2 warming and not on natural warming.

The IPCC, its models, and the climate establishment insist warming will be more than this because the warming will cause an increase in atmospheric water vapor (the major greenhouse gas) which will amplify the CO2 - caused warming, a net positive feedback.

One such feedback might exist if, as assumed in some models, relative humidity is constant, so increasing the temperature has the positive feedback of increasing the water vapor.

In fact positive water vapor feedback to the CO2 greenhouse effect is essential for the models to exhibit a frightening amount of warming just over the horizon.

Principal positive feedback processes in the model are changes in atmospheric water vapor, clouds and snowlice cover.

Water vapor feedback in climate models is positive mainly because of their roughly constant relative humidity (i.e., increasing q) in the mid-to-upper troposphere as the planet warms.

Do they start to fail when they start doing ideological things like putting in too much positive water vapor feedback and then trying to fix the model by adding aerosols that aren't really there.

Regardless, climate models are made interesting by the inclusion of «positive feedbacks» (multiplier effects) so that a small temperature increment expected from increasing atmospheric carbon dioxide invokes large increases in water vapor, which seem to produce exponential rather than logarithmic temperature response in the models.

Many of these positive feedbacks are also clear from modern observations (eg of water vapor) and theoretical modeling compared with measurements (eg of the carbon cycle).

Is there some sort of a «natural thermostat» mechanism by which atmospheric water vapor content is regulated to prevent a long - term «positive feedback» from water vapor, as is assumed by all the IPCC climate models?

The question that this raises: Is there some sort of a «natural thermostat» mechanism by which atmospheric water vapor content is regulated to prevent a long - term «positive feedback» from water vapor, as is assumed by all the IPCC climate models?

The implied positive feedback is smaller than indicated by our model (8.5 — 9.5 ppmv K - 1), but as with the case of MLS, the HALOE water vapor data show that the UT humidity — SST relationship in the present climate regime lies between the cases of constant mixing ratio and constant relative humidity.