Lower Tropospheric Temperatures 1978-2016: The Role Played By Anthropogenic Global Warming

Ayers, Gregory D.

doi:10.22499/3.6701.001

Cited by 1 publication

(2 citation statements)

References 19 publications

(34 reference statements)

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“…Thus removal of short-term variability that conceptually can be thought of arising from synoptic scale 'weather' processes, rather than weatheraveraged 'climate' processes, was tested as a means of removing weather 'noise' from the climate 'signal'. Use of a 12 month running mean as an improvement on the multiple lag/simple smoother used by Kopp and Lean (2011) was tested in a recent application of the Lean and Rind model to analysis of lower tropospheric T data covering the warming slowdown period from 1997-2016 (Ayers 2017). The running mean acts as a simple lowpass filter applied to the T series.…”

Section: Methodsmentioning

confidence: 99%

“…In the present work tests were carried out using a cubic spline and LOESS (Local Polynomial Regression) smoothers as well as the simple 12 month running mean as low pass filter. There was negligible difference in results,withverysimilarimprovementsingoodnessoffitobtained by each of these methods, thus the simple 12 month running mean as used previously (Ayers 2017) was used in this work.…”

Section: Methodsmentioning

confidence: 99%

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Climate sensitivity revisited

Ayers¹

2020

J. South. Hemisph. Earth Syst. Sci.

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The commonly used energy balance model from Gregory et al. (2002) that underlies many published estimates of Equilibrium Climate Sensitivity (ECS) and Transient Climate Response (TCR) to anthropogenic forcing requires only four parameters for calculation of ECS and three for TCR. Both estimates require a value for the increase in global mean surface air temperature (DT) over a period of time, the increment in forcing driving the temperature change over that period (DF), and knowledge of the radiative forcing resulting from a doubling in CO 2 concentration (F 2ÂCO2). For ECS a value for the associated global heating rate (DQ) is also required. Each of these parameters has a best estimate available from the IPCC's Fifth Assessment Report, but the authors did not provide best estimates for ECS and TCR within the broad uncertainty ranges quoted, 1.5-4.5 K for ECS and 1.0-2.5 K for TCR. Best estimates for ECS and TCR consistent with AR5 best estimates for DF and F 2ÂCO2 are provided here. A well-known heuristic model was modified and applied to seven observation-based global temperature datasets to isolate temperature trend due to anthropogenic forcing from confounding effects of variability due to volcanism, cycles in solar irradiance and internal climate variability. The seven estimates of ECS and TCR were remarkably similar despite very large differences in time-base of the datasets analysed, yielding best estimates of 2.36 AE 0.13 K and 1.58 AE 0.09 K respectively at 95% confidence based on the AR5 best estimates for DF, F 2ÂCO2 and DQ from Wijffels et al. (2016). The ECS and TCR best estimates here are tied to those AR5 and DQ best estimates, but can be simply scaled were those best estimate values to be refined in the future.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%