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On the numerical integration of a randomly forced system: Variation and feedback estimation

Title
On the numerical integration of a randomly forced system: Variation and feedback estimation
Authors
Choi Y.-S.Song H.-J.
Ewha Authors
최용상
SCOPUS Author ID
최용상scopus
Issue Date
2012
Journal Title
Theoretical and Applied Climatology
ISSN
0177-798XJCR Link
Citation
vol. 110, no. 41276, pp. 97 - 101
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Simulated climate variables in a simple energy balance model subject to linearly increasing external forcing (due to increasing greenhouse gas emissions) and random internal forcings have been studied for more accurate climate prediction. The numerical method for such a system requires careful treatment of random forcings. Mathematical analyses show that the effect of random forcings should be diminished in the numerical integration method by the reciprocal of the root of the integration time step (1/√Δt), which we call an attenuator. Our simulations consistently show that the attenuator desirably reduces variances of simulated climate variables and eliminates overestimation of the variances. However, the attenuator tends to bias the estimates of the climate feedback parameter obtained from a simple regression analysis of simulated variables toward unrealistically low values. This is because the reduced random forcings amplify the negative effect of a warming trend due to greenhouse emissions (when added to random forcing) on feedback estimation. Without the attenuator, the estimated feedback is much more accurate. The bias induced from the attenuator was largely resolved for the feedback estimation by the methodology of Lindzen and Choi (Asia-Pacific J Atmos Sci 47(4):377-390, 2011), which minimizes the negative effect of the warming trends by isolating short (few months) segments of increasing and decreasing temperature changes. © 2012 Springer-Verlag.
DOI
10.1007/s00704-012-0612-3
Appears in Collections:
엘텍공과대학 > 환경공학전공 > Journal papers
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