# The Linear Response Function of an Idealized Atmosphere. Part II: Implications for the Practical Use of the Fluctuation–Dissipation Theorem and the Role of Operator’s Nonnormality

@article{Hassanzadeh2015TheLR, title={The Linear Response Function of an Idealized Atmosphere. Part II: Implications for the Practical Use of the Fluctuation–Dissipation Theorem and the Role of Operator’s Nonnormality}, author={Pedram Hassanzadeh and Zhiming Kuang}, journal={Journal of the Atmospheric Sciences}, year={2015}, volume={73}, pages={3441-3452} }

AbstractA linear response function (LRF) relates the mean response of a nonlinear system to weak external forcings and vice versa. Even for simple models of the general circulation, such as the dry dynamical core, the LRF cannot be calculated from first principles owing to the lack of a complete theory for eddy–mean flow feedbacks. According to the fluctuation–dissipation theorem (FDT), the LRF can be calculated using only the covariance and lag-covariance matrices of the unforced system…

## 21 Citations

### Journal of the Atmospheric Sciences Supplemental Material : The linear response function of an idealized atmosphere . Part 1 : Construction using Green ’ s functions and applications

- Environmental Science, Physics
- 2016

A linear response function (LRF) determines the mean-response of a nonlinear climate system to weak imposed forcings, and an eddy flux matrix (EFM) determines the eddy momentum and heat flux…

### The linear response function of an idealized atmosphere. Part 1: Construction using Green's functions and applications

- Environmental Science, Physics
- 2015

A linear response function (LRF) determines the mean-response of a nonlinear climate system to weak imposed forcings, and an eddy flux matrix (EFM) determines the eddy momentum and heat flux…

### Quantifying the Annular Mode Dynamics in an Idealized Atmosphere

- Environmental Science, PhysicsJournal of the Atmospheric Sciences
- 2019

The linear response function (LRF) of an idealized GCM, the dry dynamical core with Held–Suarez physics, is used to accurately compute how eddy momentum and heat fluxes change in response to the…

### Reduced-order modeling of fully turbulent buoyancy-driven flows using the Green's function method

- Physics, Environmental SciencePhysical Review Fluids
- 2019

A One-Dimensional (1D) Reduced-Order Model (ROM) has been developed for a 3D Rayleigh-Benard convection system in the turbulent regime with Rayleigh number $\mathrm{Ra}=10^6$. The state vector of the…

### Quantifying the eddy-jet feedback strength of the annular mode in an idealized GCM and reanalysis data

- Environmental Science, Physics
- 2016

A linear response function (LRF) that relates the temporal tendency of zonal mean temperature and zonal wind to their anomalies and external forcing is used to accurately quantify the strength of the…

### Sensitivity of Surface Temperature to Oceanic Forcing via q-Flux Green’s Function Experiments. Part I: Linear Response Function

- Environmental Science
- 2018

AbstractThis paper explores the use of the linear response function (LRF) to relate the mean sea surface temperature (SST) response to prescribed ocean heat convergence (q flux) forcings. Two methods…

### Data-driven reduced modelling of turbulent Rayleigh–Bénard convection using DMD-enhanced fluctuation–dissipation theorem

- PhysicsJournal of Fluid Mechanics
- 2018

A data-driven model-free framework is introduced for the calculation of reduced-order models (ROMs) capable of accurately predicting time-mean responses to external forcings, or forcings needed for…

### Aspects of Eddy Momentum Fluxes in the General Circulation of the Troposphere

- Environmental Science, Physics
- 2017

This thesis investigates the roles of eddy momentum fluxes (EMFs) in several aspects of the tropospheric circulation. The thesis begins by examining how large-scale orographic forcing and ENSO-like…

### Climate Dependence in Empirical Parameters of Subgrid-Scale Parameterizations using the Fluctuation–Dissipation Theorem

- Environmental Science, PhysicsJournal of the Atmospheric Sciences
- 2018

Many subgrid-scale (SGS) parameterizations in climate models contain empirical parameters and are thus data dependent. In particular, it is not guaranteed that the SGS parameterization still helps…

### An Eddy-Zonal Flow Feedback Model for Propagating Annular Modes

- Environmental Science, Physics
- 2020

The variability of the zonal-mean large-scale extratropical circulation is often studied using individual modes obtained from empirical orthogonal function (EOF) analyses. The prevailing…

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