## **Research Interests**

**Nonlinear and Stochastic Reduction:**Markovian and non-Markovinan stochastic closures. Parameterizing manifolds and small-scale parameterizations in spatially extended systems. Ruelle-Pollicott resonances and reduced mixing spectrum.**Random Dynamical Systems:**Stochastic invariant manifolds and their numerical approximations. Random attractors and time-dependent invariant measures arising in dissipative stochastic systems.**Data-Driven Stochastic Modeling:**Data-adaptive harmonic spectra and multilayer Stuart-Landau models.**Optimal Control of Evolution Equations:**Reduced-order models for the optimal control of PDEs and delay differential equations: analysis and computation.**Geophysical Fluid Dynamics and Climate Dynamics:**Natural climate variability. Low-order stochastic modelling of the El Niño-Southern Oscillation. Prediction of stochastic systems. Application of the geometric and ergodic theory of dynamical systems to climate dynamics.

**From Chekroun et al. (2011), Physica D, 240 (21): 1685-1700:**

**Vimeo movie**: https://vimeo.com/240039610

## Recent Publications

Data-adaptive harmonic analysis and modeling of solar wind-magnetosphere coupling.” Journal of Atmospheric and Solar-Terrestrial Physics. Publisher's Version Abstract

. In Press, 2018. “ Galerkin approximations for the optimal control of nonlinear delay differential equations.” Radon Series on Computational and Applied Mathematics. arXiv's version Abstract

. In Press, 2018. “ Topological instabilities in families of semilinear parabolic problems subject to nonlinear perturbations.” Discrete and Continuous Dynamical Systems B, doi: 10.3934/dcdsb.2018075. Publisher's version Abstract

2018. “ Pullback attractor crisis in a delay differential ENSO model.” Advances in Nonlinear Geosciences, A. Tsonis, 1-33. Springer, 1-33. Publisher's version Abstract

. 2018. “ Data-adaptive harmonic decomposition and stochastic modeling of Arctic sea ice.” Advances in Nonlinear Geosciences, A. Tsonis, 179-205. Springer, 179-205. Publisher's Version Abstract

. 2018. “