A5049314725- Meteorological Phenomena and Simulations
- Climate variability and models
- Geology and Paleoclimatology Research
- Reservoir Engineering and Simulation Methods
- Tree-ring climate responses
- Arctic and Antarctic ice dynamics
- Fluid Dynamics and Turbulent Flows
- Geophysics and Gravity Measurements
- Groundwater flow and contamination studies
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Hydrology and Drought Analysis
- Fluid Dynamics Simulations and Interactions
- Aeolian processes and effects
- Archaeology and ancient environmental studies
- Granular flow and fluidized beds
- Geomagnetism and Paleomagnetism Studies
- Landslides and related hazards
- Computational Fluid Dynamics and Aerodynamics
- Target Tracking and Data Fusion in Sensor Networks
- Complex Systems and Time Series Analysis
- Atmospheric and Environmental Gas Dynamics
- Phase Equilibria and Thermodynamics
- Methane Hydrates and Related Phenomena
- Atmospheric aerosols and clouds
Vrije Universiteit Amsterdam
2021-2024
Centrum Wiskunde & Informatica
2007-2021
University of Kansas
2018
Utrecht University
2018
Sandia National Laboratories
2018
UCLouvain
2011-2014
Natural Environment Research Council
2013
British Antarctic Survey
2013
Oeschger Centre for Climate Change Research
2013
University of Bern
2013
We implement a data-assimilation method based on particle filter in the coupled climate model LOVECLIM focusing decadal to centennial time scales. Several tests are performed with filtering using pseudo-observations obtained from twin experiment model, as well real-data observations over last century. These demonstrate that it is possible obtain output correlated at large scale reasonable cost.
Abstract. Paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of Southern Hemisphere from 10 to 8 ka BP. In order study causes this cooling, simulations covering early Holocene period have been performed with climate model intermediate complexity LOVECLIM constrained follow signal recorded proxies using a data assimilation method based on particle filtering. The selected represent surface temperature derived terrestrial, marine glaciological records. Using our...
Abstract. Using the climate model of intermediate complexity LOVECLIM in an idealised framework, we assess three data-assimilation methods for reconstructing state. The are a nudging, particle filter with sequential importance resampling, and nudging proposal test case corresponds to high latitudes Southern Hemisphere during past 150 yr. constrain by pseudo-observations surface air temperature anomalies obtained from same model, but different initial conditions. All provide good estimations...
Abstract. The mid-Holocene (6 kyr BP; thousand years before present) is a key period to study the consistency between model results and proxy-based reconstruction data as it corresponds standard test for models reasonable number of records available. Taking advantage this relatively large amount information, we have compared compilation 50 air sea surface temperature reconstructions with three simulations performed general circulation one carried out LOVECLIM, intermediate complexity....
In this article we develop algorithms for data assimilation based upon a computational time dependent stable/unstable splitting. Our particular method is shadowing refinement and synchronization techniques motivated by work on in the unstable subspace [Carrassi et al., Chaos, 18 (2008), 023112; Trevisan, D'Isidoro, Talagrand, Q. J. R. Meteorol. Soc., 136 (2010), pp. 487--496; Palatella, Carrassi, Phys. A, 46 (2013), 254020] pseudo-orbit [Judd Smith, D, 151 (2001), 125--141; Judd Atmos. Sci.,...
We introduce optimal transport based resampling in adaptive SMC.We consider elliptic inverse problems of inferring hydraulic conductivity from pressure measurements.We two parametrizations conductivity: by Gaussian random field, and a set scalar (non-)Gaussian distributed parameters fields.We show that for SMC performs comparably to monomial but highdimensional fields outperforms SMC.When comparing ensemble Kalman inversion with mutation (EKI), we observe fields, gives comparable or worse...
In this article we study the relevance of quantities conserved by a numerical scheme for data assimilation through statistical equilibrium mechanics. We use Ensemble Kalman Filter with perturbed observations as method. consider three Arakawa discretizations quasi‐geostrophic model that either preserve energy (Arakawa E ), or enstrophy Z both ). perform twin experiment, where are generated from Hamiltonian particle‐mesh (HPM) method, which preserves and an infinite number Casimirs though...
Based on the thermodynamic concept of a reservoir, we investigate computational model for interaction with unresolved degrees freedom (a thermal bath). We assume that finite restricted system can be modelled by generalized canonical ensemble, described density which is smooth function energy system. A thermostat constructed to continuously perturb resolved dynamics, while leaving desired equilibrium distribution invariant. build thermostatting framework developed and tested in setting...
We show that the one-dimensional (1D) two-fluid model (TFM) for stratified flow in channels and pipes (in its incompressible, isothermal form) satisfies an energy conservation equation, which arises naturally from mass momentum equations constitute model. This result extends upon earlier work on shallow water (SWE), with important difference we include non-conservative pressure terms analysis, propose a formulation holds ducts arbitrary cross-sectional shape, 2D channel circular pipe...
Abstract. The mid-Holocene (6 thousand years before present) is a key period to study the consistency between model results and proxy data as it corresponds standard test for models reasonable number of records are available. Taking advantage this relatively large amount information, we have first compared compilation 50 air sea surface temperature reconstructions with three simulations performed general circulation one carried out LOVECLIM, intermediate complexity. conclusions derived from...
Data assimilation improves our understanding of the origins climate changes during past millennium in Europe. Model data-comparison presence large internal variability
In this paper we present a complete framework for the energy-stable simulation of stratified incompressible flow in channels, using one-dimensional two-fluid model. Building on earlier energy-conserving work basic model, our new includes diffusion, friction, and surface tension. We show that tension can be added an manner, diffusion friction have strictly dissipative effect energy. then propose spatial discretizations these terms such semi-discrete model is obtained has same conservation...
Over the years data assimilation methods have been developed to obtain estimations of uncertain model parameters by taking into account a few observations state. The most reliable MCMC are computationally expensive. Sequential ensemble such as Kalman filers and particle filters provide favourable alternative. However, Ensemble Filter has an assumption Gaussianity. Transform Particle does not this proven be highly beneficial for initial condition estimation small number parameter in chaotic...