A dynamical systems explanation of the Hurst effect and atmospheric low-frequency variability.
Scientific reports 5 (2015) 9068
Abstract:
The Hurst effect plays an important role in many areas such as physics, climate and finance. It describes the anomalous growth of range and constrains the behavior and predictability of these systems. The Hurst effect is frequently taken to be synonymous with Long-Range Dependence (LRD) and is typically assumed to be produced by a stationary stochastic process which has infinite memory. However, infinite memory appears to be at odds with the Markovian nature of most physical laws while the stationarity assumption lacks robustness. Here we use Lorenz's paradigmatic chaotic model to show that regime behavior can also cause the Hurst effect. By giving an alternative, parsimonious, explanation using nonstationary Markovian dynamics, our results question the common belief that the Hurst effect necessarily implies a stationary infinite memory process. We also demonstrate that our results can explain atmospheric variability without the infinite memory previously thought necessary and are consistent with climate model simulations.Observation of muon intensity variations by season with the MINOS near detector
Physical Review D American Physical Society (APS) 90:1 (2014) 012010
Observation of muon intensity variations by season with the MINOS Near Detector
(2014)
HadGEM2-CC model output prepared for CMIP5 RCP8.5, served by ESGF
University of Oxford (2014)
Abstract:
Project: IPCC Assessment Report 5 and Coupled Model Intercomparison Project data sets - These data belong to two projects:1) to the Assessment Report No 5 of the International Panel on Climate Change (IPCC-AR5) and2) to the Coupled Model Intercomparison Project No 5 (CMIP5).CMIP5 is executed by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) on behalf of the World Climate Research Programme (WCRP). Most of the data is replicated between the three data nodes at the World Data Centre for Climate (WDCC), the British Atmospheric Data Centre (BADC), and the PCMDI.The project embraces the simulations with about 30 climate models of about 20 institutes worldwide.HadGEM2-CC model output prepared for CMIP5 RCP4.5, served by ESGF
WDCC at DKRZ (2014)
Abstract:
rcp45 is an experiment of the CMIP5 - Coupled Model Intercomparison Project Phase 5 (http://cmip-pcmdi.llnl.gov/cmip5/). CMIP5 is meant to provide a framework for coordinated climate change experiments for the next five years and thus includes simulations for assessment in the AR5 as well as others that extend beyond the AR5.4.1 rcp45 (4.1 RCP4.5): Future projection (2006-2100) forced by RCP4.5. RCP4.5 is a representative concentration pathway which approximately results in a radiative forcing of 4.5 W m-2 at year 2100, relative to pre-industrial conditions. RCPs are time-dependent, consistent projections of emissions and concentrations of radiatively active gases and particles.
Experiment design is described in detail in http://cmip-pcmdi.llnl.gov/cmip5/docs/Taylor_CMIP5_design.pdf and the list of output variables and their temporal resolutions are given in http://cmip-pcmdi.llnl.gov/cmip5/docs/standard_output.pdf .
The output is stored in netCDF format as time series per variable in model grid spatial resolution. For more information on the Earth System model and the simulation please refer to the CIM repository.