The integrated nonlinear analysis (INA) toolbox cumulates some of the most used analysis methods to investigate turbulence: the Power Spectral Density (PSD) , the Probability Distribution Functions (PDFs), the structure functions and the data analysis with wavelets. It also includes novel techniques like the multifractal analysis with rank ordered fluctuations.
INA can be downloaded freely from this website as an executable file. You need to register first.
A list of dedicated tutorials for each INA module/functionality is available below.
The wavelet module of INA contains two subclasses of methods: a) Scalogram that computes the wavelet representation of the signal based on various wavelet families and b) LIM that computes the Local Intermittency Measure (LIM) based on the scalogram representation.
INA offers several options to import data and several interfaces are adapted to ingest data from files downloaded from ESA and/or NASA databases devoted to Cluster, ACE, Venus Express and Ulysses data.
The structure function analysis looks at the statistics of fluctuations at different scales and for various magnitudes. It is a useful tool to dig into the topology of turbulence.
INA adopts a strategy that drives the user to follow a linear progression from importing the data to their analysis.
The multifractal analysis based on rank ordering of fluctuations is a method invented by Chang and Wu (2004). Since the Rank Ordered Multifractal Analysis (ROMA) method is rather novel and complex this module includes several sub-modules, some of them with a dedicated technical content aiming to help the user to understand/control some of the particularities of the method itself.
The Spectal analysis tools implemented in INA include a basic level "Descriptive Statistics" and a more advanced "Power Spectral Density" Analysis.
The EXPORT functionality is an important feature of INA as it allows the user to save the results of the analysis either as a graphical or binary object or both.
The Probability Density module includes four analysis tools, all related to the Probability Distribution Functions (PDFs).