Ncsu1

class rojak.turbulence.diagnostic.Ncsu1(u_wind, v_wind, ri, vector_derivatives, vorticity)

NCSU1 CAT diagnostic as defined in [Sharman2006]

NCSU1 was developed by analysing 44 cases of severe turbulence at the synoptic-scale (in [Kaplan2005a] and [Kaplan2005b]) to develop an index for forecasting severe turbulence. It is defined in [Kaplan2006] as,

\[\text{NCSU1} = \left( U \cdot \nabla U \right) \frac{|\nabla \zeta|}{|\text{Ri}|}\]

This implementation is based on the definition in [Sharman2006],

\[\text{NCSU1} = \frac{1}{\max(\text{Ri}, 10^{-5})} \max \left(u \frac{ \partial u }{ \partial x } + v \frac{ \partial v }{ \partial y } \right) \left| \nabla \zeta \right|\]

Parameters:

• u_wind (DataArray) – Zonal wind speeds in m/s

• v_wind (DataArray) – Meridional wind speeds in m/s

• ri (DataArray) – Computed richardson diagnostic

• vector_derivatives (dict[VelocityDerivative, DataArray]) – Dictionary containing du/dx and dv/dy derivatives

• vorticity (DataArray) – Vertical component of vorticity in m/s

__init__(u_wind, v_wind, ri, vector_derivatives, vorticity)

Parameters:

• name – Name of the diagnostic

• u_wind (DataArray)

• v_wind (DataArray)

• ri (DataArray)

• vector_derivatives (dict[VelocityDerivative, DataArray])

• vorticity (DataArray)

Return type:

None

Methods

__init__(u_wind, v_wind, ri, ...)
to_zarr(output_base_dir, *[, file_name])	Export computed_value to a zarr store

Attributes

RI_THRESHOLD
computed_value	The diagnostic's computed value
name	Name of the diagnostic