pywasp.wasp.get_climate

pywasp.wasp.get_climate(output_locs, stab_source='ERA5', baro_source='ERA5', interp_method='nearest')[source]

Get climatological parameters interpolated to the output locations

Warning

This function is experimental and its signature may change

Parameters:

  • output_locs (xarray.Dataset) – Spatial dataset (point, stacked_point, or cuboid) with the output locations to interpolate to

  • stab_source (str, xarray.Dataset, None) – String indicating which data source should be used for the stability information. If it is a xarray.Dataset, this is used as a stability source. If it is set to None, it means a dataset with dummy values is returned. by default ‘ERA5’, the only available value for now.

  • baro_source (str, xarray.Dataset, None) – String indicating which data source should be used for the baroclinicity parameters. If it is a xarray.Dataset, this is used as a baroclinicity source. If it is set to None, it means a dataset with dummy values is returned. Available values are ‘ERA5’ and ‘CFSR’, defaults to ‘ERA5’.

  • interp_method (str) – Interpolation method to use. See windkit.spatial.interp_unstructured_like for available methods. Defaults to ‘nearest’

Returns:

xarray.Dataset – Dataset with mean climatological parameters for the specified output_locs

Notes

This routine extracts two things from a prepared file with data:

  1. the baroclinicity parameters dG/dz and \beta

  2. stability information (mean and standard deviation of the temperature scale and boundary layer height over land and sea)

The dgdz parameter represents the change of the geostrophic wind with height (s^-1), where as beta describes the direction in which the vector is pointing (0 for pointing towards the east). Assuming a boundary layer height of 1000 m dG/dz=0.001 and \beta=0 thus means that in a climatological sense the geostrophic wind is increasing with 1 m/s from the ground to a 1000 m from west to east. Further details on these parameters and how they affect the wind modelling in Wasp is described in [2]

In mountaineous terrain the geostrophic shear can get very large. When there is values of dG/dz>0.005 it is recommend to explore the results also with the geostrophic shear turned off. There is also a hard limit in the WAsP core which limits the geostrophic shear effect, because the geostrophic drag law is not applicable for B<0. This is set in parameter 103 in Climate.

The temperature scale represent the climatological mean effect of stability on the wind profile. In the standard profile model (which is set using Climate.set_profile_model = 0 , the heat fluxes have default values specified in parameters 56-59 and have units of W/m^2. These values are the same for all wind direction sectors.

If the Climate.set_profile_model` = 2, it means that the stability information is specified as a mean and standard deviation of a temperature scale with units K (degrees). They can generally be obtained from reanalysis data or observations of kinematic heat fluxes. They will generally depend on wind direction and vary with wind direction.

The boundary layer heights are not used in profile model 0 and 1, because h is specified to scale with cu_*/f, where u_* is the friction velocity, f the coriolis parameter and the scaling constant c is specified with param(96). When param(96)<0 one can explicitly set the boundary layer height over land and sea using the values specified in the mesoscale climate.

The dataset is required to have the following variables:

mean_temp_scale_landnumpy array

mean heat flux (W/m^2) or normalized heat flux (W m^-1 s^-1) over land

mean_temp_scale_seanumpy array

mean heat flux (W/m^2) or normalized heat flux (W m^-1 s^-1) over sea

rms_temp_scale_landnumpy array

standard deviation of heat flux or normalized heat flux over land

rms_temp_scale_seanumpy array

standard deviation of heat flux or normalized heat flux over sea

mean_pblh_scale_landnumpy array

mean boundary layer height over sea (m)

mean_pblh_scale_seanumpy array

mean boundary layer height over sea (m)

mean_dgdznumpy array

average magnitude of long-term mean geostrophic wind shear vector (s^-1)

mean_dgdz_dirnumpy array

average direction of long-term mean geostrophic wind shear vector (degrees in mathematical coordinate system, i.e. zero for vector from west to east)