Usage

Tip

Both the COARE v3.5 and COARE v3.6 algorithms use the same input variables and provide the same output variables. This example shows how to use the COARE v3.5 algorithm, but the same steps can be used for the COARE v3.6 algorithm - simply replace coare_35 with coare_36 in any code!

This package is designed around an object oriented approach, since the number of parameters that the COARE algorithm outputs can be quite unwieldy otherwise. Therefore, the first step in using the COARE algorithm is to create an instance of the coare_35 class:

>>> from pycoare import coare_35  # import the coare_35 class
>>> c = coare_35([0.0, 0.5, 1.0, 1.5, 2.0, 2.5])  # create instance of coare_35 class

Note that this (and other examples in this documentation) uses only wind speed as input. This is bad practice, and ideally you should use as many input variables as possible. See coare_35 or coare_36 for a complete list of input variables.

Note

coare_35 and coare_36 can accept NumPy ArrayLike objects (e.g., float, list, numpy.ndarray, etc.) as input. It is not yet designed to work with xarray objects (support coming soon). Please convert any xarray.DataArray to numpy.ndarray before passing them to the COARE algorithm.

Once the coare_35 object is created, the algorithm will automatically be ran. The output of the algorithm is stored in several “output classes”, which can be accessed as attributes from the coare_35 class. Output classes contain “subattributes” that store the output of the algorithm, neatly divided into categories.

For example, the fluxes output class contains the output of the algorithm related to air-sea fluxes. To access the wind stress (i.e. the air-sea momentum flux), you can use the tau subattribute of the fluxes attribute of the coare_35 object:

>>> from pycoare import coare_35
>>> c = coare_35([0.0, 0.5, 1.0, 1.5, 2.0, 2.5])  # create instance of coare_35 class
>>> c.fluxes.tau  # access the wind stress
array([0.        , 0.00060093, 0.00165957, 0.00319516, 0.00520412, 0.00768739])

Important

These “output classes” should only ever be accessed from within a coare_35 or coare_36 instance (as shown in the examples).

As another example, the transfer_coefficients output class contains the output of the algorithm related, unsurprisingly, to transfer coefficients. To access the neutral wind stress transfer coefficient (i.e., neutral drag coefficient), you can use the cdn_rf subattribute of the transfer_coffiencient attribute of the coare_35 object:

>>> from pycoare import coare_35
>>> c = coare_35([0.0, 0.5, 1.0, 1.5, 2.0, 2.5])  # create instance of coare_35 class
>>> c.transfer_coefficients.cdn_rf  # access the drag coefficient
array([1.2360058 , 1.12526078, 1.04170881, 0.98860156, 0.95127555, 0.92438611])

The available output classes accessible from a coare_35 instance are:

• fluxes

• transfer_coefficients

• stability_functions

• velocities

• temperatures

• humidities

The same output classes are available from a coare_36 instance:

• fluxes

• transfer_coefficients

• stability_functions

• velocities

• temperatures

• humidities

The links above will take you to the documentation for each of these output classes. This contains information on the subattributes that are available in each output class.