Generation of the SWOT grid#

swot_simulator.orbit_propagator module generates the SWOT grid. The ephemeris keyword sets the path to the orbit file to process. This file defines three different columns (longitude, latitude, and the corresponding time) the position of the satellite at each point of the orbit. You can specify column order with the parameters ephemeris_col (default is [1, 2, 0]). The orbit is interpolated at the along-track resolution specified by the user (parameter delta_al). At each point of the orbit, the swath is calculated with an across-track resolution defined by the delta_ac parameter.

The width of the swath (half_swath) and the gap between the nadir and the swath (half_gap) can also be defined according to Fig. 2

By default, all measurements of the swath are valid. In reality, measurements outside the requirements of the SWOT swath are subject to errors. To simulate this, you can define the limits of the swath validity with the half_gap parameter. Measurements outside the span will be set with NaN.

The generation of SWOT products is global, i.e., the products cover the globe’s entire surface. With the help of the parameter area, you can define a more restricted area of interest. The expected syntax of the parameter to define a bounding box is: area = [lon_min, lat_min, lon_max, lat_max].