Spectrum

Compute spectrum and spectrum ratio on some area

Load data

raw = RegularGridDataset(grid_name, lon_name, lat_name)
filtered = RegularGridDataset(grid_name, lon_name, lat_name)
filtered.bessel_low_filter("adt", 150, order=3)

areas = dict(
    sud_pacific=dict(llcrnrlon=188, urcrnrlon=280, llcrnrlat=-64, urcrnrlat=-7),
    atlantic_nord=dict(llcrnrlon=290, urcrnrlon=340, llcrnrlat=19.5, urcrnrlat=43),
    indien_sud=dict(llcrnrlon=35, urcrnrlon=110, llcrnrlat=-49, urcrnrlat=-26),
)

Compute and display spectrum

fig = plt.figure(figsize=(10, 6))
ax = fig.add_subplot(111)
ax.set_title("Spectrum")
ax.set_xlabel("km")
for name_area, area in areas.items():
    lon_spec, lat_spec = raw.spectrum_lonlat("adt", area=area)
    mappable = ax.loglog(*lat_spec, label="lat %s raw" % name_area)[0]
    ax.loglog(
        *lon_spec,
        label="lon %s raw" % name_area,
        color=mappable.get_color(),
        linestyle="--"
    )

    lon_spec, lat_spec = filtered.spectrum_lonlat("adt", area=area)
    mappable = ax.loglog(*lat_spec, label="lat %s high" % name_area)[0]
    ax.loglog(
        *lon_spec,
        label="lon %s high" % name_area,
        color=mappable.get_color(),
        linestyle="--"
    )

ax.set_xscale("log")
ax.legend()
ax.grid()
fig.savefig("share/png/spectrum.png")

Compute and display spectrum ratio

fig = plt.figure(figsize=(10, 6))
ax = fig.add_subplot(111)
ax.set_title("Spectrum ratio")
ax.set_xlabel("km")
for name_area, area in areas.items():
    lon_spec, lat_spec = filtered.spectrum_lonlat("adt", area=area, ref=raw)
    mappable = ax.plot(*lat_spec, label="lat %s high" % name_area)[0]
    ax.plot(
        *lon_spec,
        label="lon %s high" % name_area,
        color=mappable.get_color(),
        linestyle="--"
    )

ax.set_xscale("log")
ax.legend()
ax.grid()
fig.savefig("share/png/spectrum_ratio.png")