Esempio n. 1
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    def test_add_buoyancy_freq_squared(self):
        # This is a fairly lousy test, merely ensuring that an N^2 field was
        # calculated, and that it's not wildly different than the direct
        # calculation.
        p = np.arange(10)
        t = 20.0 * 0.2 * p
        s = 30.0 * 0.25 * p
        x = [-20.0 for _ in p]
        y = [50.0 for _ in p]
        sa = gsw.sa_from_sp(s, p, x, y)
        ct = gsw.ct_from_t(sa, t, p)
        rho = np.asarray(gsw.rho(sa, ct, p))

        cast = CTDCast(p, s, t, coordinates=(-20, 50), density=rho)
        cast.add_depth()
        cast.add_Nsquared(depthkey="depth")

        # Calculate the buoyancy frequency directly
        z = cast["depth"].values
        drhodz = -np.r_[rho[1]-rho[0], rho[2:]-rho[:-2], rho[-1]-rho[-2]] / \
                  np.r_[z[1]-z[0], z[2:]-z[:-2], z[-1]-z[-2]]
        N2_direct = -9.81 / rho * drhodz
        self.assertTrue(
            np.mean(np.abs(cast["N2"][1:] - N2_direct[1:])) < 0.0004)
        return
Esempio n. 2
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    def test_add_density(self):
        p = np.arange(10)
        t = 20.0 * 0.2 * p
        s = 30.0 * 0.25 * p
        x = [-20.0 for _ in p]
        y = [50.0 for _ in p]
        sa = gsw.sa_from_sp(s, p, x, y)
        ct = gsw.ct_from_t(sa, t, p)
        rho = gsw.rho(sa, ct, p)

        cast = CTDCast(p, s, t, coordinates=(-20, 50))
        cast.add_density()
        self.assertTrue(np.allclose(rho, cast["density"]))
        return
Esempio n. 3
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    def test_add_density(self):
        p = np.arange(10)
        t = 20.0 * 0.2 * p
        s = 30.0 * 0.25 * p
        x = [-20.0 for _ in p]
        y = [50.0 for _ in p]
        sa = gsw.sa_from_sp(s, p, x, y)
        ct = gsw.ct_from_t(sa, t, p)
        rho = gsw.rho(sa, ct, p)

        cast = CTDCast(p, s, t, coordinates=(-20, 50))
        cast.add_density()
        self.assertTrue(np.allclose(rho, cast["density"]))
        return
Esempio n. 4
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    def test_add_buoyancy_freq_squared(self):
        # This is a fairly lousy test, merely ensuring that an N^2 field was
        # calculated, and that it's not wildly different than the direct
        # calculation.
        p = np.arange(10)
        t = 20.0 * 0.2 * p
        s = 30.0 * 0.25 * p
        x = [-20.0 for _ in p]
        y = [50.0 for _ in p]
        sa = gsw.sa_from_sp(s, p, x, y)
        ct = gsw.ct_from_t(sa, t, p)
        rho = np.asarray(gsw.rho(sa, ct, p))

        cast = CTDCast(p, s, t, coordinates=(-20, 50), density=rho)
        cast.add_depth()
        cast.add_Nsquared(depthkey="depth")

        # Calculate the buoyancy frequency directly
        z = cast["depth"].values
        drhodz = -np.r_[rho[1]-rho[0], rho[2:]-rho[:-2], rho[-1]-rho[-2]] / \
                  np.r_[z[1]-z[0], z[2:]-z[:-2], z[-1]-z[-2]]
        N2_direct = -9.81 / rho * drhodz
        self.assertTrue(np.mean(np.abs(cast["N2"][1:] - N2_direct[1:])) < 0.0004)
        return