Merge pull request #32 from castelao/enthalpy_SSO_0

enthalpy_SSO_0 (3.0.5)

Author: efiring

gsw/gibbs/library.py

@@ -8,6 +8,7 @@
 from ..utilities import match_args_return, strip_mask, read_data
 
 __all__ = ['deltaSA_atlas',
+           'enthalpy_SSO_0',
            'enthalpy_SSO_0_p',
            'entropy_part',
            'entropy_part_zerop',
@@ -24,6 +25,10 @@
            'SP_from_SA_Baltic']
 
 
+h006 = -2.1078768810e-9
+h007 =  2.8019291329e-10
+
+
 class SA_table(object):
     """
     TODO: Write docstring.
@@ -694,6 +699,52 @@ def enthalpy_SSO_0_CT25(p):
     return np.ma.array(enthalpy_SSO_0_CT25, mask=mask, copy=False)
 
 
+def enthalpy_SSO_0(p):
+    """
+    Enthalpy at SSO and CT(T=0) (75-term equation)
+
+    This function calculates enthalpy at the Standard Ocean Salinty, SSO,
+    and at a Conservative Temperature of zero degrees C, as a function of
+    pressure, p, in dbar, using a streamlined version of the 75-term
+    computationally-efficient expression for specific volume, that is, a
+    streamlined version of the code "enthalpy(SA,CT,p)".
+
+    Parameters
+    ----------
+    p : array_like
+        pressure [dbar]
+
+    Returns
+    -------
+    enthalpy_SSO_0 : array_like
+                     enthalpy at (SSO, CT=0, p)
+                     [J kg :sup:`-1`]
+
+    Examples
+    --------
+    >>> import gsw
+    >>> p = np.array([10, 50, 125, 250, 600, 1000])
+    >>> gsw.library.enthalpy_SSO_0(p)
+    array([   97.26388583,   486.27439853,  1215.47517122,  2430.24907325,
+            5827.90879421,  9704.32030926])
+
+    References
+    ----------
+    .. [1] Roquet, F., G. Madec, T.J. McDougall, P.M. Barker, 2015: Accurate
+           polynomial expressions for the density and specifc volume of
+           seawater using the TEOS-10 standard. Ocean Modelling.
+    """
+
+    z = p * 1e-4
+
+    dynamic_enthalpy_SSO_0_p = z * (9.726613854843870e-4 + z * (
+        -2.252956605630465e-5 + z * (2.376909655387404e-6 + z * (
+            -1.664294869986011e-7 + z * (-5.988108894465758e-9 + z * (
+                h006 + h007 * z))))))
+
+    return dynamic_enthalpy_SSO_0_p * db2Pascal * 1e4
+
+
 # FIXME: Check if this is still used and remove it.
 def enthalpy_SSO_0_p(p):
     """