extras¶
- seawater.extras.dist(lat, lon, units='km')¶
Calculate distance between two positions on globe using the “Plane Sailing” method. Also uses simple geometry to calculate the bearing of the path between position pairs.
- Parameters:
- latarray_like
decimal degrees (+ve N, -ve S) [- 90.. +90]
- lonarray_like
decimal degrees (+ve E, -ve W) [-180..+180]
- unitsstring, optional
default kilometers
- Returns:
- distarray_like
distance between positions in units
- phaseanglearray_like
angle of line between stations with x axis (East). Range of values are -180..+180. (E=0, N=90, S=-90)
References
[1]The PLANE SAILING method as described in “CELESTIAL NAVIGATION” 1989 by Dr. P. Gormley. The Australian Antarctic Division.
Examples
>>> import seawater as sw >>> sw.dist(0, [-179, 180]) (array([111.12]), array([180.])) >>> lon = [35, 35] >>> lat = [41, 40] >>> sw.dist(lat, lon) (array([111.12]), array([-90.])) >>> # Create a distance vector. >>> lon = np.arange(30, 40, 1) >>> lat = 35 >>> np.cumsum(np.append(0, sw.dist(lat, lon, units="km")[0])) array([ 0. , 91.02417516, 182.04835032, 273.07252548, 364.09670065, 455.12087581, 546.14505097, 637.16922613, 728.19340129, 819.21757645])
- seawater.extras.f(lat)¶
Calculates the Coriolis factor \(f\) defined by:
\[\begin{split}f = 2 \\Omega \\sin(lat)\end{split}\]where:
\[\begin{split}\\Omega = \\frac{2 \\pi}{\\textrm{sidereal day}} = 7.2921150e^{-5} \\textrm{ radians sec}^{-1}\end{split}\]- Parameters:
- latarray_like
latitude in decimal degrees north [-90..+90].
- Returns:
- farray_like
Coriolis factor [s -1]
References
[1]S. Pond & G.Pickard 2nd Edition 1986 Introductory Dynamical Oceanography Pergamon Press Sydney. ISBN 0-08-028728-X
[2]A.E. Gill 1982. p.54 Eqn. 3.7.15 “Atmosphere-Ocean Dynamics” Academic Press: New York. ISBN: 0-12-283522-0
[3]Groten, E., 2004: Fundamental Parameters and Current (2004) Best Estimates of the Parameters of Common Relevance to Astronomy, Geodesy, and Geodynamics. Journal of Geodesy, 77, pp. 724-797.
Examples
>>> import seawater as sw >>> sw.f(45) 0.00010312445296824608
- seawater.extras.satAr(s, t)¶
Solubility (saturation) of Argon (Ar) in sea water.
- Parameters:
- sarray_like
salinity [psu (PSS-78)]
- tarray_like
temperature [℃ (ITS-90)]
- Returns:
- satArarray_like
solubility of Ar [ml l -1]
References
[1]Weiss, R. F. 1970. The Solubility of Nitrogen, Oxygen and Argon in Water and Seawater Deep-Sea Research Vol. 17, p. 721-735. doi:10.1016/0011-7471(70)90037-9
Examples
>>> # Data from Weiss 1970. >>> import seawater as sw >>> from seawater.library import T90conv >>> t = T90conv([[-1, -1], [10, 10], [20, 20], [40, 40]]) >>> s = [[20, 40], [20, 40], [20, 40], [20, 40]] >>> sw.satAr(s, t) array([[0.4455784 , 0.38766011], [0.33970659, 0.29887756], [0.27660227, 0.24566428], [0.19861429, 0.17937698]])
- seawater.extras.satN2(s, t)¶
Solubility (saturation) of Nitrogen (N2) in sea water.
- Parameters:
- sarray_like
salinity [psu (PSS-78)]
- tarray_like
temperature [℃ (ITS-90)]
- Returns:
- satN2array_like
solubility of N2 [ml l -1]
References
[1]Weiss, R. F. 1970. The Solubility of Nitrogen, Oxygen and Argon in Water and Seawater Deep-Sea Research Vol. 17, p. 721-735. doi:10.1016/0011-7471(70)90037-9
Examples
>>> # Data from Weiss 1970. >>> import seawater as sw >>> from seawater.library import T90conv >>> t = T90conv([[-1, -1], [10, 10], [20, 20], [40, 40]]) >>> s = [[20, 40], [20, 40], [20, 40], [20, 40]] >>> sw.satN2(s, t) array([[16.27952432, 14.00784526], [12.64036196, 11.01277257], [10.46892822, 9.21126859], [ 7.78163876, 6.95395099]])
- seawater.extras.satO2(s, t)¶
Solubility (saturation) of Oxygen (O2) in sea water.
- Parameters:
- sarray_like
salinity [psu (PSS-78)]
- tarray_like
temperature [℃ (ITS-68)]
- Returns:
- satO2array_like
solubility of O2 [ml l -1 ]
References
[1]Weiss, R. F. 1970. The Solubility of Nitrogen, Oxygen and Argon in Water and Seawater Deep-Sea Research Vol. 17, p. 721-735. doi:10.1016/0011-7471(70)90037-9
Examples
>>> # Data from Weiss 1970. >>> import seawater as sw >>> from seawater.library import T90conv >>> t = T90conv([[-1, -1], [10, 10], [20, 20], [40, 40]]) >>> s = [[20, 40], [20, 40], [20, 40], [20, 40]] >>> sw.satO2(s, t) array([[9.162056 , 7.98404249], [6.95007741, 6.12101928], [5.64401453, 5.01531004], [4.0495115 , 3.65575811]])
- seawater.extras.swvel(length, depth)¶
Calculates surface wave velocity.
- lengtharray_like
wave length
- deptharray_like
water depth [meters]
- Returns:
- speedarray_like
surface wave speed [m s -1]
Examples
>>> import seawater as sw >>> sw.swvel(10, 100) 3.949327084834294