R/gsw.R
gsw_geo_strf_dyn_height_1.RdThis calculates a geopotential anomaly, called either the dynamic height anomaly or the geostrophic streamfunction in the TEOS-10 document listed as [1] below.
To get the column-integrated value in meters, take the first value of the returned vector and divide by 9.7963\(m/s^2\). Note that this yields an integral with the top measured pressure (not zero) as an upper limit.
gsw_geo_strf_dyn_height_1(SA, CT, p, p_ref = 0, max_dp = 1, interp_method = 2)Absolute Salinity [ g/kg ]
Conservative Temperature [ degC ]
sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar
reference pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar
numeric value indicating the maximum tolerated pressure
separation between levels. If any pressure step exceeds max_dp, then
a uniform grid is constructed with max_dp as the interval.
integer specifying interpolation scheme (1 for linear, 2 for pchip)
A vector containing geopotential anomaly in \(m^2/s^2\) for each level. For more on the units, see [2].
Because of the scheme used in the underlying C code, the pressures must be in order, and must not have any repeats. Also, there must be at least 4 pressure values. Violating any of these restrictions yields an error.
If p_ref exceeds the largest p value, a vector
of zeros is returned, in accordance with the underlying C code.
This R function uses a wrapper to a C function contained within the GSW-C system as updated 2021-12-28 at https://github.com/TEOS-10/GSW-C with git commit `98f0fd40dd9ceb0ba82c9d47ac750e935a7d0459`.
The C function uses data from the library/gsw_data_v3_0.mat
file provided in the GSW-Matlab source code, version 3.06-11.
Unfortunately, this version of the mat file is no longer displayed on the
TEOS-10.org website. Therefore, in the interests of making GSW-R be
self-contained, a copy was downloaded from
http://www.teos-10.org/software/gsw_matlab_v3_06_11.zip on 2022-05-25,
the .mat file was stored in the developer/create_data directory of
https://github.com/TEOS-10/GSW-R, and then the dataset used in GSW-R
was created based on that .mat file.
Please consult http://www.teos-10.org to learn more about the various TEOS-10 software systems.
1. http://www.teos-10.org/pubs/gsw/html/gsw_geo_strf_dyn_height.html
2. Talley et al., 2011. Descriptive Physical Oceanography, Edition 6, Elsevier.
SA <- c(34.7118, 34.8915, 35.0256, 34.8472, 34.7366, 34.7324)
CT <- c(28.8099, 28.4392, 22.7862, 10.2262, 6.8272, 4.3236)
p <- c( 10, 50, 125, 250, 600, 1000)
p_ref <- 1000
dh <- gsw_geo_strf_dyn_height_1(SA, CT, p, p_ref, 1, 2)
## FIXME: The following test values fail.
## all.equal(dh, c(17.039204557769487, 14.665853784722286, 10.912861136923812,
## 7.567928838774945, 3.393524055565328, 0))