gsw_geo_strf_dyn_height_1 {gsw} | R Documentation |
Geostrophic Dynamic Height Anomaly (provisional version)
Description
This 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. Note that this yields an integral
with the top measured pressure (not zero) as an upper limit.
Usage
gsw_geo_strf_dyn_height_1(SA, CT, p, p_ref = 0, max_dp = 1, interp_method = 2)
Arguments
SA |
Absolute Salinity [ g/kg ] |
CT |
Conservative Temperature [ degC ] |
p |
sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar |
p_ref |
reference pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar |
max_dp |
numeric value indicating the maximum tolerated pressure
separation between levels. If any pressure step exceeds |
interp_method |
integer specifying interpolation scheme (1 for linear, 2 for pchip) |
Details
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.
Value
A vector containing geopotential anomaly in
for each level. For more on the units, see [2].
Implementation Note
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.
References
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.
Examples
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))