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Developing sco class #33
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Original file line number | Diff line number | Diff line change |
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#!/usr/bin/env python | ||
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""" | ||
Class to generate NEMO v4.0 s-coordinates | ||
""" | ||
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from typing import Optional # , Tuple | ||
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# import numpy as np | ||
from xarray import DataArray, Dataset | ||
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from .zgr import Zgr | ||
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# from pydomcfg.utils import is_nemo_none | ||
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class Sco(Zgr): | ||
""" | ||
Class to generate terrain-following coordinates dataset objects. | ||
Currently, four types of terrain-following grids can be genrated: | ||
*) uniform sigma-coordinates (Phillips 1957) | ||
*) stretched s-coordinates with Song & Haidvogel 1994 stretching | ||
*) stretched s-coordinates with Siddorn & Furner 2013 stretching | ||
*) stretched s-coordinates with Madec et al. 1996 stretching | ||
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Method | ||
------ | ||
*) Model levels' depths depT/W are defined from analytical function. | ||
*) Model vertical scale factors e3 (i.e., grid cell thickness) can | ||
be computed as | ||
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1) analytical derivative of depth function | ||
(ln_e3_dep=False); for backward compatibility with v3.6. | ||
2) discrete derivative (central-difference) of levels' depth | ||
(ln_e3_dep=True). The only possibility from v4.0. | ||
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References: | ||
*) NEMO v4.0 domzgr/{zgr_sco,s_sh94,s_sf12,s_tanh} subroutine | ||
*) Phillips, J. Meteorol., 14, 184-185, 1957. | ||
*) Song & Haidvogel, J. Comp. Phy., 115, 228-244, 1994. | ||
*) Siddorn & Furner, Oce. Mod. 66:1-13, 2013. | ||
*) Madec, Delecluse, Crepon & Lott, JPO 26(8):1393-1408, 1996. | ||
""" | ||
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# -------------------------------------------------------------------------- | ||
def __call__( | ||
self, | ||
bot_min: float, | ||
bot_max: float, | ||
hc: float = 0.0, | ||
rmax: Optional[float] = None, | ||
stretch: Optional[str] = None, | ||
psurf: Optional[float] = None, | ||
pbott: Optional[float] = None, | ||
alpha: Optional[float] = None, | ||
efold: Optional[float] = None, | ||
pbot2: Optional[float] = None, | ||
ln_e3_dep: bool = True, | ||
) -> Dataset: | ||
""" | ||
Generate NEMO terrain-following model levels. | ||
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Parameters | ||
---------- | ||
bot_min: float | ||
Minimum depth of bottom topography surface (>0) (m) | ||
bot_max: float | ||
Maximum depth of bottom topography surface (>0) (m) | ||
hc: float | ||
critical depth for transition from uniform sigma | ||
to stretched s-coordinates (>0) (m) | ||
rmax: float, optional | ||
maximum slope parameter value allowed | ||
stretch: str, optional | ||
Type of stretching applied: | ||
*) None = no stretching, i.e. uniform sigma-coord. | ||
*) "sh94" = Song & Haidvogel 1994 stretching | ||
*) "sf12" = Siddorn & Furner 2013 stretching | ||
*) "md96" = Madec et al. 1996 stretching | ||
psurf: float, optional | ||
sh94: surface control parameter (0<= psurf <=20) | ||
md96: surface control parameter (0<= psurf <=20) | ||
sf12: thickness of first model layer (m) | ||
pbott: float, optional | ||
sh94: bottom control parameter (0<= pbott <=1) | ||
md96: bottom control parameter (0<= pbott <=1) | ||
sf12: scaling factor for computing thickness | ||
of bottom level Zb | ||
alpha: float, optional | ||
sf12: stretching parameter | ||
efold: float, optional | ||
sf12: efold length scale for transition from sigma | ||
to stretched coord | ||
pbot2: float, optional | ||
sf12 offset for calculating Zb = H*pbott + pbot2 | ||
ln_e3_dep: bool | ||
Logical flag to comp. e3 as fin. diff. (True) or | ||
analyt. (False) (default = True) | ||
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Returns | ||
------- | ||
Dataset | ||
Describing the 3D geometry of the model | ||
""" | ||
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self._bot_min = bot_min | ||
self._bot_max = bot_max | ||
self._hc = hc | ||
self.rmax = rmax | ||
self._stretch = stretch | ||
self._ln_e3_dep = ln_e3_dep | ||
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# set stretching parameters after checking their consistency | ||
if self._stretch: | ||
self._check_stretch_par(psurf, pbott, alpha, efold, pbot2) | ||
self._psurf = psurf or 0.0 | ||
self._pbott = pbott or 0.0 | ||
self._alpha = alpha or 0.0 | ||
self._efold = efold or 0.0 | ||
self._pbot2 = pbot2 or 0.0 | ||
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# ds = self._init_ds() | ||
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# compute envelope bathymetry DataArray | ||
self._envlp = self._compute_env(self._bathy["Bathymetry"]) | ||
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# compute sigma-coordinates for z3 computation | ||
self._sigmas = self._compute_sigma(self._z) | ||
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# compute z3 depths of zco vertical levels | ||
# dsz = self._sco_z3(ds_env) | ||
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# compute e3 scale factors | ||
# dse = self._compute_e3(dsz) if self._ln_e3_dep else self._analyt_e3(dsz) | ||
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# addind this only to not make darglint complying | ||
return self._merge_z3_and_e3(self._envlp, self._envlp, self._envlp, self._envlp) | ||
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# -------------------------------------------------------------------------- | ||
def _check_stretch_par(self, psurf, pbott, alpha, efold, pbot2): | ||
""" | ||
Check consistency of stretching parameters | ||
""" | ||
if not (psurf and pbott): | ||
if self._stretch == "sh94": | ||
srf = "rn_theta" | ||
bot = "rn_bb" | ||
elif self._stretch == "md96": | ||
srf = "rn_theta" | ||
bot = "rn_thetb" | ||
elif self._stretch == "sf12": | ||
srf = "rn_zs" | ||
bot = "rn_zb_a" | ||
raise ValueError( | ||
f"{srf} and {bot} MUST be set when using {self._stretch} stretching." | ||
) | ||
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if self._stretch == "sf12": | ||
if not (alpha and efold and pbot2): | ||
raise ValueError( | ||
"rn_alpha, rn_efold and rn_zb_b MUST be set when using \ | ||
sf12 stretching." | ||
) | ||
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# -------------------------------------------------------------------------- | ||
def _compute_env(self, da: DataArray) -> DataArray: | ||
""" | ||
Compute the envelope bathymetry surface by applying the | ||
Martinho & Batteen (2006) smoothing algorithm to the | ||
actual topography to reduce the maximum value of the slope | ||
parameter | ||
r = abs(Hb-Ha) / (Ha+Hb) | ||
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where Ha and Hb are the depths of adjacent grid cells. | ||
The maximum slope parameter is reduced to be <= rmax. | ||
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Reference: | ||
*) Martinho & Batteen, Oce. Mod. 13(2):166-175, 2006. | ||
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Parameters | ||
---------- | ||
da: DataArray | ||
xarray DataArray of the 2D bottom topography | ||
Returns | ||
------- | ||
DataArray | ||
xarray DataArray of the 2D envelope bathymetry | ||
""" | ||
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return da |
Original file line number | Diff line number | Diff line change |
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@@ -22,6 +22,56 @@ def _are_nemo_none(var: Iterable) -> Iterator[bool]: | |
yield _is_nemo_none(v) | ||
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# ----------------------------------------------------------------------------- | ||
def _calc_rmax(depth: DataArray) -> float: | ||
""" | ||
Calculate rmax: measure of steepness | ||
This function returns the maximum slope paramater | ||
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rmax = abs(Hb - Ha) / (Ha + Hb) | ||
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where Ha and Hb are the depths of adjacent grid cells (Mellor et al 1998). | ||
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Reference: | ||
*) Mellor, Oey & Ezer, J Atm. Oce. Tech. 15(5):1122-1131, 1998. | ||
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Parameters | ||
---------- | ||
depth: DataArray | ||
Bottom depth (units: m). | ||
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Returns | ||
------- | ||
float | ||
Maximum slope parameter (units: None) | ||
""" | ||
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# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | ||
# Do we actually need this? mypy complains since | ||
# DataArray.reset_indexe() returns Optional["DataArray"] | ||
# | ||
# depth = depth.reset_index(list(depth.dims)) | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Interesting, not sure why they assigned that type annotation to
I was just lazy though... it's quite easy in this case to properly use the indexes. I'll open a separate PR for that as you haven't removed There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Ok, I will implement the quick solution There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. BTW, forza azzurri !!!! |
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both_rmax = [] | ||
for dim in depth.dims: | ||
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# (Hb - Ha) / (Ha + Hb) | ||
depth_diff = depth.diff(dim) | ||
depth_rolling_sum = depth.rolling({dim: 2}).sum().dropna(dim) | ||
rmax = depth_diff / depth_rolling_sum | ||
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# (rmax_a + rmax_b) / 2 | ||
rmax = rmax.rolling({dim: 2}).mean().dropna(dim) | ||
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# Fill first row and column | ||
rmax = rmax.pad({dim: (1, 1)}, constant_values=0) | ||
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both_rmax.append(np.abs(rmax)) | ||
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return np.maximum(*both_rmax) | ||
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# ----------------------------------------------------------------------------- | ||
def generate_cartesian_grid( | ||
ppe1_m, | ||
ppe2_m, | ||
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There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Missing a final
else
with a slightly different error (i.e., typo or the stretch is not supported)