# Source code for landlab.components.spatial_precip.generate_spatial_precip

```
import contextlib
import numpy as np
from scipy.stats import fisk, genextreme
from landlab import Component, RasterModelGrid
[docs]
class SpatialPrecipitationDistribution(Component):
"""Generate spatially resolved precipitation events.
A component to generate a sequence of spatially resolved storms over a
grid, following a lightly modified version (see below) of the
stochastic methods of Singer & Michaelides, Env Res Lett 12, 104011,
2017, & Singer et al., Geosci. Model Dev., accepted, 10.5194/gmd-2018-86.
The method is heavily stochastic, and at the present time is intimately
calibrated against the conditions at Walnut Gulch, described in those
papers. In particular, assumptions around intensity-duration
calibration and orographic rainfall are "burned in" for now, and are
not accessible to the user. The various probability distributions
supplied to the various run methods default to WG values, but are
easily modified. This calibration reflects a US desert southwest
"monsoonal" climate, and the component distinguishes (optionally)
between two seasons, "monsoonal" and "winter". The intensity-duration
relationship is shared between the seasons, and so may prove useful in
a variety of storm-dominated contexts.
The default is to disable the orographic rainfall functionality of the
component. However, if orographic_scenario == 'Singer', the component
requires a 'topographic__elevation' field to already exist on the grid
at the time of instantiation.
The component has two ways of simulating a "year". This choice is
controlled by the 'limit' parameter of the yield methods. If limit==
'total_rainfall', the component will continue to run until the total
rainfall for the season and/or year exceeds a stochastically generated
value. This method is directly comparable to the Singer & Michaelides
method, but will almost always result in years which are not one
calendar year long, unless the input distributions are very carefully
recalibrated for each use case. If limit=='total_time', the component
will terminate a season and/or year once the elapsed time exceeds one
year. In this case, the total rainfall will not correspond to the
stochastically generated total. You can access the actual total for the
last season using the property `(median_)total_rainfall_last_season`.
Note that this component cannot simulate the occurrence of more than one
storm at the same time. Storms that should be synchronous will instead
occur sequentially, with no interstorm time. This limitation means that
if enough storms occur in a year that numstorms*mean_storm_duration
exceeds one year, the number of simulated storms will saturate. This
limitation may be relaxed in the future.
The component offers the option to modify the maximum number of storms
simulated per year. If you find simulations encountering this limit too
often, you may need to raise this limit. Conversely, it could be lowered
to reduce memory usage over small grids. However, in increasing the value,
beware - the component maintains two limit*nnodes arrays, which will chew
through memory if the limit gets too high. The default will happily
simulate grids up to around 50 km * 50 km using the default probability
distributions.
Key methods are:
yield_storms
Generate a timeseries of storm:interstorm duration pairs, alongside
a field that describes the spatial distribution of rain during that
storm.
yield_years
Generate a timeseries of ints giving number of storms per year,
alongside a field that describes the spatial distribution of total
rainfall across that year.
yield_seasons
Generate a timeseries of ints giving number of storms per season,
alongside a field that describes the spatial distribution of total
rainfall across that season.
calc_annual_rainfall
Produce a timeseries of tuples giving total rainfall each season,
without resolving the storms spatially (i.e., fast!).
A large number of properties are available to access storm properties
during generation:
- current_year
- current_season
- storm_depth_last_storm
- storm_recession_value_last_storm
- storm_duration_last_storm
- storm_area_last_storm
- storm_intensity_last_storm
- total_rainfall_this_season
- total_rainfall_this_year
- total_rainfall_last_season
- total_rainfall_last_year
- median_total_rainfall_this_season
- median_total_rainfall_this_year
- median_total_rainfall_last_season
- median_total_rainfall_last_year
- number_of_nodes_under_storm
- nodes_under_storm
- target_median_total_rainfall_this_season
Note that becuase these are medians not means,
median_total_rainfall_last_season + median_total_rainfall_this_season
!= median_total_rainfall_this_year.
Significant differences between this component and the Singer code are:
- The component does not model evapotranspiration. Use a separate
Landlab component for this.
- The component runs only over a LL grid; there is no such thing as a
validation or simulation run.
- It produces "fuzz" around intensity values using a continuous
distribution; Singer does this with integer steps.
- Step changes mid-run cannot be explicitly modelled. Instead, run the
component for a fixed duration, make the change to the
distribution input parameter, then run it again.
- Storms can be centred at any spatial coordinate, not just over nodes.
- Edge buffering is now dynamic; i.e., big storms have a bigger edge
buffer than smaller storms. Storms can be centered off the grid
edges.
- Storms are never discarded - once a storm is drawn, it must hit the
catchment, and positions are repeatedly selected until this can
happen. Singer's method would discard such a storm and draw a new
one.
- Durations are not rescaled to ensure both total duration and total
precip are both satisfied at the same time, as in Singer's method.
Instead, the component either matches a year's duration, *or*
exactly a year's worth of rain. This choice is dictated by the
`limit` parameter in the yield methods.
Examples
--------
>>> import numpy as np
>>> from landlab import RasterModelGrid, VoronoiDelaunayGrid
>>> mg = RasterModelGrid((10, 10), xy_spacing=1000.0)
>>> rain = SpatialPrecipitationDistribution(mg)
Calling yield_storms will produce storm-interstorm duration (hr) pairs
until the model runtime has elapsed.
>>> np.random.seed(1)
>>> total_t_each_step = [
... (storm + interstorm) for (storm, interstorm) in rain.yield_storms()
... ]
>>> len(total_t_each_step)
41
>>> np.isclose(sum(total_t_each_step) / 24.0, 365.0)
True
The actual rainfall intensities during that interval are accessible in the
'rainfall__flux' field (mm/hr). The storm centre does not have to be over
the grid, but in this case, it was for the last simulated storm:
>>> mg.at_node["rainfall__flux"].argmax()
80
We can also run the component for only one season (i.e., only using one
of the pdf sets describing the storm properties):
>>> for field in ("rainfall__flux", "rainfall__total_depth_per_year"):
... _ = mg.at_node.pop(field) # clear out the existing fields
...
>>> rain = SpatialPrecipitationDistribution(mg, number_of_years=2)
>>> np.random.seed(5)
>>> total_t_each_step = [
... (storm + interstorm)
... for (storm, interstorm) in rain.yield_storms(
... style="monsoonal", monsoon_fraction_of_year=0.35
... )
... ]
>>> np.isclose(sum(total_t_each_step) / 24.0 / 365.0 / 2.0, 0.35)
True
Note this behaviour can be stopped by upping monsoon_fraction_of_year:
>>> np.random.seed(5)
>>> total_t_each_step = [
... (storm + interstorm)
... for (storm, interstorm) in rain.yield_storms(
... style="monsoonal", monsoon_fraction_of_year=1.0
... )
... ]
>>> np.isclose(round(sum(total_t_each_step) / 24.0 / 365.0 / 2.0, 2), 1.0)
True
yield_years yields the number of storms in the last whole year.
Use 'rainfall__total_depth_per_year' to access the rainfall map for the
last fully elapsed year, or equivalently, the total_rainfall_last_year
property. Note the component seamlessly handles non-raster grid types:
>>> vdg = VoronoiDelaunayGrid(
... np.random.rand(100) * 1000.0, np.random.rand(100) * 1000.0
... )
>>> np.random.seed(3)
>>> rain = SpatialPrecipitationDistribution(vdg, number_of_years=3)
>>> storms_each_year = []
>>> for total_storms in rain.yield_years(
... style="monsoonal", total_rf_trend=0.05, storminess_trend=-0.02
... ):
... storms_each_year.append(total_storms)
... assert np.all(
... np.equal(
... vdg.at_node["rainfall__total_depth_per_year"],
... rain.total_rainfall_last_year,
... )
... )
>>> sum(storms_each_year)
11
yield_seasons yields rainfall statistics for individual seasons. Access
these using the various provided component properties. Note that we can
get the component to yield a total rainfall that is calibrated to the
supplied total_rf_gaussians if we set limit to 'total__rainfall' rather
than 'total_time' (at the cost of exactly matching the season length):
>>> for field in ("rainfall__flux", "rainfall__total_depth_per_year"):
... _ = mg.at_node.pop(field) # clear out the existing fields
...
>>> rain = SpatialPrecipitationDistribution(mg, number_of_years=2)
>>> np.random.seed(5)
>>> season_list = []
>>> theoretical_median_rf_season = []
>>> median_rf_season = []
>>> median_rf_last_year = []
>>> mean_rf_season = []
>>> mean_rf_last_year = []
>>> for storm_number in rain.yield_seasons(limit="total_rainfall"):
... season_list.append(rain.current_season)
... theoretical_median_rf_season.append(
... rain.target_median_total_rainfall_this_season
... )
... median_rf_season.append(rain.median_total_rainfall_this_season)
... median_rf_last_year.append(rain.median_total_rainfall_last_year)
... mean_rf_season.append(rain.total_rainfall_this_season.mean())
... mean_rf_last_year.append(rain.total_rainfall_last_year.mean())
...
>>> season_list == ["M", "W", "M", "W"]
True
>>> [
... meas > sim
... for (meas, sim) in zip(median_rf_season, theoretical_median_rf_season)
... ] # must exceed
[True, True, True, True]
>>> np.isclose(median_rf_last_year[0], 0.0)
True
>>> for season in (0, 2): # this property must be the same in both seasons
... np.isclose(median_rf_last_year[season], median_rf_last_year[season + 1])
...
True
True
Note that because we work here with medians, the seasonal medians don't sum
to the year median, but the means do:
>>> np.isclose(median_rf_last_year[2], median_rf_season[0] + median_rf_season[1])
False
>>> np.isclose(mean_rf_last_year[2], mean_rf_season[0] + mean_rf_season[1])
True
References
----------
**Required Software Citation(s) Specific to this Component**
Singer, M., Michaelides, K., Hobley, D. (2018). STORM 1.0: a simple,
flexible, and parsimonious stochastic rainfall generator for simulating
climate and climate change. Geoscientific Model Development 11(9),
3713-3726. https://dx.doi.org/10.5194/gmd-11-3713-2018
**Additional References**
None Listed
"""
_name = "SpatialPrecipitationDistribution"
_unit_agnostic = False
_cite_as = """@Article{gmd-2018-86,
title={STORM: A simple, flexible, and parsimonious stochastic rainfall
generator for simulating climate and climate change},
author={Singer, M. B. and Michaelides, K. and Hobley, D. E. J.},
journal={Geoscientific Model Development Discussions},
volume={2018},
pages={1--25},
year={2018},
url={https://www.geosci-model-dev-discuss.net/gmd-2018-86/},
doi={10.5194/gmd-2018-86}
}"""
_info = {
"rainfall__flux": {
"dtype": float,
"intent": "out",
"optional": False,
"units": "mm/hr",
"mapping": "node",
"doc": "Depth of water delivered per unit time in each storm",
},
"rainfall__total_depth_per_year": {
"dtype": float,
"intent": "out",
"optional": False,
"units": "mm/yr",
"mapping": "node",
"doc": "Depth of water delivered in total in each model year",
},
"topographic__elevation": {
"dtype": float,
"intent": "in",
"optional": True,
"units": "m",
"mapping": "node",
"doc": "Land surface topographic elevation",
},
}
[docs]
def __init__(
self, grid, number_of_years=1, orographic_scenario=None, max_numstorms=5000
):
"""Create the SpatialPrecipitationDistribution generator component.
Parameters
----------
grid : ModelGrid
A Landlab model grid of any type.
number_of_years : int
The number of years over which to generate storms.
orographic_scenario : {None, 'Singer', func}
Whether to use no orographic rule, or to adopt S&M's 2017
calibration for Walnut Gulch. Alternatively, provide a function
here that turns the provided elevation of the storm center into
a length-11 curve weighting to select which orographic scenario
to apply.
"""
super().__init__(grid)
gaugecount = (grid.status_at_node != grid.BC_NODE_IS_CLOSED).sum()
self._gauge_dist_km = np.zeros(gaugecount, dtype="float")
self._temp_dataslots1 = np.zeros(gaugecount, dtype="float")
self._temp_dataslots2 = np.zeros(gaugecount, dtype="float")
self._numyrs = number_of_years
self._max_numstorms = max_numstorms
# This is for initializing matrices. Trailing zeros are deleted from
# matrixes at the end of the code.
assert orographic_scenario in (None, "Singer")
self._orographic_scenario = orographic_scenario
# build LL fields:
self.initialize_output_fields()
# bind the field to the internal variable:
self._rain_int_gauge = self._grid.at_node["rainfall__flux"]
self._total_rf_year = self._grid.at_node["rainfall__total_depth_per_year"]
# store some info on the open node grid extent:
open_nodes = self._grid.status_at_node != self._grid.BC_NODE_IS_CLOSED
self._minx = self._grid.node_x[open_nodes].min()
self._maxx = self._grid.node_x[open_nodes].max()
self._miny = self._grid.node_y[open_nodes].min()
self._maxy = self._grid.node_y[open_nodes].max()
self._widthx = self._maxx - self._minx
self._widthy = self._maxy - self._miny
self._running_total_rainfall_this_year = self._grid.zeros("node")
self._running_total_rainfall_this_season = self._grid.zeros("node")
self._open_area = self._grid.cell_area_at_node[open_nodes].sum()
self._scaling_to_WG = self._open_area / 275710702.0
# ^ this is the relative size of the catchment compared to WG
[docs]
def yield_storms(
self,
limit="total_time",
style="whole_year",
total_rf_trend=0.0,
storminess_trend=0.0,
monsoon_fraction_of_year=0.42,
monsoon_total_rf_gaussian=(("sigma", 64.0), ("mu", 207.0)),
monsoon_storm_duration_GEV=(
("shape", -0.570252),
("sigma", 35.7389),
("mu", 34.1409),
("trunc_interval", (0.0, 1040.0)),
),
monsoon_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
monsoon_storm_interarrival_GEV=(
("shape", -0.807971),
("sigma", 9.4957),
("mu", 10.6108),
("trunc_interval", (0.0, 720.0)),
),
monsoon_storm_radial_weakening_gaussian=(("sigma", 0.08), ("mu", 0.25)),
winter_total_rf_gaussian=(("sigma", 52.0), ("mu", 1.65)),
winter_storm_duration_fisk=(
("c", 1.0821),
("scale", 68.4703),
("trunc_interval", (0.0, 5000.0)),
),
winter_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
winter_storm_interarrival_GEV=(
("shape", 1.1131),
("sigma", 53.2671),
("mu", 47.4944),
("trunc_interval", (0.0, 720.0)),
),
winter_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
):
"""Yield a timeseries giving the number of storms occurring each year
in a rainfall simulation.
All default distributions specified as parameters reflect values for
Walnut Gulch, see Singer & Michaelides, 2017 & Singer et al, submitted.
Parameters
----------
limit : str
Controls whether a season is defined based on its total rainfall
(and can be any length), or by its duration (and can have any
amount of rainfall). One of 'total_time' or 'total_rainfall'.
If 'total_time', monsoon_fraction_of_year
sets the fraction of a year occupied by the monsoon.
style : str
Controls whether the component seeks to simulate a western US-
style "monsoonal" climate, a western US-style winter climate,
or a full year combining both. One of 'whole_year', 'monsoonal',
or 'winter' These distributions are by default
based on Singer et al.'s calibrations. Note if 'monsoonal',
the total duration of a "year" will appear to be only
`monsoon_fraction_of_year`, and the opposite for `winter`.
total_rf_trend : float
Controls if a drift is applied to the total rainfall distribution
through time. If 0., no trend. If positive, rainfall totals
increase gradually through time. If negative, they fall through
time. S&M recommend +/- 0.07 for a realistic climate change driven
drift at Walnut Gulch.
storminess_trend : float
Controls if a drift is applied to the expected intensity of
individual storms through time. If 0., no trend. If positive,
storms get more intense through time, if negative, less so. S&M
recommend +/- 0.01 for a realistic climate change driven drift at
Walnut Gulch.
monsoon_fraction_of_year : float
If limit == 'total_time', sets the fraction of one year occupied
by the monsoon season. If not, ignored. Singer's monsoon runs from
May to September, inclusive, and the default reflects this.
monsoon_total_rf_gaussian : dict
Parameters defining the normal distribution controlling the total
rainfall expected in each year. S&M use 'mu' in {143., 271.} for
step changes up/down in rainfall totals.
monsoon_storm_duration_GEV : dict
Parameters defining a generalised extreme value distribution
controlling the duration of each storm. In minutes.
monsoon_storm_area_GEV : dict
Parameters defining a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
monsoon_storm_interarrival_GEV : dict
Parameters defining a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. Note that this calibration is specifically to Walnut Gulch,
which has an area of 275 km**2. The generator directly scales this
resulting distribution to the area ratio of Walnut Gulch to the
open cells of the grid. This crudely accounts for the fact that
bigger catchments will have more storms, but note that the heavy
tail on this distribution means the default distribution shape
will not be trustworthy for catchments with big differences in
size from Walnut Gulch.
monsoon_storm_radial_weakening_gaussian : dict
Parameters defining a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
winter_total_rf_gaussian : dict
Parameters defining a normal distribution controlling the total
rainfall expected in each year. S&M use 'mu' in {143., 271.} for
step changes up/down in rainfall totals.
winter_storm_duration_fisk : dict
Parameters defining a Fisk (i.e., log-logistic) distribution
controlling the duration of each storm. Note this differs from the
summer scaling. In Minutes.
winter_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
winter_storm_interarrival_GEV : dict
Parameters defining a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. The same considerations apply here as for the monsoonal
interstorm equivalent.
winter_storm_radial_weakening_gaussian : dict
Parameters defining a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
Yields
------
(storm_t, interval_t) : (float, float)
Tuple pair of duration of a single storm, then the interstorm
interval that follows it. In hrs. The rainfall__flux field
describes the rainfall rate during the interval storm_t as the
tuple is yielded. In HRS.
Note that the rainfall__total_depth_per_year field gives the total
accumulated rainfall depth during the *last completed* model year,
not the year to the point of yield. For the latter, use the
property `total_rainfall_this_year`.
"""
return self._run_the_process(
yield_storms=True,
yield_years=False,
yield_seasons=False,
limit=limit,
style=style,
monsoon_fraction_of_year=monsoon_fraction_of_year,
total_rf_trend=total_rf_trend,
storminess_trend=storminess_trend,
monsoon_total_rf_gaussian=monsoon_total_rf_gaussian,
monsoon_storm_duration_GEV=monsoon_storm_duration_GEV,
monsoon_storm_area_GEV=monsoon_storm_area_GEV,
monsoon_storm_interarrival_GEV=monsoon_storm_interarrival_GEV,
monsoon_storm_radial_weakening_gaussian=monsoon_storm_radial_weakening_gaussian,
winter_total_rf_gaussian=winter_total_rf_gaussian,
winter_storm_duration_fisk=winter_storm_duration_fisk,
winter_storm_area_GEV=winter_storm_area_GEV,
winter_storm_interarrival_GEV=winter_storm_interarrival_GEV,
winter_storm_radial_weakening_gaussian=winter_storm_radial_weakening_gaussian,
)
[docs]
def yield_years(
self,
limit="total_time",
style="whole_year",
total_rf_trend=0.0,
storminess_trend=0.0,
monsoon_fraction_of_year=0.42,
monsoon_total_rf_gaussian=(("sigma", 64.0), ("mu", 207.0)),
monsoon_storm_duration_GEV=(
("shape", -0.570252),
("sigma", 35.7389),
("mu", 34.1409),
("trunc_interval", (1.0, 1040.0)),
),
monsoon_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
monsoon_storm_interarrival_GEV=(
("shape", -0.807971),
("sigma", 9.4957),
("mu", 10.6108),
("trunc_interval", (0.0, 720.0)),
),
monsoon_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
winter_total_rf_gaussian=(("sigma", 52.0), ("mu", 1.65)),
winter_storm_duration_fisk=(
("c", 1.0821),
("scale", 68.4703),
("trunc_interval", (1.0, 5000.0)),
),
winter_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
winter_storm_interarrival_GEV=(
("shape", 1.1131),
("sigma", 53.2671),
("mu", 47.4944),
("trunc_interval", (0.0, 720.0)),
),
winter_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
):
"""Yield a timeseries giving the number if storms occurring each year
in a rainfall simulation.
All default distributions specified as parameters reflect values for
Walnut Gulch, see Singer & Michaelides, 2017 & Singer et al, submitted.
Parameters
----------
limit : ('total_time', 'total_rainfall')
Controls whether a season is defined based on its total rainfall
(and can be any length), or by its duration (and can have any
amount of rainfall). If 'total_time', monsoon_fraction_of_year
sets the fraction of a year occupied by the monsoon.
style : ('whole_year', 'monsoonal', 'winter')
Controls whether the component seeks to simulate a western US-
style "monsoonal" climate, a western US-style winter climate,
or a full year combining both. These distributions are by default
based on Singer et al.'s calibrations. Note if 'monsoonal',
the total duration of a "year" will appear to be only
`monsoon_fraction_of_year`, and the opposite for `winter`.
total_rf_trend : float
Controls if a drift is applied to the total rainfall distribution
through time. If 0., no trend. If positive, rainfall totals
increase gradually through time. If negative, they fall through
time. S&M recommend +/- 0.07 for a realistic climate chage driven
drift at Walnut Gulch.
storminess_trend : float
Controls if a drift is applied to the expected intensity of
individual storms through time. If 0., no trend. If positive,
storms get more intense through time, if negative, less so. S&M
recommend +/- 0.01 for a realistic climate change driven drift at
Walnut Gulch.
monsoon_fraction_of_year : float
If limit == 'total_time', sets the fraction of one year occupied
by the monsoon season. If not, ignored. Singer's monsoon runs from
May to September, inclusive, and the default reflects this.
monsoon_total_rf_gaussian is a normal distribution controlling the
total rainfall expected in each year. S&M use 'mu' in {143., 271.}
for step changes up/down in rainfall totals. In mm.
monsoon_storm_duration_GEV is a generalised extreme value distribution
controlling the duration of each storm. In MIN.
monsoon_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
monsoon_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. Note that this calibration is specifically to Walnut Gulch,
which has an area of 275 km**2. The generator directly scales this
resulting distribution to the area ratio of Walnut Gulch to the
open cells of the grid. This crudely accounts for the fact that
bigger catchments will have more storms, but note that the heavy
tail on this distribution means the default distribution shape
will not be trustworthy for catchments with big differences in
size from Walnut Gulch.
monsoon_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
winter_total_rf_gaussian is a normal distribution controlling the total
rainfall expected in each year. S&M use 'mu' in {143., 271.} for
step changes up/down in rainfall totals.
winter_storm_duration_fisk is a Fisk (i.e., log-logistic) distribution
controlling the duration of each storm. Note this differs from the
summer scaling. In MIN.
winter_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
winter_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. The same considerations apply here as for the monsoonal
interstorm equivalent.
winter_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
Yields
------
number_of_storms_per_year : float
Float that gives the number of storms simulated in the year that
elapsed since the last yield. The rainfall__total_depth_per_year
field gives the total accumulated rainfall depth during the year
preceding the yield. rainfall__flux gives the rainfall intensity of
the last storm in that year.
"""
return self._run_the_process(
yield_storms=False,
yield_years=True,
yield_seasons=False,
limit=limit,
style=style,
total_rf_trend=total_rf_trend,
storminess_trend=storminess_trend,
monsoon_fraction_of_year=monsoon_fraction_of_year,
monsoon_total_rf_gaussian=monsoon_total_rf_gaussian,
monsoon_storm_duration_GEV=monsoon_storm_duration_GEV,
monsoon_storm_area_GEV=monsoon_storm_area_GEV,
monsoon_storm_interarrival_GEV=monsoon_storm_interarrival_GEV,
monsoon_storm_radial_weakening_gaussian=monsoon_storm_radial_weakening_gaussian,
winter_total_rf_gaussian=winter_total_rf_gaussian,
winter_storm_duration_fisk=winter_storm_duration_fisk,
winter_storm_area_GEV=winter_storm_area_GEV,
winter_storm_interarrival_GEV=winter_storm_interarrival_GEV,
winter_storm_radial_weakening_gaussian=winter_storm_radial_weakening_gaussian,
)
[docs]
def yield_seasons(
self,
limit="total_time",
style="whole_year",
total_rf_trend=0.0,
storminess_trend=0.0,
monsoon_fraction_of_year=0.42,
monsoon_total_rf_gaussian=(("sigma", 64.0), ("mu", 207.0)),
monsoon_storm_duration_GEV=(
("shape", -0.570252),
("sigma", 35.7389),
("mu", 34.1409),
("trunc_interval", (1.0, 1040.0)),
),
monsoon_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
monsoon_storm_interarrival_GEV=(
("shape", -0.807971),
("sigma", 9.4957),
("mu", 10.6108),
("trunc_interval", (0.0, 720.0)),
),
monsoon_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
winter_total_rf_gaussian=(("sigma", 52.0), ("mu", 1.65)),
winter_storm_duration_fisk=(
("c", 1.0821),
("scale", 68.4703),
("trunc_interval", (1.0, 5000.0)),
),
winter_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
winter_storm_interarrival_GEV=(
("shape", 1.1131),
("sigma", 53.2671),
("mu", 47.4944),
("trunc_interval", (0.0, 720.0)),
),
winter_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
):
"""Yield a timeseries giving the number if storms occurring each season
in a rainfall simulation. Only meaningfully different from yield_years
if style=='whole_year'.
All default distributions specified as parameters reflect values for
Walnut Gulch, see Singer & Michaelides, 2017 & Singer et al, submitted.
Parameters
----------
limit : ('total_time', 'total_rainfall')
Controls whether a season is defined based on its total rainfall
(and can be any length), or by its duration (and can have any
amount of rainfall). If 'total_time', monsoon_fraction_of_year
sets the fraction of a year occupied by the monsoon.
style : ('whole_year', 'monsoonal', 'winter')
Controls whether the component seeks to simulate a western US-
style "monsoonal" climate, a western US-style winter climate,
or a full year combining both. These distributions are by default
based on Singer et al.'s calibrations. Note if 'monsoonal',
the total duration of a "year" will appear to be only
`monsoon_fraction_of_year`, and the opposite for `winter`.
total_rf_trend : float
Controls if a drift is applied to the total rainfall distribution
through time. If 0., no trend. If positive, rainfall totals
increase gradually through time. If negative, they fall through
time. S&M recommend +/- 0.07 for a realistic climate chage driven
drift at Walnut Gulch.
storminess_trend : float
Controls if a drift is applied to the expected intensity of
individual storms through time. If 0., no trend. If positive,
storms get more intense through time, if negative, less so. S&M
recommend +/- 0.01 for a realistic climate change driven drift at
Walnut Gulch.
monsoon_fraction_of_year : float
If limit == 'total_time', sets the fraction of one year occupied
by the monsoon season. If not, ignored. Singer's monsoon runs from
May to September, inclusive, and the default reflects this.
monsoon_total_rf_gaussian is a normal distribution controlling the
total rainfall expected in each year. S&M use 'mu' in {143., 271.}
for step changes up/down in rainfall totals. In mm.
monsoon_storm_duration_GEV is a generalised extreme value distribution
controlling the duration of each storm. In MIN.
monsoon_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
monsoon_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. Note that this calibration is specifically to Walnut Gulch,
which has an area of 275 km**2. The generator directly scales this
resulting distribution to the area ratio of Walnut Gulch to the
open cells of the grid. This crudely accounts for the fact that
bigger catchments will have more storms, but note that the heavy
tail on this distribution means the default distribution shape
will not be trustworthy for catchments with big differences in
size from Walnut Gulch.
monsoon_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
winter_total_rf_gaussian is a normal distribution controlling the total
rainfall expected in each year. S&M use 'mu' in {143., 271.} for
step changes up/down in rainfall totals.
winter_storm_duration_fisk is a Fisk (i.e., log-logistic) distribution
controlling the duration of each storm. Note this differs from the
summer scaling. In MIN.
winter_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
winter_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. The same considerations apply here as for the monsoonal
interstorm equivalent.
winter_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
Yields
------
number_of_storms_per_season : float
Float that gives the number of storms simulated in the season that
elapsed since the last yield. The rainfall__total_depth_per_year
field gives the total accumulated rainfall depth during the *year*
preceding the yield, *so far*. rainfall__flux gives the rainfall
intensity of the last storm in that year.
NB: Use the component property total_rainfall_last_season to access
the *actual* amount of rainfall in the season that has the number
of storms that the method generates.
"""
return self._run_the_process(
yield_storms=False,
yield_years=False,
yield_seasons=True,
limit=limit,
style=style,
total_rf_trend=total_rf_trend,
storminess_trend=storminess_trend,
monsoon_fraction_of_year=monsoon_fraction_of_year,
monsoon_total_rf_gaussian=monsoon_total_rf_gaussian,
monsoon_storm_duration_GEV=monsoon_storm_duration_GEV,
monsoon_storm_area_GEV=monsoon_storm_area_GEV,
monsoon_storm_interarrival_GEV=monsoon_storm_interarrival_GEV,
monsoon_storm_radial_weakening_gaussian=monsoon_storm_radial_weakening_gaussian,
winter_total_rf_gaussian=winter_total_rf_gaussian,
winter_storm_duration_fisk=winter_storm_duration_fisk,
winter_storm_area_GEV=winter_storm_area_GEV,
winter_storm_interarrival_GEV=winter_storm_interarrival_GEV,
winter_storm_radial_weakening_gaussian=winter_storm_radial_weakening_gaussian,
)
def _run_the_process(
self,
yield_storms=True,
yield_years=False,
yield_seasons=False,
limit="total_time",
style="whole_year",
monsoon_fraction_of_year=0.42,
total_rf_trend=0.0,
storminess_trend=0.0,
monsoon_total_rf_gaussian=(("sigma", 64.0), ("mu", 207.0)),
monsoon_storm_duration_GEV=(
("shape", -0.570252),
("sigma", 35.7389),
("mu", 34.1409),
("trunc_interval", (1.0, 1040.0)),
),
monsoon_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
monsoon_storm_interarrival_GEV=(
("shape", -0.807971),
("sigma", 9.4957),
("mu", 10.6108),
("trunc_interval", (0.0, 720.0)),
),
monsoon_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
winter_total_rf_gaussian=(("sigma", 52.0), ("mu", 1.65)),
winter_storm_duration_fisk=(
("c", 1.0821),
("scale", 68.4703),
("trunc_interval", (1.0, 5000.0)),
),
winter_storm_area_GEV=(
("shape", 0.0),
("sigma", 2.83876e07),
("mu", 1.22419e08),
("trunc_interval", (5.0e06, 3.0e08)),
),
winter_storm_interarrival_GEV=(
("shape", 1.1131),
("sigma", 53.2671),
("mu", 47.4944),
("trunc_interval", (0.0, 720.0)),
),
winter_storm_radial_weakening_gaussian=(
("sigma", 0.08),
("mu", 0.25),
("trunc_interval", (0.15, 0.67)),
),
):
"""This is the underlying process that runs the component, but it
should be run by a user through the yield_storms and yield_years
methods.
Fuzz to the chosen values is now selected from a continuous
distribution, not from integer values.
total_rf_trend controls if a drift is applied to the total rainfall
distribution through time. If 0., no trend. If positive, rainfall
totals increase gradually through time. If negative, they fall through
time. S&M recommend +/- 0.07 for a realistic climate chage driven drift
at Walnut Gulch.
storminess_trend controls if a drift is applied to the expected
intensity of individual storms through time. If 0., no trend. If
positive, storms get more intense through time, if negative, less so.
S&M recommend +/- 0.01 for a realistic climate change driven drift at
Walnut Gulch.
All default distributions reflect values for Walnut Gulch, see Singer &
Michaelides, submitted:
monsoon_total_rf_gaussian is a normal distribution controlling the
total rainfall expected in each year. S&M use 'mu' in {143., 271.}
for step changes up/down in rainfall totals. In mm.
monsoon_storm_duration_GEV is a generalised extreme value distribution
controlling the duration of each storm. In MIN.
monsoon_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
monsoon_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. Note that this calibration is specifically to Walnut Gulch,
which has an area of 275 km**2. The generator directly scales this
resulting distribution to the area ratio of Walnut Gulch to the
open cells of the grid. This crudely accounts for the fact that
bigger catchments will have more storms, but note that the heavy
tail on this distribution means the default distribution shape
will not be trustworthy for catchments with big differences in
size from Walnut Gulch.
monsoon_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
winter_total_rf_gaussian is a normal distribution controlling the total
rainfall expected in each year. S&M use 'mu' in {143., 271.} for
step changes up/down in rainfall totals.
winter_storm_duration_fisk is a Fisk (i.e., log-logistic) distribution
controlling the duration of each storm. Note this differs from the
summer scaling. In MIN.
winter_storm_area_GEV is a generalised extreme value distribution
controlling the plan view area of each storm. S&M use 'shape': 0.,
which collapses the distribution to a plain extreme value
distribution.
winter_storm_interarrival_GEV is a generalised extreme value
distribution controlling the interarrival time between each storm.
In HRS. The same considerations apply here as for the monsoonal
interstorm equivalent.
winter_storm_radial_weakening_gaussian is a normal distribution
controlling the rate of intensity decline with distance from storm
center. For more detail see Rodriguez-Iturbe et al., 1986; Morin
et al., 2005.
"""
monsoon_total_rf_gaussian = dict(monsoon_total_rf_gaussian)
monsoon_storm_duration_GEV = dict(monsoon_storm_duration_GEV)
monsoon_storm_area_GEV = dict(monsoon_storm_area_GEV)
monsoon_storm_interarrival_GEV = dict(monsoon_storm_interarrival_GEV)
monsoon_storm_radial_weakening_gaussian = dict(
monsoon_storm_radial_weakening_gaussian
)
winter_total_rf_gaussian = dict(winter_total_rf_gaussian)
winter_storm_duration_fisk = dict(winter_storm_duration_fisk)
winter_storm_area_GEV = dict(winter_storm_area_GEV)
winter_storm_interarrival_GEV = dict(winter_storm_interarrival_GEV)
winter_storm_radial_weakening_gaussian = dict(
winter_storm_radial_weakening_gaussian
)
FUZZMETHOD = "DEJH"
FUZZWIDTH = 5.0 # if DEJH
self._phantom_storm_count = 0
# ^this property tracks the number of storms in the run that received
# zero intensity (and thus didn't really exist)
self._opennodes = self._grid.status_at_node != self._grid.BC_NODE_IS_CLOSED
self._total_rainfall_last_season = self._grid.zeros("node")
# safety check for init conds:
if yield_storms:
assert yield_years is False
assert yield_seasons is False
if yield_years:
assert yield_storms is False
assert yield_seasons is False
if yield_seasons:
assert yield_storms is False
assert yield_years is False
# add variable for number of simulations of simyears
simyears = self._numyrs # number of years to simulate
numcurves = 11 # number of intensity-duration curves (see below for
# curve equations)
hrsinyr = 24.0 * 365.0
hrsinmonsoon = monsoon_fraction_of_year * hrsinyr
hrsinwinter = (1.0 - monsoon_fraction_of_year) * hrsinyr
assert limit in ("total_rainfall", "total_time")
assert style in ("whole_year", "monsoonal", "winter")
if style == "whole_year":
reps = 2
else:
reps = 1
opennodes = self._opennodes
num_opennodes = np.sum(opennodes)
IDs_open = np.where(opennodes)[0] # need this later
X1 = self._grid.node_x
Y1 = self._grid.node_y
Xin = X1[opennodes]
Yin = Y1[opennodes]
try:
Zz = self._grid.at_node["topographic__elevation"][opennodes]
except KeyError:
assert self._orographic_scenario is None
numgauges = Xin.size # number of rain gauges in the basin.
# NOTE: In this version this produces output on a grid, rather than at
# real gauge locations.
assert FUZZMETHOD == "DEJH", "The Singer method for fuzz is no longer supported"
# lambda_, kappa, and C are parameters of the intensity-duration curves
# of the form: intensity =
# lambda*exp(-0.508*duration)+kappa*exp(-0.008*duration)+C
lambda_ = [
642.2,
578.0,
513.8,
449.5,
385.3,
321.1,
256.9,
192.7,
128.4,
64.1,
21.0,
]
kappa = [93.1, 83.8, 74.5, 65.2, 55.9, 46.6, 37.2, 27.9, 18.6, 9.3, 0.9]
C = [4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.25, 0.05]
# Unlike MS's original implementation, we no longer pull ET values, as
# this should be a different component.
self._Ptot_ann_global = np.zeros(simyears)
self._Ptot_monsoon_global = np.zeros(simyears)
master_storm_count = 0
storm_trend = 0
for syear in range(simyears):
self._year = syear
year_time = 0.0 # tracks simulation time per year in hours
storm_trend += storminess_trend
year_storm_count = 0
breaker = False
Storm_total_local_year = np.zeros((self._max_numstorms, num_opennodes))
self._storm_running_sum_of_seasons = np.zeros(num_opennodes)
self._storm_running_sum_1st_seas = np.zeros(num_opennodes)
storms_yr_so_far = 0
for seas in range(reps):
seas_time = 0.0 # tracks elapsed season time in hours
Storm_running_sum_seas = np.zeros((2, num_opennodes))
# ^ 1st col is running total, 2nd is data to add to it
if seas == 0 and style != "winter":
self._current_season = "M"
# This is the pdf fitted to all available station precip
# data (normal dist). It will be sampled below.
Ptot_pdf_norm = monsoon_total_rf_gaussian
# This is the pdf fitted to all available station duration
# data (GEV dist). It will be sampled below.
# #### matlab's GEV is (shape_param, scale(sigma), pos(mu))
# note that in Scipy, we must add a minus to the shape
# param for a GEV to match Matlab's implementation
Duration_pdf = monsoon_storm_duration_GEV
# This is the pdf fitted to all available station area
# data (EV dist). It will be sampled below.
# #### matlab's EV is (mu, sigma)
Area_pdf_EV = monsoon_storm_area_GEV
# This is the pdf fitted to all available station area
# data (GEV dist). It will be sampled below.
Int_arr_pdf_GEV = monsoon_storm_interarrival_GEV
# This is the pdf of storm gradient recession coefficients
# from Morin et al, 2005 (normal dist). It will be sampled
# below.
Recess_pdf_norm = monsoon_storm_radial_weakening_gaussian
seas_total = hrsinmonsoon
else:
self._current_season = "W"
Ptot_pdf_norm = winter_total_rf_gaussian
Duration_pdf = winter_storm_duration_fisk
Area_pdf_EV = winter_storm_area_GEV
Int_arr_pdf_GEV = winter_storm_interarrival_GEV
Recess_pdf_norm = winter_storm_radial_weakening_gaussian
seas_total = hrsinwinter
if not np.isclose(total_rf_trend, 0.0):
mu = Ptot_pdf_norm.pop("mu")
mu += mu * total_rf_trend
Ptot_pdf_norm["mu"] = mu
# sample from normal distribution and saves global value of
# Ptot (that must be equalled or exceeded) for each year
season_rf_limit = self.calc_annual_rainfall(
style=style, monsoon_total_rf_gaussian=Ptot_pdf_norm
)[seas]
self._season_rf_limit = season_rf_limit
self._Ptot_ann_global[syear] += season_rf_limit
if seas == 0 and style != "winter":
self._Ptot_monsoon_global[syear] = season_rf_limit
Storm_total_local_seas = np.zeros((self._max_numstorms, num_opennodes))
seas_cum_Ptot_gauge = np.zeros(numgauges)
self._entries = 0
for seas_storm_count, storm in enumerate(range(self._max_numstorms)):
self._rain_int_gauge.fill(0.0)
int_arr_val = genextreme.rvs(
c=Int_arr_pdf_GEV["shape"],
loc=Int_arr_pdf_GEV["mu"],
scale=Int_arr_pdf_GEV["sigma"],
)
try:
int_arr_val = np.clip(
int_arr_val,
Int_arr_pdf_GEV["trunc_interval"][0],
Int_arr_pdf_GEV["trunc_interval"][1],
)
except KeyError:
# ...just in case
if int_arr_val < 0.0:
int_arr_val = 0.0
# now, correct the scaling relative to WG
int_arr_val /= self._scaling_to_WG
self._int_arr_val = int_arr_val
# ^Samples from distribution of interarrival times (hr).
# This can be used to develop STORM output for use in
# rainfall-runoff models or any water balance application.
# sample uniformly from storm center matrix from grid w
# 10 m spacings covering basin:
area_val = genextreme.rvs(
c=Area_pdf_EV["shape"],
loc=Area_pdf_EV["mu"],
scale=Area_pdf_EV["sigma"],
)
try:
area_val = np.clip(
area_val,
Area_pdf_EV["trunc_interval"][0],
Area_pdf_EV["trunc_interval"][1],
)
except KeyError:
# ...just in case
if area_val < 0.0:
area_val = 0.0
self._area_val = area_val
# ^Samples from distribution of storm areas
r = np.sqrt(area_val / np.pi) # value here shd be selected
rsq = r**2
# based on area above in meters to match the UTM values
# This way of handling storm locations is really quite
# different to MS's. He uses a fixed buffer width, and
# throws away any storm that doesn't intersect. We
# instead retain all storms, and *make sure* the storm
# intersects using a dynamic buffer. MS's method will
# preferentially sample larger storms, though unclear
# what that would mean in practice.
# MS also snaps his storms onto the grid. This seems
# unnecessary, and we don't do it here.
while 1:
cx, cy = self._locate_storm(r)
# Determine which gauges are hit by Euclidean geometry:
gdist = (Xin - cx) ** 2 + (Yin - cy) ** 2
mask_name = gdist <= rsq # this is defacto MS's aa
# this short circuits the storm loop in the case that
# the storm does not affect any 'gauging' location
if np.any(np.equal(mask_name, True)):
break
self._x = cx
self._y = cy
year_storm_count += 1
seas_storm_count += 1
master_storm_count += 1
# This routine below determines to which orographic group
# the closest gauge to the storm center belongs to, and
# censors the number of curves accordingly
# missing top curve in GR1, top and bottom curves for GR2,
# and bottom curve for GR3
# NOTE again, DEJH thinks this could be generalised a lot
# original curve# probs for 30%-20%-10%: [0.0636, 0.0727,
# 0.0819, 0.0909, 0.0909, 0.0909, 0.0909, 0.0909, 0.1001,
# 0.1090, 0.1182]
# original curve# probs are modified as below
# add weights to reflect reasonable probabilities that
# favor lower curves:
if self._orographic_scenario is not None:
# this routine below allows for orography in precip by
# first determining the closest gauge and then
# determining its orographic grouping
cc = np.argmin(gdist)
closest_gauge_z = Zz[cc] # this will be
# compared against orographic gauge groupings to
# determine the appropriate set of intensity-duration
# curves
if self._orographic_scenario == "Singer":
wgts = Singer_orographic_rainfall(closest_gauge_z)
else:
wgts = self._orographic_scenario(closest_gauge_z)
elif self._orographic_scenario is None:
wgts = [
0.0636,
0.0727,
0.0819,
0.0909,
0.0909,
0.0909,
0.0909,
0.0909,
0.1001,
0.1090,
0.1182,
]
if seas == 0 and style != "winter":
duration_val = genextreme.rvs(
c=Duration_pdf["shape"],
loc=Duration_pdf["mu"],
scale=Duration_pdf["sigma"],
)
else:
duration_val = fisk.rvs(
c=Duration_pdf["c"], scale=Duration_pdf["scale"]
)
# hacky fix to prevent occasional < 0 values:
# (I think because Matlab is able to set limits manually)
try:
duration_val = np.clip(
duration_val,
Duration_pdf["trunc_interval"][0],
Duration_pdf["trunc_interval"][1],
)
except KeyError:
# ...just in case
if duration_val < 0.0:
duration_val = 0.0
durationhrs = duration_val / 60.0
self._durationhrs = durationhrs
year_time += durationhrs
seas_time += durationhrs
# we will always do the next storm, even if it exceeds the
# specified "total" time
# which curve did we pick?:
int_dur_curve_val = np.random.choice(numcurves, p=wgts)
intensity_val = (
lambda_[int_dur_curve_val] * np.exp(-0.508 * duration_val)
+ kappa[int_dur_curve_val] * np.exp(-0.008 * duration_val)
+ C[int_dur_curve_val]
)
# ...these curves are based on empirical data from WG
# this dist should look identical, w/o discretisation
fuzz_int_val = FUZZWIDTH * 2.0 * (np.random.rand() - 0.5)
intensity_val += fuzz_int_val
# ^this allows for specified fuzzy tolerance around
# selected intensity (but it can go -ve)
# formerly, here MS used a rounding and threshold to
# prevent storms with a value < 1. We're going to remove
# the rounding and threshold at zero instead. (below)
# This scales the storm center intensity upward, so the
# values at each gauge are realistic once the gradient is
# applied.
intensity_val += intensity_val * storm_trend
# storminess trend is applied and its effect rises each
# year of simulation
# DEJH has removed the rounding
# Note that is is now possible for intensity_val to go
# negative, so:
if intensity_val < 0.0:
intensity_val = 0.0
self._phantom_storm_count += 1
# note storms of zero intensity are now permitted (though
# should hopefully remain pretty rare.)
self._intensity_val = intensity_val
# area to determine which gauges are hit:
recess_val = np.random.normal(
loc=Recess_pdf_norm["mu"], scale=Recess_pdf_norm["sigma"]
)
with contextlib.suppress(KeyError):
recess_val = np.clip(
recess_val,
Recess_pdf_norm["trunc_interval"][0],
Recess_pdf_norm["trunc_interval"][1],
)
self._recess_val = recess_val
# this pdf of recession coefficients determines how
# intensity declines with distance from storm center (see
# below)
# determine cartesian distances to all hit gauges and
# associated intensity values at each gauge hit by the
# storm
# This is a data storage solution to avoid issues that can
# arise with slicing grid areas with heavy tailed sizes
self._entries = np.sum(mask_name) # only open nodes
entries = self._entries
# NOTE _gauge_dist_km only contains nodes under the storm!
# The remaining entries are garbage
# Xin -> only the open nodes, note
self._gauge_dist_km[:entries] = np.sqrt(gdist[mask_name]) / 1000.0
self._temp_dataslots2[:entries] = gdist[mask_name] / 1.0e6
self._temp_dataslots2[:entries] *= -2.0 * recess_val**2
np.exp(
self._temp_dataslots2[:entries],
out=self._temp_dataslots2[:entries],
)
self._temp_dataslots2[:entries] *= intensity_val
mask_incl_closed = IDs_open[mask_name]
self._nodes_hit = mask_incl_closed
# ^note this is by ID, not bool
self._rain_int_gauge[mask_incl_closed] = self._temp_dataslots2[
:entries
]
# calc of _rain_int_gauge follows Rodriguez-Iturbe et al.,
# 1986; Morin et al., 2005 but sampled from a distribution
# only need to add the bit that got rained on, so:
self._temp_dataslots2[:entries] *= duration_val / 60.0
seas_cum_Ptot_gauge[mask_name] += self._temp_dataslots2[:entries]
# collect storm totals for all gauges into rows by storm
Storm_total_local_seas[storm, :] = (
self._rain_int_gauge[opennodes] * duration_val / 60.0
)
Storm_total_local_year[
(storm + storms_yr_so_far), :
] = Storm_total_local_seas[storm, :]
self._max_storm_depth = Storm_total_local_seas[storm, :].max()
self._Storm_total_local_seas = Storm_total_local_seas
self._Storm_total_local_year = Storm_total_local_year
Storm_running_sum_seas[1, :] = Storm_total_local_seas[storm, :]
np.nansum(
Storm_running_sum_seas, axis=0, out=Storm_running_sum_seas[0, :]
)
if np.any(Storm_total_local_seas < 0.0):
raise ValueError(syear, storm)
self._median_seas_rf_total = np.nanmedian(
Storm_running_sum_seas[0, :]
)
self._Storm_running_sum_seas = Storm_running_sum_seas[0, :]
if limit == "total_time":
if seas_time + int_arr_val > seas_total:
int_arr_val = (seas_total - seas_time).clip(0.0)
breaker = True
else:
if self._median_seas_rf_total > season_rf_limit:
breaker = True
if yield_storms is True:
yield (durationhrs, int_arr_val)
seas_time += int_arr_val
year_time += int_arr_val
if breaker:
# Don't create Ptotal_local per MS... just
breaker = False
break
if storm + 1 == self._max_numstorms:
raise ValueError("_max_numstorms set too low for this run")
storms_yr_so_far = seas_storm_count
self._storm_running_sum_of_seasons += Storm_running_sum_seas[0, :]
self._total_rainfall_last_season[
self._opennodes
] = Storm_running_sum_seas[0, :]
self._storm_running_sum_1st_seas += Storm_running_sum_seas[0, :]
if yield_seasons:
yield seas_storm_count
self._total_rf_year[opennodes] = self._storm_running_sum_of_seasons
if yield_years is True and yield_seasons is False:
yield year_storm_count
[docs]
def calc_annual_rainfall(
self,
style="whole_year",
monsoon_total_rf_gaussian=(("sigma", 64.0), ("mu", 207.0)),
winter_total_rf_gaussian=(("sigma", 52.0), ("mu", 1.65)),
):
"""Return a tuple of rainfall totals (mm) for the year, with entries
subdividing the yearly total into seasons as appropriate.
Parameters
----------
style : ('whole_year', 'monsoonal', 'winter')
Whether to simulate 2 seasons, or a single season.
monsoon_total_rf_gaussian : dict of sigma and mu for the summer
distribution (if used). Defaults to Walnut Gulch.
winter_total_rf_gaussian : dict of sigma and mu for the summer
distribution (if used). Defaults to Walnut Gulch.
Returns
-------
tuple : (first_season_total, [second_season_total])
If style=='monsoonal' or 'winter', a len(1) tuple of the total rf.
If style=='whole_year', a len(2) tuple of (monsoon, winter) totals.
Examples
--------
>>> mg = RasterModelGrid((10, 10), xy_spacing=500.0)
>>> z = mg.add_zeros("topographic__elevation", at="node")
>>> rain = SpatialPrecipitationDistribution(mg)
>>> mytotals = []
>>> for yr in range(5):
... mytotals.append(rain.calc_annual_rainfall(style="whole_year"))
...
>>> [len(x) == 2 for x in mytotals]
[True, True, True, True, True]
>>> mytotals = []
>>> for yr in range(3):
... mytotals.append(rain.calc_annual_rainfall(style="monsoonal"))
...
>>> [len(x) == 1 for x in mytotals]
[True, True, True]
"""
monsoon_total_rf_gaussian = dict(monsoon_total_rf_gaussian)
winter_total_rf_gaussian = dict(winter_total_rf_gaussian)
assert style in ("whole_year", "monsoonal", "winter")
if style in ("whole_year", "monsoonal"):
# sample from normal distribution and saves global value of Ptot
# (that must be equalled or exceeded) for each year
summer_rf_limit = np.random.normal(
loc=monsoon_total_rf_gaussian["mu"],
scale=monsoon_total_rf_gaussian["sigma"],
)
try:
summer_rf_limit = np.clip(
summer_rf_limit,
monsoon_total_rf_gaussian["trunc_interval"][0],
monsoon_total_rf_gaussian["trunc_interval"][1],
)
except KeyError:
# ...just in case
if summer_rf_limit < 0.0:
summer_rf_limit = 0.0
if style in ("whole_year", "winter"):
# sample from normal distribution and saves global value of Ptot
# (that must be equalled or exceeded) for each year
winter_rf_limit = np.random.normal(
loc=winter_total_rf_gaussian["mu"],
scale=winter_total_rf_gaussian["sigma"],
)
try:
winter_rf_limit = np.clip(
winter_rf_limit,
winter_total_rf_gaussian["trunc_interval"][0],
winter_total_rf_gaussian["trunc_interval"][1],
)
except KeyError:
# ...just in case
if winter_rf_limit < 0.0:
winter_rf_limit = 0.0
if style == "monsoonal":
return (summer_rf_limit,)
elif style == "winter":
return (winter_rf_limit,)
else:
return (summer_rf_limit, winter_rf_limit)
def _locate_storm(self, storm_radius):
"""Because of the way the stats fall out, any simulated storm from the
distribution must intersect the catchment somewhere.
Note written in a grid-agnostic fashion.
"""
stormposx = np.random.rand() * (self._widthx + 2.0 * storm_radius)
stormposy = np.random.rand() * (self._widthy + 2.0 * storm_radius)
stormx = self._minx - storm_radius + stormposx
stormy = self._miny - storm_radius + stormposy
return stormx, stormy
@property
def current_year(self):
"""Get the current year as an int."""
return self._year
@property
def current_season(self):
"""Get the current season.
'M' is monsoon, 'W' is winter.
"""
return self._current_season
@property
def storm_depth_last_storm(self):
"""Get the maximum storm depth during the last storm (mm)."""
return self._max_storm_depth
@property
def storm_recession_value_last_storm(self):
"""Get the recession parameter (radial die-off) for the last storm."""
return self._recess_val
@property
def storm_duration_last_storm(self):
"""Get the duration (in hrs) of the last storm."""
return self._durationhrs
@property
def storm_area_last_storm(self):
"""Get the area (in m**2) of the last storm."""
return self._area_val
@property
def storm_intensity_last_storm(self):
"""Get the intensity (mm/hr) of the last storm, averaged under the
storm.
footprint. Note that duration * intensity != storm max depth.
"""
return self._intensity_val
@property
def total_rainfall_last_season(self):
"""Get the total recorded rainfall over the last (completed) simulated
season, spatially resolved (mm)."""
return self._total_rainfall_last_season
@property
def total_rainfall_last_year(self):
"""Get the total recorded rainfall over the last (completed) simulated
year, spatially resolved (mm).
Equivalent to the field 'rainfall__total_depth_per_year'.
"""
return self._total_rf_year
@property
def total_rainfall_this_season(self):
"""Get the accumulated, spatially resolved total rainfall over the grid
for the season so far (mm)."""
self._running_total_rainfall_this_season[
self._opennodes
] = self._Storm_running_sum_seas
return self._running_total_rainfall_this_season
@property
def total_rainfall_this_year(self):
"""Get the accumulated, spatially resolved total rainfall over the grid
for the year so far (mm)."""
self._running_total_rainfall_this_year[self._opennodes] = (
self._storm_running_sum_1st_seas + self._Storm_running_sum_seas
)
return self._running_total_rainfall_this_year
@property
def median_total_rainfall_last_season(self):
"""Get the median total rainfall recorded over the open nodes of the
grid during the last (completed) simulated season (mm)."""
return np.nanmedian(self._total_rainfall_last_season[self._opennodes])
@property
def median_total_rainfall_last_year(self):
"""Get the median total rainfall recorded over the open nodes of the
grid during the last (completed) simulated year (mm)."""
return np.nanmedian(self.total_rainfall_last_year[self._opennodes])
@property
def median_total_rainfall_this_season(self):
"""Get the accumulated median total rainfall over the open nodes of the
grid so far this season (mm)."""
return self._median_seas_rf_total
@property
def median_total_rainfall_this_year(self):
"""Get the accumulated median total rainfall over the open nodes of the
grid so far this year (mm)."""
return np.nanmedian(self.total_rainfall_this_year[self._opennodes])
@property
def number_of_nodes_under_storm(self):
"""Get the number of nodes under the last storm."""
return self._entries
@property
def nodes_under_storm(self):
"""Get the IDs of the nodes under the last storm."""
return self._nodes_hit
@property
def coordinates_of_last_storm_center(self):
"""Get the coordinates of the center of the last storm as (x, y)."""
return (self._x, self._y)
@property
def target_median_total_rainfall_this_season(self):
"""Get the stochastically generated "target" average total rainfall
amount over the catchment for the current season.
If limit == 'total_rainfall', this will be very close to
median_total_rainfall_last_season. If 'total_time', it will
diverge from this value.
"""
return self._season_rf_limit
def Singer_orographic_rainfall(z_closest_node_to_center):
"""Return a set of curve weights for a provided z, assuming an orographic
rule following that presented in Singer & Michaelides 2017 & Singer et al.
2018 and applicable specifically to Walnut Gulch. i.e., there are three
orographic divisions, divided at 1350 m and 1500 m.
Parameters
----------
z_closest_node_to_center : float
The elevation of the node closest to the storm center.
Returns
-------
wgts : length 11 list
The weighting parameters to use in selecting a storm distribution
curve.
"""
if z_closest_node_to_center <= 1350:
wgts = [
0.0318,
0.0759,
0.0851,
0.0941,
0.0941,
0.0941,
0.0941,
0.0941,
0.1033,
0.1121,
0.1213,
]
elif 1350 < z_closest_node_to_center <= 1500:
wgts = [
0.0478,
0.0778,
0.0869,
0.0959,
0.0959,
0.0959,
0.0959,
0.0959,
0.1051,
0.1141,
0.0888,
]
elif z_closest_node_to_center > 1500:
wgts = [
0.0696,
0.0786,
0.0878,
0.0968,
0.0968,
0.0968,
0.0968,
0.0968,
0.1060,
0.1149,
0.0591,
]
return wgts
if __name__ == "__main__":
from matplotlib.pyplot import show
nx = 17
ny = 8
dx = 1000.0
mg = RasterModelGrid((nx, ny), xy_spacing=dx)
z = mg.add_zeros("topographic__elevation", at="node")
z += 1400.0
rain = SpatialPrecipitationDistribution(mg, number_of_years=1)
total_t = 0.0
for count, dt, interval_t in enumerate(
rain.yield_storms(style="whole_year", limit="total_time")
):
total_t += dt + interval_t
print(dt, interval_t)
if count % 100 == 0:
print("Season:", rain.current_season, "of yr", rain.current_year)
print("Current storm:", count)
show()
print("Effective total years:")
print(total_t / 24.0 / 365.0)
print("Storms simulated:")
print(count)
```