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roches-probabilistic-hazard.../slr/generate_slr_timeseries.py

106 lines
2.9 KiB
Python

import os
import re
import numpy as np
import pandas as pd
from scipy import stats
import matplotlib.pyplot as plt
START_YEAR = 2020
END_YEAR = 2100
n_runs = 100000
df = pd.read_csv('cauchy-values.csv', index_col=0)
years = np.arange(START_YEAR, END_YEAR + 1)
# Squeeze distribution to zero in 2020
df.loc[2020, 'scale'] = 0.0001
df.loc[2020, 'min'] = df.loc[2020, 'loc'] - 0.0001
df.loc[2020, 'max'] = df.loc[2020, 'loc'] + 0.0001
# Interpolate intermediate values
df = df.reindex(years).interpolate(method='cubic')
# Prepare array for SLR values
slr = np.zeros([len(years), n_runs], dtype=float)
for i, (year, row) in enumerate(df.iterrows()):
# Get probability distribution
dist = stats.cauchy(loc=row['loc'], scale=row['scale'])
# Generate random samples
for factor in range(2, 10):
s_raw = dist.rvs(n_runs * factor)
# Take first samples within valid range
s = s_raw[(s_raw > row['min']) & (s_raw < row['max'])]
if len(s) > n_runs:
break # Success
else:
continue # We need more samples, so try larger factor
# Add the requried number of samples
slr[i] = s[:n_runs]
# Sort each row to make SLR trajectories smooth
slr = np.sort(slr, axis=1)
# Randomise run order (column-wise)
slr = np.random.permutation(slr.T).T
# Set first year to zero
slr[0, :] = df.loc[2020, 'loc']
# Plot first few trajectories
if True:
fig, ax = plt.subplots(1,
3,
figsize=(12, 5),
sharey=True,
gridspec_kw={
'wspace': 0.05,
'width_ratios': [3, 1, 1]
})
ax[0].plot(years, slr[:, :100], c='#444444', lw=0.2)
ax[1].hist(slr[-1, :],
bins=100,
fc='#cccccc',
ec='#aaaaaa',
orientation='horizontal')
i = len(years) - 1
dff = df.T.loc['5':'95', years[i]]
ax[2].hist(
slr[i, :],
bins=100,
fc='#cccccc',
ec='#aaaaaa',
orientation='horizontal',
cumulative=True,
)
ax[2].plot(dff.index.astype(int) / 100 * n_runs,
dff.values,
'o',
c='C3',
label='IPCC AR6 data')
ax[0].set_xlim(right=years[i])
ax[0].set_title(f'SLR trajectories\n(first 100 out of {n_runs:,} runs)')
ax[1].set_title(f'Probability\ndistribution\nin year {years[i]}')
ax[2].set_title(f'Cumulative\ndistribution\nin year {years[i]}')
ax[0].set_ylabel('SLR (m)', labelpad=10)
ax[2].legend()
ax[0].spines['top'].set_visible(False)
ax[0].spines['right'].set_visible(False)
for a in ax[1:]:
a.spines['top'].set_visible(False)
a.spines['right'].set_visible(False)
a.spines['bottom'].set_visible(False)
a.xaxis.set_visible(False)