Évolution de la vitesse moyenne des vents à 10 m et 100 m d'altitude entre 1959 et 2021

winds_analysis.py

#!/usr/bin/env python3

from itertools import product
import numpy as np
from tqdm import tqdm
from netCDF4 import Dataset
import csv


HOURS_PER_YEAR = 24 * 365
NB_YEARS = 2

ds = Dataset("winds_data.nc")
latitudes, longitudes = ds["latitude"][:], ds["longitude"][:]
timestamps = ds["time"]

assert len(timestamps) == NB_YEARS * HOURS_PER_YEAR

mean_wind_speed_10 = np.zeros(shape=(NB_YEARS, len(latitudes), len(longitudes)), dtype=np.float64)
mean_wind_speed_10_u = np.zeros_like(mean_wind_speed_10)
mean_wind_speed_10_v = np.zeros_like(mean_wind_speed_10)

mean_wind_speed_100 = np.zeros(shape=(NB_YEARS, len(latitudes), len(longitudes)), dtype=np.float64)
mean_wind_speed_100_u = np.zeros_like(mean_wind_speed_100)
mean_wind_speed_100_v = np.zeros_like(mean_wind_speed_100)

u10, v10 = ds["u10"], ds["v10"]
u100, v100 = ds["u100"], ds["v100"]

def accumulate(u, v, iyear, m, mu, mv):
    m[iyear] += np.hypot(u, v)
    mu[iyear] += u
    mv[iyear] += v

for itime in tqdm(range(len(timestamps)), desc="Computing"):
    iyear = itime // HOURS_PER_YEAR

    accumulate(u10[itime], v10[itime], iyear, 
        mean_wind_speed_10, mean_wind_speed_10_u, mean_wind_speed_10_v)

    accumulate(u100[itime], v100[itime], iyear, 
        mean_wind_speed_100, mean_wind_speed_100_u, mean_wind_speed_100_v)

mean_wind_speed_10 /= HOURS_PER_YEAR
mean_wind_speed_10_u /= HOURS_PER_YEAR
mean_wind_speed_10_v /= HOURS_PER_YEAR  

mean_wind_speed_100 /= HOURS_PER_YEAR
mean_wind_speed_100_u /= HOURS_PER_YEAR
mean_wind_speed_100_v /= HOURS_PER_YEAR  

diff_10 = mean_wind_speed_10[1] - mean_wind_speed_10[0]
diff_10_percent = diff_10 / mean_wind_speed_10[0]

diff_100 = mean_wind_speed_100[1] - mean_wind_speed_100[0]
diff_100_percent = diff_100 / mean_wind_speed_100[0]

with open("mean_winds_speed.csv", "w", encoding="UTF8", newline="") as f:
    writer = csv.writer(f)
    writer.writerow([
        "lat", "long", 
        "wind_speed_10_1959", "wind_speed_10_2021",
        "wind_speed_100_1959", "wind_speed_100_2021", 
        "wind_speed_10_1959_u", "wind_speed_10_1959_v", 
        "wind_speed_10_2021_u", "wind_speed_10_2021_v", 
        "wind_speed_100_1959_u", "wind_speed_100_1959_v", 
        "wind_speed_100_2021_u", "wind_speed_100_2021_v", 
        "diff_10", "diff_10_percent", "diff_100", "diff_100_percent",
    ])

    for ((ilat, lat), (ilon, lon)) in product(enumerate(latitudes), enumerate(longitudes)):
        writer.writerow([
            float(lat), float(lon),
            mean_wind_speed_10[0, ilat, ilon].item(), mean_wind_speed_10[1, ilat, ilon].item(),
            mean_wind_speed_100[0, ilat, ilon].item(), mean_wind_speed_100[1, ilat, ilon].item(),
            mean_wind_speed_10_u[0, ilat, ilon].item(), mean_wind_speed_10_v[0, ilat, ilon].item(),
            mean_wind_speed_10_u[1, ilat, ilon].item(), mean_wind_speed_10_v[1, ilat, ilon].item(),
            mean_wind_speed_100_u[0, ilat, ilon].item(), mean_wind_speed_100_v[0, ilat, ilon].item(),
            mean_wind_speed_100_u[1, ilat, ilon].item(), mean_wind_speed_100_v[1, ilat, ilon].item(),
            diff_10[ilat, ilon].item(), diff_10_percent[ilat, ilon].item(),
            diff_100[ilat, ilon].item(), diff_100_percent[ilat, ilon].item(),
        ])