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f4f5ef6 3d75674 f4f5ef6 d9d8a99 f4f5ef6 2663734 f4f5ef6 26490e3 3d75674 2663734 d9d8a99 2663734 d9d8a99 2663734 d9d8a99 2663734 d9d8a99 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | """Small plotting helpers for the CAMulator timescales tutorial."""
import cartopy.crs as ccrs
import numpy as np
def map_axis(fig, nrows, ncols, index, region=None, extent=None, central_longitude=180):
"""Add a map axis with coastlines. region = {'lat': (min, max), 'lon': (min, max)}, longitudes in degrees east
(negative = west; lon min > max crosses the date line). (The older extent = (lon_min, lon_max, lat_min, lat_max) in
0-360 also works.)"""
if region is not None:
lo0, lo1 = region["lon"]
if lo1 < lo0:
lo1 += 360
extent = (lo0, lo1, *region["lat"])
central_longitude = (lo0 + lo1) / 2
ax = fig.add_subplot(nrows, ncols, index, projection=ccrs.PlateCarree(central_longitude=central_longitude))
if extent is not None:
ax.set_extent(extent, crs=ccrs.PlateCarree())
ax.coastlines(linewidth=0.6)
return ax
DATA_CRS = ccrs.PlateCarree() # pass as transform= when plotting lat/lon data on a map axis
def sinlat_axis(ax, ticks=(-60, -30, -10, 0, 10, 30, 60)):
"""Label an x axis that holds sin(latitude) with latitudes, so each band takes the room its area does."""
ax.set_xticks(np.sin(np.deg2rad(ticks)))
ax.set_xticklabels([f'{abs(t)}°{"S" if t < 0 else "N" if t > 0 else ""}' for t in ticks])
ax.set_xlabel("Latitude (spaced by area)")
def sinlat(lat):
return np.sin(np.deg2rad(lat))
def polar_axis(fig, nrows, ncols, index, lat_min=50):
"""Add a north-polar stereographic map axis with coastlines, showing latitudes north of lat_min."""
ax = fig.add_subplot(nrows, ncols, index, projection=ccrs.NorthPolarStereo())
ax.set_extent([-180, 180, lat_min, 90], crs=ccrs.PlateCarree())
ax.coastlines(linewidth=0.6)
return ax
# Plain-language names, units and reading notes for variables participants can choose (everyday units, see
# core.EVERYDAY_UNITS).
VARIABLES = {
"FLUT": ("OLR", "W/m²", "outgoing longwave radiation; lower = more deep cloud"),
"PRECT": ("Rain", "mm/day", None),
"TREFHT": ("2-m temperature", "K", None),
"TS": ("Surface temperature", "K", None),
"PS": ("Surface pressure", "hPa", None),
"U10": ("10-m wind speed", "m/s", None),
"westerly_stress": ("Surface wind stress", "mN/m²", "positive = westerly"),
"rain": ("Rain", "mm/day", None),
"T": ("2-m temperature", "K", None),
"vapour": ("Column water vapour", "mm", None),
}
def name(variable):
"""Short display name, e.g. 'OLR', 'Rain'."""
return VARIABLES[variable][0] if variable in VARIABLES else variable
def units(variable):
return VARIABLES[variable][1] if variable in VARIABLES else ""
def label(variable):
"""Axis / colour-bar label: name, units and a reading note, e.g. 'OLR (W/m²; ... lower = more deep cloud)'."""
if variable not in VARIABLES:
return variable
short, unit, note = VARIABLES[variable]
return f"{short} ({unit}; {note})" if note else f"{short} ({unit})"
def symmetric_limit(field, quantile=0.98):
"""A colour limit that covers almost all of a field's values, the same on both sides of zero."""
return float(np.nanquantile(np.abs(np.asarray(field)), quantile)) or 1.0
def km_axis(ax, circumference_km):
"""Add a top x axis showing the wavelength in km for an axis of zonal wavenumbers."""
top = ax.secondary_xaxis("top", functions=(lambda k: circumference_km / np.maximum(k, 1e-9),
lambda km: circumference_km / np.maximum(km, 1e-9)))
top.set_xlabel("Wavelength (km)")
return top
def region_text(region):
"""{'lat': (-5, 5), 'lon': (35, 45)} -> '5°S-5°N, 35-45°E' (for titles)."""
def lat(v):
return f"{abs(v):g}°{'S' if v < 0 else 'N'}" if v else "0°"
def lon(v):
return f"{abs(v):g}°{'W' if v < 0 else 'E'}" if v else "0°"
la0, la1 = region["lat"]
text = f"{lat(la0)}-{lat(la1)}"
if "lon" in region:
text += f", {lon(region['lon'][0])}-{lon(region['lon'][1])}"
return text
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