Temperature as a glowing flame / plume¶

This recolours CAMS Aerosol Optical Depth look — a dark, hillshaded Earth with glowing, wispy plumes — for 2 m temperature. Two shipped data-style presets do it in one call:

• temperature_flame — black → red → yellow → white (the hottest areas blow out to yellow-white).
• temperature_flame_amber — a warmer gold/orange ramp, less blown-out.

Each preset carries the flame colour ramp and a value-linked opacity: a pixel's opacity is tied to its value (cool → transparent, so the dark terrain shows through; hot → opaque, glowing). Composed over a dark hillshaded backdrop — drawn with the glyph's own add_relief / add_features — the warm areas glow while the cool ones fade into the relief. ArrayGlyph applies the preset and runs the animation; no hand-rolled alpha_scaled_image, FuncAnimation, or standalone cleopatra.basemap.reference calls.

In [1]:

from pathlib import Path

import matplotlib.pyplot as plt
import numpy as np

from cleopatra.glyphs.base.animation import embed_gif
from cleopatra.glyphs.gridded.array_glyph import ArrayGlyph, FrameLabel

# --- data: an ERA5-Land 2 m-temperature stack over Europe (°C, 23 daily frames) ---
npz = np.load(Path("../../../examples/data/europe_t2m.npz"), allow_pickle=True)
celsius = npz["celsius"][::2]  # every other day, to keep the GIFs light
labels = list(npz["labels"])[::2]
west, south, east, north = (float(v) for v in npz["extent"])
extent = [west, east, south, north]


def add_backdrop(glyph):
    """Give the glyph a hillshaded Earth using its OWN methods.

    Call it directly on the glyph (not as a `basemap=` callback). `add_relief`
    creates the axes on demand (so it can come before `animate`) and draws the
    global relief at true lon/lat, cropped to the view; `add_features` overlays
    faint coastlines/borders. All on `glyph.ax`, no standalone helpers. The dark
    canvas itself comes from the `temperature_flame*` preset (its
    `background`), so nothing here paints the figure.
    """
    glyph.add_relief("medium", alpha=0.45, zorder=-2)  # creates the axes if needed
    glyph.add_features("coastline", "50m", color="0.5", linewidth=0.5, zorder=0)
    glyph.add_features("borders", "50m", color="0.35", linewidth=0.4, zorder=0)


print("stack:", celsius.shape, "| frames:", labels[0], "->", labels[-1])
from cleopatra.styling.params import DataStyle

from pathlib import Path import matplotlib.pyplot as plt import numpy as np from cleopatra.glyphs.base.animation import embed_gif from cleopatra.glyphs.gridded.array_glyph import ArrayGlyph, FrameLabel # --- data: an ERA5-Land 2 m-temperature stack over Europe (°C, 23 daily frames) --- npz = np.load(Path("../../../examples/data/europe_t2m.npz"), allow_pickle=True) celsius = npz["celsius"][::2] # every other day, to keep the GIFs light labels = list(npz["labels"])[::2] west, south, east, north = (float(v) for v in npz["extent"]) extent = [west, east, south, north] def add_backdrop(glyph): """Give the glyph a hillshaded Earth using its OWN methods. Call it directly on the glyph (not as a `basemap=` callback). `add_relief` creates the axes on demand (so it can come before `animate`) and draws the global relief at true lon/lat, cropped to the view; `add_features` overlays faint coastlines/borders. All on `glyph.ax`, no standalone helpers. The dark canvas itself comes from the `temperature_flame*` preset (its `background`), so nothing here paints the figure. """ glyph.add_relief("medium", alpha=0.45, zorder=-2) # creates the axes if needed glyph.add_features("coastline", "50m", color="0.5", linewidth=0.5, zorder=0) glyph.add_features("borders", "50m", color="0.35", linewidth=0.4, zorder=0) print("stack:", celsius.shape, "| frames:", labels[0], "->", labels[-1]) from cleopatra.styling.params import DataStyle

stack: (23, 111, 164) | frames: Jun 01 -> Jul 15

Still comparison — both flame presets on the hottest day¶

Each panel draws an ArrayGlyph(celsius[-1], style=...) into a subplot with plot(ax=...), then add_backdrop lays the hillshaded Earth underneath with the glyph's own add_relief/add_features. The preset carries the flame ramp and the value-linked opacity, so the warm areas glow and the cool ones fade into the relief.

In [2]:

fig, axs = plt.subplots(1, 2, figsize=(15, 6))
fig.set_facecolor("black")   # the flame preset blackens each panel's axes; the shared figure is ours to paint
for ax, style in zip(axs, ["temperature_flame", "temperature_flame_amber"]):
    glyph = ArrayGlyph(celsius[-1], extent=extent)
    glyph.plot(data_style=DataStyle(style=style), ax=ax, add_colorbar=False)
    add_backdrop(glyph)
    ax.set_title(style, color="white", loc="left", fontweight="bold")
    ax.set_xticks([])
    ax.set_yticks([])
fig.tight_layout()
plt.show()

fig, axs = plt.subplots(1, 2, figsize=(15, 6)) fig.set_facecolor("black") # the flame preset blackens each panel's axes; the shared figure is ours to paint for ax, style in zip(axs, ["temperature_flame", "temperature_flame_amber"]): glyph = ArrayGlyph(celsius[-1], extent=extent) glyph.plot(data_style=DataStyle(style=style), ax=ax, add_colorbar=False) add_backdrop(glyph) ax.set_title(style, color="white", loc="left", fontweight="bold") ax.set_xticks([]) ax.set_yticks([]) fig.tight_layout() plt.show()

Animation A — white-hot (temperature_flame)¶

The builder flow: make the glyph, add_backdrop (which creates the axes and draws the dark Earth), then animate (which reuses that axes). FrameLabel(color="white") puts a legible date label on the black scene.

In [3]:

glyph = ArrayGlyph(celsius, extent=extent)
add_backdrop(glyph)  # dark hillshaded backdrop, drawn before the frames
anim_a = glyph.animate(data_style=DataStyle(style="temperature_flame"), 
    time=labels,
    add_colorbar=False,
    frame_label=FrameLabel(color="white"),
)
embed_gif(anim_a, fps=8)

glyph = ArrayGlyph(celsius, extent=extent) add_backdrop(glyph) # dark hillshaded backdrop, drawn before the frames anim_a = glyph.animate(data_style=DataStyle(style="temperature_flame"), time=labels, add_colorbar=False, frame_label=FrameLabel(color="white"), ) embed_gif(anim_a, fps=8)

Out[3]:

<IPython.core.display.Image object>

Animation B — amber (temperature_flame_amber)¶

The same builder flow with the warmer preset — the only change is style="temperature_flame_amber".

In [4]:

glyph = ArrayGlyph(celsius, extent=extent)
add_backdrop(glyph)
anim_b = glyph.animate(data_style=DataStyle(style="temperature_flame_amber"), 
    time=labels,
    add_colorbar=False,
    frame_label=FrameLabel(color="white"),
)
embed_gif(anim_b, fps=8)

glyph = ArrayGlyph(celsius, extent=extent) add_backdrop(glyph) anim_b = glyph.animate(data_style=DataStyle(style="temperature_flame_amber"), time=labels, add_colorbar=False, frame_label=FrameLabel(color="white"), ) embed_gif(anim_b, fps=8)

Out[4]:

<IPython.core.display.Image object>

The whole flame/plume look — colour ramp, value-linked glow, dark hillshaded backdrop, per-frame labels — is ArrayGlyph(..., style="temperature_flame") with add_backdrop (the glyph's own add_relief/add_features) and .plot() / .animate(), because the glow is baked into the preset. The temperature_flame* presets are pinned to 0…40 °C with opacity ramping in over the warm end; the generic temperature presets auto-range instead.