← INDEX — FIG. 00 — 35,786 KM · 10 MIN · 16 BANDS TIROS · GOES · METEOSAT

FORECAST
TIROS, GOES, METEOSAT & WEATHER FROM ORBIT

On 1 April 1960 TIROS-1 sent down the first television picture of clouds.

BEGIN — CHAPTER 01 →

CH.01 / 09 — TIROS, NIMBUS, METEOR, 1960–69

The first look down at the weather

TIROS-1, 1 April 1960 [1][2][3].

Nimbus, SIRS and Meteor [4][5][6][7].

TWO KINDS OF MEASUREMENT FROM THE START

pictures (where the clouds are) · soundings (how warm and moist each layer is)

Pictures and soundings.

CH.02 / 09 — GEOSTATIONARY vs POLAR

Stare at one face, or sweep the whole globe

GEO: 35,786 km, every 10 minutes, 42.4 % of Earth [14][15].

Polar: 824 km, 14 orbits a day, twice-daily coverage [26][27][28].

HOW FAR A GEOSTATIONARY SATELLITE SEES

r = (μT²/4π²)^⅓ = 42,164 km · cos ψ_limb = R/r · f = (1 − R/r)/2 = 42.4 %

Geometry.

LATITUDE—

USABLE UP TO A VIEWING ANGLE OF—

Model notes.

CH.03 / 09 — ATS-1, SMS, GOES, METEOSAT, 1966–77

“The weather moves, not the satellite”

ATS-1 and the spin-scan camera [9][10][11].

SMS-1, GOES-1, Meteosat-1 [12][13].

FROM 30 MINUTES TO 10 — AND TO 30 SECONDS

Meteosat-1: full disc / 30 min, 3 channels → GOES-19 ABI: full disk / 10 min, 16 bands, a 1,000 km box every 30–60 s

Scan modes.

CH.04 / 09 — IFOV × DISTANCE

A pixel is an angle, not a size

ABI 0.5/1/2 km at nadir; IFOV is an angle [14][28][40].

Off-nadir stretch on the fixed grid [34][35].

GROUND SAMPLE DISTANCE

GSD (nadir) = IFOV × h · off nadir: E–W ≈ IFOV × d, N–S ≈ IFOV × d / cos θ

Exact projection.

LATITUDE—

LONGITUDE—

ALTITUDE FOR THE SAME ANGLE (log)—

Notes.

CH.05 / 09 — 10.3 µm, PLANCK, 6.5 K/km

A cloud's height, read from its glow

The window, Planck and brightness temperature [14].

Lapse rate 6.5 K/km [33].

RADIANCE ↔ BRIGHTNESS TEMPERATURE ↔ HEIGHT

L = c₁ν³ / (e^(c₂ν/T) − 1) · T_b = c₂ν / ln(1 + c₁ν³/L) · z = (288.15 K − T_b) / 6.5 K km⁻¹

Planck in wavenumber.

CLOUD-TOP HEIGHT—

SHARE OF THE PIXEL COVERED—

Model and split window [32].

CH.06 / 09 — AS OF OCTOBER 2026

A ring in the sky and a net around the poles

Geostationary ring [16]–[25].

Polar net [8][26][27][29][39].

CH.07 / 09 — NUMERICAL PREDICTION & HURRICANES

From radiances to forecasts

Sounders feed models: AMSU-A ~21 % [26][30][41].

Hurricanes and the Dvorak technique [14][31][41].

CH.08 / 09 — LEGACY

Sixty-six years of watching the weather from above

The first weather satellite sent pictures for 78 days.

CH.09 / 09 — REFERENCES