About the Data

Earth Coverage

The AIRS instrument on NASA's Aqua satellite orbits Earth from pole-to-pole, approximately fifteen times each day. The orbit of the Aqua satellite is polar sun-synchronous with a nominal altitude of 705 kilometers (438 miles) and an orbital period of 98.8 minutes, completing approximately 14.5 orbits per day. The same area on Earth is covered two times per day, in a descending orbital pass which occurs at 1:30 am local time, and an ascending orbital pass at 1:30 pm local time (satellite equatorial crossing local times are 1:30 am in a descending orbit and 1:30 pm in an ascending orbit.) The repeat cycle period is 233 orbits (16 days) with a ground track repeatability of +/- 20 kilometers (12 miles).

As the instrument moves along, it scans from side to side, creating a swath in which data is collected. At the north pole the swaths overlap but at the equator gaps occur between swaths. These gaps are eventually scanned within two to three days.

Specifications

Orbit type sun synchronous polar

Orbit altitude 705 kilometers (438 miles)

Period 98.88 minutes

Orbits per day 14.5

Overpasses 2 per day: Daytime ascending pass (south pole to north pole) at 1:30 pm local time; Nighttime descending pass (north pole to south pole) occurs at 1:30 am local time

Daily coverage more than 95% of Earth’s surface

Swath width 1650 kilometers (1025 mi)

Resolution at nadir 13.5 kilometers (8.4 miles)

Resolution at scan extremes 41 x 21.4 kilometers (25.4 x 13.2 miles)

Samples per scanline across swath 90 footprints, each footprint is 1.1 degree

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Orbit Track Maps

Available on the Granularity page.