Earthdata Forum

How do I know what time of day the image was taken?

To find out what time of day an image was taken for the Terra, Aqua, Aura, and Global Precipitation Measurement (GPM) satellites and several other satellites, you must activate the corresponding Orbit Track & Time layer.

OR

• In the Layer List, display the desired imagery by clicking on the eye icon, e.g. Corrected Reflectance (True Color) Terra / MODIS

• Click on the Layer settings button for the layer e.g. Corrected Reflectance (True Color) Terra / MODIS layer, click on the check box under the Orbit Tracks title next to Descending/Day

• In the Layer List, click on the "Add Layers" tab

• Type “Orbit Tracks” in the search box

• Add the corresponding Orbit Track overlay, e.g. Terra - Orbit Track & Time Terra / Space-Track.org. Acquisition Time (UTC) - Descending/Day. Orbit track example

The orbit tracks represent when the satellite will be passing over a particular location on Earth on that day. The orbit tracks show a series of dots, each dot representing 1 minute along the satellite orbit path with time stamps shown every 5 minutes. The time is shown in Coordinated Universal Time, or UTC.

Orbit Track layers include ascending and descending satellite orbits for day and night-time orbits. Terra’s descending/day time orbit (North-South) will cross the equator at 10:30 a.m. local time during each orbit and ascending/night time orbit will pass over the equator at 10:30 p.m. local time. Aqua’s ascending/day time orbit crosses the equator at 1:30 p.m. local time and descending/night time orbit passes over the equator at 1:30 a.m. local time. Aura and GPM are on the same orbit track as Aqua and the satellites follow each other closely, passing over the equator within minutes of each other at 1:30 p.m. local time and 1:30 a.m. local time. These satellites, as well as a few others, form the Afternoon Constellation—“A-Train” for short. The A-Train flies in the following order: Orbiting Carbon Observatory-2 (OCO-2), Global Change Observation Mission-Water "SHIZUKU" 1 (GCOM-W1), Aqua, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat, and Aura.

Not all layers are available for the night time orbit. For MODIS surface/corrected reflectance imagery, you must pick a day time orbit as it is not possible to create a surface reflectance image without sunlight.