Question

What is the temporal resolution of MODIS?

• A. 1 day
• B. 5 days
• C. 10 days
• D. 14 days

Hint:

• Temporal resolution is the revisit frequency of a satellite for the same location.
• MODIS is on two NASA satellites (Terra and Aqua).
• Due to its wide viewing swath, MODIS provides near-daily global coverage. Most locations are imaged every 1-2 days.
• This high temporal resolution is excellent for monitoring dynamic environmental phenomena (e.g., vegetation phenology, snow cover, sea surface temperature).

Answer 1

The Correct Option is A

MODIS (Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard NASA's Terra (EOS AM) and Aqua (EOS PM) satellites. These satellites are in sun-synchronous, near-polar orbits. The temporal resolution of a satellite sensor refers to how frequently it can observe the same area on the Earth's surface.

• The MODIS instrument has a wide swath width of 2,330 km.
• With two MODIS instruments (one on Terra, one on Aqua) in orbit, they provide global coverage almost daily. Specifically, most of the Earth's surface is imaged every 1 to 2 days.
• For many locations, especially at mid to high latitudes, it is possible to get imagery from MODIS at least once per day, and sometimes twice a day (once from Terra in the morning, once from Aqua in the afternoon).

Therefore, the effective temporal resolution of MODIS for global coverage is approximately 1 day, considering the combined capability of the two satellites. Option (a) "1 day" is the most accurate representation of MODIS's high temporal resolution for global observation. Options (b), (c), and (d) represent much longer revisit times, which are characteristic of higher spatial resolution satellites with narrower swaths (e.g., Landsat has a 16-day revisit cycle with one satellite). \[ \boxed{\text{1 day}} \]