Solar radiation enters the Earth's atmosphere with a portion being scattered by clouds and aerosols.

Processing, archiving and distributing Earth science data
at the NASA Langley Research Center

What is Local Mode (LM)? Global Mode (GM)? Calibration Mode?

The MISR instrument can acquire measurement in Global Mode (GM), Local Mode (LM), and Calibration. Global Mode is the normal acquisition with pole to pole coverage on the day-lit side or the orbit, full resolution (275m) in all 4 nadir bands and the red band of all other angles and 1.1km sampling in all other off nadir bands.

MISR can be configured to disable the on-board data averaging and provide high resolution images in all 36 channels for selected targets and observation times. This capability is referred to as Local Mode (LM). The result is a scene with a crosstrack pixel spacing of 275 meters, with downtrack sampling also at 275 meters, over a spatial area of approximately 300 kilometers downtrack by 360 kilometers crosstrack. LM acquisition can be requested by providing latitude and longitude coordinates, dates, and explanation of data need to User and Data Services.

Global
  • Pole-to-pole coverage on orbit dayside
  • Full resolution in all 4 nadir bands, and red band of off-nadir cameras (275-m sampling)
  • 4x4 pixel averaging in all other channels (1.1-km sampling)
Local
  • Implemented for pre-established targets (1-2 per day)
  • Provides full resolution in all 36 channels (275-m sampling)
  • Pixel averaging is inhibited sequentially from camera Df to camera Da over targets approximately 300 km in length
Calibration
  • Implemented bi-monthly
  • Spectralon solar diffuser panels are deployed near poles and observed by camera and a set of stable photodiodes