Deep Space Climate Observatory National Institute of Standards and Technology Advanced Radiometer Level 1A Radiance, Version 3

DSCOVR_NISTAR_L1A is the Deep Space Climate Observatory (DSCOVR) National Institute of Standards & Technology Advanced Radiometer (NISTAR) Level 1A Radiance, Version 3 data product.

NISTAR is a 4-band radiometer onboard NOAA’s DSCOVR spacecraft located at the Earth-Sun Lagrange-1 (L-1) point, from which vantage it continuously measures the reflected and emitted radiances of the sunlit face of the Earth. These measurements provide an accurate energy balance measurement that improves our understanding of the Earth’s radiation budget.

NISTAR employs three electrical substitution radiometers and a photodiode to measure reflected sunlight and infrared emission from the Earth. NISTAR measures the absolute irradiance integrated over the entire sunlit face of Earth in four broadband channels minute-by-minute. NISTAR has a 1º field of view (FOV) that acts as one large pixel that encompasses the entire sunlit side of the Earth, and a 7º field of regard.

The four measurement bands and their uses are:

1) Total Radiation – 0.2 µm to 100 µm: total radiant power in the UV, visible, and infrared wavelengths emerging from Earth.
2) Total Solar Reflected – 0.2 µm to 4 µm: reflected solar radiance in UV, visible, and near infrared wavelengths from Earth.
3) Near Infrared Solar Reflected – 0.7 µm to 4 µm: reflected near infrared solar radiation from Earth.
4) Photodiode – 0.2 µm to 1.1 µm: tracks the stability of the filters, and to verify co-alignment of NISTAR and EPIC.

The Level 1A products have been converted to engineering units, but retain their one to one associations with the items in the raw telemetry from which they were derived. These data products are in HDF5 format.