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GeoXO Night Band

Nighttime image of the U.S. southeast coast showing city lights from Arkansas to North Carolina, while Hurricane Isaac, as a large rounded area of clouds, makes landfall in Louisiana.
Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band imagery of Hurricane Isaac making landfall near New Orleans in 2012.

The GeoXO Night Band would be a function of a satellite instrument that allows scientists to monitor various nighttime phenomena on the Earth's surface and atmosphere in low-light conditions on a daily basis. Images would be displayed in greyscale.

The addition of a Night Band is being studied as an addition to either the GeoXO Sounder (GXS) or Ocean Color (OCX) Instrument. 

A GeoXO Night Band would have the ability to detect the low levels of visible light that occur at night from reflected moonlight. Most visible-wavelength sensors don’t work at night because the signal is well below the noise of the instrument. Night Band imagery would also detect city lights, which would be helpful for monitoring power outages.

Weather satellite sensors typically operate in the visible and infrared portion of the electromagnetic spectrum. Such is the case with the Suomi NPP and NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) instruments, which have 22 bands (channels) that range in wavelength from 0.412 micrometers (µm) to 12.01 µm. The Day/Night Band is a broadband channel sensitive to radiation in the wavelength range from about 0.5 – 0.9 µm, which covers much of the visible wavelengths and into the near-infrared wavelengths.

Improvements Over Current Capabilities

Currently, NOAA cannot fully observe nighttime hazards in the visible wavelength in real-time as the two satellites with that capability are polar orbiters that fly over a fixed location on earth twice daily – once during the day, and once at night.  

There is not a Night Band on the current GOES-R satellites. These geostationary satellites detect nighttime clouds by infrared data that provides estimates of cloud and surface temperatures. However, if clouds are the same temperature as the land and ocean below them, it’s hard to discern one from the other. 

Benefits of a Geostationary Night Band

Having a Night Band aboard a geostationary satellite could help distinguish between clouds and land/ocean surfaces. It would also observe weather and hazard events continuously at night and enhance warnings.

Continuous nighttime imagery would improve the ability of forecasters to see clouds much sooner after they're observed. It would dramatically improve the ability to detect and track fog at night, characterize the formation of tropical storms, monitor power outages/recovery in real-time, and provide a new lights-based search and rescue utility, Nighttime visible imagery would improve nighttime monitoring of warm, low-level clouds, weather systems, auroras, and urban lights. It would improve the ability to detect and track air quality and visibility hazards such as wildfires, smoke and dust and even light emitted by molten-hot magma from an erupting volcano at night. Long-term composites reveal global patterns of infrastructure development and energy use.  

Night Band imagery would also be useful for showing patterns of human activity and energy behaviors such as cities and highways, the tracking of shipping and fishing fleets at night, and the burning of waste natural gas (gas flares) from onshore and off-shore oil/gas production sites. 

 

Dave Snider of Alaska Weather Facts talks about Day/Night Band imagery with Eric Stevens of GINA, the Geographic Information Network of Alaska at the University of Alaska, Fairbanks.