The main weather satellite is taken offline, which may affect the forecast


In the midst of the very active North Atlantic hurricane season, the main weather satellites used by scientists to keep tabs on weather in eastern North America and the Atlantic Ocean went offline. The outage began late on September 23, after a period in which the satellite, known as GOES-13, experienced increasing vibrations, or “noise,” in particular instruments that degraded its performance. According to Capital weather gang blogthe satellite has been put into sleep mode while engineers work to fix the problem from the ground.

Illustration of a GOES satellite.
Credit: NOAA.

Meanwhile, NOAA has took action commissioning a spare satellite. According to a message on NOAA websitethere is no estimate of when the failed satellite will resume service.

The shutdown of this geostationary satellite – so named because the satellite remains in a fixed orbit above the equator – does not mean that forecasters are flying blind and yet have lost all their sources of imagery for the Atlantic and East Coast.

At first, NOAA placed a satellite that covers the west coast – known as GOES-15, in “Full Disk Scan” mode, which will allow it to take pictures of the eastern areas once every half hour. . According to a post on the University of Wisconsin satellite blogpolar-orbiting satellites can also make up for some of the lost imaging capacity, but they cannot image the North Atlantic and eastern United States as frequently as the GOES-13 satellite.

In a move indicative of the possibility of the GOES-13 outage continuing, NOAA has now commissioned its backup GOES satellite, known as GOES-14, to take over from the troubled GOES-13. However, GOES-14 does not yet provide all the data that the faulty satellite was contributing.

“GOES-14 will remain the primary GOES satellite over the Atlantic Basin and continental United States until the imager and sonar data issues on GOES-13 can be fully diagnosed and hopefully corrected. resolved,” NOAA said in a statement. online declaration. “NOAA maintains backup GOES satellites for unplanned events, providing full redundancy for severe weather monitoring over the United States and its territories.”

Launched in 2006 but commissioned in 2010, GOES-13 should have several more years of service before reaching the end of its life.

One of the most significant impacts of the brief degradation in satellite coverage could be felt in the area of ​​computer modelling, since satellites are one of the main sources of data for weather models. This could in particular have an impact on the reliability of hurricane forecasts. On Monday there was a tropical system in the Atlantic, Tropical Storm Nadinelocated in the eastern Atlantic, far from land and within the GOES-13 coverage area.

A satellite image taken by GOES-13 before it was put into sleep mode, showing some of the interference, or “noise”, that was affecting its images. Click on the image for a larger version.
Credit: CIMSS satellite blog.

NOAA spokesman John Leslie said the absence of certain types of data typically provided by GOES-13 could slightly degrade the accuracy of some computer model projections. “The loss of temperature and humidity data used in numerical weather prediction models and advice to forecast centers and offices is relatively small because this information also comes from polar satellites and radiosondes. [weather balloons],” Leslie said in an email to Climate Central. “Loss of wind data tracked by imagery over the ocean could lead to slight degradation of the models as there are no other sources of data. Wind data derived from GOES 14 will need to be tested before being replaced on an operational basis.

The loss of GOES-13, while temporary, may give forecasters a glimpse of what lies ahead due to delays in the development of the next generation of polar-orbiting satellites. The delays mean that the polar satellite program will not have the redundancy that is present in the GOES program.

Polar-orbiting satellites constantly scan the planet from north to south, and the instruments on board these satellites are used for many applications in addition to weather forecasting, such as monitoring volcanic eruptions, collecting temperature data sea ​​surface and the location of emergency beacons for airmen or sailors in distress.

NOAA has warned that starting in 2017, there will be at least a one-year gap between the design life of the last polar-orbiting satellite and the scheduled launch date of its replacement.

This would mean that the United States would depend on a single polar-orbiting satellite, rather than the two that have been in service for a long time. NOAA has racked up billions in cost overruns for the next generation of polar-orbiting weather satellites, and congressional delays and lack of funding have put that program, known as the Joint Polar Satellite System (JPSS), years behind.

NOAA has warned that such a data gap could significantly erode the agency’s ability to provide advanced warning of significant weather events, such as the 2010 “Snowmageddon” blizzard. The GOES-13 outage also comes shortly time after an independent NOAA review team criticized the monitoring of its weather satellite programs, according to a article in Aviation Week and Space Technology.

NOAA’s Leslie downplayed the GOES-13 malfunction. “To put things into perspective, this is a technical anomaly, which is not unusual during the lifetime of a satellite mission. NOAA continues to work with its partner, NASA, on the development and the launch of next-generation JPSS and GOES-R satellites,” he said.


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