NOAA’s Orbital Observatories

By Eric Tegler

You may not realize it, but the National Oceanic and Atmospheric Administration is a major satellite operator. A constellation of 16 satellites is currently flying for NOAA, and every day it reveals a wealth of useful – and sometimes lifesaving – information about our amazing planet and even the sun around which we orbit. Along with operating its own fleet, NOAA also collects and analyzes information gathered by satellites from the Department of Defense, NASA, and several other countries and international organizations.

Monitoring & Understanding

The heart of the mission for which NOAA’s satellites were launched is pretty simple. Earth is a dynamic system of systems, which it pays to monitor and understand. NOAA’s satellites are the tools with which the government provides data and awareness of weather, climate trends, terrestrial and undersea changes, and the global environment in general.

Using a combination of geostationary, polar and deep space satellites, NOAA’s National Environmental Sat- ellite, Data, and Information Service (NESDIS) provides secure and timely access to global environmental data to promote and protect the nation’s security, environment, economy, and quality of life.

The constellation of satellites that NOAA operates, oversees, or gathers data from.

NESDIS data sources also include international satellites operated by partners, including the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), the European Commission, the Japan Meteorological Agency (JMA) and Japan Aerospace Exploration Agency (JAXA), the National Space Organization (NSPO) Taiwan, the Indian Space Research Organization (ISRO), the Canadian Space Agency (CSA), and the four-party (NOAA, NASA, French Space Agency [CNES], EUMETSAT) Jason satellites.

Drawing on these overhead assets, an array of ground/sea based sensors, and data processing tools, NOAA paints a comprehensive picture of the state of global weather and the environment that is updated by the minute, hour, day, and month. NOAA Assistant Administrator for Satellite and Information Services Stephen Volz recently referred to the combination as akin to “creating a digital Earth.”

“NESDIS is about the environmental satellites, but it’s also about the data and information systems,” Volz told online viewers of NOAA’s July 2020 Environmental Leadership seminar. “The information is the value of what we do. The satellites are how we collect it. Digital Earth is going from pretty pictures to critical, useful information. That’s where NESDIS plays a key role as an intermediary with our internal NOAA partners and partners around the world.”

Weather is critical, useful information, and NOAA operates the nation’s weather satellites 24/7. Volz pointed out that 95 percent of the data used in weather forecast models comes from satellites. That included NOAA’s early August prediction that the 2020 Atlantic hurricane season would likely bring from 19 to 25 named storms, nearly twice the normal number of named storms on average.

Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, told National Public Radio that the nine named storms that had already formed before Aug. 1, 2020 were – “the most ever recorded since the satellite era began in 1966.”

Bell’s observations and projections could not have been made without NOAA’s satellites.

GOES

NOAA’s Geostationary Operational Environmental Satellites (GOES) provide consistent, reliable monitoring of the Western Hemisphere. They’re the satellites that identify and track severe weather, snow storms, tropical cyclones and, as part of the Cospas- Sarsat Program, emergency locator beacons carried by ships, planes, and even hikers.

GOES satellites fly in a geostationary, medium Earth orbit. With an orbital period equal to the Earth’s rotational period, they’re essentially motionless to ground observers, staying in a fixed position in the sky about 22,000 miles above Earth. NOAA currently operates the GOES-16 satellite in the “GOES East” position (over the U.S./Atlantic Ocean), GOES-17 in the “GOES West” position (over the Pacific Ocean), and GOES-14 and 15 as on-orbit back-ups.

In 2019, America saw 14 billion-dollar disasters. They included eight severe storm events, three flooding events, two tropical cyclones, and one wildfire event in multiple locations. Overall, these events caused at least 44 casualties and had significant economic impacts. There were many more less-severe weather events during the course of the year, and NOAA’s GOES-16 and 17 sats – equipped with the Advanced Baseline Imager instrument – saw them all, providing the data for life-saving forecasts by NOAA and others in 2019.

They also mapped the flooding that accounted for three of the billion-dollar disasters in 2019, including devastating floods along the Mississippi, Missouri, and Arkansas rivers. NOAA and George Mason University partnered to develop flood-mapping products that use data and imagery from GOES-16 and GOES- 17 as well as the NOAA-NASA Suomi NPP and NOAA-20 satellites.

Spotting Wildfires from Space

Extreme weather put more people in peril than usual, but so did fires. Wildfires arose across the U.S. in 2019, but California was particularly hard hit. The destructive Kincade Fire was the state’s largest, and NOAA satellites provided guidance to the firefighters who battled it.

GOES satellites can detect and pinpoint fires before they are spotted on the ground, even in remote regions like the Alaskan wilderness.

“We use the satellites to inform decisions on where to stage assets across the country,” Brad Quayle of the Forest Service’s Geospatial Technology and Applications Center told a NESDIS interviewer. “When there’s high competition for firefighters, tankers, and aircraft, decisions have to be made on how to distribute those assets.”

Cospas-Sarsat Lifesavers

As the backbone of the international Cospas-Sarsat constellation, NOAA’s GOES satellites helped locate and rescue an estimated 421 people in the United States and its surrounding waters in 2019. A breakdown of the rescues shows 306 people rescued in 96 incidents at sea, 38 people rescued from 20 aviation incidents, and 77 people rescued in 61 incidents using personal locator beacons (PLBs) on land.

GOES satellites carry a SARSAT transponder that detects distress signals from emergency beacons and relays them to the closest ground stations. From there, the information is sent to the SARSAT Mission Control Center at NOAA’s Satellite Operations Facility in Suitland, Maryland, before rapid routing to rescue coordination centers, operated either by the U.S. Air Force for land rescues, or the U.S. Coast Guard for water rescues.

Polar Satellites

Satellites orbiting above the North and South poles provide a critical source of weather and environmental data to NOAA and its partners. They fly in a non-geosynchronous low Earth orbit (LEO) about 500 miles above the poles. These polar-orbiting satellites circle the Earth from North Pole to South Pole 14 times each day as the planet spins below.

The weather forecasting and climate research data they gather is collected alongside global sea surface temperature measurements, atmospheric soundings of temperature and humidity, ocean dynamics research, volcanic eruption monitoring, global vegetation analysis, and other applications.

NOAA has been flying polar satellites since the 1960s, but the current crop – NOAA-15, 18, 19, 20 and Suomi NPP – has been aloft since 1998. They started off as part of the Polar-orbiting Operational Environmental Satellite (POES) constellation (15, 18, 19) which shifted to a program called National Polar-orbiting Operational Environmental Satellite System (NPOESS). Aborted in the mid-2000s, it was followed by the launch of just one new polar satellite in 2011, the NASA-owned Suomi NPP, which was to bridge capability until NOAA’s latest generation of Joint Polar Satellite System (JPSS) satellites came online.

NOAA 20 is the first of these. Rotating between the poles, it can see the entire Earth twice a day. It’s in the same orbit as Suomi NPP, about 50 minutes ahead of the older satellite, which allows for a useful overlap in observational coverage.

Protecting New Routes for Trade and Travel

This year, as it did last year, NOAA-20 has been helping ships navigate the Northwest Passage. Famed and sought after as a shorter trade route between Europe and Asia, this pathway through the Arctic has been clear of ice for seasonal periods in recent years, a phenomenon scientists attribute to climate change.

Safe travel through the Northwest Passage requires up-to-date monitoring of ice-floes and weather conditions. Along with Suomi NPP, NOAA-20 can provide the necessary ice-condition data, filling gaps over areas not well covered by observing systems on the ground. NOAA-20’s Advanced Technology Microwave Sounder (ATMS) Microwave Integrated Retrieval System (MiRS) technology produces maps of temperature, water vapor, precipitation, and snow and ice cover each day.

In addition, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the NOAA-20 can observe the entire Arctic within 12 hours at sub-kilometer spatial resolution. Several more polar satellites are slated to be launched into the JPSS constellation, including NOAA-21, scheduled to blast off in 2022.

Ocean Satellites

NOAA is interested in a range of ocean data for everything from fisheries and undersea life studies to weather and hydrological conditions. But satellites can also provide crucial data for studying sea level rise.

NOAA operates the Jason-3 satellite, which is owned by the French National Centre for Space Studies (CNES) agency. Jason-3 can deliver highly detailed measurements of sea surface height to assess sea levels. Sea surface height data is also used to study hurricane intensity, tsunami dynamics, El Niño Southern Oscillation, eddy dynamics, ocean boundary currents, coastal and shallow water tides, as well as weather and climate forecasting.

Situated in non-sun synchronous low-Earth orbit, Jason-3 uses a radar altimeter to determine sea surface height. Sea level measurement is important because it can be used to estimate the depth of the thermocline, or the transition layer in a body of water where the mixed warm water from the surface and the cooler water from below meet.

By measuring how deep ocean heat extends below the ocean surface, NOAA is better able to estimate tropical cyclone heat potential and thus the likelihood of tropical cyclones.

Eric Leuliette, NOAA Satellite Oceanography & Climatology Division Ocean Physics branch chief said in a 2017 NESDIS news piece that Jason-3 (and its predecessor, Jason-2) help resolve small eddies and ocean currents, “more accurately mapping La Niña conditions in the Pacific.”

Leuliette added that the satellite also provides data to improve Atlantic hurricane intensity forecasts. Heightened sea surface temperatures add up to the formation of more hurricanes.

“When the tropical Atlantic is warmer than usual, that makes more energy available for the storms, so there tends to be greater numbers and more intense hurricanes,” said Mark DeMaria, with NOAA’s National Hurricane Center.

Sea surface temperature detection has played a major role in the NOAA Climate Prediction Center’s 2020 Atlantic hurricane forecast.

Deep Space Satellites

Keeping track of weather on Earth isn’t enough to keep us truly informed and alert. What happens in space matters too. There is such a thing as “space weather.”

The Deep Space Climate Observatory, or DSCOVR, satellite monitors solar wind and other space weather events in real time. It’s the nation’s first operational satellite in deep space, orbiting at a unique location called Lagrange point 1, or L1, approximately 1 million miles away from Earth.

The nearly ice-free Northwest Passage seen from space.

The orbit is a gravity-neutral point in space, allowing DSCOVR to essentially hover between the sun and Earth at all times, maintaining a constant view of the sun and sun-lit side of Earth. From its vantage, the satellite can provide advanced solar measurements and early warnings of potentially dangerous space weather events, acting as a solar storm buoy in deep space.

Early warning of space weather is critical. Events like the geomagnetic storms caused by changes in solar wind have the potential to disrupt nearly every major public infrastructure system, including power grids, telecommunications, aviation and GPS.

DSCOVR can provide a 15- to 60-minute warning time before the surge of particles and magnetic field, known as a coronal mass ejection (or CME), associated with a geomagnetic storm reaches Earth. The warnings potentially spare public infrastructure and advanced technology systems from major damage and disruption.

Using NASA’s Earth Polychromatic Imaging Camera (EPIC), a four megapixel CCD camera and telescope, that is part of DSCOVR’s payload, the satellite can also record and display for us a full year of life on earth from its orbital position. EPIC takes a new picture every two hours, capturing the ever-changing motion of clouds and weather systems and the fixed features of Earth such as deserts, forests, and the distinct blues of different seas.

The Dark Side of the Moon

This year marks the five-year anniversary of an iconic image captured by DSCOVR in July of 2015. While collecting an image of Hurricane Dolores, then spinning over the eastern Pacific Ocean before it brought flooding rainfall to Southern California, DSCOVR inadvertently captured an otherworldly object that blocked part of its view of the Earth.

It was the renowned but rarely seen “dark side of the moon.”

The rarely seen dark side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft’s Earth Polychromatic Imaging Camera (EPIC) and telescope and the Earth – 1 million miles away.

DSCOVR caught it as the moon passed directly between the satellite and the Earth. It was of value because it allowed scientists to see the half of the moon that is always facing away from the Earth. Only satellites farther away than the moon, which is approximately 238,000 miles from the Earth, can accomplish this feat.

NASA and NOAA scientists can use DSCOVR to study features on the far side of the moon, an opportunity that arises no more than twice a year.

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On behalf of NOAA, NASA awarded a delivery contract to Ball Aerospace & Technologies of Boulder, Colorado, for the Space Weather Follow On-Lagrange 1 (SWFO-L1) spacecraft in June 2020. The SWFO-L1 satellite is scheduled to launch in 2024 as a rideshare with the NASA Interstellar Mapping and Acceleration Probe. Like DSCOVR, it will collect solar wind data and coronal imagery to support NOAA’s mission to monitor and forecast space weather events.

An Archive of Weather and Climate

In addition to the satellites mentioned above, NOAA operates four Defense Meteorological Satellite Program (DMSP) satellites that are owned by the U.S. Air Force. Considered complementary to NOAA’s polar-orbiting satellites, they provide the military with important environmental information used in planning and conducting U.S. military operations worldwide.

The GOES-East satellite, also known as GOES-16, captured this high-resolution imagery of a derecho – a line of severe thunderstorms – on May 4, 2020. Derechos are often accompanied by high winds, heavy downpours, and hail. GOES-East keeps watch over most of North America, including the U.S. and Mexico, as well as Central and South America, the Caribbean, and the Atlantic Ocean to the west coast of Africa.

The GOES-East satellite, also known as GOES-16, captured this high-resolution imagery of a derecho – a line of severe thunderstorms – on May 4, 2020. Derechos are often accompanied by high winds, heavy downpours, and hail. GOES-East keeps watch over most of North America, including the U.S. and Mexico, as well as Central and South America, the Caribbean, and the Atlantic Ocean to the west coast of Africa.

DMSP satellites support NOAA’s three to seven-day operational weather forecasts, operational weather “nowcasting” in Alaska and polar regions, and environmental monitoring and prediction.

With the other satellites that NOAA has on orbit, they not only provide for forecasting, early warning and observation – they contribute data to an essential archive of climate and Earth-trends information.

“It’s not just weather. It’s not just the atmosphere or the solar system that we observe,” NESDIS’ Stephen Volz said. “We maintain one of the most significant archives of environmental data on the planet. All of the observations that NES- DIS makes are intended to be part of this national archive. When you think about any observation from NESDIS, [the archive] can place it in context for what’s happened in the last 50 years – in some cases, the last 1,000 years.”

That long-term view – from above – will help the U.S. and the global community to try to steer a course in managing the climate over the next century and beyond.