Our oceans are in warm waters

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In addition to the grim list of record ice losses, record air temperatures and record droughts, which have all made headlines lately, the surface water temperature of our oceans has also reached record levels. With El Niño on the way, it is feared we will soon see the worst of the extremes.

Orbiting satellites are used to closely monitor the patterns leading to El Niño in order to better understand and predict the impact of this periodic phenomenon on the background of climate change. The ocean-atmosphere system associated with El Niño and La Niña, collectively known as the El Niño Southern Oscillation, results in large changes in global temperature and precipitation, as well as a warming trend due to climate change.

El Niño occurs every few years when the trade winds weaken, shifting the warm waters of the western Pacific Ocean to the east, causing changes in wind patterns and ocean dynamics. This could have major impacts on global weather, including changes in ecosystems, fisheries, droughts, floods and storms. According to climate models, after three years of La Niña, which has a general cooling effect on the planet, we will again encounter a more problematic El Niño in the coming months.

Climate change has already led to the recent temperature extremes many of us have experienced, so the troubling question is whether a looming El Niño will make things worse. Tracking changes in sea surface temperature and elevation, along with surface wind patterns generated by interactions between the ocean and the atmosphere, can help us understand the mechanisms driving El Niño events. In addition, scientists must consider climate change, which is likely to amplify El Niño extremes and future El Niño events. Satellites orbiting over Earth are of paramount importance in providing data for this type of research because the equatorial Pacific Ocean, where El Niño occurs, is too large to monitor.

Photo: ESA

ESA’s chief scientist, Craig Donlon, said, “More than 70% of our planet is covered by oceans. They play a huge role in the climate system.” We all know our climate is warming, but I think most people think of warmer air temperatures first. In fact, our oceans absorb much of this extra heat, keeping the atmosphere relatively cool. This has taken its toll, and the temperature of our oceans is now at its highest since records began.”

“Scientists around the world use Copernicus Sentinel-3 data, which, together with sea surface altitude data, provides reference measurements of surface temperature. They also use Copernicus Sentinel-6, which gives us the most accurate measurements of sea level height. Sea. Surface “When seawater warms, it expands—one of the main causes of sea level rise. Together, these complementary data sets provide a unique picture of an evolving El Niño.”

The Copernicus Sentinel 3 mission, built by the European Space Agency and operated by Eumetsat, is unique in providing sea surface temperature and sea elevation measurements from the same satellite platform. The mission consists of two identical satellites, each with the same set of instruments — one is the Sea-Ground Temperature Radiometer, which measures the global sea surface temperature each day with an accuracy of more than 0.3 K.

The other is a radar altimeter that measures sea level height, wave height, and wind speed. In addition, the imager, depicting oceans and land color, allows scientists to study biological features in the ocean that have been altered by El Niño. The Sentinel-3 radiometer is being used by the Commission on Earth Observing Satellites as part of a hypothetical sea surface temperature constellation to understand phenomena such as El Niño and La Niña, ocean currents and heat exchange between the ocean and atmosphere.

Sentinel-6 is the reference altimeter used to homogenize data from other satellite altimeters and to provide sea level height measurements every ten days. Most importantly, data from both tasks is delivered in near real time. The European Space Agency is currently building two more Sentinel-3 satellites, Sentinel-3C and Sentinel-3D, to ensure continuity of such measurements. Looking ahead, the European Space Agency is also developing the follow-up Copernicus Sentinel-3 Next Generation mission.

A second Sentinel-6 satellite is currently in storage and will be launched in the coming years to track sea level data. Because sea surface temperature is an important primary climate variable, the European Space Agency’s Climate Change Initiative also provides Sentinel-3 data for the Sea Surface Temperature project.

The future Copernicus Microwave Imaging Radiometer mission will provide high-resolution measurements of sea surface temperature under all weather conditions. In addition, the Copernicus Earth Surface Temperature Monitoring mission will provide high-resolution data on sea surface temperature in coastal regions. In short, the Copernicus program is well prepared to continue observing our oceans into the future. Ocean warming is already a cause for concern, and with El Niño looming, the world is preparing for its consequences. El Niño is likely to affect more than 60 million people, mostly in eastern and southern Africa, the Horn of Africa, Latin America and the Caribbean, and the Asia-Pacific region.

Severe drought and associated food insecurity, floods, rains and higher temperatures due to El Niño can cause a wide range of health problems, including disease outbreaks, malnutrition, heat stress and respiratory illnesses. “Satellites orbiting the Earth now and in the future, not only monitoring our oceans, but also measuring many other aspects of our planet, are more important than ever. They provide compelling evidence for science and for decision-making to protect society,” added Dr. Donlon for that.

source: ESA