The quest to understand our planet's energy dynamics has spanned decades, with NASA leading the charge. But here's a mind-boggling fact: this journey began with a satellite that orbited Earth over 58,000 times!
The Early Days of Space Exploration:
On January 31, 1958, Explorer 1, the first satellite launched by the United States, embarked on its mission. Its cosmic ray detector was designed to measure Earth's radiation environment, but its impact extended far beyond its final transmission in May 1958. This pioneering satellite laid the foundation for NASA's exploration of Earth's systems.
Fast forward to 1975, just five years after Explorer 1's fiery demise in Earth's atmosphere, and NASA's Nimbus instrument provided groundbreaking insights. It offered the first global, direct observations of solar radiation entering and exiting our planet, refining early climate models and paving the way for the Earth Radiation Budget Experiment (ERBE).
Defining the Boundaries of Space:
The ERBE team faced a fascinating challenge in the 1970s: determining the exact location of the top of the atmosphere. Bruce Barkstrom, a retired ERBE scientist, vividly recalls the team's intense debate, ultimately assigning this task to a researcher at NASA's Langley Research Center. Their conclusion? The top of the atmosphere is approximately 18 miles (30 kilometers) above Earth's surface.
ERBE Takes Flight:
In October 1984, ERBE embarked on its journey aboard the Earth Radiation Budget Satellite (ERBS), launched from the space shuttle Challenger (STS-41G). Barkstrom reminisces about the early morning launch, describing how the shuttle's bright exhaust illuminated the overcast sky, creating a memorable spectacle.
Unraveling the Sun-Earth-Cloud Connection:
For a decade, ERBE delivered invaluable data, revealing the intricate energy interactions between the Sun, clouds, and Earth. Its measurements shed light on Earth's radiation at the top of the atmosphere and the significant role of clouds in modulating incoming and outgoing energy.
Clouds: Earth's Climate Regulators:
In the late 1980s, satellite instruments confirmed that clouds cool Earth's climate. Bruce Wielicki, a former CERES Principal Investigator, developed an algorithm to quantify cloud forcing, a critical factor in understanding Earth's energy budget. This discovery underscored the importance of clouds in climate regulation.
CERES: Extending the Legacy:
In 1997, the Clouds and the Earth's Radiant Energy System (CERES) instruments were launched, building upon ERBE's achievements. These instruments have since been activated in space to measure solar energy reflection, planetary heat emission, and the complex role of clouds in this process.
Kory Priestley, CERES Principal Investigator, praises the instrument's accuracy and elegance, striving to develop the next generation of technology. The seventh and final CERES instrument launched in November 2017, continuing NASA's 42-year-long mission to observe Earth's energy budget.
The Ever-Evolving Understanding:
NASA Langley's Earth Radiation Budget Science Team remains at the forefront of ERB data production. Despite the monumental progress since Explorer 1 and Nimbus, Barkstrom emphasizes the ongoing nature of this scientific pursuit. Earth observations, he notes, are a never-ending journey of discovery, always subject to new insights and adjustments.
The Significance of Earth's Energy Budget:
Efforts to comprehend Earth's energy budget date back to the 1880s. It represents the delicate balance between solar energy and the energy radiated back into space. Long-term, accurate data are vital for refining models that forecast seasonal and long-term changes, guiding industries and policymakers in their decision-making.
NASA's Ongoing Mission:
NASA's Total and Spectral Solar Irradiance Sensor (TSIS)-1, currently aboard the International Space Station, measures the Sun's energy input to Earth. Since 1978, various satellites have captured continuous solar energy records, enabling scientists to study the Sun's impact on Earth's ozone layer, atmospheric circulation, clouds, and ecosystems.
ERBE and CERES: Unlocking Earth's Secrets:
The radiation budget, a balance between incoming solar energy and outgoing thermal and reflected energy, was recognized as crucial in the 1970s. NASA's Langley Research Center developed advanced instruments, and the Goddard Space Flight Center built the ERBS, which carried the first ERBE instruments. ERBE instruments were also launched on NOAA weather satellites in 1984 and 1986.
CERES, a high-priority instrument for NASA's Earth Observing System, was first launched in 1997. It collects data on multiple satellite missions, including EOS Terra and Aqua observatories, the Suomi National Polar-orbiting Partnership, and the Joint Polar Satellite System. The final CERES instrument, launched in 2017, continues the legacy of studying Earth's interconnected systems with long-term data.
And this is the part most people miss: the continuous evolution of our understanding of Earth's energy dynamics. As technology advances, so does our ability to measure and interpret these complex interactions. But what does this mean for the future of climate science and our planet's well-being? The debate is open, and your thoughts are welcome!
