Why is it in the News?

NASA is ready to enhance our understanding of Earth’s atmosphere with the upcoming Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission, scheduled for launch in early 2024.

What is NASA's PACE Mission?

• The mission will leverage advanced polarimeters to investigate the intricate interactions of light, aerosols, and clouds, enhancing our understanding of their impact on both air quality and climate.
• Beyond aerosol analysis, the PACE mission will delve into the study of ocean colour.
• At its core, the Ocean Colour Instrument (OCI) serves as the primary science instrument for PACE, designed to measure the ocean's colour across a spectrum ranging from ultraviolet to shortwave infrared.
• The mission includes two polarimeters:
  • The Spectro-polarimeter for Planetary Exploration (SPEXone) and
  • The Hyper Angular Research Polarimeter (HARP2)
• Working in tandem, these instruments offer complementary spectral and angular sampling, ensuring polarimetric accuracy and extensive spatial coverage.
• This integrated approach aims to deliver enhanced atmospheric correction and a comprehensive dataset on aerosols and clouds, surpassing the capabilities of OCI alone.
• The collaborative payload of OCI, SPEXone, and HARP2 is poised to achieve significant breakthroughs in aerosol-cloud-ocean research.

What are Aerosols and their Effect?

• Aerosols are comprised of liquid or solid particles suspended in a gaseous or liquid medium.
• In the atmosphere, these particles are predominantly found in the lower layers (< 1.5 km) since aerosol sources are terrestrial.
• However, specific aerosols may extend into the stratosphere, particularly those ejected by volcanoes at high altitudes.
• Sources of Aerosols:
  • Natural Sources: Generated from breaking waves (sea salt), wind-blown mineral dust from the surface, and volcanic emissions.
  • Anthropogenic Aerosols: These include sulphate, nitrate, and carbonaceous aerosols, primarily originating from fossil fuel combustion.
• Effects of Aerosols:
  • Impact on Atmospheric Chemistry.
  • Reduction of Visibility.
• Significance for Air Quality and Human Health: Aerosols can adversely affect the heart and lungs.
• Role as Nuclei: Serve as nuclei for cloud droplets or ice crystals in ice clouds.