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On "PACE" for space

- December 15, 2014

Dal's Susanne Craig. (Bruce Bottomley photo)
Dal's Susanne Craig. (Bruce Bottomley photo)

Susanne Craig is seeing colours — and this time, she’ll be sharing her sights with the world.

An expert in the field of oceanography, Dr. Craig has recently been accepted as a member of a science team for National Aeronautics and Space Administration (NASA)’s upcoming satellite mission: Pre-Aerosol, Clouds, and ocean Ecosystem (PACE), which will measure the world’s oceans using a satellite that orbits the Earth.

PACE will keep track of colour variations of the oceans around the world, recording the data and transmitting it back to Earth on a daily basis. While the satellite’s launch date is still to be determined, it could be as early as 2021. The satellite will record ocean colour around the world, which reveals the physical and biological properties of the ocean to Dr. Craig.

“There’s no question that the ocean is being affected by climate change,” says Dr. Craig, principal investigator and research associate in the Department of Oceanography and FGS adjunct in Process Engineering and Applied Science (PEAS).

“What we want to know is how climate changes are affecting the type and distribution of phytoplankton, the tiny microscopic plants that are the base of aquatic food webs, and that play a fundamental role in the global carbon cycle.

Coastal focus


The coastal ocean comprises only about seven per cent of the surface area of the world ocean yet it punches above its weight, providing vital services such as CO2 uptake and supports crucial industries such as fisheries, tourism and recreation. Around 40 per cent of the world’s population lives within 100 km of a coastline, but often ocean colour satellites have difficulty in acquiring accurate data over these important waters.

“The coastal zone is one of my core interests as an ocean colour scientist,” says Dr. Craig. "This part of the ocean is particularly affected by anthropogenic, or man-made, influences. It’s a dynamic region where we see lots of biological activity, and changing biological patterns that may be linked to climate change. Coastal areas are biogeochemically important.”  

Important, yes, but studying the shallow bodies of the ocean comes with a catch: atmospheric influences get in the way and may actually skew the data the PACE satellite will gather. For this reason, Craig has developed a mathematical solution for the complexities that exist in studying coastal ocean colour. This may improve a process called atmospheric correction — notoriously difficult over optically complex coastal waters — and yield more accurate results.

“There is a synergy between the ocean and the atmosphere”, says Dr. Craig. “In a separate, but related, project with colleague Mark Gibson (PEAS), we’re investigating how phytoplankton evolve a suite of volatile organic compounds. The substances released by these small organisms into the atmosphere can form aerosols, which ultimately influence our climate because they scatter radiation away from the Earth that would other wise heat the planet.“

A team effort


Dr. Craig will be the only Canadian science team member on the PACE mission. Other US scientists with different specialties and research interests will be teaming up with the oceanographer to find the connection between ocean ecology and climate change.

“What NASA is encouraging for this mission is a move away from individualized research in little silos towards a more consensus-driven approach. The project will adopt this new model, which is probably more efficient. We’ll be working together so as not to replicate each others’ efforts.”

Some will be working more closely than others, as two teams are formed to best utilize their expertise and knowledge on the atmosphere and marine environments. The first will work on methods to determine inherent optical properties (IOPs) from ocean colour, providing data about levels of sediment, dissolved carbon and chlorophyll, the pigment present in phytoplankton. The second team will be the atmospheric correction team, focused on finding the best methods for “removing” the effects of the atmosphere from the signal that PACE will record.

Luckily, Dr. Craig will be able to assist on both teams because of her research background in phytoplankton dynamics and interest in atmospheric correction.

The scientists on the PACE mission will formally meet this January to strategize and talk about how they will achieve their goals and objectives for the project. Many of these researchers have connected previously, through their association to the scientific community.

Informing the community


“NASA has been an exceptional citizen of the planet,” says Dr. Craig. “They are ensuring that the data collected by PACE and other satellites will be available free of charge, not only to the research community but also to the general public.”

A major goal of the PACE Science Team project is production of a report detailing the team’s findings and recommendations. This will be shared fully with the global scientific community and will act as a springboard for interested parties to post their thoughts and ideas about the mission to NASA and others involved in the discussion. Global ocean colour data is and will be updated on a daily basis for science lovers around the globe.

The data on ocean color is now available on NASA’s website.


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