PACE

This visualization shows the planned orbit of NASA’s PACE mission (Plankton, Aerosol, Cloud, ocean Ecosystem). The visualization is organized into three sections.

1. In the first section, PACE's orbit is shown from a global view. PACE will be in a 98-degree-inclination, sun-synchronous polar orbit with an equatorial crossing time of 1:00 pm local time. PACE's orbital period (i.e., the time it takes to complete one orbit) is 98.3 minutes at an altitude of 676.5 km.
2. In second section, the camera zooms in to look at the fields of view of each of PACE's instruments: • The Ocean Color Instrument (OCI) viewing width is 113 degrees. During each orbit on the sunlit side of the Earth, OCI will change its pointing from 20 degrees behind the spacecraft (aft) when south of the Sun's latitude to 20 degrees ahead of the spacecraft (fore) when north. This is to avoid having the instrument’s field of view look into Sun glint. OCI will change its pointing back from fore to aft on the dark side of each orbit. • The Hyper Angular Research Polarimeter (HARP2) instrument has a viewing width of 94 degrees. HARP2 has 10 viewing angles along the orbit track for its blue, green, and near-infrared wavelength channels and 60 viewing angles for its red wavelength channel. These viewing angles vary along the direction of travel over a range of 114 degrees. The ground swath as viewed on Earth will vary in width with viewing angle. • The Spectro-polarimeter for Planetary Exploration (SPEXone) instrument's ground swath is about 100 km wide. SPEXone has 5 different viewing angles from -50 degrees (aft) to +50 degrees (fore). Like HARP2, the ground swath as viewed on Earth will vary in width with viewing angle.
3. The third section shows example ground swaths for each instrument. SPEXone has a relatively narrow swath. HARP2 has a wider swath for its nadir (straight down) view. OCI has an even wider swath. At the end all 3 instruments swaths are shown at the same time.

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In terms of life on Earth, color describes more than simply how features look. In many cases color serves as a proxy for biological processes. When studying ocean biology, colors count in a big way. The PACE mission has been conceived principally as a way to measure ocean color for assessing large scale ocean health. These measurements will provide data to determine the distribution of phytoplankton, tiny plants and algae that sustain the marine food web. A simple way to think about this is the more “green” that’s visible from space, the more prevalent are plant cells containing chlorophyll, an essential green pigment responsible for energy-producing photosynthesis in plants. Phytoplankton populations are fundamental to understanding the overall health of the ocean food web, as well as a wide range of related processes. PACE will be able to see other colors too—a broad range of color, in fact, stretching beyond the bounds of visible light into both ultraviolet as well as infrared. PACE will also be able to make measurements of aerosols in the atmosphere, essential for scientists to improve our understanding of and our ability to forecast weather and climate. PACE continues a more than 20 year legacy of ocean color measurements, providing the scientific community with a long time series of data. That legacy enables better assessments of long term trends about complex processes on Earth. PACE will be able to see other colors too—a broad range of color, in fact, stretching beyond the bounds of visible light into both ultraviolet as well as infrared. PACE will also be able to make measurements of aerosols in the atmosphere, essential for scientists to improve our understanding of and our ability to forecast weather and climate. PACE continues a more than 20-year legacy of ocean color measurements, providing the scientific community with a long time series of data. That legacy enables better assessments of long-term trends about complex processes on Earth.

In terms of life on Earth, color describes more than simply how features look. In many cases color serves as a proxy for biological processes. When studying ocean biology, colors count in a big way. NASA’s PACE mission (Plankton, Aerosol, Cloud, ocean Ecosystem) has been conceived principally as a way to measure ocean color for assessing large scale ocean health. These measurements will provide data to determine the distribution of phytoplankton, tiny plants and algae that sustain the marine food web. A simple way to think about this is the more “green” that’s visible from space, the more prevalent are plant cells containing chlorophyll, an essential green pigment responsible for energy-producing photosynthesis in plants. Phytoplankton populations are fundamental to understanding the overall health of the ocean food web, as well as a wide range of related processes. PACE will be able to see other colors too—a broad range of color, in fact, stretching beyond the bounds of visible light into both ultraviolet as well as infrared. PACE will also be able to make measurements of aerosols in the atmosphere, essential for scientists to improve our understanding of and our ability to forecast weather and climate. PACE continues a more than 20 year legacy of ocean color measurements, providing the scientific community with a long time series of data. That legacy enables better assessments of long term trends about complex processes on Earth.

Between September 2019 and March 2020, wildfires killed billions of animals and decimated more than 200 thousand square kilometers of Australian forest, an area larger than Nebraska. Later, thousands of kilometers away in the Southern Ocean, massive algae blooms covered a surface larger than the area of Australia itself. The connection between these major wildfires and the subsequent explosion of phytoplankton production is an example of the events NASA's upcoming Plankton, Aerosols, Clouds, and ocean Ecosystem (PACE) mission will help investigate. PACE's suite of instruments will allow scientists to get a clearer picture of carbon as it links land use and fires, atmospheric aerosols and marine communities, and ultimately improves those uncertain the data we put into climate models.

Aerosols are small solid or liquid particles suspended in the air that affect climate change directly throuhg interaction with solar radiation. Aerosols affect climate indirectly by changing the micro-and macro- physical properties of clouds. Scientists who study climate change rely on detailed data to properly characterize the the amount of radiative forcing that aerosols cause. SPEXone is a new instrument designed to pursue that data with superb accuracy. It's a polarimeter, intended to measure the intensity, Degree of Linear Polarization (DoLP) and Angle of Linear Polarization (AoLP) of sunlight reflected back from Earth's atmosphere, land surface, and ocean. Built by engineers at The Netherlands Institute for Space Research (SRON) and Airbus Defence and Space Netherlands (Airbus DS NL), SPEXone will fly on the PACE spacecraft as one of that mission's suite of sensors.

The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will deliver the most comprehensive look at global ocean color measurements in NASA's history. Not only will PACE monitor the health of our ocean, its science data will expand atmospheric studies by sensing our skies over an exceptionally broad spectrum of wavelengths. A strategic climate continuity mission in support of NASA's Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space (2010), PACE wil monitor aerosol particles, clouds, and many factors related to the marine carbon cycle including the phytoplankton pigment, chlorophyll. Moreover, PACE applications will help with many of our most pressing environmental issues such as harmful algal bloom and air quality forecasts.

PACE stands for "Plankton, Aerosol, Cloud, ocean Ecosystem". PACE's advanced technologies will provide unprecedented insight into Earth's ocean and atmosphere, which impact our everyday lives by regulating climate and making our planet habitable. Our oceans teem with life, supporting many of Earth's economies. New discoveries in Earth's living ocean will be revealed with PACE's global observations, such as the diversity of organisms fueling marine food webs and how ecosystems respond to environmental change. PACE will observe our atmosphere to study clouds along with the tiny airborne particles known as aerosols. Looking at the ocean, clouds, and aerosols together will improve our knowledge of the roles each plays in our changing planet. PACE's data will reveal interactions between the ocean and atmosphere, including how they exchange carbon dioxide and how atmospheric aerosols might fuel phytoplankton growth in the surface ocean. Novel uses of PACE data – from identifying the extent and duration of harmful algal blooms to improving our understanding of air quality – will result in direct economic and societal benefits. By extending and expanding NASA's long record of satellite observations of our living planet, we will take Earth's pulse in new ways for decades to come. The videos presented here show four specific themes that the mission will study. There are two versions of each video, one with the PACE logo and mission name in the narration, one that's simply branded with the NASA "meatball" logo and a larger "earth science" message in the narration.

Jeremy Werdell is studying how microscopic plankton in the oceans are responding to our changing climate. As a scientist at NASA’s Goddard Space Flight Center, he knows that Earth's oceans and land cover have been doing us a favor. As people burn fossil fuels and clear forests, only half of the carbon dioxide released stays in the atmosphere, warming and altering Earth’s climate. The other half is removed from the air by the planet’s vegetation ecosystems and oceans. But Jeremy and other scientists are still trying to answer important questions about how carbon dioxide emissions get absorbed by the land and the ocean — and how this could change in the future. Later this month, the United Nations climate meeting in Paris (Conference of Parties, aka COP-21) will focus on setting limits on future levels of human-produced carbon emissions.