How Will NASA’s EMIT Help Us Learn More About Earth's Climate Effects?


Climate change has become a pressing issue in recent years. As Earth continues warming from carbon emissions, scientists learn more about how climate change affects the entire world. One of the essential pieces of technology for studying this type of effect is NASA's EMIT satellite system.

The three EMIT satellites orbit Earth, each equipped with an instrument specifically designed to study Earth's atmosphere and climate. The first two EMIT satellites have already been in orbit since 2009. The recently launched third satellite will soon join the other two.

EMIT's measurements are a continuation of the existing NASA Climate Absolute Radiance and Refractivity Observatory, which stopped operating in 2005, says Drew Shindell, a NASA scientist and leader of the research team working to develop better climate models with EMIT data. EMIT's goal is to make measurements that fill some critical gaps. One important goal is to improve models that depict the role of water in Earth's climate.

The EMIT satellite system uses a technique called limb spectroscopy. The satellites orbit directly over Earth's poles, and every few days, they pass now above some regions of the planet. It allows scientists to measure the spatial and temporal variations in infrared radiation from those areas.

The EMIT instruments can measure the optical properties of Earth's atmosphere at a much higher resolution than other instruments, Shindell says. They can make these measurements uniformly over time, different from the other available satellite data.

The EMIT instruments can make these detailed measurements because of their unique orbit and design. The satellites fly at a low altitude of about 310 miles, compared with many other Earth observation satellites that orbit more than 500 miles. It ensures that the instruments measure radiation from space, not from sunlight reflecting from Earth's surface.

Benefits of NASA's EMIT

NASA's Earth Observing System satellites study and monitor our home planet from space, collecting images and other information. The four current Earth-observing fleets represent four generations of more advanced technology, capturing the world in multiple wavelengths of light. Image Credit: NASA's Goddard Space Flight Center/Reto Stöckli.

The EMIT orbit also lets scientists observe the atmosphere at different times of the day. It is important because the atmosphere changes as the sun rises and sets over 24 hours.

The sun heats the surface at different times of day, so the atmospheric structure is different at other times, says Ricardo Ramirez, an atmospheric scientist with NASA's Jet Propulsion Laboratory in Pasadena, California. It's essential to measure these differences because water vapor responds differently depending on how solar energy is distributed.

The satellites also pass over the same spot on Earth every 14 days. It allows scientists to study the atmosphere's variability from one pass to another. The EMIT instruments measure infrared radiation over a wide range of wavelengths. They can research both the temperature and the distribution of water molecules throughout the atmosphere, which can change due to climate variations such as El Niño.

EMIT will fill an essential gap in our knowledge by providing measurements from orbit that are currently unavailable, says Tom Woods, a scientist at Colorado State University working with EMIT data.

Long-term studies of the entire globe will help scientists understand how climate patterns are different in the tropics and subtropics, where Earth's atmosphere is a small fraction of the total surface area. These areas aren't directly visible from space, but rising air temperatures help scientists learn more about climate changes on Earth. This knowledge will allow them to make better predictions about future changes in Earth's atmosphere.

Because of their unique orbit, data from the two EMIT satellites are beneficial for studying the tropics and subtropics, says David Schimel, a scientist at NASA's Jet Propulsion Laboratory in Pasadena.

The next step for these scientists is to use the EMIT data to improve global climate models. The models are used to predict future climate changes, but they aren't very accurate over large areas of the Earth's surface.

The improvements NASA's EMIT data will make to the models are essential because the predictions of future climate change depend on how accurate we can make these models, Schimel says.

With EMIT's data, scientists can improve climate models by studying how variations in climate over large areas affect water in the atmosphere. To do so, they will use measurements made by both new and historical satellite data.

There are thousands of different satellite measurements collected over the last several decades, Schimel says. We are using data from previous satellite missions to help us better understand how to improve the model predictions. For example, we can use NASA's Cloudsat spacecraft measurements to compare how well a climate model predicts water vapor in certain areas.

Scientists will soon begin using the EMIT data in Earth's atmosphere and climate models. The models will help researchers understand the processes that control atmospheric water vapor variations and expand their knowledge about future climate change on Earth.

NASA's Earth Observations System satellites observe Earth's land and oceans, monitor weather, study climate change and monitor natural resources. EMIT is a joint mission between NASA and the German Aerospace Center (DLR). Image Credit: NASA

EMIT Data from Space

The EMIT satellites use a technique called limb spectroscopy. The satellites orbit directly over Earth's poles, and every few days, they pass now above some regions of the planet. It allows scientists to measure the spatial and temporal variations in infrared radiation from those areas.

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