Transcripts of Aqua Ep5 CERES



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[music] Narrator: In order to understand the Earth’s climate, it’s critical we understand how warm the planet is, how its temperature changes over time and what factors can force those changes. The sun is the Earth’s primary source of heat, constantly bathing us with solar radiation. The land surface, cloud cover and our atmosphere help determine how much of that heat is reflected and how much is retained. Loeb: How that changes over time is really critical because in a climate system that’s in equilibrium those two should really balance and if they do  then the temperatures will remain relatively constant with time. Now when you add greenhouse gases such as carbon dioxide, methane, you change that radiation balance at the top of the atmosphere, you reduce the amount of outgoing radiation and so that imbalance means more energy is in the system. Part of it goes into the ocean, is stored in the ocean, and part of it goes into actually warming the Earth. Narrator: One of NASA’s most important tools for measuring that heat is an instrument on board the Aqua, Terra, TRMM, and NPP satellites, called CERES, Clouds and the Earth’s Radiant Energy System. Parkinson: The CERES instrument has exactly three channels, but those three channels have been tuned to get really really important information about long wave radiation from the Earth’s system, the reflected short wave radiation from the sun, and then a window channel of radiation. So it’s got three channels that give us huge amounts of information about the radiation budget of the Earth. Narration: CERES observations complement data from another instrument on Aqua and Terra called MODIS. MODIS has a smaller footprint, but much higher resolution to its data, illuminating how the energy budget is affected by clouds, dust particles, oceans, and land cover. That energy budget can also be influenced by natural events such as the La Nina and El Nino weather patterns, the amount of ice and snow covering the Earth, and events that impact the Earth’s atmosphere like volcanoes. Researchers use CERES data and similar data sets from the past, to establish a long term trend that encompasses  all those factors and the natural variation of the Earth’s radiation budget. Loeb: If you want to look at changes in the system that are significant that might be associated with actual global warming, you have to measure above that natural variablility, so you need a long record. Narration: The CERES instruments and their predecessors have been taking the Earth's temperature for almost 30 years, and this data can be used in conjunction with other measurements of the Earth's vital signs. Loeb: And so having the CERES measurements, the ocean heat storage measurements, measurements of sea level rise, measurements of land ice volume, all of those should give you a coherent picture of how things are changing as we are warming the climate.  

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