Jeff Key connects polar winds with local weather

“The polar regions are intimately connected to the mid and lower latitude regions of the Earth. Whatever is going on in the polar regions will certainly impact the lower latitudes, through in part the position of the jet stream, but more broadly in terms of atmospheric and oceanic circulation. So the more we can learn about the Arctic and the Antarctic, the more we’re going to understand weather that impacts us directly here in the mid-latitudes.” – Jeff Key

Atmospheric scientist Jeff Key explained why scientists study weather at Earth’s poles – and he talked more about how they do this using a variety of methods, including those on NASA’s Terra research satellite, with EarthSky’s Jorge Salazar.

Dr. Jeff Key is the Branch Chief of the Advanced Satellite Products Branch of NOAA’s Center for Satellite Applications and Research located at the University of Wisconsin-Madison. Our thanks today to NASA’s Terra mission, helping us better understand and protect our home planet.

Jeff Key: The more we can learn about the Arctic and the Antarctic, the more we’re going to understand weather that impacts us directly here in the mid-latitudes.

Atmospheric scientist Jeff Key of the National Oceanic and Atmospheric Administration studies winds at Earth’s poles. He said that those of us at mid-latitudes might be most familiar with the effects of polar winds when an Arctic blast of cold weather blows in.

Jeff Key: The term for that particular area of weather and that aspect of the global circulation that influences the movement of storms is the jet stream.

The jet stream is like a river of strong wind high above the Earth that steers storms around the world.

Jeff Key: I think probably the most important connection between high latitudes and lower latitude weather, is the position of the jet stream.

Key gets wind information from NASA’s polar-orbiting satellites, called Terra and Aqua. He uses this wind information to analyze the jet stream, and help predict global weather.

Jeff Key: Now the difference that the winds make in the position of the jet stream may seem relatively minor to the layperson, but in fact a difference of a few tens of kilometers actually makes a huge difference in the weather.

Key added that polar winds can even effect hurricanes.

Jeff Key: We found that using the Terra and Aqua wind information in numerical weather forecasts has improved the prediction of hurricane tracks.

Jeff Key described the science being done using the MODIS instrument aboard NASA’s Terra and Aqua research satellites.

Jeff Key: First of all, we use the MODIS instrument on the Terra satellite, the Moderate Resolution Imaging Spectroradiaometer, and the important point there is that it is an imager. It’s in some sense a camera, but a camera that looks at the Earth in many different wavelengths, the visible wavelengths, thermal wavelengths, so it’s measuring reflected information as well as emitted information, something that we think of as heat. It also has some important observations in the water vapor portion of the electromagnetic spectrum. And what that really means, or what that boils down to is that we are observing water vapor in the atmosphere. We can also observe carbon dioxide in the atmosphere with the MODIS instrument. Now for the winds, we use what is called the infrared window channel that allows us to look at clouds. And we also use a water vapor channel, which allows us to look at atmospheric water vapor, even in the clear sky areas.

As of 2009, both Terra and Aqua have operated years beyond their expected ‘lifespans’.

Jeff Key: Both Terra and Aqua are well behind their life expectancies, which is typically six years. So we exceeded that for Terra back in 2006, and then probably last year for Aqua. I think we’re fortunate that they are continuing to operate, very well in fact, and we hope that they continue into the future. Now, are we ready for the loss of MODIS in particular, but Terra and Aqua in general? We are ready in that we have plans for new satellites.

Our thanks today to NASA’s Earth Observatory and TERRA mission, helping us better understand and protect our home planet.

To read more about Dr. Key, see Polar Wind Data Blow New Life into Forecasts on the Earth Observatory.

Our thanks to:
Jeff Key is an atmospheric scientist who researches Earth’s polar regions using satellite meteorology and climatology. Key is the Branch Chief of the Advanced Satellite Products Branch, Center for Satellite Applications and Research (STAR), NOAA/NESDIS, located at the University of Wisconsin-Madison in the Cooperative Institute for Meteorological Satellite Studies. Key has also developed algorithms and models for use in the retrieval of cloud properties, radiative fluxes, snow and ice characteristics, and tropospheric winds from optical satellite data. His current research includes the spatial and temporal variability of polar cloud, surface, and radiation properties, polar winds, and recent climate trends.