Don't complain to electrical engineer Bill Anselm about the weather, he just builds the weather satellites.

What do you do and what is most interesting about your role here at Goddard? How do you help support Goddard's mission?

I manage the contracts that build and support weather satellites. Currently, I'm involved with supporting Suomi-Polar Orbiting Partnership S-NPP and building the Joint Polar Satellite System. NASA has built national weather systems for decades in partnership with the National Oceanic and Atmospheric Administration. After NASA builds the weather satellites, NOAA assumes the day-to-day operations.

JPSS-1 is the new satellite weather system. JPSS-1 will overlap with, and eventually replace, S-NPP, and has the same complement of weather sensors. There are at least three satellites planned for this system, but that could be expanded or re-defined as technology and budgets evolve. Each of the planned satellites has five scientific weather sensing instruments.

Ideally, we try to launch a satellite while the last satellite is in-orbit and still functioning, to avoid a data gap. It takes about five years to build and launch each satellite and each has a 7-year lifespan.

S-NPP was launched into a polar sun-synchronous Earth orbit. A sun-synchronous satellite passes over any given latitude on Earth at about the same time every orbit. This means the lighting on Earth is consistent from the satellite's point of view, so the images the instruments capture for any given area can be compared and analyzed over time, providing a consistent basis to trend weather.

Whether it is sunny, cloudy or nighttime over the point on Earth being measured, the instruments record the different frequencies of reflected light. The scientists then interpret what this means and can tell the difference between high clouds, fog, snow, rain and the like.

How does each satellite measure weather over the entire earth?

As the satellite orbits the earth, it maintains the same relative orientation to the sun, with the earth rotating below. This means every time the satellite crosses the earth's equator it is looking at a different spot on the ground. Think, for example, of how you lick an ice cream cone, turning it slowly with your hand so that you lick a slightly different part of the cone each time.

A composite image from all these earth views can be assembled to provide a complete cloud-free picture of the entire earth over about 30 days. The latest "Blue Marble" and "Black Marble" images are results of this assembly process.

(Editor's note: Meet Mr. Blue Marble, a/k/a Robert Simmon and his New Guinea Singing Dogs).

What is the difference between "climate" and "weather"?

The official discriminator between "climate" and "weather" is about two weeks. If you measure something for less than two weeks, it is weather. If you measure the same thing for two weeks or more, it is climate.

What is the neatest thing about these weather satellites?

These satellites are transmitting all the time, all over the globe. The only equipment you need to get the signal is a satellite receiver. Our data is received by weather forecasters around the world, who then interpret and distribute the information through their local weather forecasts to the public. Anyone listening to or reading the local forecast, especially extreme weather predictions, is relying on our data. We are saving lives all over the world.

Why are weather predictions, even for the next day, so often incorrect?

Weather is really complicated because it is a function of the wind, moisture and heat, all of which constantly change. It's pretty easy to know the weather at any given moment wherever you happen to be, but to predict for certain what the weather will be at the same place tomorrow depends on changing conditions and a lot of unknowns.

Even with all that, weather predictions today are much better than they were 20 or 30 years ago. For example, computer models said that Hurricane Sandy was going to go east into the Atlantic. But S-NPP showed that it was moving west into New Jersey. Forecasters agreed with S-NPP, alerted emergency response teams and were able to get into pre-position early to save lives and protect property.

Other than the obvious, what is the importance of weather predictions?

I went to a conference once and heard Home Depot's vice president for weather talk about the importance of advance notice of extreme weather. He wants to pre-position resources. If a storm hits, the local employees will be taking care of their own homes and unavailable. He wants to know when he needs to add staff, where to stage them safely and how to bring them in, so that those hit by the storm can get the salt, shovels, generators or whatever they need to get life going again.

He also needs to identify a nearby, safe and dry place to put the goods for quick access. The example he gave was a hurricane that was going to hit both sides of a river. He needs to know whether he should place supplies on a particular side of the river. He said that even with four hours better advance notice, he would be able to help a lot more people.

Why did you come to work at Goddard and what makes you stay?

There are so many great things being done here. To me, the work on weather is the neatest because of its beneficial impact on everybody.

Do your friends and family complain to you about the accuracy of weather forecasts?

Yes, and I tell them about the complexity of weather forecasting. I even took a group of friends and family to a launch to have them see for themselves all that is involved. They don't complain to me anymore.

As an engineer, what do you find different about working with so many scientists?

The scientists I work with amaze me; they knew back in college what scientific field they wanted to dedicate their lives to studying. They live their science and they love talking about it. Associating with these people, listening to their enormous knowledge base and their passion is inspirational. It's so upbeat.

Is there something surprising about you?

I sang in the barbershop quartet Knights of Harmony, which was led by Dr. Gilbert Mead, the astrophysicist director of Goddard's Music and Drama productions. A barbershop quartet has a bass, baritone, tenor and lead. I was the lead. We specialized in songs from the 1930s and 1940s such as "Yes, Sir, That's My Baby" and "Lida Rose." One of my favorite songs to sing is "Beautiful Girl," about a father singing to his daughter. I tried to sing that to my daughter when she was a baby, but I got too choked up.

[Editor's note: For more about Dr. Gilbert Mead and his wife, Dr. Jaylee Mead, see "MAD About Theater."]

If you gave a dinner party and could invite six people, who would they be?

Garrison Keillor, Neil de Grasse Tyson, Sojourner Truth, Thomas Jefferson, Ellen DeGeneres and my late Swedish grandfather Pop-Pop. I'd start with a conversation about the weather. Everybody talks about the weather!