Weather forecast for the launch of the meteorological satellite


In the days leading up to a launch at Vandenberg Space Force Base, most of the attention is focused on preparing the rocket and payload for their journey into space. In this case, it is NOAA’s Joint Polar Satellite System-2 (JPSS-2) satellite and its secondary payload, LOFTID.

But there is another operation going on at the base that makes these launches possible. About 1.5 miles north of the Visitor Center is the Weather Operations Center, or “The Weather Shop”, where a 15-member team monitors the weather around the clock. And in a meeting of worlds, the JPSS series satellites provide an important source of data that powers their weather forecasts.

Vandenberg is located in the seaside town of Lompoc, California, an area known for the so-called marine layer that arrives at night, covering the area with low clouds and fog.

Although the marine layer affects visibility, it does not pose a threat to launch safety. Winds, rain and lightning are more dangerous for a launch, said Capt. Zackery Zounes, the launch weather officer. In fact, he said, if the right conditions exist inside a cloud, a rocket itself can trigger lightning. Lightning is particularly dangerous, as it can short out electronic and navigation systems.

Meteorologists on site are also monitoring the wind closely. And Vandenberg is a windy place.

“You don’t want the rocket to be pushed by the wind and tip over,” Zounes said. “You don’t want him pushed off course.”

Fortunately, the 99,000-acre base has a robust array of instruments to help monitor weather conditions. On the base are 26 wind towers with more than 200 instruments.

“Small changes in wind direction and speed have a huge impact on the space elevator mission here, so we have to be very good at what we do,” said Captain Addison Nichols, launch weather officer. “Fortunately, Vanderberg is one of the few places that has a robust meteorological instrumentation network that allows us to do our job.”

Weather surveillance planes flying over the area on launch day provide measurements of cloud height, temperature and other data important to assessing lightning risk.

But airplanes don’t fly above 30,000 feet. In order to track a developing thunderstorm, you need to know the conditions at a slightly higher altitude of 40,000 or 50,000 feet. And since rockets pass through the upper atmosphere, it’s important to understand what’s going on much higher than that.

Enter the weather balloons.

At the Vandenberg Surface and Upper Observatory, seasoned weather observers like Daniel Day launch weather balloons with bottom-mounted instruments called radiosondes. Radiosondes measure wind speed and direction, temperature, pressure and humidity in the atmosphere. The balloons expand as they rise through the atmosphere until at their largest they are about the size of a Greyhound bus. They generally fly between 100,000 and 120,000 feet.

Weather security officers track data from balloons as they rise and feed it into a model.

Weather models are fed by data from weather balloons, radars, ground-based instruments and weather satellites like JPSS-2. In reality, 85% of the data that powers today’s weather forecasting models comes from polar-orbiting satellites like those in the JPSS fleet.

Adding more polar-orbiting weather satellites, like JPSS-2, could improve the accuracy of models by increasing the frequency and amount of data collected from the oceans upstream, Zounes said.

All of this data will be put together to provide reliable weather forecasts for the launch day of the JPSS-2 satellite.

“Here it’s rocket science,” Nichols said, “and so we have to be very, very specific.”


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