Weather images of Iowa show the variation in data that can result from satellites and ground-based technology. NASA displayed the slide this week as part of a Google+ hangout focusing on a new mission that will help scientists better predict floods.
Improved prediction of global flooding and other precipitation-related weather events is expected as part of a NASA mission set to begin in February 2014, researchers say.
Already, instrumentation studies are underway in Iowa for Global Precipitation Measurement (GPM), which officially begins early next year with the launch of a core satellite. The satellite will communicate with an existing constellation of similar devices, providing weather data points previously unavailable at a rate of every one to three hours, said Walt Petersen, GPM ground validation scientist, during a Google+ hangout hosted by NASA’s Goddard Space Flight Center. That’s up from the twice-daily sampling that happens now.
By combining data from a larger satellite network with on-ground tools such as radar and rain gauges, scientists hope to improve predictions. Farmers can use resulting models to decide whether to irrigate on a particular day, while emergency management personnel can warn communities and save lives.
The research underway in Iowa is intended to ground truth satellite images with the latest data available using technology on the ground. The state provided ample opportunities for weather researchers, starting with last year’s drought and a historic snowstorm that followed.
"Things turned around quite a bit," says Witold Krajewski, Iowa Flood Center. "Not only did we get plenty of rainfall, but you also get some flooding, so we will have very good information to analyze that entire cycle from rainfall all the way to flooding."
The potential of the GPM mission is substantial. Consider that if all of the known rain gauges in the world were gathered up, they would fill the area of about two basketball courts, Petersen says. That’s a relatively small fraction of the earth being sampled, even when accounting for the fact that three-quarters of the Earths’ surface is covered by water.
Researchers will gather data from the satellites, which are positioned at various distances from Earth and contain sensors operating at different frequencies. That information will be sent along to scientists who prepare weather models, enhancing their ability to predict flooding and related events such as landslides.
GPM will extend the capabilities of the Tropical Rainfall Measuring Mission (TRMM), which uses satellites to gather data about rainfall and storms such as tropical cyclones.
In the future, scientists will use data to provide better forecasts for traditionally hard-to-predict regions such as the Red River Valley in North Dakota. The region features complicated hydrology, experienced drought in 2012 followed by heavy snowfall in winter, and includes thousands of miles of drainage tile, says Pedro Restrepo, hydrologist in charge, National Weather Service North Central River Forecast Center.
"Hopefully, in the coming years, we will be able to improve our models and our knowledge of the conditions there," Restrepo says.