Who Are NASA's Earth Explorers?

The elementary school student questioning if El Niño occurs anywhere besides the Pacific Ocean. The researcher investigating connections between Arctic ozone depletion and global climate change. The citizen scientist interested in how changing land cover and use affects animal migration patterns. And the businessperson projecting future needs for harvest, delivery and storage of crops. All of these people are Earth Explorers -- they are all connected by their curiosity about Earth system processes. This monthly series will introduce you to NASA Earth Explorers, young and old, with a variety of backgrounds and interests.

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Tell us about the Earth Explorers you know. We're looking for students, teachers, scientists and others who are working with NASA Earth science data and imagery to better understand our home planet. Send your nominations to Dan Stillman: dan_stillman@strategies.org.

Society depends on the balance in distribution of Earth's water. Too little, and life can come to a halt. Too much in the form of storms and floods can cause chaos.

Faisal Hossain is using satellite data to help countries better manage their freshwater supply.

Faisal Hossain, a civil and environmental engineering professor at Tennessee Technological University, understands this all too well. In his home country of Bangladesh, flash floods destroy homes and crops every year. The country is prone to flooding because it sits on the Ganges delta. Melting glaciers due to changing climate are also a threat -- half the country would be submerged if sea levels rose by one meter.

Hossain uses NASA satellite data to help Bangladeshi authorities monitor their water resources and prepare for water-related disasters. With the help of NASA grants, Hossain's research group -- Sustainability, Satellites, Water and Environment -- also studies how human activities affect parts of the global water cycle. In December 2009, Hossain used satellite data to show that dams in arid and semi-arid regions of the world have created heavier storms with more rainfall, which have increased the possibility of flooding. "We are looking for ways to translate the applications of these satellites to societal benefits," Hossain said.

Hossain and his colleagues in the SASWE group take their education mission seriously. In April, they were awarded an education excellence award by the National Association of Environment Professionals.

The SASWE researchers have developed software tools for teaching college students the satellite techniques used in hydrology. And they regularly visit middle schools and high schools in rural Tennessee to share their enthusiasm with students about hydrology and management of water resources. "We want to inspire the future generation of Earth scientists to pursue a career in one of the science, technology, engineering and math fields," Hossain said.

As part of their education mission, the group plans to host and train staff members from the Institute of Water Modeling in Bangladesh. Right now, an IWM staff member is pursuing a master's degree focusing on understanding how to use satellites for real-time flood forecasting.

Countries besides Bangladesh that face water management challenges also could benefit from Hossain's research. Many developing nations in Asia, Africa and South America have strong wet and dry seasons. They depend heavily on rainfall and rivers for fresh water, but they do not have the necessary instruments and trained personnel to predict water shortages or overflowing riverbanks.

Politics further complicates matters, Hossain points out. For instance, five different countries share the Niger River basin in Africa. Rivers such as the Ganges and the Mekong originate in one country but cross several boundaries. "Downstream countries wouldn't know what kind of rainfall the upstream countries are getting," Hossain said. "If you could know the rainfall in upstream countries ... you could put the data in a (computer) hydrologic model that could predict for the next couple of days what the river level might look like."

Satellite data can help predict flash floods like this one in Arizona.

Satellites are the easiest, most cost-effective way to measure rainfall and water movement, Hossain said. Instead of having hundreds of instruments on the ground, a single satellite circling hundreds of kilometers above Earth can look at large areas. It can provide data on how much rain falls in an area, how much water is in a river and how fast is it flowing downstream. Researchers can use this information to anticipate whether drought or flood conditions are a threat.

The Tropical Rainfall Measurement Mission run by NASA and the Japanese Aerospace Exploration Agency was the first satellite dedicated to rainfall measurement. It gave rainfall maps of the tropical regions near the equator, which get two-thirds of the world's total rain.

NASA and JAXA are now planning a new satellite mission for 2013 called the Global Precipitation Measurement mission. It will cover over 80 percent of the globe and, unlike the TRMM satellite, be able to measure light rainfall. In 2016, NASA plans to launch another hydrology satellite mission, called Surface Water and Ocean Topography, in partnership with the French space agency. The SWOT satellite will repeatedly measure the height of water in rivers, lakes and wetlands, which researchers can use to gauge the volume and flow of water in those bodies.

Hossain's group is now trying to identify which countries could most benefit from the Global Precipitation Measurement and SWOT missions. Their plan is to take data from both satellites and use it in sophisticated computer models to help these countries improve hydrological forecasts and better manage their freshwater supply.

Bangladeshi authorities today can predict flooding only up to three days ahead of time, and often with low accuracy. "This is where GPM could really make an impact," Hossain said. "We'd be able to forecast on a much longer time scale. I'm pretty confident we could do up to 10 days in advance, and that would be a big improvement."

Who are NASA's Earth Explorers?

The elementary school student wondering how El Niño will affect tomorrow's weather. The scientist studying connections between ozone and climate change. And the farmer using satellite pictures to keep track of crops. All of these people are Earth Explorers -- they are all curious about the Earth system. This monthly series will introduce you to NASA Earth Explorers, young and old, with many backgrounds and interests.

Most people's eyes would be glued to the window -- or tightly shut -- when flying through a hurricane. Instead, Robbie Hood stares mostly at her computer monitor.

Hood, an atmospheric scientist at NASA's Marshall Space Flight Center in Huntsville, Alabama, has flown several times into the fury of the whirling storms. She claims it's actually not as scary as it sounds.

Robbie Hood and crew member Mark Corlew on a NASA DC-8 aircraft used to fly into hurricanes

"The view out of the aircraft windows can be somewhat boring," said Hood, who served as lead scientist on two of NASA's hurricane-probing CAMEX (Convection And Moisture Experiment) missions. "The aircraft is often flying through clouds so there is not much to see."

There is plenty to look at on her laptop, however, which displays a continuous stream of real-time atmospheric data being collected by an array of instruments and sensors outside the aircraft. The goal is to use the data to improve understanding and prediction of hurricanes.

Specifically, Hood is interested in how rainfall intensity affects overall storm strength. (When water vapor condenses into rain, energy is released to the surrounding air.) The research conducted by Hood and her colleagues helps models more accurately predict a hurricane's track, strength at landfall and potential for inland flooding. Improved forecasts could eliminate unnecessary coastal evacuations while increasing the warning time for those in harm's way.

But why send an airplane into the middle of a hurricane when there are satellites that can make observations from space? Hood says that the aircraft data, when combined with satellite information, gives scientists a more detailed, three-dimensional view of how hurricanes work. Measurements taken from inside the storm are also used to verify the accuracy of the satellite data.

"We're putting the storm under a microscope," said Hood, who is joined at about 40,000 feet up by other scientists, engineers, and the pilot and crew. "You can see the storm structures in higher detail (than from satellites alone)."

Hurricane Bonnie, seen here from the NOAA-12 satellite, is one of several hurricanes Robbie Hood has flown through

While intensely focused on the important scientific work at hand, Hood admits that she does enjoy peeking out the window every once in a while, especially when a break in the clouds at flight level reveals a pretty picture down below.

"The variety of cloud layers and types can be quite impressive," Hood said. "It's like seeing every cloud you could imagine all in one place."

Image to left: Hurricane Bonnie, seen here from the NOAA-12 satellite, is one of several hurricanes Robbie Hood has flown through
Credit: NASA

Hood's fascination with weather and hurricanes goes back to her days growing up in the South. Raised on a cattle farm in Missouri, she became very familiar with the economic impact weather can have on agriculture. Hood's family also happened to be in Mississippi when, in 1969, Hurricane Camille slammed into the Gulf Coast.

"To see the kind of damage that it could do made a big impression on me," said Hood, who remembers the storm knocking out power, downing trees, and blowing the roofs off of houses.

Their severity is not the only thing that sparks Hood's interest in hurricanes. She is also attracted by the human qualities assigned to, and taken on by, the storms. In fact, Hood has always been a bit of a people person.

"I credit my Native American heritage with my intense interest and appreciation of people," said Hood, who is a member of the western tribe of the Cherokee nation. "I think I like studying hurricanes because they act so much like people. Hurricanes have names and personalities and don't behave like we expect them to sometimes."

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