Text Size

Know Your Earth 3.0: Jason-2
Jason banner with Michelle Hite-Gierach

About Michelle Hite-Gierach

Michelle Hite-Gierach is an ocean scientist in NASA's Oceans and Ice Group, and also serves as the project scientist for the Physical Oceanography Distributed Active Archive Center (PO.DAAC) at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Hite-Gierach was born and raised in Lake Mary, Fla. As a young girl, she became keenly interested in understanding weather after being fascinated by the power of Hurricane Andrew in 1992 and seeing first-hand the damage a Category 5 hurricane could cause. After graduating high school, she studied at Florida State University, where she received both a bachelor's and master's degree in meteorology. She then went on to earn her doctorate in marine sciences from the University of South Carolina.

Hite-Gierach came to JPL in 2011. She now uses observations from satellites, such as the Ocean Surface Topography Mission/Jason-2 satellite, to understand the ocean's impact on tropical cyclones and the impact of tropical cyclones on the ocean. Jason-2 uses a radar altimeter to measure the topography of the ocean surface, or sea surface height, which is strongly correlated with the thermal structure of the upper ocean. The thermal structure in the upper ocean has been shown to play a significant role in tropical cyclone intensification and de-intensification. Prior to making landfall, Hurricanes Katrina, Rita, and Wilma of 2005 all intensified to category 5 storms after they passed over ocean features in the Gulf of Mexico where warm water extended deeper into the water column. These features provided energy for the hurricanes to grow. These hurricanes also de-intensified over cold waters near the surface, which provide much less energy and result in a rapid loss of hurricane strength.

About Jason-2

Satellite image of El Nino

An image generated using Jason-2 data in 2010 shows an eastward-moving wave of warm water in the Pacific Ocean contributing to the planet's El Niño weather pattern.
Credit: NASA/JPL Ocean Surface Topography Team
› Larger image

With its successful launch on June 7, 2008, the Ocean Surface Topography Mission on the Jason-2 satellite extended the continuous record of sea surface height measurements that began in 1992 during the Topex/Poseidon mission and continued with the 2001 Jason-1 mission. This record spanning multiple decades has already helped scientists study global sea level rise and better understand how ocean circulation and climate change are related.

Developed and proven through the joint efforts of NASA and Centre National d'Etudes Spatiales (CNES) French Space Agency, the Jason-2 high-precision ocean altimeter measures the distance between the satellite and the ocean surface to within a few centimeters. Accurate observations of variations in sea surface height—also known as ocean topography—provide scientists with information about the speed and direction of ocean currents and heat stored in the ocean.

Ocean altimeter data have both scientific and practical applications, ranging from lake level monitoring and hurricane intensity forecasting to routing ships and improving the safety and efficiency of offshore industry operations. The Jason-2 data are adding to our improved understanding of ocean circulation, the ocean's role in climate, and the effects that a warming climate have on the ocean.

Topex/Poseidon and Jason-1 are joint missions between NASA and CNES. Jason-2 is a four-member international partnership mission between NASA, CNES, the National Oceanic and Atmospheric Administration (NOAA), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).

Additional Links

› Know Your Earth 3.0
› Jason-2
› NASA's climate website
› NASA's Jason-2 mission page
› Jason-2 International Laser Ranging Service page