MSGID: 1:3828/7 a4022014
Taking the Surprise out of Hurricane Season
 
Prior to the 1960's, the biggest storms on Earth could take people by surprise.
Someone standing on a beach in Florida might not know if a distant bank of
clouds was a routine squall or . the harbinger of a powerful hurricane.
 
The Space Age changed all that. Satellites orbiting the Earth can image, probe,
and track hurricanes, alerting forecasters and laypeople alike to storms in the
offing. In recent decades, the introduction of supercomputers and physics-based
models of storm dynamics, combined with satellite, airborne, and surface data,
have pushed the accuracy of forecasts issued by the National Oceanic and
Atmospheric Administration (NOAA) to a new level of precision.
 
https://www.youtube.com/watch?v=uEfntUc90dE
 
As forecasters have improved storm tracks, however, an area of forecasting has
lagged behind: predicting the intensity of storms. In other words, how strong
will the winds be blowing when a hurricane makes landfall?
 
Scott Braun, hurricane expert at NASA's Goddard Space Flight Center in
Greenbelt, MD says, "From 1990 to around 2010, there wasn't much improvement in
the accuracy of hurricane intensity forecasts. In the last several years, we
have started to see drops in intensity forecast errors. This can be credited to
a number of factors, including better measurements from satellite and airborne
platforms, improvements to the physics in numerical weather prediction models,
and improved methods of ingesting NOAA and NASA data into models that describe
the state of the atmosphere."
 
An important part of predicting intensity is seeing what's going on deep inside
a storm. Evaporation of water from the warm ocean surface powers hurricanes and
causes them to intensify. Hotter sea surface temperatures at the base of a
storm, therefore, can load a hurricane with more energy. On the other hand,
wind shear can tear a storm apart, causing it to weaken.
 
So, how do you collect data from inside a giant storm?
 
First, you can fly right into it. In recent years NASA has sent research
aircraft directly into or over storms as part of the Genesis and Rapid
Intensification (GRIP) experiment in 2010 and the Hurricane and Severe Storm
Sentinel (HS3) mission from 2012-2014. These aircraft were flown to investigate
the formation and intensification of storms. Operational airplanes such as
NOAA's P-3s and the Air Force's C-130s are hurricane hunters, and fly missions
into the heart of storms to collect valuable airborne data sets. Additionally,
NOAA's Sensing Hazards with Operational Unmanned Technology (SHOUT) program
utilizes a NASA unmanned Global Hawk aircraft to observe and predict high
impact oceanic weather.
 
You can also get a view from an eye in the sky. The Global Precipitation
Measurement (GPM) Core Observatory, a joint mission between NASA and the Japan
Aerospace Exploration Agency (JAXA), launched in February 2014 and carries
instruments that show precipitation location and intensity at higher
resolutions than were previously available.
 
Microwave imagers such as the one onboard GPM can look through the cloud tops
to observe where and how much precipitation occurs. Additionally, GPM's
Dual-frequency Precipitation Radar provides a 3D view of precipitation
structure.
 
Dalia Kirschbaum, a deputy project scientist for GPM says, "Images from GPM and
similar sensors are posted on the internet in near real-time so forecasters can
immediately see the latest data."
 
An upcoming NASA mission aims to improve storm intensity forecasting even more.
The Cyclone Global Navigation Satellite System (CYGNSS) is scheduled to launch
in 2016. CYGNSS's eight micro-satellites will utilize Global Positioning System
(GPS) signals to make surface wind measurements. Direct GPS signals will
pinpoint CYGNSS observatory positions, while GPS signals reflected off of the
ocean surface will indicate wind speed based on how much the winds rough up
that surface (the stronger the winds, the rougher the ocean surface).
 
CYGNSS will be able to measure winds in heavy rain regions inside the storm
where current wind-sensing satellites have problems, and will provide much more
frequent observations compared to the once- or twice-a-day measurements from
current sensors.
 
Earth-orbiting satellites: helping take the surprise out of hurricane season
since the 1960s.
 
For more information about hurricane season in ever-improving detail, visit
science.nasa.gov.
 
 
Regards,
 
Roger

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