NASA's Concludes GRIP Mission

Comprehensive hurricane research project proves successful!

Last week NASA concluded its GRIP (Genesis and Rapid Intensification Process) hurricane research mission aimed at gaining a better understanding of tropical cyclone behavior—how they form, evolve and strengthen, and how they weaken and die. GRIP, which launched in mid-July, promises to revolutionize tropical weather forecasts in years to come.

How it worked
The GRIP mission analyzed storms with manned and unmanned aircraft as well as satellite imagery. The aircraft, ready for deployment at a moments notice, were based along the U.S. Gulf coast and northern Caribbean islands and were equipped with 15 weather instruments, ranging from an advanced microwave sounder to dropsondes—gadgets that record atmospheric and surface measurements as they fall through the atmosphere to the ocean surface.

The perfect specimens
While tropical cyclone impact for the season remains quite low for U.S. coastal communities, two hurricanes, Earl and Karl were significant for GRIP's research. Earl, a category 4 storm that spun through the central and western Atlantic, was analyzed as it rapidly intensified and degraded off the southeast coast before heading northward towards the Canadian maritime region. During this time GRIP sent several aircraft into the storm, penetrating its eye and sending back critical storm data that offered insight into wind speed and direction as well as wind shear's affect on hurricanes moving swiftly through northern latitudes. Similarly, Karl, which was a strengthening category 3 at landfall, was penetrated by additional aircraft as it plowed into the Mexican coast. These aircraft captured valuable data such as cloud temperature, air pressure, humidity, precipitation, convection and sea surface temperatures. GRIP continued it's research after Karl moved inland and deteriorated, also providing perspective on how land friction affects hurricane degradation.

The seasonal scorecard
The 2010 Atlantic hurricane season concludes November 31 and remains quite active, with 18 storms, of which 16 have been named. 8 of those named storms became hurricanes, of which 5 were major.

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Cityscapes Could Impact Hurricane's Path, Study Says

A team of researchers at the University of Hong Kong developed a computer model to track the movement of a simulated tropical cyclone traveling across varying terrain, and found that big cities such as New York, Miami, New Orleans and Houston could act as magnets for hurricane landfalls.

How so? The results of the research, which will soon be published in the Journal of Geophysical Research, indicates that tropical cyclones tend to be attracted towards areas of higher friction. Therefore rough areas of land, including city buildings and naturally jagged land cover might actually attract what would ordinarily be passer-by hurricanes.

To obtain that conclusion the team modeled the effects that different terrain has on these storms to determine how cities that lie in the path of a hurricane change the storm's motion. They found that rough cityscapes (and forests alike) trap and compresses air, forcing it up into the atmosphere, which translates to added energy in the storm and a pulling of the center of circulation towards the rough region. Their model suggests that a city can cause a hurricane to swerve from its predicted path by as much as 20 miles.

Interesting, but not a concept I haven't heard before. Just look at that last-minute easterly jog of Charley right before landfall in southwest Florida! Friction all the way!

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Could A Greener Ocean Mean More Hurricanes?

Last week Discovery News posted a story about how colossal blooms of plankton in tropical oceans could potentially effect hurricane development. The story recaps a study that will soon be released in the journal, Geophysical Research Letters.

According to scientists who worked on the "Blue Ocean" experimental study, plankton have the ability to determine whether clusters of tropical thunderstorms spin up into monster hurricanes. How so? Well, plankton's tiny photosynthetic bodies tint blue ocean green with chlorophyll. Green water traps light and heat from the sun shallow ocean water, which results in greater sea surface temperatures which as we know, makes for prime hurricane-forming conditions.

In using a computer simulation of a lifeless ocean, the scientists found that a blue ocean not containing plankton's chlorophyll laden specimen reduces typhoons in the northwest Pacific by 70 percent. What few storms did form in the simulation hugged the equator, the only area of water warm enough to sustain them.

However, it is noted that because it takes time for the sun's heat to propagate through the ocean and have its full effect on the atmosphere, it likely takes several high- or low-plankton years to change the course and intensity of storms significantly.

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PREDICT to Investigate Hurricane Origination and Behavior

Hurricane formation and movement is now largely tracked by satellites, but a new project set to launch on August 15 hopes to change that!

The project is called PREDICT and stands for the Pre-Depression Investigation of Cloud Systems in the Tropics, and is funded by the National Science Foundation (NSF) with support from the National Center for Atmospheric Research (NCAR). PREDICT will run for 45 days through September 30 and it is going to study why some tropical thunderstorms grow into the often-deadly hurricanes while many others dissipate.

Flying aboard Gulfstream aircraft, PREDICT researchers will make observations from close proximity, and above, storm systems. In addition to deploying dropsondes – parachute-borne instrument packages, the researchers will use remote sensing and cloud physics instruments to gather data on temperature, humidity, wind speed and direction, and characteristics of ice particles and their nuclei, which may include African dust.

PREDICT will coordinate its effort with two additional concurrent, but independent, missions in the region – one organized by NASA and one run by NOAA. While all three projects have independent objectives, scientists hope that the collective data will paint a more complete picture of a hurricane's life cycle.

Want to learn more? Check out this great video that explains the PREDICT concept from an experts point of view!



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