Analysing Typhoons for Future Use
NASA's Tropical Rainfall Measuring Mission (TRMM) satellite captured a typhoon in mid-growth on the third of December 2012. At that time, the typhoon, codenamed Bopha was a category 3 storm, and was still intensifying, growing towards a category 4 as it headed for the Philippines . It made landfall 18 hours later.
What made this particular typhoon special was TRMM. The satellite was able to capture in full 3D, the development of the storm as it grew over this 18 hour period, and was able to measure in unprecedented detail, the precise structures the typhoon developed, and how it developed them as it crossed the open water.
Whilst current virtual environments are nowhere near large enough to make use of a full-size typhoon as a weather system, this kind of data is excellent in the fight to understand precisely how they form, and what factors guide their development. The scope of our environments are growing in pace with developments in computing capability and interface development, so there will come a time when we are ready to implement these things outside of dedicated weather simulations.
Of course, that particular area of VR research the weather simulator is where such data will be useful the earliest. As we gather more information on what makes a typhoon tick, so we are able to more accurately predict their course and size in simulation, and save many lives.
TRMM's main advantage is its radar system, which is the most sensitive anyone has ever used to date. The radar system is best compared to a high-definition camera with a flash that reveals vertical structure. The TRMM radar has 5 km (3.1 mile) horizontal resolution and 250 meter(820 foot) vertical resolution, giving a three dimensional image of every cloud that contained particles the size of raindrops, and every chunk of ice large enough to fall out of its cloud.
In this particular case, TRMM managed to discern that Bopha's main engine consisted
of two hot towers simultaneously reaching a 15.5 km (9.6 mile) altitude on the
northeast side of the eyewall where the storm's forward motion is added to the
counter-clockwise winds circling under the eyewall. TRMM studies have suggested
that even a single hot tower exceeding a 14.5 km (9 mile) height may be sufficient
to indicate intensification is on-going. At the base of the hot towers, radar
reflectivity exceeded 45 dBZ indicating heavy rainfall (as shown in deep red
in the image).
Fourth, the TRMM Lightning Imaging system (LIS) saw two lightning flashes in
the inner edge of one of the eyewall hot towers. Lightning flashes are relatively
rare in eyewalls, even in the eyewalls of intensifying tropical cyclones. Lightning
tends to occur where updrafts are strong enough to suspend in mid-air a mix
of supercooled water and grauple or hail-sized chunks of ice. Such large chunks
of ice can only form when updrafts repeatedly "bob" ice particles
up and down through a lower cloud layer with liquid water droplets and then
a higher cloud layer cold enough to promote freezing.
Even without any further processing, the satellite has gathered enough data that Bopha could be recreated in its entirety as an interactive simulation itself, allowing research up close and personal, to each of the structures driving the storm's growth, as they unfolded over many hours. This alone would be a worthy simulation to explore, regardless of the other benefits of this new class of weather imaging system.
With each new typhoon TRMM locates and analyses, we gain more valuable data to help unravel the mysteries of these storms and of course, volumetric data straight from the satellite sensor systems that is open-source and usable as raw, to create violent weather systems in our own environments with minimal processing.