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Super Typhoon Lupit from NASA

OR why PAGASA is not alone in second-guessing typhoons.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) is in the news again after supposedly making a  blunder in its prediction of Typhoon Basyang’s strength and path.  This is allegedly the reason why  its current Director,  Dr. Prisco Nilo was relieved of his post.

A lot of typhoons visit the Philippines every year,  so why does PAGASA seem to ‘not’  know anything about them?  The answer is neither they lack the skills nor the best equipment.  The answer is simple,

there is a lack of basic understanding on the intrinsic nature of typhoon genesis and evolution, and it is not clear which dynamic behaviour can best describe it.

as written by Á. Coral et. al. in their recent Nature paper [1].

Researchers from Spain discover that the relation of the number of typhoons and energy they released obeys power-law regardless on where ever they appear in the planet.  This means it is scale invariant.  The weaker tropical depressions can be described similar to the most severe typhoons.

Scale-invariance as the authors say, could indicate that the atmosphere or the ocean- atmosphere system is close to a critical state.  In Physics, a critical state specifies the conditions (temperature, pressure and sometimes composition) at which a phase boundary ceases to exist [2].

The authors add,
an important property of critical systems is that perturbations can evolve while keeping a delicate balance between growth and attenuation, resulting sometimes in sudden intensifications and deintensifications.

OR unpredictability.

There are however improvements in path determination but the error in path prediction is still in the ~120km range[3].  The path of a typhoon can be guessed  with an accuracy that is even greater than the distance from Manila to Tarlac city with the best technology present.  PAGASA even with the most sophisticated equipment cannot say whether the typhoon will be in Tarlac or in Manila.

So next time you blame PAGASA for a missed forecast, be consoled by the fact that it may not be just due to technical limitations of weather forecasters BUT may be a fundamental criticality feature of typhoon evolution.

Typhoons are just like that.


[1] Á. Coral, A. Ossó and J. E. Llebot,  Scaling of tropical-cyclone dissipation,  Nature Physics (2010).  DOI: 10.1038/NPHYS1725
[2] Critical state. http://en.wikipedia.org/wiki/Critical_point_(thermodynamics)
[3] National Hurricane Center Forecast Verification.  http://www.nhc.noaa.gov/verification/

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