Characteristic of Philippines–Taiwan Oscillation, and its contrast to Pacific climate Indices. 2012 / 07/26 Introduction. Yu-Lin Eda Chang. Goal: . Typhoon activity: dipole structure of PTO, seek for the connection between the two
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Characteristic of Philippines–Taiwan Oscillation, and its contrast to Pacific climate Indices
Yu-Lin Eda Chang
Goal: contrast to Pacific climate Indices
Typhoon Information contrast to Pacific climate Indices
Joint Typhoon Warning Center (JTWC), 1950~2012 (use 1979~2012 for this study)
ECMWF contrast to Pacific climate Indices
North & South poles are separated by 18N contrast to Pacific climate Indices
180E is selected as eastern boundary
North: 20% less contrast to Pacific climate Indices
South: 65% more
Wind curl affected the cyclone genesis
Ocean Conditions: contrast to Pacific climate Indices
SSHA strength of typhoon
(*~2008 from Chang and Oey, 2012)
Repeat this to 2012 later
Does the strength of typhoon behave like a seesaw??
First try: contrast to Pacific climate Indices
Group typhoon’s track by different category
Also sort it by PTO
Here only show the large PTO events
(PTO>1 or PTO <-1)
Sorting method: contrast to Pacific climate Indices
Create 1 x 1 degree grid, covering the western Pacific Ocean
Sort the typhoon category when it hits the grid
Each typhoon has different path & life cycle (just like drifter), so the longitude, latitude, time, moving speed are also recorded.
The same grid may be hit by several times
Mean category: take the mean of all hits
Max category (Potential category): record the maximum category
Both are further sepearated by positive & negative PTO
Fast moving typhoon may not have chance to get the energy from the ocean.
Therefore, I further group the typhoon by the moving speed.
Moving speed = distance/time takes
Slow moving typhoon.
Slow to moderate moving typhoon.