Typhoon TRIX in 1952

[大野 悠斗521313]

Hello,

I realized when comparing the RSMC Tokyo Best Track Data (JMA) and IBTrACS data that for Typhoon TRIX in 1952, the JMA data starts at 00 UTC October 16 1952 (the initial latitude and longitude is N8.7 E136.2), but the IBTrACS data for TOKYO starts at 12 UTC October 16 1952 (the initial latitude and longitude is also N8.7 E136.2). 

So, is the IBTrACS data incorrectly 12 hours behind?

I look forward to hearing from you.

Yuto Ono

Mie University (Japan)

[Jennifer Gahtan - NOAA Federal]

Hello Yuto Ono,

Thanks for reaching out.

Especially in the older data, dates and times of some storms may be unreliable, with resulting discrepancies between sources (including when storms are relatively strong) that makes the merging of tracks more difficult. To account for this challenge, the IBTrACS algorithm may add a time offset for the data from some sources in certain storms to better allow the overall track to match up.  

In the case of TRIX 1952, 8 different tracks were used as sources in IBTrACS. The JMA, CMA, and one set of TD9636 data were offset by 12 hours such that storm positions could better align. For example, in JMA, before the offset, only 5 out of 39 positions matched whereas the offset allowed 35 of 39 positions to match within 111km of the other group of tracks.

We acknowledge that this is an added source of uncertainty, especially if the specific timing of a particular storm is needed, in which case it may be preferable to consider timings in the source data (JMA in this instance), however the overall statistics of the storm should remain the same.

Best,

Jennifer

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Jennifer Gahtan, Ph.D. (she/her)

Physical Scientist
Climate Science and Services Division (CSSD)
NOAA's National Centers for Environmental Information (NCEI)
151 Patton Ave. Asheville, NC 28801

jennife...@noaa.gov

[大野 悠斗521313]

---------- 転送メッセージ ---------
From: 大野 悠斗521313 <521...@m.mie-u.ac.jp>
日付: 2024年5月2日(木) 9:35
件名: Re: [ibtracs-qa] Typhoon TRIX in 1952
To: Jennifer Gahtan - NOAA Federal <jennife...@noaa.gov>

Hello Jennifer,

Thanks for your reply.

I understand the algorithm to correct the discrepancy.

When I looked up Typhoon TRIX in 1952, I checked the contents of two old documents (JMA; note that they are written in Japan Standard Time(UTC+9)) that describe the strength, position of the typhoon and aircraft observation data in October 1952, as well as the position of the typhoon on the weather charts of JMA (1200GMT) and NOAA Central Library (1230GMT).

However, I could not find any contradictory descriptions in the current RSMC Tokyo Best Track Data (JMA), so I suspected that there was a problem with the USA data, but this was not a definitive reason.

Yuto Ono

Mie University (Japan)

2024年5月2日(木) 6:22 Jennifer Gahtan - NOAA Federal <jennife...@noaa.gov>: