------------------------------------------------------------------------
  Philippines/Laoag - Operational Radiosonde by PAGASA
  during YMC-BSM 2018 field campaign

  revised						13 Aug 2021
  revised						13 Mar 2021
  revised						26 Aug 2020
  drafted						18 Feb 2019
------------------------------------------------------------------------

1. Summary

Operational radiosonde by PAGASA Laoag Synop-Airport-Upper Air station.
During this campaign period, Lockheed Martin LMS6 radiosonde with LMG6
Radiosonde Ground System was used.


2. Spatial Type

vertical profile


3. Frequency

Six hourly (Nominal time; 0000, 0600, 1200, 1800 UTC)


4. Temporal coverage

From	2018-07-01 0000 UTC
To	2018-08-31 1800 UTC


5. Spatial coverage	

Launched at (18.18N, 120.53E)


6. Remarks

(1) Based on intercomparison with Vaisala RS41 as well as GNSS-derived
precipitable water vapor, CDF (cumulative distribution function) method
was applied to match relative humidity data of LMS6 onto RS41 RH data.
A table which contains correction values is provided just for reference.
Since correction has already been applied, there is no need to add those
values onto datasets contained here.

(2) Near the ground surface, heating in the daytime was confirmed.
Thus, two types of datasets are provided; one is no correction for this
heating (indicated as level-3.2/4.2)*1, and the other is corrected based
on the method of Yoneyama et al. (2002) (indicated as level-3.3/4.3)*2.
It is recommended to use the former to study local effect, while the 
latter might be useful to see large-scale feature.

*1,2 ... When we released the data as of 26 August 2020, we labeled
         them as level-3.0/4.0 and level-3.1/4.1, respectively.
         However, recently we decided a correction based on CDF-matching
         should be applied onto the data only taken during clear sky daytime.
         Thus, this time we re-relased data sets as level-3.2/4.2 and
         level-3.3/4.3, to indicate their difference.
         Note that a look-up table for this correction was not changed.
         More details are described in Yoneyama et al.(2021),

If you have questions, please contact "ymc-joffice @ jamstec.go.jp".


7. References.

Yoneyama, K., M. Hanyu, S. Sueyoshi, F. Yoshiura, and M. Katsumata 2002: 
Radiosonde observation from the ship in the tropical region. JAMSTECR, 45, 31-39.
http://www.jamstec.go.jp/res/ress/yoneyamak/PDFs/Yoneyama-etal_2002_JAMSTECR.pdf

Yoneyama, K., M. Fujita, A. Seiki, R. Shirooka, S. Yokoi, E. O. Cayanan,
C. O. Iglesia, and O. C. Cabrera, 2021: Evaluation of LMS6 and RS41 radiosonde
humidity data obtained during YMC-Boreal Summer Monsoon study in 2018 and 2020.
J. Meteor. Soc. Japan, 99, 1115-1125. https://doi.org/10.2151/jmsj.2021-054


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