------------------------------------------------------------------------
  Philippines/Laoag - Radiosonde Intercomparison by JAMSTEC/PAGASA/UP
  during YMC-BSM 2018 field campaign

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

1. Summary

Radiosonde intercomparison among Lockheed Martin LMS6, Graw DFM-09, and
Vaisala RS41-SGPD has been made.
In this directory, corrected LMS6 data are stored.
At this moment, no data/description is provided for DFM-09, since we
have not established the way for assessment for DFM-09.


2. Spatial Type

vertical profile


3. Frequency

20 times / 8 days
including 8 times done as routine observation.


4. Temporal coverage

From	2018-07-27
To	2018-08-03


5. Spatial coverage	

Launched at (18.18N, 120.53E)


6. Remarks

(1) Based on intercomparison among three types of radiosonde as well as
comparison with GNSS-derived precipitable water vapor, we have adjusted
RH values of LMS6 data onto that of RS41-SGDP.
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.
Namely, "Table_CDF_LMS_12LT.dat" contains "RH_add" in the following
equation, while RH data stored here are "RH_corrected" values.
RH_corrected = RH_raw + RH_add

(2) Correction values (RH %) in Table_CDF_LMS_12LT.dat are stored in
1ºC and 1% bins as a function of temperature (from +30 to -90ºC;
from top to bottom) and RH (from 0 to 100%; from left to right).
Sample to read correction values is as below.
---
      parameter(idata=101, jdata=121)
      real RHadd(idata,jdata)
      open(2,file='Table_CDF_LMS_12LT.dat', status='old')
      do j=1,jdata
        read(2,1000) (RHadd(i,j),i=1,idata)
 1000   format(101f8.1)
      enddo
      close(2)
---

(3) 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.godac.jamstec.go.jp/catalog/data/doc_catalog/media/shiken45_04.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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