# ------------------------------------------------------------------------------
#          WHOLE-ATMOSPHERE MONTHLY MEAN CH4 CONCENTRATION
# ------------------------------------------------------------------------------
#  The whole-atmosphere monthly mean concentration of CH4 is
# calculated by using GOSAT data that reflect CH4 levels in all layers of the
# atmosphere.
#
#  See the following web page for more details on the estimation approach used.
#  http://www.gosat.nies.go.jp/recent-global-ch4.html
# ------------------------------------------------------------------------------
# * Ownership of Products etc.
#     The GOSAT Project is a joint effort of the Japan Aerospace Exploration
#   Agency (JAXA), the National Institute for Environmental Studies (NIES), and
#   the Ministry of the Environment (MOE).
#     Right for GOSAT data products and GOSAT image data, etc. belongs to these
#   three parties.
#     See the website of the NIES GOSAT Project for more details.
# * Terms and Conditions for the Product Utilization
#     Usage of the GOSAT data products, image data, and any document provided
#   through this website is allowed only for purposes of academic research and
#   educational activities, etc.
#     For other purposes such as commercial use, it must be consulted with the
#   NIES GOSAT Project beforehand.
#     When disclosing your research results by utilizing the GOSAT data products,
#   image data, and any document provided through this website, the source of
#   those materials must be clearly specified by marking on
#   "Provided by JAXA/NIES/MOE" or "Courtesy JAXA/NIES/MOE".
#     Distribution and transfer of the GOSAT data products, image data, and any
#   document provided through this website to any third parties are prohibited.
#     When third parties wish to obtain those materials, indicate them to access
#   the website of the NIES GOSAT Project.
# * Disclaimer
#     JAXA, NIES and MOE are not liable for any loss or damage whatsoever arising
#   out of the use of the GOSAT data products, image data, and any document.
#    The content and the specification of this product might be changed without
#   a previous notice.
# ------------------------------------------------------------------------------
# CONTACT:
#   GOSAT Project, Satellite Observation Center,
#   National Institute for Environmental Studies (NIES)
#     email  : gosat-prj1@nies.go.jp
#     address: 16-2 Onogawa, Tsukuba-City, Ibaraki, 305-8506 Japan
#     phone  : +81-29-850-2035
# ------------------------------------------------------------------------------
# FILE_CREATION: May 13 07:42:55 2026
# ------------------------------------------------------------------------------
# NOTE:
#  Trend values are results at the 15th day of each month.
#
#  Missing values are represented by the symbol NA (Not Available).
#
#  The monthly value for January 2015 is not available due to the change of the FTS 
#  pointing system from the primary system (PM-A) to the backup system (PM-B).
#
#  March 12, 2019
#  New GOSAT FTS SWIR Level 2 products (V02.80) were used.
#  A new bias correction scheme was adopted.
#
#  October 25, 2019
#  New GOSAT FTS SWIR Level 2 products (V02.81) were used.
#
#  May 11, 2020
#  A new bias correction scheme was adopted.
#
#  August 6, 2020
#  New GOSAT FTS SWIR Level 2 products (V02.90/V02.91) were used.
#
#  April 6, 2021
#  New GOSAT Level 4B CH4 products (V01.05) were used.
#
#  May 10, 2021
#  A new bias correction scheme was adopted.
#
#  May 11, 2022
#  New GOSAT Level 4B products (V01.06) were used.
#
#  September 15, 2023
#  New GOSAT Level 4B products (V01.07) were used.
#  New GOSAT FTS SWIR level 2 products (V03.05) were used.
# ------------------------------------------------------------------------------
# year month  monthly_mean (ppm)         trend (ppm)
  2009     4             1.74759             1.75097
  2009     5             1.74245             1.75115
  2009     6             1.74135             1.75133
  2009     7             1.74164             1.75152
  2009     8             1.75039             1.75171
  2009     9             1.75551             1.75194
  2009    10             1.75694             1.75219
  2009    11             1.75962             1.75250
  2009    12             1.75768             1.75285
  2010     1             1.75847             1.75326
  2010     2             1.75475             1.75373
  2010     3             1.75363             1.75425
  2010     4             1.75344             1.75483
  2010     5             1.74860             1.75545
  2010     6             1.74575             1.75610
  2010     7             1.74748             1.75677
  2010     8             1.75254             1.75745
  2010     9             1.76040             1.75812
  2010    10             1.76607             1.75877
  2010    11             1.76887             1.75939
  2010    12             1.76688             1.75996
  2011     1             1.76380             1.76049
  2011     2             1.76573             1.76096
  2011     3             1.76515             1.76138
  2011     4             1.76041             1.76175
  2011     5             1.75504             1.76207
  2011     6             1.75130             1.76236
  2011     7             1.75147             1.76262
  2011     8             1.75971             1.76287
  2011     9             1.76587             1.76311
  2011    10             1.76859             1.76335
  2011    11             1.77148             1.76360
  2011    12             1.77029             1.76388
  2012     1             1.76787             1.76418
  2012     2             1.76827             1.76451
  2012     3             1.76382             1.76486
  2012     4             1.76306             1.76525
  2012     5             1.75784             1.76566
  2012     6             1.75473             1.76610
  2012     7             1.75734             1.76656
  2012     8             1.76517             1.76705
  2012     9             1.77175             1.76754
  2012    10             1.77686             1.76806
  2012    11             1.77658             1.76858
  2012    12             1.77697             1.76912
  2013     1             1.77246             1.76967
  2013     2             1.77033             1.77023
  2013     3             1.77074             1.77081
  2013     4             1.77050             1.77140
  2013     5             1.76417             1.77201
  2013     6             1.76059             1.77264
  2013     7             1.76354             1.77328
  2013     8             1.76967             1.77393
  2013     9             1.77952             1.77460
  2013    10             1.78381             1.77528
  2013    11             1.78309             1.77597
  2013    12             1.78456             1.77667
  2014     1             1.78291             1.77737
  2014     2             1.78078             1.77807
  2014     3             1.77781             1.77876
  2014     4             1.77657             1.77944
  2014     5             1.77210             1.78011
  2014     6             1.76894             1.78076
  2014     7             1.77011             1.78140
  2014     8             1.77929             1.78203
  2014     9             1.78735             1.78264
  2014    10             1.79137             1.78324
  2014    11             1.79366             1.78384
  2014    12             1.79165             1.78443
  2015     1                  NA             1.78503
  2015     2             1.78919             1.78565
  2015     3             1.78544             1.78628
  2015     4             1.78295             1.78693
  2015     5             1.77896             1.78762
  2015     6             1.77379             1.78834
  2015     7             1.77869             1.78909
  2015     8             1.78836             1.78989
  2015     9             1.79427             1.79071
  2015    10             1.79934             1.79156
  2015    11             1.79918             1.79243
  2015    12             1.80006             1.79331
  2016     1             1.80039             1.79419
  2016     2             1.79745             1.79505
  2016     3             1.79438             1.79590
  2016     4             1.79403             1.79671
  2016     5             1.78972             1.79748
  2016     6             1.78835             1.79820
  2016     7             1.79181             1.79887
  2016     8             1.79902             1.79950
  2016     9             1.80378             1.80009
  2016    10             1.80728             1.80064
  2016    11             1.80783             1.80116
  2016    12             1.80984             1.80168
  2017     1             1.80739             1.80219
  2017     2             1.80424             1.80272
  2017     3             1.80279             1.80327
  2017     4             1.80055             1.80386
  2017     5             1.79654             1.80450
  2017     6             1.79358             1.80518
  2017     7             1.79511             1.80591
  2017     8             1.80273             1.80669
  2017     9             1.80982             1.80752
  2017    10             1.81310             1.80838
  2017    11             1.81724             1.80927
  2017    12             1.81889             1.81018
  2018     1             1.81834             1.81110
  2018     2             1.81472             1.81201
  2018     3             1.81627             1.81291
  2018     4             1.81202             1.81378
  2018     5             1.80576             1.81462
  2018     6             1.80320             1.81542
  2018     7             1.80551             1.81618
  2018     8             1.81365             1.81691
  2018     9             1.82033             1.81759
  2018    10             1.82779             1.81824
  2018    11             1.82675             1.81885
  2018    12             1.82649             1.81944
  2019     1             1.82684             1.82001
  2019     2             1.82282             1.82057
  2019     3             1.81999             1.82113
  2019     4             1.81803             1.82168
  2019     5             1.81432             1.82225
  2019     6             1.81094             1.82284
  2019     7             1.81426             1.82346
  2019     8             1.82219             1.82412
  2019     9             1.82843             1.82482
  2019    10             1.83410             1.82557
  2019    11             1.83505             1.82639
  2019    12             1.83373             1.82726
  2020     1             1.83412             1.82821
  2020     2             1.82938             1.82922
  2020     3             1.82876             1.83031
  2020     4             1.82886             1.83147
  2020     5             1.82379             1.83270
  2020     6             1.82012             1.83399
  2020     7             1.82536             1.83534
  2020     8             1.83485             1.83673
  2020     9             1.84250             1.83818
  2020    10             1.84872             1.83965
  2020    11             1.85042             1.84115
  2020    12             1.85147             1.84266
  2021     1             1.84865             1.84417
  2021     2             1.84823             1.84568
  2021     3             1.84682             1.84717
  2021     4             1.84547             1.84864
  2021     5             1.84184             1.85008
  2021     6             1.83877             1.85148
  2021     7             1.84180             1.85285
  2021     8             1.84769             1.85418
  2021     9             1.86011             1.85548
  2021    10             1.86647             1.85674
  2021    11             1.86980             1.85796
  2021    12             1.86843             1.85916
  2022     1             1.86884             1.86033
  2022     2             1.86536             1.86149
  2022     3             1.86255             1.86262
  2022     4             1.85772             1.86375
  2022     5             1.85222             1.86485
  2022     6             1.85044             1.86595
  2022     7             1.85508             1.86703
  2022     8             1.86478             1.86809
  2022     9             1.87268             1.86912
  2022    10             1.87904             1.87013
  2022    11             1.88028             1.87110
  2022    12             1.88329             1.87202
  2023     1             1.88045             1.87289
  2023     2             1.87956             1.87372
  2023     3             1.87566             1.87449
  2023     4             1.87253             1.87520
  2023     5             1.86531             1.87587
  2023     6             1.86089             1.87649
  2023     7             1.86495             1.87707
  2023     8             1.87294             1.87763
  2023     9             1.88190             1.87817
  2023    10             1.88776             1.87870
  2023    11             1.89068             1.87924
  2023    12             1.88866             1.87980
  2024     1             1.88897             1.88037
  2024     2             1.88315             1.88098
  2024     3             1.88014             1.88161
  2024     4             1.87613             1.88227
  2024     5             1.87412             1.88296
  2024     6             1.86781             1.88366
  2024     7             1.87140             1.88438
  2024     8             1.88113             1.88509
  2024     9             1.88870             1.88580
  2024    10             1.89734             1.88650
  2024    11             1.89880             1.88717
  2024    12             1.89728             1.88781
  2025     1             1.89740             1.88842
  2025     2             1.89586             1.88900
  2025     3             1.88952             1.88954
  2025     4             1.88613             1.89005
  2025     5             1.88027             1.89053
  2025     6             1.87232             1.89097
  2025     7             1.88000             1.89140
  2025     8             1.88848             1.89179
  2025     9             1.89467             1.89217
  2025    10             1.90142             1.89252
  2025    11             1.90360             1.89285
  2025    12             1.90091             1.89316
  2026     1                  NA             1.89345
  2026     2             1.89700             1.89371
  2026     3             1.89447             1.89394
  2026     4             1.89142             1.89416
