# ------------------------------------------------------------------------------
#          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: Oct 08 15:50:40 2025
# ------------------------------------------------------------------------------
# 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             1.75072
  2009     5             1.74245             1.75088
  2009     6             1.74135             1.75104
  2009     7             1.74164             1.75121
  2009     8             1.75039             1.75142
  2009     9             1.75551             1.75167
  2009    10             1.75694             1.75196
  2009    11             1.75962             1.75230
  2009    12             1.75768             1.75270
  2010     1             1.75847             1.75315
  2010     2             1.75475             1.75366
  2010     3             1.75363             1.75422
  2010     4             1.75344             1.75482
  2010     5             1.74860             1.75546
  2010     6             1.74575             1.75612
  2010     7             1.74748             1.75680
  2010     8             1.75254             1.75747
  2010     9             1.76040             1.75814
  2010    10             1.76607             1.75878
  2010    11             1.76887             1.75938
  2010    12             1.76688             1.75995
  2011     1             1.76380             1.76046
  2011     2             1.76573             1.76093
  2011     3             1.76515             1.76134
  2011     4             1.76041             1.76171
  2011     5             1.75504             1.76203
  2011     6             1.75130             1.76232
  2011     7             1.75147             1.76258
  2011     8             1.75971             1.76283
  2011     9             1.76587             1.76307
  2011    10             1.76859             1.76331
  2011    11             1.77148             1.76357
  2011    12             1.77029             1.76385
  2012     1             1.76787             1.76415
  2012     2             1.76827             1.76447
  2012     3             1.76382             1.76483
  2012     4             1.76306             1.76522
  2012     5             1.75784             1.76563
  2012     6             1.75473             1.76607
  2012     7             1.75734             1.76653
  2012     8             1.76517             1.76701
  2012     9             1.77175             1.76751
  2012    10             1.77686             1.76802
  2012    11             1.77658             1.76855
  2012    12             1.77697             1.76909
  2013     1             1.77246             1.76964
  2013     2             1.77033             1.77020
  2013     3             1.77074             1.77078
  2013     4             1.77050             1.77137
  2013     5             1.76417             1.77198
  2013     6             1.76059             1.77260
  2013     7             1.76354             1.77325
  2013     8             1.76967             1.77390
  2013     9             1.77952             1.77457
  2013    10             1.78381             1.77525
  2013    11             1.78309             1.77594
  2013    12             1.78456             1.77664
  2014     1             1.78291             1.77734
  2014     2             1.78078             1.77803
  2014     3             1.77781             1.77872
  2014     4             1.77657             1.77941
  2014     5             1.77210             1.78008
  2014     6             1.76894             1.78073
  2014     7             1.77011             1.78137
  2014     8             1.77929             1.78200
  2014     9             1.78735             1.78261
  2014    10             1.79137             1.78321
  2014    11             1.79366             1.78381
  2014    12             1.79165             1.78440
  2015     1                  NA             1.78500
  2015     2             1.78919             1.78561
  2015     3             1.78544             1.78625
  2015     4             1.78295             1.78690
  2015     5             1.77896             1.78759
  2015     6             1.77379             1.78831
  2015     7             1.77869             1.78906
  2015     8             1.78836             1.78986
  2015     9             1.79427             1.79068
  2015    10             1.79934             1.79153
  2015    11             1.79918             1.79240
  2015    12             1.80006             1.79328
  2016     1             1.80039             1.79416
  2016     2             1.79745             1.79502
  2016     3             1.79438             1.79587
  2016     4             1.79403             1.79668
  2016     5             1.78972             1.79744
  2016     6             1.78835             1.79817
  2016     7             1.79181             1.79884
  2016     8             1.79902             1.79947
  2016     9             1.80378             1.80006
  2016    10             1.80728             1.80061
  2016    11             1.80783             1.80113
  2016    12             1.80984             1.80165
  2017     1             1.80739             1.80216
  2017     2             1.80424             1.80269
  2017     3             1.80279             1.80324
  2017     4             1.80055             1.80383
  2017     5             1.79654             1.80446
  2017     6             1.79358             1.80515
  2017     7             1.79511             1.80588
  2017     8             1.80273             1.80666
  2017     9             1.80982             1.80749
  2017    10             1.81310             1.80835
  2017    11             1.81724             1.80924
  2017    12             1.81889             1.81015
  2018     1             1.81834             1.81107
  2018     2             1.81472             1.81198
  2018     3             1.81627             1.81287
  2018     4             1.81202             1.81375
  2018     5             1.80576             1.81458
  2018     6             1.80320             1.81539
  2018     7             1.80551             1.81615
  2018     8             1.81365             1.81687
  2018     9             1.82033             1.81756
  2018    10             1.82779             1.81821
  2018    11             1.82675             1.81882
  2018    12             1.82649             1.81941
  2019     1             1.82684             1.81998
  2019     2             1.82282             1.82054
  2019     3             1.81999             1.82109
  2019     4             1.81803             1.82165
  2019     5             1.81432             1.82222
  2019     6             1.81094             1.82281
  2019     7             1.81426             1.82343
  2019     8             1.82219             1.82409
  2019     9             1.82843             1.82479
  2019    10             1.83410             1.82554
  2019    11             1.83505             1.82635
  2019    12             1.83373             1.82723
  2020     1             1.83412             1.82818
  2020     2             1.82938             1.82919
  2020     3             1.82876             1.83028
  2020     4             1.82886             1.83144
  2020     5             1.82379             1.83266
  2020     6             1.82012             1.83396
  2020     7             1.82536             1.83530
  2020     8             1.83485             1.83670
  2020     9             1.84250             1.83814
  2020    10             1.84872             1.83962
  2020    11             1.85042             1.84111
  2020    12             1.85147             1.84262
  2021     1             1.84865             1.84414
  2021     2             1.84823             1.84564
  2021     3             1.84682             1.84714
  2021     4             1.84547             1.84860
  2021     5             1.84184             1.85004
  2021     6             1.83877             1.85145
  2021     7             1.84180             1.85282
  2021     8             1.84769             1.85415
  2021     9             1.86011             1.85545
  2021    10             1.86647             1.85671
  2021    11             1.86980             1.85793
  2021    12             1.86843             1.85913
  2022     1             1.86884             1.86030
  2022     2             1.86536             1.86146
  2022     3             1.86255             1.86259
  2022     4             1.85772             1.86371
  2022     5             1.85222             1.86482
  2022     6             1.85044             1.86592
  2022     7             1.85508             1.86700
  2022     8             1.86478             1.86806
  2022     9             1.87268             1.86909
  2022    10             1.87904             1.87010
  2022    11             1.88028             1.87107
  2022    12             1.88329             1.87199
  2023     1             1.88045             1.87287
  2023     2             1.87956             1.87369
  2023     3             1.87566             1.87446
  2023     4             1.87253             1.87517
  2023     5             1.86531             1.87584
  2023     6             1.86089             1.87645
  2023     7             1.86495             1.87704
  2023     8             1.87294             1.87759
  2023     9             1.88190             1.87813
  2023    10             1.88776             1.87866
  2023    11             1.89068             1.87920
  2023    12             1.88866             1.87975
  2024     1             1.88897             1.88033
  2024     2             1.88315             1.88094
  2024     3             1.88014             1.88158
  2024     4             1.87613             1.88225
  2024     5             1.87412             1.88295
  2024     6             1.86781             1.88367
  2024     7             1.87140             1.88441
  2024     8             1.88113             1.88515
  2024     9             1.88870             1.88589
  2024    10             1.89734             1.88660
  2024    11             1.89880             1.88728
  2024    12             1.89728             1.88792
  2025     1             1.89740             1.88851
  2025     2             1.89586             1.88905
  2025     3             1.88952             1.88952
  2025     4             1.88613             1.88993
  2025     5             1.88027             1.89028
  2025     6             1.87232             1.89057
  2025     7             1.88000             1.89082
  2025     8             1.88848             1.89103
  2025     9             1.89467             1.89120
