37
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      A study of synthetic <sup>13</sup>CH<sub>4</sub> retrievals from TROPOMI and Sentinel 5/UVNS Part 1: non scattering atmosphere

        , , ,
      Atmospheric Measurement Techniques Discussions
      Copernicus GmbH

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          <p><strong>Abstract.</strong> Retrievals of methane isotopologues have the potential to differentiate between natural and anthropogenic methane sources types, which can provide much needed information about the current global methane budget. We investigate the feasibility of retrieving the second most abundant isotopologue of atmospheric methane (13CH4, roughly 1.1<span class="thinspace"></span>% of total atmospheric methane) from the Shortwave Infrared (SWIR) channels of the future Sentinel 5/UVNS and current Copernicus Sentinel 5 Precursor TROPOMI instruments. With the intended goal of calculating the &amp;delta;<sup>13</sup>C ratio, we assume that a &amp;delta;<sup>13</sup>C uncertainty of better than 10<span class="thinspace"></span>‰ is sufficient to differentiate between source types, which corresponds to a <sup>13</sup>CH<sub>4</sub> uncertainty of &amp;lt;0.2<span class="thinspace"></span>ppb. Using the well established Information Content analysis techniques and assuming clear sky, non-scattering conditions, we find that the SWIR3 (2305&amp;ndash;2385<span class="thinspace"></span>nm) channel on the TROPOMI instrument can achieve a mean uncertainty of &amp;lt;1<span class="thinspace"></span>ppb, while the SWIR1 channel (1590&amp;ndash;1675<span class="thinspace"></span>nm) on the Sentinel 5 UVNS instrument can achieve &amp;lt;0.68<span class="thinspace"></span>ppb. These uncertainties combined with modest spatial and/or temporal averaging techniques can reduce &amp;delta;<sup>13</sup>C uncertainty to the target magnitude or better. However, we find that <sup>13</sup>CH<sub>4</sub> retrievals are highly sensitive to errors in a priori knowledge of temperature and pressure, and accurate knowledge of these profiles are required before <sup>13</sup>CH<sub>4</sub> retrievals can be performed on TROPOMI and future Sentinel 5/UVNS data.</p>

          Related collections

          Author and article information

          Journal
          Atmospheric Measurement Techniques Discussions
          Atmos. Meas. Tech. Discuss.
          Copernicus GmbH
          1867-8610
          January 21 2019
          : 1-36
          Article
          10.5194/amt-2018-450
          0aa01107-b702-45af-81b3-62b39bcf20b4
          © 2019

          https://creativecommons.org/licenses/by/4.0/

          History

          Comments

          Comment on this article