Deconstruction of tropospheric chemical reactivity using aircraft measurements: the Atmospheric Tomography Mission (ATom) data
<p>The NASA Atmospheric Tomography Mission (ATom) completed four seasonal deployments (August 2016, February 2017, October 2017, May 2018), each with regular 0.2–12 km profiling by transecting the remote Pacific Ocean and Atlantic Ocean basins. Additional data were also acquired for the Southe...
Main Authors: | , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2023-07-01
|
Series: | Earth System Science Data |
Online Access: | https://essd.copernicus.org/articles/15/3299/2023/essd-15-3299-2023.pdf |
Summary: | <p>The NASA Atmospheric Tomography Mission (ATom) completed
four seasonal deployments (August 2016, February 2017, October 2017, May 2018), each with regular 0.2–12 km profiling by transecting the remote
Pacific Ocean and Atlantic Ocean basins. Additional data were also acquired for the Southern Ocean, the Arctic basin, and two flights over Antarctica.
ATom in situ measurements provide a near-complete chemical characterization
of the <span class="inline-formula">∼</span> 140 000 10 s (80 m by 2 km) air parcels measured
along the flight path. This paper presents the Modeling Data Stream (MDS), a
continuous gap-filled record of the 10 s parcels containing the chemical
species needed to initialize a gas-phase chemistry model for the budgets of
tropospheric ozone and methane. Global 3D models have been used to calculate
the Reactivity Data Stream (RDS), which is comprised of the chemical
reactivities (production and loss) for methane, ozone, and carbon monoxide,
through 24 h integration of the 10 s parcels. These parcels accurately
sample tropospheric heterogeneity and allow us to partially deconstruct the
spatial scales and variability that define tropospheric chemistry from
composition to reactions. This paper provides a first look at and analysis of
the up-to-date MDS and RDS data including all four deployments (Prather et
al., 2023, <a href="https://doi.org/10.7280/D1B12H">https://doi.org/10.7280/D1B12H</a>).</p>
<p>ATom's regular profiling of the ocean basins allows for weighted averages to
build probability densities for the key species and reactivities presented here.
These statistics provide climatological metrics for global chemistry models,
e.g., the large-scale pattern of ozone and methane loss in the lower
troposphere and the more sporadic hotspots of ozone production in the
upper troposphere. The profiling curtains of reactivity also identify
meteorologically variable and hence deployment-specific hotspots of
photochemical activity. Added calculations of the sensitivities of the
production and loss terms relative to each species emphasize the few
dominant species that control the ozone and methane budgets and whose
statistical patterns should be key model–measurement metrics. From the
sensitivities, we also derive linearized lifetimes of ozone and methane on a
parcel-by-parcel basis and average over the basins, providing an
observational basis for these previously model-only diagnostics. We had
found that most model differences in the ozone and methane budgets are
caused by the models calculating different climatologies for the key species
such as O<span class="inline-formula"><sub>3</sub></span>, CO, H<span class="inline-formula"><sub>2</sub></span>O, NO<span class="inline-formula"><sub><i>x</i></sub></span>, CH<span class="inline-formula"><sub>4</sub></span>, and <span class="inline-formula"><i>T</i></span>, and thus these ATom
measurements make a substantial contribution to the understanding of
model differences and even identifying model errors in global tropospheric
chemistry.</p> |
---|---|
ISSN: | 1866-3508 1866-3516 |