Volcanic SO<sub>2</sub> layer height by TROPOMI/S5P: evaluation against IASI/MetOp and CALIOP/CALIPSO observations
<p>Volcanic eruptions eject large amounts of ash and trace gases such as sulfur dioxide (SO<span class="inline-formula"><sub>2</sub></span>) into the atmosphere. A significant difficulty in mitigating the impact of volcanic SO<span class="inline-formul...
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-04-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/5665/2022/acp-22-5665-2022.pdf |
| Summary: | <p>Volcanic eruptions eject large amounts of ash and trace gases such
as sulfur dioxide (SO<span class="inline-formula"><sub>2</sub></span>) into the atmosphere. A significant difficulty
in mitigating the impact of volcanic SO<span class="inline-formula"><sub>2</sub></span> clouds on air traffic safety
is that these gas emissions can be rapidly transported over long distances.
The use of space-borne instruments enables the global monitoring of volcanic
SO<span class="inline-formula"><sub>2</sub></span> emissions in an economical and risk-free manner. Within the
European Space Agency (ESA) Sentinel-5p<span class="inline-formula">+</span> Innovation project, the S5P
SO<span class="inline-formula"><sub>2</sub></span> layer height (S5P<span class="inline-formula">+</span>I: SO2LH) activities led to the improvements of
the retrieval algorithm and generation of the corresponding near real-time
S5P SO<span class="inline-formula"><sub>2</sub></span> LH products. These are currently operationally provided, in
near real-time, by the German Aerospace Center (DLR) within the framework of the
Innovative Products for Analyses of Atmospheric Composition (INPULS)
project. The main aim of this paper is to present its extensive
verification, accomplished within the S5P<span class="inline-formula">+</span>I: SO2LH project, over major
recent volcanic eruptions, against collocated space-borne measurements from
the IASI/Metop and CALIOP/CALIPSO instruments as well as assess its impact
on the forecasts provided by the Copernicus Atmospheric Monitoring Service (CAMS). The mean difference between S5P and IASI observations for the Raikoke
2019, the Nishinoshima 2020 and the La Soufrière-St Vincent 2021
eruptive periods is <span class="inline-formula">∼</span> 0.5 <span class="inline-formula">±</span> 3 km, while for the Taal 2020
eruption, a larger difference was found, between 3 <span class="inline-formula">±</span> 3 km and 4 <span class="inline-formula">±</span> 3 km. The comparison of the daily mean SO<span class="inline-formula"><sub>2</sub></span> LH further
demonstrates the capabilities of this near real-time product, with slopes
between 0.8 and 1 and correlation coefficients ranging between 0.6 and 0.8.
Comparisons between the S5P SO<span class="inline-formula"><sub>2</sub></span> LH and the CALIOP/CALIPSO ash plumes
revealed an expected bias at <span class="inline-formula">−</span>2.5 <span class="inline-formula">±</span> 2 km, considering that the injected
SO<span class="inline-formula"><sub>2</sub></span> and ash plume locations do not always coincide over an eruption.
Furthermore, the CAMS assimilation of the S5P SO<span class="inline-formula"><sub>2</sub></span> LH product led to much
improved model output against the non-assimilated IASI LH, with a
mean difference of 1.5 <span class="inline-formula">±</span> 2 km, compared to the original CAMS analysis,
and improved the geographical spread of the Raikoke volcanic plume following
the eruptive days.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |