Articles | Volume 17, issue 2
https://doi.org/10.5194/cp-17-969-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-17-969-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
30 Apr 2021
Research article | Highlight paper |
| 30 Apr 2021
| 30 Apr 2021
On the phenomenon of the blue sun
Nellie Wullenweber
Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald, Germany
Anna Lange
Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald, Germany
Alexei Rozanov
Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
Christian von Savigny
CORRESPONDING AUTHOR
Institute of Physics, University of Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald, Germany
Related authors
No articles found.
Mian Chin, Jonathon S. Wright, Huisheng Bian, Qian Tan, Xiaohua Pan, Toshihiko Takemura, Hitoshi Matsui, Kostas Tsigaridis, Susanne Bauer, Paul Ginoux, Yiran Peng, Zengyuan Guo, Suvarna Fadnavis, Anton Laakso, John P. Burrows, Ghassan Taha, Jayanta Kar, Alexei Rozanov, Carlo Arosio, Landon Rieger, and Adam Bourassa
EGUsphere, https://doi.org/10.5194/egusphere-2025-6257, https://doi.org/10.5194/egusphere-2025-6257, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Aerosols in the upper troposphere influence weather and climate. The Asian summer monsoon efficiently transports surface pollutants upward, shaping aerosol amounts and variability in the upper troposphere. Using multiple global models, this study finds a summertime increase in upper-tropospheric aerosols of about 1.2 % per year from 2000 to 2018 over Asia, consistent with rising pollutant emissions, while year-to-year changes are mainly driven by climate variability affecting monsoon dynamics.
Anna Lange, Ulrike Niemeier, Alexei Rozanov, and Christian von Savigny
EGUsphere, https://doi.org/10.5194/egusphere-2025-5446, https://doi.org/10.5194/egusphere-2025-5446, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
We investigate which wavelengths, depending on the latitude, are required for aerosol measurements after continuous sulphur injections of 30 Tg S/y into the stratosphere, here at 19 km, in order to obtain physically meaningful stratospheric aerosol extinction profile retrieval results from the perspective of a typical satellite instrument with the so-called solar occultation geometry. Consistent with expectations, a longer wavelength is required for the latitude range of and near the injection.
Christian Löns, Ronald Eixmann, Christine Pohl, Alexei Rozanov, and Christian von Savigny
Atmos. Chem. Phys., 25, 18209–18225, https://doi.org/10.5194/acp-25-18209-2025, https://doi.org/10.5194/acp-25-18209-2025, 2025
Short summary
Short summary
During the polar vortex season, so-called streamers can transport tropical air towards the pole in the middle stratosphere. This tropical air can get trapped in high-pressure areas at high latitudes after the polar vortex breaks down. In this study, remote sensing instruments are used to observe the course of such streamers by measuring the scattered solar radiation. Aerosols get transported to high latitudes at an altitude of about 25–35 km, increasing the aerosol mass there significantly.
Linlu Mei, Vladimir Rozanov, Alexei Rozanov, and John P. Burrows
EGUsphere, https://doi.org/10.5194/egusphere-2025-4846, https://doi.org/10.5194/egusphere-2025-4846, 2025
Short summary
Short summary
As climate change causes this ice to melt, this reflective shield shrinks, accelerating global warming. We improved how the software calculates light interaction with snow and ice and then verified its accuracy against real-world measurements. This freely available tool provides scientists with a more precise way to predict the pace of climate change, helping us understand the future of our warming planet.
Arno Keppens, Daan Hubert, José Granville, Oindrila Nath, Jean-Christopher Lambert, Catherine Wespes, Pierre-François Coheur, Cathy Clerbaux, Anne Boynard, Richard Siddans, Barry Latter, Brian Kerridge, Serena Di Pede, Pepijn Veefkind, Juan Cuesta, Gaelle Dufour, Klaus-Peter Heue, Melanie Coldewey-Egbers, Diego Loyola, Andrea Orfanoz-Cheuquelaf, Swathi Maratt Satheesan, Kai-Uwe Eichmann, Alexei Rozanov, Viktoria F. Sofieva, Jerald R. Ziemke, Antje Inness, Roeland Van Malderen, and Lars Hoffmann
Atmos. Meas. Tech., 18, 6893–6916, https://doi.org/10.5194/amt-18-6893-2025, https://doi.org/10.5194/amt-18-6893-2025, 2025
Short summary
Short summary
The first Tropospheric Ozone Assessment Report (TOAR) encountered discrepancies between several satellite sensors’ estimates of the distribution and change of ozone in the free troposphere. Therefore, contributing to the second TOAR, we harmonise as much as possible the observational perspective of sixteen tropospheric ozone products from satellites. This only partially accounts for the observed discrepancies, with a reduction of 10–40 % of the inter-product dispersion upon harmonisation.
Anna Lange, Ulrike Niemeier, Alexei Rozanov, and Christian von Savigny
Atmos. Chem. Phys., 25, 11673–11688, https://doi.org/10.5194/acp-25-11673-2025, https://doi.org/10.5194/acp-25-11673-2025, 2025
Short summary
Short summary
Our paper investigates whether it is possible to observe continuous injections of 1 and 2 Tg S y-1 (sulfur per year) into the stratosphere with the currently active satellite occultation instruments. The calculations show that, considering the natural variability and the assumptions made here, the stratospheric aerosols formed from continuous emissions of 1 and 2 Tg S y-1 in the quasi-steady-state phase can be detected, which is not the case in the first month of the 2-year initial phase.
Carlo Arosio, Viktoria Sofieva, Andrea Orfanoz-Cheuquelaf, Alexei Rozanov, Klaus-Peter Heue, Diego Loyola, Edward Malina, Ryan M. Stauffer, David Tarasick, Roeland Van Malderen, Jerry R. Ziemke, and Mark Weber
Atmos. Meas. Tech., 18, 3247–3265, https://doi.org/10.5194/amt-18-3247-2025, https://doi.org/10.5194/amt-18-3247-2025, 2025
Short summary
Short summary
Tropospheric ozone affects air quality and climate, being a pollutant and a greenhouse gas. We analyze satellite data of tropospheric ozone columns obtained by combining two types of observations: one providing stratospheric and the other total ozone. We compare common climatological features and study the influence of the tropopause (troposphere to stratosphere boundary) on the results. We also examine trends over the last 20 years and compare satellite data with ozonesondes to identify drifts.
Clair Duchamp, Bernard Legras, Aurélien Podglajen, Pasquale Sellitto, Adam E. Bourassa, Alexei Rozanov, Ghassan Taha, and Daniel J. Zawada
EGUsphere, https://doi.org/10.5194/egusphere-2025-3355, https://doi.org/10.5194/egusphere-2025-3355, 2025
Short summary
Short summary
We analyzed the stratospheric aerosol plume from the 2022 Hunga eruption using satellite lidar data. We implemented a method to retrieve some aerosol properties, as standard products failed in this case. We found very high optical depth values in the days following the eruption, which decreased rapidly but remained elevated for months. Our results are broadly validated, though some satellite products underestimate the values due, in part, to the unusual aerosol size distribution in the plume.
Sandra Wallis, Matthew DeLand, and Christian von Savigny
Atmos. Chem. Phys., 25, 3635–3645, https://doi.org/10.5194/acp-25-3635-2025, https://doi.org/10.5194/acp-25-3635-2025, 2025
Short summary
Short summary
The 2022 Hunga Tonga – Hunga Ha'apai eruption emitted about 150 Tg H2O that partly reached the upper polar Southern Hemisphere mesosphere in the beginning of 2024. Noctilucent clouds (NLCs) did not show a clear perturbation in their occurrence frequency, but the slight increase from mid-January to February could potentially have been caused by the additional H2O. It needed 2 years to reach the summer polar mesopause region, analogous to the 1883 Krakatoa eruption that is argued to have caused the first sightings of NLCs.
Felix Wrana, Terry Deshler, Christian Löns, Larry W. Thomason, and Christian von Savigny
Atmos. Chem. Phys., 25, 3717–3736, https://doi.org/10.5194/acp-25-3717-2025, https://doi.org/10.5194/acp-25-3717-2025, 2025
Short summary
Short summary
There is a natural and globally occurring layer of small droplets (aerosols) at roughly 20 km altitude in the atmosphere. In this work, the size of these droplets is calculated from satellite measurements for the years 2002 to 2005, which is important for the aerosol cooling effect on Earth's climate. These years are interesting because there were no large volcanic eruptions that would change the background state of the aerosols. The results are compared to reliable balloon-borne measurements.
Alexei Rozanov, Christine Pohl, Carlo Arosio, Adam Bourassa, Klaus Bramstedt, Elizaveta Malinina, Landon Rieger, and John P. Burrows
Atmos. Meas. Tech., 17, 6677–6695, https://doi.org/10.5194/amt-17-6677-2024, https://doi.org/10.5194/amt-17-6677-2024, 2024
Short summary
Short summary
We developed a new algorithm to retrieve vertical distributions of aerosol extinction coefficients in the stratosphere. The algorithm is applied to measurements of scattered solar light from the spaceborne OMPS-LP (Ozone Mapper and Profiler Suite Limb Profiler) instrument. The retrieval results are compared to data from other spaceborne instruments and used to investigate the evolution of the aerosol plume following the eruption of the Hunga Tonga–Hunga Ha'apai volcano in January 2022.
Falco Monsees, Alexei Rozanov, John P. Burrows, Mark Weber, Annette Rinke, Ralf Jaiser, and Peter von der Gathen
Atmos. Chem. Phys., 24, 9085–9099, https://doi.org/10.5194/acp-24-9085-2024, https://doi.org/10.5194/acp-24-9085-2024, 2024
Short summary
Short summary
Cyclones strongly influence weather predictability but still cannot be fully characterised in the Arctic because of the sparse coverage of meteorological measurements. A potential approach to compensate for this is the use of satellite measurements of ozone, because cyclones impact the tropopause and therefore also ozone. In this study we used this connection to investigate the correlation between ozone and the tropopause in the Arctic and to identify cyclones with satellite ozone observations.
Christine Pohl, Felix Wrana, Alexei Rozanov, Terry Deshler, Elizaveta Malinina, Christian von Savigny, Landon A. Rieger, Adam E. Bourassa, and John P. Burrows
Atmos. Meas. Tech., 17, 4153–4181, https://doi.org/10.5194/amt-17-4153-2024, https://doi.org/10.5194/amt-17-4153-2024, 2024
Short summary
Short summary
Knowledge of stratospheric aerosol characteristics is important for understanding chemical and climate aerosol feedbacks. Two particle size distribution parameters, the aerosol extinction coefficient and the effective radius, are obtained from SCIAMACHY limb observations. The aerosol characteristics show good agreement with independent data sets from balloon-borne and satellite observations. This data set expands the limited knowledge of stratospheric aerosol characteristics.
Matthew S. Johnson, Alexei Rozanov, Mark Weber, Nora Mettig, John Sullivan, Michael J. Newchurch, Shi Kuang, Thierry Leblanc, Fernando Chouza, Timothy A. Berkoff, Guillaume Gronoff, Kevin B. Strawbridge, Raul J. Alvarez, Andrew O. Langford, Christoph J. Senff, Guillaume Kirgis, Brandi McCarty, and Larry Twigg
Atmos. Meas. Tech., 17, 2559–2582, https://doi.org/10.5194/amt-17-2559-2024, https://doi.org/10.5194/amt-17-2559-2024, 2024
Short summary
Short summary
Monitoring tropospheric ozone (O3), a harmful pollutant negatively impacting human health, is primarily done using ground-based measurements and ozonesondes. However, these observation types lack the coverage to fully understand tropospheric O3. Satellites can retrieve tropospheric ozone with near-daily global coverage; however, they are known to have biases and errors. This study uses ground-based lidars to validate multiple satellites' ability to observe tropospheric O3.
Andrea Orfanoz-Cheuquelaf, Carlo Arosio, Alexei Rozanov, Mark Weber, Annette Ladstätter-Weißenmayer, John P. Burrows, Anne M. Thompson, Ryan M. Stauffer, and Debra E. Kollonige
Atmos. Meas. Tech., 17, 1791–1809, https://doi.org/10.5194/amt-17-1791-2024, https://doi.org/10.5194/amt-17-1791-2024, 2024
Short summary
Short summary
Valuable information on the tropospheric ozone column (TrOC) can be obtained globally by combining space-borne limb and nadir measurements (limb–nadir matching, LNM). This study describes the retrieval of TrOC from the OMPS instrument (since 2012) using the LNM technique. The OMPS-LNM TrOC was compared with ozonesondes and other satellite measurements, showing a good agreement with a negative bias within 1 to 4 DU. This new dataset is suitable for pollution studies.
Christian von Savigny, Anna Lange, Christoph G. Hoffmann, and Alexei Rozanov
Atmos. Chem. Phys., 24, 2415–2422, https://doi.org/10.5194/acp-24-2415-2024, https://doi.org/10.5194/acp-24-2415-2024, 2024
Short summary
Short summary
It is well known that volcanic eruptions strongly affect the colours of the twilight sky. Typically, volcanic eruptions lead to enhanced reddish and violet twilight colours. In rare cases, however, volcanic eruptions can also lead to green sunsets. This study provides an explanation for the occurrence of these unusual green sunsets based on simulations with a radiative transfer model. Green volcanic sunsets require a sufficient stratospheric aerosol optical depth and specific aerosol sizes.
Anna Lange, Alexei Rozanov, and Christian von Savigny
Atmos. Chem. Phys., 23, 14829–14839, https://doi.org/10.5194/acp-23-14829-2023, https://doi.org/10.5194/acp-23-14829-2023, 2023
Short summary
Short summary
We were able to demonstrate quantitatively that the blue colour of the sky cannot be solely attributed to Rayleigh scattering. The influence of ozone on the blue colour of the sky is calculated for different viewing geometries, total ozone columns and an enhanced stratospheric aerosol scenario. Furthermore, the effects of polarisation, surface albedo and observer height are investigated.
John M. C. Plane, Jörg Gumbel, Konstantinos S. Kalogerakis, Daniel R. Marsh, and Christian von Savigny
Atmos. Chem. Phys., 23, 13255–13282, https://doi.org/10.5194/acp-23-13255-2023, https://doi.org/10.5194/acp-23-13255-2023, 2023
Short summary
Short summary
The mesosphere or lower thermosphere region of the atmosphere borders the edge of space. It is subject to extreme ultraviolet photons and charged particles from the Sun and atmospheric gravity waves from below, which tend to break in this region. The pressure is very low, which facilitates chemistry involving species in excited states, and this is also the region where cosmic dust ablates and injects various metals. The result is a unique and exotic chemistry.
Christoph G. Hoffmann, Lena G. Buth, and Christian von Savigny
Atmos. Chem. Phys., 23, 12781–12799, https://doi.org/10.5194/acp-23-12781-2023, https://doi.org/10.5194/acp-23-12781-2023, 2023
Short summary
Short summary
The Madden–Julian oscillation is an important feature of weather in the tropics. Although it is mainly active in the troposphere, we show that it systematically influences the air temperature in the layers above, up to about 100 km altitude and from pole to pole. We have linked this to another known far-reaching process, interhemispheric coupling. This is basic research on atmospheric couplings and variability but might also be of interest for intraseasonal weather forecasting models.
Michael Kiefer, Dale F. Hurst, Gabriele P. Stiller, Stefan Lossow, Holger Vömel, John Anderson, Faiza Azam, Jean-Loup Bertaux, Laurent Blanot, Klaus Bramstedt, John P. Burrows, Robert Damadeo, Bianca Maria Dinelli, Patrick Eriksson, Maya García-Comas, John C. Gille, Mark Hervig, Yasuko Kasai, Farahnaz Khosrawi, Donal Murtagh, Gerald E. Nedoluha, Stefan Noël, Piera Raspollini, William G. Read, Karen H. Rosenlof, Alexei Rozanov, Christopher E. Sioris, Takafumi Sugita, Thomas von Clarmann, Kaley A. Walker, and Katja Weigel
Atmos. Meas. Tech., 16, 4589–4642, https://doi.org/10.5194/amt-16-4589-2023, https://doi.org/10.5194/amt-16-4589-2023, 2023
Short summary
Short summary
We quantify biases and drifts (and their uncertainties) between the stratospheric water vapor measurement records of 15 satellite-based instruments (SATs, with 31 different retrievals) and balloon-borne frost point hygrometers (FPs) launched at 27 globally distributed stations. These comparisons of measurements during the period 2000–2016 are made using robust, consistent statistical methods. With some exceptions, the biases and drifts determined for most SAT–FP pairs are < 10 % and < 1 % yr−1.
Felix Wrana, Ulrike Niemeier, Larry W. Thomason, Sandra Wallis, and Christian von Savigny
Atmos. Chem. Phys., 23, 9725–9743, https://doi.org/10.5194/acp-23-9725-2023, https://doi.org/10.5194/acp-23-9725-2023, 2023
Short summary
Short summary
The stratospheric aerosol layer is a naturally occurring and permanent layer of aerosol, in this case very small droplets of mostly sulfuric acid and water, that has a cooling effect on our climate. To quantify this effect and for our general understanding of stratospheric microphysical processes, knowledge of the size of those aerosol particles is needed. Using satellite measurements and atmospheric models we show that some volcanic eruptions can lead to on average smaller aerosol sizes.
Sandra Wallis, Hauke Schmidt, and Christian von Savigny
Atmos. Chem. Phys., 23, 7001–7014, https://doi.org/10.5194/acp-23-7001-2023, https://doi.org/10.5194/acp-23-7001-2023, 2023
Short summary
Short summary
Strong volcanic eruptions are able to alter the temperature and the circulation of the middle atmosphere. This study simulates the atmospheric response to an idealized strong tropical eruption and focuses on the impact on the mesosphere. The simulations show a warming of the polar summer mesopause in the first November after the eruption. Our study indicates that this is mainly due to dynamical coupling in the summer hemisphere with a potential contribution from interhemispheric coupling.
Linlu Mei, Vladimir Rozanov, Alexei Rozanov, and John P. Burrows
Geosci. Model Dev., 16, 1511–1536, https://doi.org/10.5194/gmd-16-1511-2023, https://doi.org/10.5194/gmd-16-1511-2023, 2023
Short summary
Short summary
This paper summarizes recent developments of aerosol, cloud and surface reflectance databases and models in the framework of the software package SCIATRAN. These updates and developments extend the capabilities of the radiative transfer modeling, especially by accounting for different kinds of vertical inhomogeneties. Vertically inhomogeneous clouds and different aerosol types can be easily accounted for within SCIATRAN (V4.6). The widely used surface models and databases are now available.
Christian von Savigny, Anna Lange, Anne Hemkendreis, Christoph G. Hoffmann, and Alexei Rozanov
Clim. Past, 18, 2345–2356, https://doi.org/10.5194/cp-18-2345-2022, https://doi.org/10.5194/cp-18-2345-2022, 2022
Short summary
Short summary
This study investigates the possibility of inferring information on aerosol optical depth from photographs of historic paintings. The idea – which has been applied in previous studies – is very interesting because it would provide an archive of the atmospheric aerosol loading covering many centuries. We show that twilight colours depend not only on the aerosol optical thickness, but also on several other parameters, making a quantitative estimate of aerosol optical depth very difficult.
Carlo Arosio, Alexei Rozanov, Victor Gorshelev, Alexandra Laeng, and John P. Burrows
Atmos. Meas. Tech., 15, 5949–5967, https://doi.org/10.5194/amt-15-5949-2022, https://doi.org/10.5194/amt-15-5949-2022, 2022
Short summary
Short summary
This paper characterizes the uncertainties affecting the ozone profiles retrieved at the University of Bremen through OMPS limb satellite observations. An accurate knowledge of the uncertainties is relevant for the validation of the product and to correctly interpret the retrieval results. We investigate several sources of uncertainties, estimate a total random and systematic component, and verify the consistency of the combined OMPS-MLS total uncertainty.
John T. Sullivan, Arnoud Apituley, Nora Mettig, Karin Kreher, K. Emma Knowland, Marc Allaart, Ankie Piters, Michel Van Roozendael, Pepijn Veefkind, Jerry R. Ziemke, Natalya Kramarova, Mark Weber, Alexei Rozanov, Laurence Twigg, Grant Sumnicht, and Thomas J. McGee
Atmos. Chem. Phys., 22, 11137–11153, https://doi.org/10.5194/acp-22-11137-2022, https://doi.org/10.5194/acp-22-11137-2022, 2022
Short summary
Short summary
A TROPOspheric Monitoring Instrument (TROPOMI) validation campaign (TROLIX-19) was held in the Netherlands in September 2019. The research presented here focuses on using ozone lidars from NASA’s Goddard Space Flight Center to better evaluate the characterization of ozone throughout TROLIX-19 as compared to balloon-borne, space-borne and ground-based passive measurements, as well as a global coupled chemistry meteorology model.
Sandra Wallis, Christoph Gregor Hoffmann, and Christian von Savigny
Ann. Geophys., 40, 421–431, https://doi.org/10.5194/angeo-40-421-2022, https://doi.org/10.5194/angeo-40-421-2022, 2022
Short summary
Short summary
Although the 1991 eruption of Mt Pinatubo had a severe impact on Earth's climate, the effect of this event on the mesosphere is not well understood. We investigated satellite-borne temperature measurements from the HALOE instrument and found indications that a positive temperature anomaly is present in the tropical upper mesosphere at the beginning of the HALOE time series, which may be related to the eruption of Mt. Pinatubo.
Anna Lange, Gerd Baumgarten, Alexei Rozanov, and Christian von Savigny
Ann. Geophys., 40, 407–419, https://doi.org/10.5194/angeo-40-407-2022, https://doi.org/10.5194/angeo-40-407-2022, 2022
Short summary
Short summary
We investigate the influence of different parameters on the colour of noctilucent clouds (highest clouds in the atmosphere), using radiative transfer calculations. We determined the effect of the particle size, optical depth, single scattering/multiple scattering and ozone. For sufficiently large optical depth and for specific viewing geometries, ozone plays only a minor role in the blueish colour of noctilucent clouds (new result).
William G. Read, Gabriele Stiller, Stefan Lossow, Michael Kiefer, Farahnaz Khosrawi, Dale Hurst, Holger Vömel, Karen Rosenlof, Bianca M. Dinelli, Piera Raspollini, Gerald E. Nedoluha, John C. Gille, Yasuko Kasai, Patrick Eriksson, Christopher E. Sioris, Kaley A. Walker, Katja Weigel, John P. Burrows, and Alexei Rozanov
Atmos. Meas. Tech., 15, 3377–3400, https://doi.org/10.5194/amt-15-3377-2022, https://doi.org/10.5194/amt-15-3377-2022, 2022
Short summary
Short summary
This paper attempts to provide an assessment of the accuracy of 21 satellite-based instruments that remotely measure atmospheric humidity in the upper troposphere of the Earth's atmosphere. The instruments made their measurements from 1984 to the present time; however, most of these instruments began operations after 2000, and only a few are still operational. The objective of this study is to quantify the accuracy of each satellite humidity data set.
Nora Mettig, Mark Weber, Alexei Rozanov, John P. Burrows, Pepijn Veefkind, Anne M. Thompson, Ryan M. Stauffer, Thierry Leblanc, Gerard Ancellet, Michael J. Newchurch, Shi Kuang, Rigel Kivi, Matthew B. Tully, Roeland Van Malderen, Ankie Piters, Bogumil Kois, René Stübi, and Pavla Skrivankova
Atmos. Meas. Tech., 15, 2955–2978, https://doi.org/10.5194/amt-15-2955-2022, https://doi.org/10.5194/amt-15-2955-2022, 2022
Short summary
Short summary
Vertical ozone profiles from combined spectral measurements in the UV and IR spectral ranges were retrieved by using data from TROPOMI/S5P and CrIS/Suomi-NPP. The vertical resolution and accuracy of the ozone profiles are improved by combining both wavelength ranges compared to retrievals limited to UV or IR spectral data only. The advancement of our TOPAS algorithm for combined measurements is required because in the UV-only retrieval the vertical resolution in the troposphere is very limited.
Mireia Papke Chica, Valerian Hahn, Tiziana Braeuer, Elena de la Torre Castro, Florian Ewald, Mathias Gergely, Simon Kirschler, Luca Bugliaro Goggia, Stefanie Knobloch, Martina Kraemer, Johannes Lucke, Johanna Mayer, Raphael Maerkl, Manuel Moser, Laura Tomsche, Tina Jurkat-Witschas, Martin Zoeger, Christian von Savigny, and Christiane Voigt
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-255, https://doi.org/10.5194/acp-2022-255, 2022
Preprint withdrawn
Short summary
Short summary
The mixed-phase temperature regime in convective clouds challenges our understanding of microphysical and radiative cloud properties. We provide a rare and unique dataset of aircraft in situ measurements in a strong mid-latitude convective system. We find that mechanisms initiating ice nucleation and growth strongly depend on temperature, relative humidity, and vertical velocity and variate within the measured system, resulting in altitude dependent changes of the cloud liquid and ice fraction.
Julia Koch, Adam Bourassa, Nick Lloyd, Chris Roth, and Christian von Savigny
Atmos. Chem. Phys., 22, 3191–3202, https://doi.org/10.5194/acp-22-3191-2022, https://doi.org/10.5194/acp-22-3191-2022, 2022
Short summary
Short summary
The mesopause, the region of the earth's atmosphere between 85 and 100 km, is hard to access by direct measurements. Therefore we look for parameters that can be measured using satellite or ground-based measurements. In this study we researched sodium airglow, a phenomenon that occurs when sodium atoms are excited by chemical reactions. We compared satellite measurements of the airglow and resulting sodium concentration profiles to gain a better understanding of the sodium in that region.
Sandip S. Dhomse, Carlo Arosio, Wuhu Feng, Alexei Rozanov, Mark Weber, and Martyn P. Chipperfield
Earth Syst. Sci. Data, 13, 5711–5729, https://doi.org/10.5194/essd-13-5711-2021, https://doi.org/10.5194/essd-13-5711-2021, 2021
Short summary
Short summary
High-quality long-term ozone profile data sets are key to estimating short- and long-term ozone variability. Almost all the satellite (and chemical model) data sets show some kind of bias with respect to each other. This is because of differences in measurement methodologies as well as simplified processes in the models. We use satellite data sets and chemical model output to generate 42 years of ozone profile data sets using a random-forest machine-learning algorithm that is named ML-TOMCAT.
Elizaveta Malinina, Alexei Rozanov, Ulrike Niemeier, Sandra Wallis, Carlo Arosio, Felix Wrana, Claudia Timmreck, Christian von Savigny, and John P. Burrows
Atmos. Chem. Phys., 21, 14871–14891, https://doi.org/10.5194/acp-21-14871-2021, https://doi.org/10.5194/acp-21-14871-2021, 2021
Short summary
Short summary
In the paper, changes in the stratospheric aerosol loading after the 2018 Ambae eruption were analyzed using OMPS-LP observations. The eruption was also simulated with the MAECHAM5-HAM global climate model. Generally, the model and observations agree very well. We attribute the good consistency of the results to a precisely determined altitude and mass of the volcanic injection, as well as nudging of the meteorological data. The radiative forcing from the eruption was estimated to be −0.13 W m−2.
Nora Mettig, Mark Weber, Alexei Rozanov, Carlo Arosio, John P. Burrows, Pepijn Veefkind, Anne M. Thompson, Richard Querel, Thierry Leblanc, Sophie Godin-Beekmann, Rigel Kivi, and Matthew B. Tully
Atmos. Meas. Tech., 14, 6057–6082, https://doi.org/10.5194/amt-14-6057-2021, https://doi.org/10.5194/amt-14-6057-2021, 2021
Short summary
Short summary
TROPOMI is a nadir-viewing satellite that has observed global atmospheric trace gases at unprecedented spatial resolution since 2017. The retrieval of ozone profiles with high accuracy has been demonstrated using the TOPAS (Tikhonov regularised Ozone Profile retrievAl with SCIATRAN) algorithm and applying appropriate spectral corrections to TROPOMI UV data. Ozone profiles from TROPOMI were compared to ozonesonde and lidar profiles, showing an agreement to within 5 % in the stratosphere.
Andrea Orfanoz-Cheuquelaf, Alexei Rozanov, Mark Weber, Carlo Arosio, Annette Ladstätter-Weißenmayer, and John P. Burrows
Atmos. Meas. Tech., 14, 5771–5789, https://doi.org/10.5194/amt-14-5771-2021, https://doi.org/10.5194/amt-14-5771-2021, 2021
Short summary
Short summary
OMPS/NPP (2012–present) allows obtaining the tropospheric ozone column by combining ozone data from limb and nadir observations from the same instrument platform. In a first step, the retrieval of the total ozone column from the OMPS Nadir Mapper using the weighting function fitting approach (WFFA) is described here. The OMPS total ozone was compared with ground-based and other satellite measurements, showing agreement within 2.5 %.
Daniel Zawada, Ghislain Franssens, Robert Loughman, Antti Mikkonen, Alexei Rozanov, Claudia Emde, Adam Bourassa, Seth Dueck, Hannakaisa Lindqvist, Didier Ramon, Vladimir Rozanov, Emmanuel Dekemper, Erkki Kyrölä, John P. Burrows, Didier Fussen, and Doug Degenstein
Atmos. Meas. Tech., 14, 3953–3972, https://doi.org/10.5194/amt-14-3953-2021, https://doi.org/10.5194/amt-14-3953-2021, 2021
Short summary
Short summary
Satellite measurements of atmospheric composition often rely on computer tools known as radiative transfer models to model the propagation of sunlight within the atmosphere. Here we have performed a detailed inter-comparison of seven different radiative transfer models in a variety of conditions. We have found that the models agree remarkably well, at a level better than previously reported. This result provides confidence in our understanding of atmospheric radiative transfer.
Michaela I. Hegglin, Susann Tegtmeier, John Anderson, Adam E. Bourassa, Samuel Brohede, Doug Degenstein, Lucien Froidevaux, Bernd Funke, John Gille, Yasuko Kasai, Erkki T. Kyrölä, Jerry Lumpe, Donal Murtagh, Jessica L. Neu, Kristell Pérot, Ellis E. Remsberg, Alexei Rozanov, Matthew Toohey, Joachim Urban, Thomas von Clarmann, Kaley A. Walker, Hsiang-Jui Wang, Carlo Arosio, Robert Damadeo, Ryan A. Fuller, Gretchen Lingenfelser, Christopher McLinden, Diane Pendlebury, Chris Roth, Niall J. Ryan, Christopher Sioris, Lesley Smith, and Katja Weigel
Earth Syst. Sci. Data, 13, 1855–1903, https://doi.org/10.5194/essd-13-1855-2021, https://doi.org/10.5194/essd-13-1855-2021, 2021
Short summary
Short summary
An overview of the SPARC Data Initiative is presented, to date the most comprehensive assessment of stratospheric composition measurements spanning 1979–2018. Measurements of 26 chemical constituents obtained from an international suite of space-based limb sounders were compiled into vertically resolved, zonal monthly mean time series. The quality and consistency of these gridded datasets are then evaluated using a climatological validation approach and a range of diagnostics.
Felix Wrana, Christian von Savigny, Jacob Zalach, and Larry W. Thomason
Atmos. Meas. Tech., 14, 2345–2357, https://doi.org/10.5194/amt-14-2345-2021, https://doi.org/10.5194/amt-14-2345-2021, 2021
Short summary
Short summary
In this paper, we describe a new method for calculating the size of naturally occurring droplets (aerosols) made mostly of sulfuric acid and water that can be found roughly at 20 km altitude in the atmosphere. We use data from the instrument SAGE III/ISS that is mounted on the International Space Station. We show that our method works well, and that the size parameters we calculate are reasonable and can be a valuable addition for a better understanding of aerosols and their effect on climate.
Larry W. Thomason, Mahesh Kovilakam, Anja Schmidt, Christian von Savigny, Travis Knepp, and Landon Rieger
Atmos. Chem. Phys., 21, 1143–1158, https://doi.org/10.5194/acp-21-1143-2021, https://doi.org/10.5194/acp-21-1143-2021, 2021
Short summary
Short summary
Measurements of the impact of volcanic eruptions on stratospheric aerosol loading by space-based instruments show show a fairly well-behaved relationship between the magnitude and the apparent changes to aerosol size over several orders of magnitude. This directly measured relationship provides a unique opportunity to verify the performance of interactive aerosol models used in climate models.
Cited articles
Ångström, A.: The Blue Sun of September 1950, Tellus, 3, 135–140, https://doi.org/10.3402/tellusa.v3i3.8635, 1951. a
Ball, J. G. C., Reed, B. E., Grainger, R. G., Peters, D. M., Mather, T. A., and Pyle, D. M.: Measurements of the complex refractive index of volcanic ash at 450, 546.7, and 650 nm, J. Geophys. Res.-Atmos., 120, 7747–7757, https://doi.org/10.1002/2015JD023521, 2015. a
Bates, D. R.: Rayleigh scattering by air, Planet. Space Sci., 32, 785–790, https://doi.org/10.1016/0032-0633(84)90102-8, 1984. a
Bauch, M.: The Day the Sun Turned Blue: A Volcanic Eruption in the Early 1460s and Its Possible Climatic Impact – A Natural Disaster
Perceived Globally in the Late Middle Ages?, in: Historical Disaster Experiences. Transcultural Research – Heidelberg Studies on Asia and Europe in a Global Context, edited by: Schenk, G. J., Springer, Cham, 107–138, 2017. a
Bohren, C. F. and Huffman, D. R.: Absorption and Scattering by a Sphere, in: Absorption and Scattering of Light by Small Particles, edited by: Bohren, C. F. and Huffman, D. R., https://doi.org/10.1002/9783527618156.ch4, 1998. a, b
Choudhury, A. K. R. (Ed.): Chapter 4 – Principles of colour perception, in: Principles of Colour and Appearance Measurement, Woodhead Publishing, 144–184, https://doi.org/10.1533/9780857099242.144, 2014. a
Dietze, G.: Die anormale Trübung der Atmosphäre September/Oktober 1950, Z. Meteorol., 5, 86–87, 1951. a
Grainger, R. G.: Some Useful Formulae for Aerosol Size Distributions and Optical Properties, Earth Observation Data Group, Physical Department, University of Oxford, Oxford, UK, Section 2, p. 6,
available at: http://eodg.atm.ox.ac.uk/user/grainger/research/aerosols.pdf (last access: 23 April 2021), 2017. a
IUP (Institute of Environmental Physics): User's Guide for the Software Package SCIATRAN (Radiative Transfer Model and Retrieval Algorithm) – Version 3.8, Institute of Environmental Physics/Institute of Remote Sensing (IUP/IFE), University of Bremen, Germany, available at: http://www.iup.uni-bremen.de/sciatran/ (last access: 18 March 2021), 2018. a, b, c
Jenne, W.: Das Phänomen “Blaue Sonne”, Tellus, 3, 129–134, https://doi.org/10.3402/tellusa.v3i3.8636, 1951. a
Judd, D. B.: Report of U.S. Secretariat Committee on Colorimetry and Artificial Daylight, in: Proceedings of the Twelfth Session of the CIE, Stockholm, Bureau Central de la CIE, Paris, 1, 11 pp., 1951. a
Kravitz, B., MacMartin, D. G., and Caldeira, K.: Geoengineering: Whiter skies?, Geophys. Res. Lett., 39, L11801, https://doi.org/10.1029/2012GL051652, 2012. a
Larrabee, W. H.: Green suns and red sunsets, Popular Science Monthly, 24, 598–603, 1884. a
Mie, G.: Beiträge zur Optik trüber Medien, speziell kolloidaler Metallösungen, Ann. Phys., 25, 377–445, 1908. a
Patterson, E. M.: Measurements of the Imaginary Part of the Refractive Index Between 300 and 700 nm for Mount St. Helens Ash, Science, 211, 836–838, 1981. a
Patterson, E. M., Pollard, C. O., and Galindo, I.: Optical properties of the ash from El Chichon volcano, Geophys. Res. Lett., 10, 317–320, 1983. a
Porch, W. M., Ensor, D. S., Charlson, R. J., and Heintzenberg, J.: Blue Moon: Is this a Property of Background Aerosol?, Appl. Optics, 12, 34–36, 1973. a
Schüepp, W.: Beitrag zum Phänomen der blauen Sonne, Experientia, 6, 457–459, https://doi.org/10.1007/BF0215410, 1950. a
Sinnhuber, B.-M., Weber, M., Amankwah, A., and Burrows, J. P.: Total ozone during the unusual Antarctic winter of 2002, Geophys. Res. Lett., 30, 1580, https://doi.org/10.1029/2002GL016798, 2003. a
Simon, K.: Farbe im Digitalen Publizieren – Konzepte der digitalen Farbwiedergabe für Office, Design und Software, Springer-Verlag Berlin Heidelberg, 2008. a
Strutt, J. W.: On the light from the sky, its polarization and colour, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 41, 107–120, https://doi.org/10.1080/14786447108640452, 1871. a
Van de Hulst, H. C.: Light scattering by small particles, Wiley, New York, 1957. a
von Savigny, C. and Hoffmann, C. G.: Issues related to the retrieval of stratospheric-aerosol particle size information based on optical measurements, Atmos. Meas. Tech., 13, 1909–1920, https://doi.org/10.5194/amt-13-1909-2020, 2020. a
Vos, J. J.: Colorimetric and photometric properties of a 2-deg fundamental observer, Color Res. Appl., 3, 125–128, 1978. a
Short summary
This study investigates the physical processes leading to the rare phenomenon of the sun appearing blue or green. The phenomenon is caused by anomalous scattering by, e.g., volcanic or forest fire aerosols. Unlike most other studies, our study includes a full treatment of the effect of Rayleigh scattering on the colour of the sun. We investigate different factors and revisit a historic example, i.e. the Canadian forest fires in 1950, that led to blue sun events in different European countries.
This study investigates the physical processes leading to the rare phenomenon of the sun...
