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August 2022:

Globale N2O Karten aus GOSAT-2 Satellitendaten

Stickstoffdioxid (N2O), auch als Lachgas bekannt, ist nach Kohlendioxid (CO2) und Methan (CH4) das wichtigste anthropogene Treibhausgas. N2O wird vorwiegend durch natürliche Prozesse (z.B. durch Bakterien) erzeugt, es wird aber auch in der Landwirtschaft (Einsatz von Düngemitteln) sowie bei der Verbrennung von Biomasse freigesetzt. Die Konzentration von N2O in der Atmosphäre ist etwa 1000-mal kleiner als die von CO2, aber das Treibhauspotential von N2O ist fast 300-mal größer, wodurch N2O bedeutsam zum Klimawandel beiträgt.

Es gibt allerdings nur wenige globale Messungen von N2O, speziell durch Satelliten. Die im Bild dargestellte Karte (aus Noël et. al, 2022) zeigt die atmosphärische Verteilung von XN2O (d.h. die mittlere trockene Gesamtsäule von N2O) für April 2019, die am IUP aus Messungen des japanischen GOSAT-2 Satelliten bestimmt wurden.

Wie man darin sieht, sind die Gesamtsäulen von N2O in den Tropen größer als in höheren Breiten. Das liegt daran, dass das meiste N2O in der unteren Atmosphäre, der Troposphäre, erzeugt wird und vorhanden ist und die Troposphäre in den Tropen in größere Höhen reicht.

Referenz:

Noël et al., Retrieval of greenhouse gases from GOSAT and GOSAT-2 using the FOCAL algorithm, Atmos. Meas. Tech. , 15(11), 3401–3437, 2022, doi: rm10.5194/amt-15-3401-2022.
https://amt.copernicus.org/articles/15/3401/2022/

Kontakt:

Stefan Noël (stefan.noel@iup.physik.uni-bremen.de)

Juli 2022:

Eine jüngst von der IUP Gruppe „ Cloud Aerosol Surface PArameter Retrieval“ im Rahmen des Transregios (AC)⊃3; durchgeführte Studie untersucht die Wolken, ihre Eigenschaften und die Größe des Strahlungseffektes von Wolken in der Arktis auf der Basis von Satellitendaten.

Arktische Wolken sind ein wichtiger Faktor in der Beeinflussung des arktischen Klimas. Sie wirken dabei sowohl erwärmend als auch abkühlend. Die Gründe wann sie erwärmend oder abkühlend wirken hängen von verschiedenen Bedingungen ab. Hierzu gehören die mikrophysikalischen Eigenschaften der Wolken, die Beleuchtung, die thermodynamische Phase der Wolken (also bis zu welchem Grad sie flüssig oder gefrorenes Wasser beinhalten) und die Reflektivität des Bodens.

Wenngleich bei der Betrachtung über die gesamte Arktis der Bewölkungsgrad sich nicht nennenswert über die Zeit verändert hat, so haben dies einige Wolkeneigenschaften sehr wohl. So z.B. die optische Dicke von Flüssigwasserwolken und der von reinen Eiswolken. Auffällig ist auch teilweise deutliche Veränderung der Wolkenhelligkeit (Cloud albedo).

Reference: The aerosol, cloud and surface property group "Pan-Arctic and regional trends of reflectance, clouds and fluxes: implications for Arctic Amplification" (2022)


Kontakt/contact: Marco Vountas vountas@iup.physik.uni-bremen.de
or Luca Lelli luca@iup.physik.uni-bremen.de

https://www.iup.uni-bremen.de/aerosol

Juni 2022:

Figure 1:
Figure 1: (a) Diamond HK36TTC-ECO Super Dimona D-KWHV aircraft operated by Jade Hochschule Wilhelmshaven and the team from the University Bremen und Jade Hochschule. (b) University of Bremen measurement suite comprising an in-situ greenhouse gas analyser from LRG and a 5-hole turbulence probe. Both are mounted underneath the right wing in an underwing pod. (c) Fligh-by at the ICOS measurement tower in Steinkimmen/Ganderkesee operated be the DWD during the second calibration flight. (d) Vertical wind profile measured during the very first calibration flight of the turbulence probe.

New measurement suite to improve Greenhouse Gases observations from aircraft,
University Bremen, Institute of Environmental Physics

Scientists at the Institute of Environmental Physics are specialised in the development and deployment of various types of airborne sensors to locate and quantify emissions of anthropogenic greenhouse gases by measuring atmospheric Methane (CH4) and Carbon dioxide (CO2) distributions. To accurately estimate emissions from those distributions, precise knowledge of the local wind field is necessary. Therefore, in spring 2022, a newly acquired 5-hole turbulence probe together with a in-situ greenhouse gas analyser, were successfully mounted in one of the wing pods of the motor glider of Jade Hochschule Wilhelmshaven. The Diamond HK36TTC-ECO is a flexible platform for different remote sensing tasks, as it needs no certification process to install sensors. First test flights in cooperation with Jade Hochschule Wilhelmshaven were successfully conducted in northern Germany to calibrate the new instrument. Additionally, fly-bys at the ICOS measurement tower in Steinkimmen/Ganderkesee operated by the German Weather Service DWD, which observes the vertical wind profile at 5 different altitudes till an altitude of 250m, were carried out. Those measurements are used for comparisons and will improve the calibration quality of the wind probe further. Additional, calibration flights comparing measurements from airborne, LIDAR, drone, and tower measurements are planned.

Contact: heinrich.bovensmann@uni-bremen.de

Mai 2022:

Example Figure:
Example Figure: TROPOMI (A) Kd-UVAB, (B) Kd-UVA, and (C) Kd-blue in the Atlantic Ocean gridded at 0.083° as mean for 11 May to 9 June 2018. Accordingly, Kd-UVAB, Kd-UVA, and Kd-blue measured in-situ at 19 stations during expedition PS113 are overlayed as diamonds (match-ups) and circles (unmatched stations). Adapted from Oelker et al. 2022, Fig. 5.

TROPOMI-retrieved underwater light attenuation in three spectral regions in the ultraviolet to blue. Frontiers in Marine Science 9: 787992. doi:10.3389/fmars.2022.787992

Sunlight plays an important role for biological, chemical, and physical processes in the ocean. High-energetic ultraviolet (UV) radiation can have damaging and beneficial effects for aquatic organisms and its interaction with the ocean is generally complex. Most processes feedback with climate warming. Satellite-based observations of light penetration into the ocean in combination with modeling are used to understand these processes and make predictions for the future ocean and climate scenarios in general. Traditional satellite ocean color sensors don’t measure the ultraviolet range. Information on UV light penetration is only inferred indirectly from measurements in the visible wavelength range, naturally connected to lager uncertainties.

This study exploited backscattered UV to blue light data at continuous spectral resolution of 0.5 nm of the TROPOMI sensor onboard the Sentinel-5-Precursor satellite. We present the first direct satellite-based observations of shortwave penetration, in terms of the diffuse attenuation (Kd) into the ocean ranging from the ultraviolet to the blue spectral domain. Our approach is based on Differential Optical Absorption Spectroscopy to retrieve the vibrational Raman scattering (VRS) signal and then combined with coupled ocean-atmosphere radiative transfer modeling (RTM) to derive Kd in the UV range (312.5-338.5 nm and 356.5-390 nm), additionally to the blue Kd (390-423 nm). The VRS signal is well detected in TROPOMI measurements (fit errors <15%) and TROPOMI Kd retrievals exhibit low sensitivity to parametrization of oceanic and atmospheric effects and show good agreement to in situ Kd obtained from in situ measured underwater light spectra.

These products have high potential satisfying user needs in the modeling community which require spectral information on shortwave light penetration for improving estimates of the ocean’s heat budget, primary productivity, photochemical reaction rates of climatically important compounds, and the UV dose rates as an indicator for damaging effects on aquatic organisms.

April 2022:

Figure:
Figure: Colour ratio gradients (a,b) as altitudinal changes of the radiance ratio L(869nm)/L(460nm), as well as retrieved extinction coefficients at 869 nm (c,d) from OMPS-LP limb observations of two selected orbits. Areas of NaN values are scratched out. The map in the top row shows the location of the orbits and the volcano (triangle).

Hunga Tonga-Hunga Ha'apai eruption

On 15th of January 2022, the undervolcano Hunga Tonga-Hunga Ha'apai (20.55°S, 175.40°W), ejected material consisting of gas, steam, and ash up to an altitude of 58 km. This plume height is exceptional and the highest known since satellite observations. Even the second largest volcanic eruption of Mount Pinatubo in the Philippines in 1991 „only“ reached a height of 35 km. Probably, the combination of volcanic heat and superheated moisture from the ocean pushes the aerosols in such unprecedented altitudes.

The uppermost part of the plume sublimated quickly due to the extreme dryness in the mesosphere. In around 30 km altitude, the volcanic plume formed an extensive umbrella carried westward by the strong stratospheric winds. As can be seen from the Figure, this umbrella rose and expanded due to thermal buoyancy and dispersion. It circled the globe within two weeks. The volcanic aerosols will remain in the stratosphere for a long time but have no significant impact on the global climate. The injected aerosol content of 0.4 teragram of sulphur dioxide was too low for that. For comparison: Mount Pinatubo emitted about 18.5 teragram of sulphur dioxide into the stratosphere, temporarily lowering the global temperature by about 0.6°C.

References:

Malinina, E., Rozanov, A., Niemeier, U., Wallis, S., Arosio, C., Wrana, F., Timmreck, C., von Savigny, C., and Burrows, J. P.: Changes in stratospheric aerosol extinction coefficient after the 2018 Ambae eruption as seen by OMPS-LP and MAECHAM5-HAM, Atmos. Chem. Phys., 21, 14871–14891, https://doi.org/10.5194/acp-21-14871-2021, 2021.

https://earthobservatory.nasa.gov

März 2022:

Abbildung:
Abbildung: Einsatz eines akustischen Doppler-Profilstrommessers (ADCP) während der Expedition SO283 mit dem Forschungsschiff SONNE im Südatlantik, April 2021 (oben). Energiefluss Interner Schwerewellen (rot) und der Ausbreitungsweg der Agulhas-Wirbel (blau) im Südatlantik. Sterne und Kreise kennzeichnen die Einsatzpositionen der Instrumente (unten links). Strömungsmessungen (Pfeile) entlang der Fahrtroute und Höhe der Meeresoberfläche (SSH) aus Satellitenaltimetrie (unten rechts).

Forschungsfahrt in den Südatlantik

Die Expedition 283 des Forschungsschiffs SONNE, die im Frühjahr 2021 durchgeführt wurde, war etwas Besonderes. Aufgrund der Corona-Pandemie waren viele Forschungsfahrten abgesagt worden, und nun mussten mehrere ozeanographische Verankerungen im Südatlantik geborgen und neue Instrumente eingesetzt werden. Wissenschaftler*innen und Studierende aus vier Instituten begaben sich auf die lange Reise, die aus Gründen des Infektionsschutzes in Emden begann und dort nach 64 Tagen auf See und mehr als 17.000 Seemeilen auch wieder endete. Unsere Gruppe vom IUP setzte zwei tiefe Verankerungen mit Strommessern und Thermistoren sowie 5 Inverted Echo Sounder aus, die Teil des Beobachtungsprogramms des Sonderforschungsbereichs TRR 181 "Energietransfers in Atmosphäre und Ozean" sind (www.trr-energytransfers.de).

Ziel des Experiments ist es, monatelange Zeitreihen von Strömungsgeschwindigkeiten und Temperaturen zu erhalten, um Wechselwirkungen zu untersuchen, zwischen internen Schwerewellen, die vom Walvis-Rücken ausgehen, und Agulhas-Wirbeln, die sich von Südafrika in den Südatlantik ausbreiten. Diese Wechselwirkungen zwischen Wellen und Wirbeln und ihr Austausch von kinetischer Energie sind noch nicht vollständig verstanden. Gezeitenströmungen an Seamounts und Kontinentalabhängen beispielsweise regen interne Schwerewellen an, die Hunderte von Kilometern über Ozeanbecken hinweg wandern können, bevor sie schließlich zur turbulenten Vermischung in der Wassersäule beitragen. Ihr Energieverlust wird durch eine Reihe von Prozessen und Wechselwirkungen bestimmt. In unserem Projekt untersuchen wir die Streuung und Brechung der Gezeitenwellen im Inneren der Ozeane mit dem Ziel, diese Prozesse besser in Klimamodelle zu integrieren.

Februar 2022:

Figure:
Figure: GMAP-2021 campaign in South Korea. Top left: Group picture of some participants. Top right: The IUP Bremen MAX-DOAS instrument on the roof of the NIER building. Bottom figures: Two days of NO2 observations in the Seoul Metropolitan Area. Background values are GEMS tropospheric NO2 columns retrieved by IUP Bremen. The overlaid line are matching car-DOAS measurements performed within +/- 2 hours of the satellite overpass.

The GMAP-2021 campaign
In October and November 2021, IUP Bremen participated in the GMAP-2021 (GEMS Map of Air Pollution) campaign in South Korea. This campaign brought together instruments from South Korea, the US, Belgium, the Netherlands, and Germany to collect data on air pollution in South Korea for the validation of the GEMS (Geostationary Environment Monitoring Spectrometer) satellite instrument. GEMS is the first geostationary satellite instrument dedicated to air quality, launched by the South Korean space agency in February 2020 and providing measurements of key pollutants over Asia in hourly resolution. Similar instruments will be launched by the US (TEMPO) and Europe (Sentinel-4) in the coming years.

During the GMAP campaign, IUP Bremen installed a multi-azimuth MAX-DOAS instrument on the rooftop of the NIER (National Institute of Environmental Research) building at Incheon. This instrument provides data on the abundance of NO2, HCHO, SO2and other pollutants valuable for long-term validation of GEMS retrievals. It will continue to operate at the location for the coming months. Similar instruments have been deployed by other groups in the Seoul Metropolitan Area and other parts of South Korea, and are expected to help in characterizing and improving the satellite data products.

In addition to the stationary measurements, a large number of mobile DOAS measurements was performed from cars to investigate the spatial variability of NO2, to monitor temporal changes and to estimate NOx emissions from Seoul. The observations show a large variability of NO2within individual GEMS satellite pixels, rapid changes over time and the impact of both, local emissions and transport to the observed NO2column amounts. These data are complemented by both in-situ and remote sensing observations from several aircraft overpasses over the same area.

Further reading:

Jhoon Kim et al., New Era of Air Quality Monitoring from Space: Geostationary Environment Monitoring Spectrometer (GEMS), BAMS, 2020, DOI: https://doi.org/10.1175/BAMS-D-18-0013.1

Januar 2022:

Figure 1:
Figure 1: The Carbon Dioxide (CO2) plume emitted from the power plant Jänschwalde observed with the new airborne instrument MAMAP2D-Light could be detected up to 10 km away from the power plant itself. Reddish colors indicate high CO2 concentrations, while the white areas have been filtered out due to too low signal over water (Image: IUP, University Bremen).

Scientists of the Institute of Environmental Physics are developing new optical sensors to image atmospheric Methane (CH4) and CO2 distributions from aircraft in a similar way as future satellites, but with higher sensitivity to point source emissions. The prototype of the push broom imaging spectrometer – called MAMAP2D-Light – was successfully mounted in the wing pods of the motor glider of Jade Hochschule Wilhelmshaven (see IUP picture of the month June 2021) and successfully performed its first flight over the power plant Jänschwalde near Cottbus, Germany.

Subsequent data analysis resulted in the image shown above, where the CO2 plume of the power plant Jänschwalde is clearly visible in reddish colors. The emissions estimated from this data set matches within its uncertainty range the average emissions during the week of the overflight, and the results and additional performance characteristics have been presented at the fall meeting of the American Geophysical Union in December 2021 (1). In summer 2022 this instrument will be flown onboard the German high altitude research aircraft HALO as part of the international COMET 2.0 campaign targeting high latitude emissions of CH4 and CO2 from wetlands as well as geological seeps and oil/gas production in Canada.

Contact: heinrich.bovensmann@uni-bremen.de

(1) Jakob Borchardt, Konstantin Gerilowski, Sven Krautwurst, Wilke Thomssen, Jan Franke, Martin Kumm, Pascal Janßen, Jens Wellhausen, Heinrich Bovensmann, John P. Burrows(2021), The New Imaging Spectrometer MAMAP2D-Light– Initial Calibration and First Measurement Results, [A25G-1759] presented at 2021 Fall Meeting, AGU, 13-17 Dec., https://agu2021fallmeeting-agu.ipostersessions.com/default.aspx?s=65-03-4F-E7-23-6B-ED-73-35-C6-6C-C5-C7-C1-9E-A9