The UK’s large atmospheric research aircraft is a converted BAe 146 operated by the Facility for Airborne Atmospheric Measurements (FAAM). With a range of 2000 nautical miles, the FAAM aircraft is capable of operating all over the world and it has taken part in science campaigns in over 30 different countries since 2004. The aircraft can fly as low as 50 feet over the sea and sustain flight at 100 feet high. The service ceiling is nearly 11 km high. Typically, flights will last anywhere between one and six hours, and we will carry up to 18 scientists onboard, who guide the mission and support the operation of up to 4 tonnes of scientific equipment. Currently, the aircraft is undergoing a £49 million mid-life upgrade (MLU) program, which will extend its lifetime to at least 2040. The three overarching objectives of the MLU are to:

Safeguard the UK’s research capability – allowing the facility to meet the needs of the research community, enhance the range of services available, and respond to environmental emergencies.

Provide frontier science capability – meeting new and existing research needs and supporting ground-breaking science discoveries, with a flexible and world-class airborne laboratory.

Reduce environmental impact – maintaining and improving the performance of the facility, and minimising emissions and resource use from aircraft operation.

Presented here will be a brief history of the aircraft operations, including example science outcomes from all flights all over the world. In addition, detail of the ongoing upgrades, in particular the new and cutting-edge measurement capability for gases, aerosols, clouds, radiation and meteorology. Also presented will be the expected reductions in environmental impact of the aircraft and how these will be monitored.

How to cite: Lee, J.: The FAAM large atmospheric research aircraft: a brief history and future upgrades, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3473, https://doi.org/10.5194/egusphere-egu23-3473, 2023.

Despite the reduced nitrogen (N) cycle being central to global biogeochemistry, there are large uncertainties surrounding its sources and rate of cycling. Here, we present the first observations of gas-phase urea (CO(NH₂)₂) in the atmosphere from airborne high-resolution mass spectrometer measurements over the North Atlantic Ocean. We show that urea is ubiquitous in the marine lower troposphere during the Summer, Autumn and Winter flights but was found to be below the limit of detection during the Spring flights. The observations suggest the ocean is the primary emission source but further studies are required to understand the processes responsible for the air-sea exchange of urea. Urea is also frequently observed aloft due to long-range transport of biomass-burning plumes. These observations alongside global model simulations point to urea being an important, and as yet unaccounted for, component of reduced-N to the remote marine environment.  Since we show it readily partitions between gas and particle phases, airborne transfer of urea between nutrient rich and poor parts of the ocean can occur readily and could impact ecosystems and oceanic uptake of CO₂, with potentially important atmospheric implications.  

How to cite: Matthews, E., Bannan, T., Khan, M. A., Shallcross, D., Stark, H., Browne, E., Archibald, A., Bauguitte, S., Reed, C., Thamban, N., Wu, H., Lee, J., Carpenter, L., Yang, M., Bell, T., Allen, G., Percival, C., McFiggans, G., Gallagher, M., and Coe, H.: Airborne observations over the North Atlantic Ocean reveal the first gas-phase measurements of urea in the atmosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6620, https://doi.org/10.5194/egusphere-egu23-6620, 2023.

Since 1^st January 2020 the legal sulphur content of shipping fuel was decreased – from 3.5% to 0.5% by mass outside of the Sulphur Emission Control Areas (SECAs) to improve coastal air quality. A possible downside of this change was acceleration of climate change since sulphur is believed to be a negative climate forcer and sipping is one of its main sources. Further question was the level of compliance to the new rules, especially in the open waters. Another climate related aspect of shipping is recent growth in the liquified natural gas (LNG) tanker fleets. LNG is considered the greenest of the fossil fuels, however there are few empirical studies of methane emissions from marine LNG transport.

The Atmospheric Composition and Radiative forcing changes due to UN International Ship Emissions regulations (ACRUISE) project aims to address the above considerations. During three field campaigns the FAAM Airborne Laboratories’ large research aircraft was deployed to target ships in coastal shipping lanes and open waters. First measurements were performed in July 2019 (before regulation change) in shipping lanes along the Portuguese coast, the English Channel SECA and the Celtic Sea. Further two campaigns were delayed by the COVID-19 pandemic until September 2021 and April 2022, targeting ships in the Bay of Biscay, the English Channel SECA and the Celtic Sea. Throughout the project, nearly 300 ships were measured during 30 research flights, varying from plume aging and cloud interaction studies, through collecting bulk statistics in busy shipping lanes to comparing emissions in and out of SECA. This work focuses on the gaseous species measurements (SO₂, CO₂, CH₄ and VOCs from whole air samples). They are used to study changes in apparent sulphur fuel content of the ships observed throughout ACRUISE, plume composition and methane emissions from LNG tankers.

How to cite: Pasternak, D., Lee, J., Nelson, B., Alexiadou, M., Temple, L., Bauguitte, S., Batten, S., Hopkins, J., Andrews, S., Mathews, E., Bannan, T., Wu, H., Thamban, N., Marsden, N., Yang, M.-X., Bell, T., Coe, H., and Bower, K.: Ship emissions and apparent sulphur fuel content measured of board of a large research aircraft in international waters and Sulphur Emission Control Area, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7986, https://doi.org/10.5194/egusphere-egu23-7986, 2023.

Svalbard Integrated Arctic Earth Observing System (SIOS) is an international collaboration of 28 scientific institutions from 10 countries to build a collaborative research infrastructure that will enable better estimates of future environmental and climate changes in the Arctic. SIOS' mission is to develop an efficient observing system in Svalbard, share technology and data using FAIR principles, fill knowledge gaps in Earth system science and reduce the environmental footprint of science in the Arctic. This study presents SIOS' efforts to strengthen science, international collaboration and capacity building in the high Arctic archipelago of Svalbard through its airborne research infrastructure. SIOS supports the coordinated usage of its airborne remote sensing resources such as the Dornier aircraft and uncrewed aerial vehicles (UAVs) for improved research activities in Svalbard, complementing in situ and space-borne measurements and reducing the environmental footprint of research in Svalbard. Since 2019, SIOS in collaboration with its member institution Norwegian Research Centre (NORCE) installed, tested, and operationalised optical imaging sensors in the Lufttransport Dornier (DO228) passenger aircraft stationed in Longyearbyen under the SIOS-InfraNor project making it compatible with research use in Svalbard. Two optical sensors are installed onboard the Dornier aircraft; (1) the PhaseOne IXU-150 RGB camera and (2) the HySpex VNIR-1800 hyperspectral sensor. The aircraft with these cameras is configured to acquire aerial RGB imagery and hyperspectral remote sensing data in addition to its regular logistics and transport operation in Svalbard. Since 2020, SIOS has supported and coordinated around 50 flight hours to acquire airborne data using the Dornier aircraft and UAVs in Svalbard supporting around 20 scientific projects. The use of airborne imaging sensors in these projects enabled a variety of applications within glaciology, biology, hydrology, and other fields of Earth system science: Mapping glacier crevasses, generating DEMs for glaciological applications, mapping and characterising earth (e.g., minerals, vegetation), ice (e.g., sea ice, icebergs, glaciers and snow cover) and ocean surface features (e.g., colour, chlorophyll). The use of passenger aircraft warrants the following benefits: (1) regular logistics and research activities are optimally coordinated to reduce flight hours in carrying scientific observations, (2) project proposals for the usage of aircraft-based measurements facilitate international collaboration, (3) measurements conducted during 2020-21 are useful in filling the gaps in field based observations occurred due to the Covid-19 pandemic, (4) airborne data are used to train polar scientists as a part of the annual SIOS training course and upcoming data usability contest, (5) data is also useful for Arctic field safety as it can be used to make products such as high-resolution maps of crevassed areas on glaciers. In short, SIOS airborne remote sensing activities represent optimized use of infrastructure, promote capacity building, Arctic safety and facilitate international cooperation.

How to cite: Jawak, S., Sivertsen, A., Harcourt, W. D., Denkmann, R., Matero, I., Godøy, Ø., and Lihavainen, H.: Airborne remote sensing research infrastructure for strengthening science, international collaboration and capacity building in the Arctic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8329, https://doi.org/10.5194/egusphere-egu23-8329, 2023.

 From December 2021 to May 2022, MeteoSwiss conducted a proof of concept with Meteomatics to demonstrate the capability of drones to provide data of sufficient quality and reliability on a routine operational basis. Meteodrones MM-670 were operated automatically 8 times per night at Payerne, Switzerland. 864 meteorological profiles were measured and compared to co-localized measurements including radiosoundings and remote-sensing instruments. To our knowledge, it is the first time that Meteodrone measurements are evaluated in such an intensive campaign.

The availability of the Meteodrone measurements over the whole campaign was 75.7% with 82.2% of the flights reaching the nominal altitude of 2000m above sea level. Using the radiosondes as a reference, the quality of the Meteodrone measurements can be quantified according to WMO requirements (WMO OSCAR , 2022). Applying this method, the temperature measured by the Meteodrone can be considered as a “breakthrough”, meaning that they are a significant improvement if they are used for high resolution Numerical Weather Prediction. The Meteodrone’s humidity and wind profiles are classified as “useful” for high-resolution numerical weather predictions, suggesting they can be used for assimilation in numerical models. The quality is similar compared to the temperature measured by a microwave radiometer and the humidity measured by a Raman Lidar. However, the wind measured by a Doppler Lidar was more accurate than the estimation of the Meteodrone.

This campaign opens the door for operational usage of automatic drones for meteorological applications.

How to cite: Hervo, M., Pasquier, J., Hammerschmidt, L., Weusthoff, T., Fengler, M., and Haefele, A.: First evaluation of a 6-months Meteodrone campaign, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11813, https://doi.org/10.5194/egusphere-egu23-11813, 2023.

Measurements involving water in the vapor phase have to deal with the stickiness of the H₂O molecule: The associated adsorption and desorption processes can increase the response time of these measurements significantly. To achieve short response times in scientific instrument design, hydrophobic surface materials are used to reduce surface interactions in the tubing that guides the sample towards the analyzer. The study presented here focuses on the effects of the tubing material choice, length, humidity level, gas flow rate, and temperature on the observed response time. We use an Optical Feedback Cavity Enhanced Absorption Spectrometer (OFCEAS) designed for stable water isotope measurements at low water concentration (< 1000 ppm), which we connect to two bottles containing humidified synthetic air of different water concentration using 6.6-m tubing of different materials and surface treatments. Other parameters that are varied are the flow rate and the temperature of the tubing. With proper selection of tubing material and surface treatment, the contribution from the tubing to the overall response time for low water concentration isotopic measurements can be sufficiently suppressed for it to be neglected.

How to cite: Miltner, M., Stoltmann, T., and Kerstel, E.: How inlet tubing material affects the response time of water vapor concentration measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13766, https://doi.org/10.5194/egusphere-egu23-13766, 2023.

In-Service Aircraft for a Global Observing System (IAGOS) is a European research infrastructure that uses the infrastructure of commercial aviation to make in-situ measurements of the atmosphere. We present data from the cloud sensing instrument installed on these aircraft between 2011 and 2021. This includes 1000s of flights across the globe that detect the concentration of cloud particles over the range 5-75 um and this provides information about seasonal variation in cloud frequency across different parts of the globe. From these measurements we are able to estimate properties such as Liquid/Ice Water Content (LWC/IWC), The Effective Diameter (ED) and Mean Volume Diameter (MVD).

How to cite: Lloyd, G. and Gallagher, M.: Global measurements of cloud properties using commercial aircraft, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15334, https://doi.org/10.5194/egusphere-egu23-15334, 2023.

Aerosols have important effects on both local and global climate, as well as on clouds and precipitations. We present here some original results of the AErosol RadiatiOn and CLOud in Southern Africa (AEROCLO-sA) field campaign led in Namibia in August and September 2017. This region shows a strong response to climate change and is associated with large uncertainties in climate models. Large amounts of biomass burning aerosols emitted by vegetation fires in Central Africa are transported far over the Namibian deserts and are also detected over the stratocumulus clouds covering the South Atlantic Ocean along the coast of Namibia. Absorbing aerosols above clouds are associated with strong positive direct radiative forcing (warming) that are still underestimated in climate models (De Graaf etal.,2021). The absorption of solar radiation by absorbing above clouds may also cause a warming where the aerosol layer is located. This warming would alter the thermodynamic properties of the atmosphere, which would impact the vertical development of low-level clouds impacting the cloud top height and its brightness.

The airborne field campaign consisted in ten flights performed with the French F-20 Falcon aircraft in this region of interest. Several instruments were involved: the OSIRIS polarimeter, prototype of the next 3MI spaceborne instrument of ESA (Chauvigné etal.,2021), the LNG lidar, an airborne photometer called PLASMA, as well as fluxmeters and dropsondes used to measure thermodynamical quantities, supplemented with in situ aerosol measurements of particles size distribution.

In order to quantify the aerosols radiative impact on the Namibian regional radiative budget, we use an original approach that combines polarimeter and lidar data to derive heating rate of the aerosols. This approach is evaluated during massive transports of biomass burning particles. To calculate this parameter, we use a radiative transfer code and additional meteorological parameters, provided by the dropsondes. We will introduce, the flight of September 8, 2017, aerosol pollution was very important. Emissions and dust were carried along the Namibian coast, and an aerosol plume was observed above a stratocumulus. We will present vertical profiles of heating rates computed in the solar and thermal parts of the spectrum with this technique. Our results indicated particularly strong heating rate values retrieved above clouds due to aerosols, in the order of 8K per day, which is likely to perturbate the dynamic of the below cloud layers.

In order to validate and to quantify this new methodology, we used the flux measurements acquired during loop descents performed during dedicated parts of the flights, which provides unique measurements of flux distribution (upwelling and downwelling) and heating rates in function of the altitude.

Finally, we will discuss the possibility to apply this method to available spaceborne passive and active observations in order to provide the first estimates of heating rate profiles above clouds at global scale.

How to cite: Ventura, M., Waquet, F., Brobgniez, G., Parol, F., Mallet, M., Ferlay, N., Dubovic, O., Goloub, P., Flamant, C., and Formenti, P.: Synergy of active and passive airborne observations for the evaluation of the radiative impacts of aerosols. Application to the AEROCLO-SA field campaign in Namibia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17533, https://doi.org/10.5194/egusphere-egu23-17533, 2023.

Monitoring climate change and stratospheric ozone budget requires accurate knowledge of the abundances of greenhouse gases and ozone depleting substances from the lower troposphere to the stratosphere. An infrared laser absorption spectrometer called SPECIES (acronym for SPECtromètre Infrarouge à lasErs in Situ) has been developed for balloon-borne trace gases measurements.

The complete instrument has been validated on the occasion of a flight in August 2021 in the polar region (Kiruna, Sweden) within the frame of the “KLIMAT 2021” campaign managed by CNES for the “MAGIC” project using concomitant balloon and aircraft flights. Results of this flight concerning CH4 and CO2 will be presented.

How to cite: Catoire, V., Xue, C., Krysztofiak, G., Jacquet, P., Chartier, M., and Robert, C.: In-situ trace-gas measurements from the ground to the stratosphere by an OF-CEAS balloon-borne instrument, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7804, https://doi.org/10.5194/egusphere-egu23-7804, 2023.

Land Surface Temperature (LST) is a key parameter to the understanding and modelling of many Earth system processes. Viewing and illumination geometry are known to have significant impacts on remotely sensed retrieval of LST, particularly for heterogeneous regions with mixed components. However, it is difficult to accurately quantify these impacts, in part due to the challenges of retrieving high-quality data for the different components in a scene at a variety of different viewing and illumination geometries over a time period where the real surface temperature and sun-sensor geometries are invariant. Previous field studies have attempted this through observations with aircraft-mounted single-band thermal cameras to further understanding of real-world conditions, but these sensors have limited accuracies and cannot be used to consider the angular variability of emissivity or to simulate multi-band satellite observations.

To redress this, the National Centre for Earth Observation’s Airborne Earth Observatory (NAEO) have developed and manufactured a modified mount for their state-of-the-art commercial pushbroom longwave hyperspectral airborne sensor, the Specim AisaOWL (102 narrowband channels across the 7.6 – 12.6 µm region). When mounted in standard mode, the field-of-view of the OWL sensor is 24° (± 12°), however the modified mount enables off-nadir measurements up to 48°. This has the potential to evaluate both thermal radiation and spectral emissivity directionality up to and beyond the view angles of most thermal satellite sensors. With LST now classified as an Essential Climate Variable, this work is particularly relevant as it will help to improve the accuracy of retrievals from current and future satellites (e.g. LSTM, SBG, TRISHNA).

In this presentation, we first present an overview of the design modifications that enable these high-angle observations and preliminary results from test flights before detailing how this setup will be used in an upcoming joint ESA-NASA campaign dedicated to quantifying and simulating thermal radiation directionality over agricultural regions at the satellite scale.

How to cite: Langsdale, M., Middleton, C., Wooster, M., Grosvenor, M., and Schuettemeyer, D.: Multi-angular airborne thermal observations: A new hyperspectral setup for simulating thermal radiation and emissivity directionality at the satellite scale, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14164, https://doi.org/10.5194/egusphere-egu23-14164, 2023.