As of 14 December 2020, almost 90% of the IMS facilities (including radionuclide laboratories) were built and certified, data is transmitted in either real-time or on request from IMS stations to IDC for processing and analyzing. IDC analysts review automatic bulletins generated continuously and release the Reviewed Event Bulletin (REB) on a daily basis since February 2000. We present the statistics of mostly natural seismicity waveform events processed and analyzed over the past 20 years, as the network grew in size and became established. Multiple parameters including magnitude for those events associated with detections from seismic, hydroacoustic and infrasonic stations are analyzed. Techniques and rules related to waveform data analysis and the need to correct the automatic bulletin are discussed. This discussion should be beneficial for analysts work and data processing system optimization.

How to cite: Wang, H., Rambolamanana, G., Graham, G., Le Bras, R., Bittner, P., Mumladze, T., Kasmi, A., Mohamed, A. S., Chegeni Ehsan, E., Villarroel, M., Applbaum, D., Makhonina, M., and Joseph Gutierrez, J. A.: Twenty years of IDC Reviewed Event Bulletin (REB) statistics using data from a sparse IMS network to one reaching near completion, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16259, https://doi.org/10.5194/egusphere-egu23-16259, 2023.

Bogazici University-Kandilli Observatory and Earthquake Research Institute (KOERI) is operating IMS Primary Seismic Station (PS-43) under Belbasi Nuclear Tests Monitoring Center for the verification of compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT) since February 2000. PS-43 is composed of two seismic arrays (Ankara and Keskin). The medium-period array equipped with Guralp CMG-3TB instruments is located in the capital city of Ankara whereas the short-period array with Geotech 23900 sensors is located in Keskin. The data quality of the some of the array elements are degraded by the quarry blasts especially if there is an earthquake occurred at the same time with the explosion. There are more than 10 operational stone quarries spread across the city and there are more applications for new quarries each year. In this study, we show the importance of monitoring the quarry activities for the operation of the Turkish NDC. For this purpose, each blast is detected by automatically using cross-correlation and confirmed manually by the analyst.

How to cite: Destici, C., Şemin, K., Koçak, S., and Özener, H.: Monitoring and Data Quality Issues of Mining Activites Around BRTR, Turkiye, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14132, https://doi.org/10.5194/egusphere-egu23-14132, 2023.

Various techniques of Atmospheric Transport Modelling were applied after the announced nuclear tests conducted by the DPRK in order to support the analysis of potentially connected radionuclide detections. Forward dispersion forecasts from the test-site predicted potentially affected IMS stations; forward ATM for known background sources assessed their potential contribution to measured concentrations.

In case of detections, backward ATM has shown consistency with certain emitter locations and identified coincident source regions for multiple detections.

The presentation gives a comprehensive overview how ATM supported the analysis within the German NDC for all six nuclear test explosions announced by the DPRK.  It is particularly in focus how potential interference with known background sources had an impact on the assessment. In several cases, measurements of releases from nuclear facilities caused ambiguous radioxenon detections in the aftermath of DPRK tests.    

Finally, for two DPRK tests (2009 and 2016-Sep) it was not possible to identify potentially related radioxenon detections, for two tests there were consistent but not conclusive detections of Xe-133 only  (2016-Jan, 2017) and for two tests there were matching isotopic ratios and fitting atmospheric conditions (2006, 2013) indicating strong evidence for the actual nuclear fission event.

How to cite: Ross, J. O., Gaebler, P., and Ceranna, L.: Atmospheric Transport Modelling for potential releases and detections of radioxenon possibly connected with nuclear test explosions conducted in North Korea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13272, https://doi.org/10.5194/egusphere-egu23-13272, 2023.

This presentation summarizes the currently best available estimates of radioxenon emissions from all nuclear facilities for a specific year. It is a unique data set to be used in studies to enhance data analysis from the noble gas component of the International Monitoring System (IMS). Global radioactivity monitoring for the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) includes the four xenon isotopes ^131mXe, ¹³³Xe, ^133mXe and ¹³⁵Xe. These four isotopes are serving as important indicators of nuclear explosions. The state-of-the-art radioxenon emission inventory uses generic release estimates for each known nuclear facility. However, the release amount can vary by several orders of magnitude from year to year. The year 2014 was selected for a single year radioxenon emission inventory with minimized uncertainty. Whenever 2014 emissions reported by the facility operator are available these are incorporated into the 2014 emission inventory.

This presentation summarizes this newly updated radioxenon emission inventory. It comprises all relevant nuclear facilities. For the three strong sources ANSTO (Australia), CNL (Canada), and IRE (Belgium), stack release data with a high time resolution are available. Annual emissions are provided for all other medial isotope production facilities, including new updates for the NIIAR facility (Russia) and the Karpov Institute (Russia). For nuclear power plants (NPP) in Europe and the USA the reported release for the whole year is applied in combination with information about their operational schedule. For all other NPPs the best estimates are used. The estimated releases of nuclear research reactor sources are included as well. For the first time, estimates were made for radioxenon releases from spallation neutron sources and from spent nuclear fuel reprocessing plants. The new emission data are compared with previous studies highlighting discrepancies which in many cases are as large as several orders of magnitude.

The global radioxenon emission inventory for 2014 can be used for studies to estimate the contribution of this anthropogenic source to the observed ambient concentrations at IMS noble gas sensors to support CTBT monitoring activities, including calibration and performance assessment of the verification system as described in the Treaty as well as developing and validating methods for enhanced detection capabilities of signals that may indicate a nuclear test. One specific application is the 1st Nuclear Explosion Signal Screening Open Inter-Comparison Exercise that was announced end of 2021 and conducted in 2022. The emission inventory in combination with radioxenon observations at IMS stations may as well be used for global or regional atmospheric tracer studies and for the validation of atmospheric transport simulation methods.

How to cite: Kalinowski, M.: Updated global radioxenon emission inventory from all types of nuclear facilities specific for the year 2014, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3411, https://doi.org/10.5194/egusphere-egu23-3411, 2023.

Demand for calibration at infrasonic frequencies has emerged. It is supported by earth monitoring issues and particularly by the Comprehensive nuclear Test Ban Treaty Organization (CTBTO), which provides a global international coverage for nuclear testing ban, and requires for the IMS (International Monitoring System). In the presentation, a new laser pistonphone design is presented with the objective of establishing primary standards for sound pressure at very low frequencies down to 10 mHz. The piston is a modified accessorized loudspeaker driver whose diameter is equal to the diameter of the front pistonphone cavity. The volume velocity of the piston is measured through a laser interferometer and it was designed to have an upper frequency limit of 20 Hz, to overlap with the reciprocity method of calibration. Particular attention has been given with the-sealing to avoid the pressure leakage loss. The dimensions of the front cavity were designed to allow the calibration of a large variety of sensors, including microphones, barometers, manometers and microbarometers. Examples of calibrations for several sensors are presented with the uncertainty. Finally, the metrological performance of the laser pistonphone is demonstrated by comparing the calibration results with those obtained with alternative methods.

How to cite: Rodrigues, D., Vincent, P., Barham, R., and Larsonnier, F.: A laser pistonphone designed for absolute calibration of infrasound sensors from 10 mHz up to 20 Hz, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7953, https://doi.org/10.5194/egusphere-egu23-7953, 2023.

The reliable and comparable assessment of any physical quantity requires traceability to the international system of units (SI). Sound pressure is traditionally quantified using measurement microphones as transfer standards, for which the established primary calibration methods are currently limited to frequencies of 2 Hz and higher. These frequencies do not fully cover the range of interest for the International Monitoring System (IMS). For this reason, multiple calibration methods for airborne infrasound based on different physical principles are currently in development.

In this poster, a primary calibration method for the realization of the unit Pascal and a secondary calibration method for the transfer of the unit to field devices are presented. The primary calibration method utilizes the vertical gradient of the ambient pressure as stimulus. Moving a microphone periodically up and down subjects it to an alternating pressure with calculable amplitude. The secondary calibration, which transfers the unit to field devices such as microbarometers, is conducted as a comparison calibration in a closed chamber. Both the reference microphone and a device under test are placed in a closed chamber and subjected to a low-frequency alternating pressure. The sensitivity of the device under test is determined by comparison to the reference.

These methods extend the frequency range for the calibration of sensors for airborne infrasound to lower frequencies and improve the reliability of the assessment of airborne infrasound. In this contribution, the capabilities and limitations of both measurement setups are discussed.

How to cite: Kling, C., Rust, M., and Koch, C.: Calibration of sensors for airborne infrasound utilizing the hydrostatic pressure gradient, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13437, https://doi.org/10.5194/egusphere-egu23-13437, 2023.

Low frequency Acoustics, Underwater Acoustics and Vibration (AUV) phenomena in water are used to detect major natural events such as earthquakes, tsunamis and volcanic activity, and are also used by the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) to check compliance with the treaty. Low frequency sound and vibration monitoring technologies are well established; however the lowest frequencies of interest are not sufficiently well covered by current measurement standards, limiting the reliability of data obtained. In addition, monitoring stations are also often located in extreme environments posing additional challenges for assuring the accuracy of measurements recorded by hydrophones. In this poster we describe the work that NPL, TUBITAK and ASN are doing in the Infra-AUV project to develop calibration methods for hydroacoustics in the frequency range from 0.5 Hz to 100 Hz.

The project is establishing both primary standards (based on absolute realisations of the acoustic pascal), and secondary comparison methods to provide routes for effective dissemination and traceability. Two independent primary calibration methods are under development. The first uses a laser pistonphone (NPL and ASN) which uses optical interferometry to determine the motion (and therefore the generated pressure) of a piston driving a small chamber containing the hydrophone under test. The second is the coupler reciprocity method (TUBITAK and NPL) which allows hydrophones to be calibrated in more realistic ocean conditions (increased static pressure). Secondary calibration methods have been developed based on comparison of two devices in a small coupler (NPL and TUBITAK). The resulting calibration capability will underpin new measurement services and improve traceability in low frequency sound measurement and monitoring applications.

How to cite: Malcher, F., Ford, B., Barham, R., Çorakçi, C., Biber, A., Robinson, S., Cheong, S.-H., Ablitt, J., and Wang, L.: Low-frequency standards for hydroacoustics in the Infra-AUV project, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5620, https://doi.org/10.5194/egusphere-egu23-5620, 2023.

At present, seismometers are not traceably calibrated. This means that their output sensitivity is not determined in a way that is traceable to the International Systems of Units (SI). The European research project 19ENV03 Infra-AUV, which is part of the EMPIR programme, develops methods and procedures to enable such traceable calibrations.

In contrast to many other sensors, seismometers are operated stationary in their typical measurement application, i.e., they must not be moved after their deployment. Conventional calibration approaches which involve a laboratory calibration of the seismometer to be calibrated are therefore not feasible. For this reason, a new concept currently developed by different European partners within the Infra-AUV project proposes an on-site calibration scheme.

For the on-site calibration, a reference seismometer is traceably calibrated to the SI in a laboratory. This reference is then used on-site to provide a secondary calibration of other seismometers, e.g. in a seismic station, using natural excitation sources [Schwardt et al., 2022, DOI: 10.1007/s10712-022-09713-4].

The calibration of reference seismometers in the laboratory is carried out as a primary calibration. This means that the measured quantity (the velocity-proportional voltage output) is compared to a different quantity, in this case to a dynamic displacement measurement traced back to the units length and time, which can be measured very precisely by laser interferometry. In this calibration, the seismometer is excited with low-frequency mechanical vibrations generated by electrodynamic exciters. These calibrations must be performed for the horizontal and vertical axes. The frequency range of interest is from 20 Hz down to 0.01 Hz, depending on the seismometer under test. Either mono-frequency sinusoidal excitations of different frequencies are applied subsequently, or multiple frequencies are excited simultaneously using a multi-sine approach. The magnitudes and phases of both measured signals, the interferometric reference and the seismometer under test, are determined by using sine approximation algorithms or by applying a discrete Fourier transform (DFT).

The results of the laboratory calibration, the transfer function of the reference seismometer, can then be derived from the ratios of the measured magnitudes and the differences of the phase angles for the different excitation frequencies. In addition, the associated measurement uncertainties are estimated and are part of the calibration result. Influences that may change the sensitivity of a seismometer, e.g., temperature effects, electromagnetic sensitivity, or ground stiffness need to be analysed and additionally taken into account for the uncertainty estimation.

For the uncertainty of the on-site calibration, differences between the laboratory and the on-site environment also need to be taken into account. This includes, for example, aspects like typically different temperatures or different ground materials.

How to cite: Klaus, L., Larsonnier, F., Winther, J. H., Schwardt, M., Kobusch, M., and Bruns, T.: Traceable Calibration of Seismometers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13404, https://doi.org/10.5194/egusphere-egu23-13404, 2023.

Transfer standards have an important role in calibration, in enabling traceability to be transferred across calibration facilities or physical locations. It is often the case in laboratory calibration, that the sensors best suited to achieving the optimum calibration accuracy, or measurement uncertainty, have different characteristics to those that need to be deployed in the field. Laboratory calibration techniques are often tailored to work with sensors of a specific type or form factor, and requirements on ruggedness and tolerance of a wide range of environmental conditions are usually of lesser importance under laboratory conditions. Conversely, a transfer standard is ideally suited to both laboratory and field environments. The Infra-AUV project is developing a complete calibration-chain solution to establish measurement traceability for IMS measurements, and consideration has therefore been given to the specification of suitable transfer standard sensors. The thought process behind this, and the infrasound sensors, hydrophones and seismometers ultimately proposed for designation as transfer standards will be presented, together with some characteristic calibration data.

How to cite: Barham, R., Rodrigues, D., Larsonnier, F., Schwardt, M., Ford, B., and Malcher, F.: Transfer standard sensors for disseminating traceable calibrations to the field, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8100, https://doi.org/10.5194/egusphere-egu23-8100, 2023.

As part of the joint research project "Metrology for low-frequency sound and vibration - 19ENV03 Infra-AUV" laboratory calibration methods for seismometers and microbarometers in the low frequency range down to 0.01 Hz have been developed. These procedures provide the possibility of traceable on-site calibration during operation for field sensors of the Comprehensive Nuclear-Test-Ban Treaty Organization’s (CTBTO) International Monitoring System (IMS). The traceable calibration allows for accurate amplitude and phase information as well as for an assignment of uncertainties in amplitude and phase. Thereby, data quality and the identification of treaty-relevant events is improved. The on-site calibration procedure requires a reference sensor with a precise and traceable response function which is provided by the newly developed laboratory calibration methods, as well as the record of sufficient coherent excitation signals within the relevant frequency range. The reference sensors can be installed as transfer standards co-located to the operational IMS station sensors without disturbing their regular measurements for treaty validation purposes.

At IMS stations PS19 and IS26 in Germany we performed on-site calibration tests with both seismometers and microbarometers calibrated in the laboratories at PTB and CEA, respectively, using signals from different natural and anthropogenic excitation sources. Following the approach of Gabrielson (2011) with modifications from Charbit et al. (2015) and Green et al. (2021), the gain ratio between the station sensor under test and the reference sensor is calculated. By multiplying the gain ratio with the precise frequency response of the reference, the frequency response function for both magnitude and phase of the station sensors including site-specific factors such as the wind noise reduction system or possible effects of pre-amplifiers and data loggers are determined.

We present calibration results derived from the comparison of IMS station sensors with the laboratory-calibrated instruments along with the nominal responses. The results show agreement with deviations of less than 5% from the nominal response function for frequencies below 10 Hz for all components. The traceable determination of the response for the individual components in detail improves the sensor quality; subsequently waveform amplitudes can be estimated correctly.

How to cite: Schwardt, M., Pilger, C., Kristoffersen, S., Larsonnier, F., Klaus, L., Bruns, T., and Ceranna, L.: Determination of the frequency response of seismic and infrasonic IMS station sensors using a traceable on-site calibration approach, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11059, https://doi.org/10.5194/egusphere-egu23-11059, 2023.

In the context of the joint research project "Metrology for low-frequency sound and vibration - 19ENV03 Infra-AUV" we evaluated natural, anthropogenic and controlled sources of seismic, infrasonic, and hydroacoustic waves with respect to their potential use as excitation signals for on-site calibration of the respective sensors in the range of 0.01 to 20 Hz. In that context, man-made controlled sources such as drop weights, hammer blows or vibrator sources exhibit properties such as broad frequency content and high repeatability that make them an interesting source signal for the calibration of seismometers.

At IMS station PS19 in Germany we conducted an excitation experiment using both a portable electrodynamic seismic vibrator source and simple hammer blows on the ground for the purpose of covering the higher frequencies of interest from 8 to 20 Hz and above for on-site seismometer calibration. As previous on-site calibration experiments have shown, insufficient coherent natural excitation signals within the relevant high frequency range have been recorded, leading to missing information in the frequency response estimation. Using the seismic vibrator source either P- or S-waves could be excited for example as monofrequent (18 Hz) or sweep (10-100 Hz) signals of 10 s time duration. The distance between excitation source and station/reference sensors as well as the direction of signal arrival at the sensors was varied.

We present calibration results for the conducted excitation experiment using a comparison between station and laboratory-calibrated instruments, showing that the frequency response can be determined for the higher frequencies of interest using the different signals from the excitation experiment.

How to cite: Pilger, C. and Schwardt, M.: Application of controlled vibration sources for traceable on-site calibration of seismometers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6393, https://doi.org/10.5194/egusphere-egu23-6393, 2023.

Infrasound stations, including those of the International Monitoring System (IMS) as part of the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO), are used to determine the location of infrasound sources (such as earthquakes, volcanoes, explosions etc.). The triangulation of these sources is done by considering the delay of the arrival times of the signal using several detectors at precisely known locations in an array with an aperture of typically a few kilometers. It is, therefore, of great importance that the amplitude and, especially, the phase of the signal at each sensor in the array is precisely known. Although the calibration of microbarometers can be performed in a laboratory setting, it is much more difficult to determine the transfer function of the wind noise reduction systems (WNRS), designed to reduce the wind associated noise. In-situ calibration of these WNRS’s can be performed using a co-located reference sensor, and comparing the response to that of the array sensor (considering only highly coherent signals) to determine the relative response of the WNRS. System defects, such as flooded pipes or blocked inlets, have significant impacts on the response of the WNRS, and are therefore of interest for the infrasound community. Comparisons between models of these defective WNRS’s and experimental results will allow for the characterization of these effects on the measurements and improvements of the models and WNRS designs. The results of these calibration and WNRS defect experiments will be presented, and compared with models.

How to cite: Vincent, P., Kristoffersen, S., Le Pichon, A., and Alcoverro, B.: A study of defects on infrasound Wind-Noise-Reduction Systems (WNRS) using in-situ calibration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7525, https://doi.org/10.5194/egusphere-egu23-7525, 2023.

Detection of environmental concentrations of radionuclides is the next step to complement data on abnormal events recorded by seismic, hydro-acoustic and infrasound station networks prior to asking for the approval of the on-site inspection. Radionuclides can travel hundreds of kilometres away from their source and under favourable meteorological conditions, be detectable in the air and when deposited on the ground. In order to determine and assess contributions to the anthropogenic radionuclides in the environment and to firmly distinguish it from previous global nuclear tests or emissions from nuclear facilities, it is essential to screen the background “zero point” of the anthropogenic radionuclides. This is especially important around existing sources e.g. nuclear power plants. In this work the radiochemical separation of radionuclides, alpha-, gamma- and mass-spectrometry measurement techniques were combined to determine concentrations and compositions of anthropogenic radionuclides in soil samples within 70 km radius around the Belarussian nuclear power plant in Astravec, on the territory of Lithuania. Gamma spectrometric measurements were performed with state-of-the-art alpha spectrometers and gamma spectra were acquired using an HPGe coaxial detector. Radionuclide isotopic ratios were measured by a sector field mass spectrometer combined with a high-sensitivity APEX sample introduction system. In this work 137Cs/239,240Pu, 238Pu/239,240Pu, 240Pu/239Pu isotopic “fingerprint” values revealed that previous nuclear weapon tests in the Northern hemisphere are prevailing in most of the sampling sites within a 70 km radius around Astravec NPP on the Lithuania territory.

How to cite: Puzas, A., Bernhardsson, C., Pédehontaa-Hiaa, G., Jönsson, M., Mattsson, S., Tarasiuk, N., Konstantinova, M., Gvozdaite, R., Druteikiene, R., Juzikiene, V., and Remeikis, V.: “Zero Point” Background Screening of 137Cs and Pu isotopic composition for radiation environment in Eastern Lithuania, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8287, https://doi.org/10.5194/egusphere-egu23-8287, 2023.

Detection of radioisotopes of noble gases produced by nuclear detonations is one of the methodologies employed by the Comprehensive Nuclear-Test-Ban Treaty. Whereas noble gases are chemically inert, adsorption of pure noble gases has been reported to exhibit non-conservative behavior in naturally occurring nanoporous minerals, albeit under idealized single-component laboratory conditions. Extrapolation of single-component gas adsorption measurements to the multi-component ambient environment that is predominately nitrogen and oxygen, but importantly water, requires numerous assumptions and introduces uncertainty.

This work aims to experimentally examine multicomponent adsorption of Ar, Kr, and Xe on zeolitic materials using an adaptation of the volumetric method. In the most generic sense, the volumetric method measures porosity and gas adsorption by expanding a reference volume of gas to a sample material and the change on the resulting pressure of the system. To apply this method to a multicomponent system where different species are different in the amount of adsorption and speed, it is necessary to monitor the composition of the gas phase in addition to total pressure. In this work, gas composition is monitored using a quadrupole mass spectrometer continuously, enabling Ar, Kr, and Xe to be measured concurrently.

Tests were first conducted on natural clinoptilolite samples which were vacuum-dried and then were exposed to dry air. Relatively little Ar is adsorbed under all conditions tested. However, the heavier noble gases Kr and Xe continue to exhibit significant adsorption effects in vacuum-dried clinoptilolite, despite the overwhelming abundance of nitrogen and oxygen. When the samples were additionally exposed to wet air with different humidity levels, the quantity of Kr and Xe adsorbed was significantly reduced. However, while the quantity of Xe adsorbing was most significantly reduced between 0% to 8 % relative humidity, non-negligible Kr adsorption persisted up to at least 55% relative humidity, the highest humidity level tested. As Kr continued to adsorb, albeit to a lesser degree, but Xe did not, this indicates the reduction in noble gas adsorption is not simply a function of surface coverage. To further explore this phenomenon, additional zeolitic materials, both pure mineral phases and heterogenous rock samples, will be examined.

As this work shows that water can not only to decrease the total adsorption significantly but also can potentially differentiate gas compositions. Consequently, the scenarios where radioactive noble gases can be modeled as being conservative tracer gases may vary with both environmental conditions as well as subsurface geology. In systems where there is appreciable noble gas adsorption occurring, the timing and magnitude of radioactive noble gas signatures may be altered as observed by the International Monitoring System or during a potential On-Site Inspection.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

How to cite: Paul, M., Xu, G., Powell, M., Hearne, G., and Greathouse, J.: Noble Gas Adsorption onto Zeolitic Materials in Atmospheric Conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10471, https://doi.org/10.5194/egusphere-egu23-10471, 2023.