Abstract
We present the first continuous observations of three-dimensional spatially resolved wind fields and atmospheric motions in the mesosphere and lower thermosphere in the mid-latitudes of the Northern Hemisphere. Our observations were performed during a 19-month campaign from January 2022 to July 2023 and exploited the composite data from the first multistatic meteor radar system in China and an adjacent monostatic meteor radar. To retrieve the atmospheric kinetic properties, we introduce an improved volume velocity processing method including coordinate transformations and non-linear constraints to minimize errors. The vertical winds are estimated separately from the iteration of the horizontal divergence to avoid potential biases or contamination from the horizontal winds. The winds and air motions show annual/semiannual variation characteristics within certain altitudes, usually more variable around the equinoxes. The vertical winds are basically within the magnitude of 1 m/s and are upward as expected at the mesopause during the summer, which corresponds to the adiabatic cooling.
No abstract is available for this article.
Abstract
In this study, we measure seismic velocity variations during two cycles of crustal inflation and deflation in 2020 on the Reykjanes peninsula (SW Iceland) by applying coda wave interferometry to ambient noise recorded by distributed dynamic strain sensing (also called DAS). We present a new workflow based on spatial stacking of raw data prior to cross-correlation which substantially improves the spatial coherency and the time resolution of measurements. Using this approach, a strong correlation between velocity changes and ground deformation (in the vertical and horizontal direction) is revealed. Our findings may be related to the infiltration of volcanic fluids at shallow depths, even though the concurrent presence of various processes complicates the reliable attribution of observations to specific geological phenomena. Our work demonstrates how the spatial resolution of DAS can be exploited to enhance existing methodologies and overcome limitations inherent in conventional seismological data sets.
No abstract is available for this article.
Noise filtering options for conically scanning Doppler lidar measurements with low pulse accumulation
Eileen Päschke and Carola Detring
Atmos. Meas. Tech., 17, 3187–3217, https://doi.org/10.5194/amt-17-3187-2024, 2024
Little noise in radial velocity Doppler lidar measurements can contribute to large errors in retrieved turbulence variables. In order to distinguish between plausible and erroneous measurements we developed new filter techniques that work independently of the choice of a specific threshold for the signal-to-noise ratio. The performance of these techniques is discussed both by means of assessing the filter results and by comparing retrieved turbulence variables versus independent measurements.
Estimating errors in vehicle secondary aerosol production factors due to oxidation flow reactor response time
Pauli Simonen, Miikka Dal Maso, Pinja Prauda, Anniina Hoilijoki, Anette Karppinen, Pekka Matilainen, Panu Karjalainen, and Jorma Keskinen
Atmos. Meas. Tech., 17, 3219–3236, https://doi.org/10.5194/amt-17-3219-2024, 2024
Secondary aerosol is formed in the atmosphere from gaseous emissions. Oxidation flow reactors used in secondary aerosol research do not immediately respond to changes in the inlet concentration of gases because of their broad transfer functions. This may result in incorrect secondary aerosol production factors determined for vehicles. We studied the extent of possible errors and found that oxidation flow reactors with faster responses result in smaller errors.
A lightweight holographic imager for cloud microphysical studies from an untethered balloon
Thomas Edward Chambers, Iain Murray Reid, and Murray Hamilton
Atmos. Meas. Tech., 17, 3237–3253, https://doi.org/10.5194/amt-17-3237-2024, 2024
Clouds have been identified as the largest source of uncertainty in climate modelling. We report an untethered balloon launch of a holographic imager through clouds. This is the first time a holographic imager has been deployed in this way, enabled by the light weight and low cost of the imager. This work creates the potential to significantly increase the availability of cloud microphysical measurements required for the calibration and validation of climate models and remote sensing methods.
An improved and extended parameterization of the CO2 15 µm cooling in the middle and upper atmosphere (CO2_cool_fort-1.0)
Manuel López-Puertas, Federico Fabiano, Victor Fomichev, Bernd Funke, and Daniel R. Marsh
Geosci. Model Dev., 17, 4401–4432, https://doi.org/10.5194/gmd-17-4401-2024, 2024
The radiative infrared cooling of CO2 in the middle atmosphere is crucial for computing its thermal structure. It requires one however to include non-local thermodynamic equilibrium processes which are computationally very expensive, which cannot be afforded by climate models. In this work, we present an updated, efficient, accurate and very fast (~50 µs) parameterization of that cooling able to cope with CO2 abundances from half the pre-industrial values to 10 times the current abundance.
Abstract
State-of-the-art climate models simulate a large spread in the mean-state Atlantic meridional overturning circulation (AMOC), with strengths varying between 12 and 25 Sv. Here, we introduce a framework for understanding this spread by assessing the balance between the thermal-wind expression and surface water mass transformation in the North Atlantic. The intermodel spread in the mean-state AMOC strength is shown to be related to the overturning scale depth: climate models with a larger scale depth tend to have a stronger AMOC. We present a physically motivated scaling relationship that links intermodel variations in the scale depth to surface buoyancy fluxes and stratification in the North Atlantic, and thus connects North Atlantic surface processes to the interior overturning circulation. Climate models with a larger scale depth tend to have stronger surface buoyancy loss and weaker stratification in the North Atlantic. These results offer a framework for reducing mean-state AMOC biases in climate models.
No abstract is available for this article.
Abstract
The southern portion of the eastern North American margin (SENAM) is an archetypical volcanic passive margin formed during Mesozoic rifting. How past magmatic events affect the evolution of the SENAM remains an open question of fundamental importance. To better understand this question, here we construct a high-resolution 3-D crustal velocity model from the oceanic side to the continental interior with a combination of multimodal dispersion inversion and full-waveform ambient noise tomography. Our new model reveals an oceanic-continental transitional crust over a short horizonal distance of 100–150 km across the SENAM, with a local-scale lower-than-surrounding velocity anomaly directly beneath the transitional crust. Furthermore, the new model shows three intra-crustal higher-than-average velocity anomalies beneath the SENAM continent. We suggest that the magmatism assisted the Mesozoic rifting process to form the narrow ocean-continent transitional crust along the coastline. The underplating of magma beneath the transitional crust led to a reduction of seismic velocity of the uppermost mantle. In addition, it is probable that the emplacement of the Central Atlantic Magmatic Province caused widespread magmatic intrusions within the continental crust of the SENAM, which were later solidified into intra-crustal high-velocity plutons. Our findings provide new insights into crustal modification history at the passive margin.
Abstract
De-aliasing products are used in the estimation process of satellite-based gravity field computation to reduce errors from high-frequency mass variations that alias into monthly gravity fields. The latest official product is AOD1B RL07 and describes non-tidal atmosphere and oceanic mass variations at 3-hourly resolution. However, the model-based de-aliasing products are inevitably incomplete and prone to temporally and spatially correlated errors that substantially contribute to errors in the estimated gravity fields. Here, we investigate possible enhancement of current de-aliasing products by nesting a regional high-resolution atmospheric reanalysis over Europe into a global reanalysis. As further novelty we include almost mass consistent terrestrial water storage variability from a regional hydrological model nested into a global model as additional component of the de-aliasing product. While we find in agreement with earlier studies only minor contributions from increasing the temporal resolution beyond 3-hourly data, our investigations suggest that contributions from continental hydrology and from regional non-hydrostatic atmospheric modeling to sub-monthly mass variations could be relevant already for gravity fields estimated from current gravity missions. Moreover, in the context of extreme events, we find regionally contributions from additional moisture fields, such as cloud liquid water, in the order of a few mm over Europe. We suggest this needs to be taken into account when preparing data analysis schemes for future space gravimetric missions.
Abstract
Mass movements and delta collapses are significant sources of tsunamis in lacustrine environments, impacting human societies enormously. Paleotsunamis studies play an essential role in understanding historical events and their consequences, along with their return periods. This study investigates a paleotsunami induced by a subaqueous mass movement during the Younger Dryas to Early Holocene transition, ca. 11,700 years ago in Lake Aiguebelette (NW Alps, France). Utilizing high-resolution seismic and bathymetric surveys associated with sedimentological, geochemical, and magnetic analyses, we uncovered a paleotsunami triggered by a seismically induced mass transport deposit. Numerical simulations of mass movement have been conducted using a visco-plastic Herschel-Bulkley rheological model and corresponding tsunami wave modeled with dispersive and nondispersive models. Our findings reveal for the first time that dispersive effects may be negligible for subaqueous landslides in a relatively small lake. This research reconstructs a previously unreported paleotsunami event and enhances our understanding of tsunami dynamics in lacustrine environments.
Use of an uncrewed aerial system to investigate aerosol direct and indirect radiative forcing effects in the marine atmosphere
Patricia K. Quinn, Timothy S. Bates, Derek J. Coffman, James E. Johnson, and Lucia M. Upchurch
Atmos. Meas. Tech., 17, 3157–3170, https://doi.org/10.5194/amt-17-3157-2024, 2024
An uncrewed aerial observing system has been developed for the measurement of vertical profiles of aerosol and cloud properties that affect Earth's radiation balance. The system was successfully deployed from a ship and from a coastal site and flown autonomously up to 3050 m and for 4.5 h. These results indicate the potential of the observing system to make routine, operational flights from ships and land to characterize aerosol interactions with radiation and clouds.
Observing atmospheric rivers using GNSS radio occultation data
Bahareh Rahimi and Ulrich Foelsche
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-81,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study explores the use of GNSS-RO data to improve understanding of the vertical structure of humidity in Atmospheric Rivers (ARs). Specific humidity profiles and IWV values from GNSS-RO are evaluated to assess if this method offers additional insights into ARs' vertical characteristics. The results suggest that combining GNSS-RO data, with its high vertical resolution, with SSMI/S data, known for high horizontal resolution, provides a more complete view of the 3D structure of ARs.
Assessment of Operational Non-Time Critical Sentinel-6A Michael Freilich Radio Occultation Data: Insights into Tropospheric GNSS Signal Cutoff Strategies and Processor Improvements
Saverio Paolella, Axel Von Engeln, Sebastiano Padovan, Riccardo Notarpietro, Christian Marquardt, Francisco Sancho, Veronica Rivas Boscan, Nicolas Morew, and Francisco Martin Alemany
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-82,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study evaluates the ability of the EUMETSAT Sentinel-6A RO-NTC processor to provide high quality bending angle profiles. The analysis spans from the signals SNR and phase noise to the determination of the optimal signals cut-off points in the tropospheric region. Some processor enhancements and the impact on the data quality is also discussed. Data were compared against ECMWF confirming the ability of the EUMETSAT RO processors in maintaining consistent and high-quality data.
A new approach to crystal habit retrieval from far-infrared spectral radiance measurements
Gianluca Di Natale, Marco Ridolfi, and Luca Palchetti
Atmos. Meas. Tech., 17, 3171–3186, https://doi.org/10.5194/amt-17-3171-2024, 2024
This work aims to define a new approach to retrieve the distribution of the main ice crystal shapes occurring inside ice and cirrus clouds from infrared spectral measurements. The capability of retrieving these shapes of the ice crystals from satellites will allow us to extend the currently available climatologies to be used as physical constraints in general circulation models. This could could allow us to improve their accuracy and prediction performance.
Permutation entropy and complexity analysis of large-scale solar wind structures and streams
Emilia K. J. Kilpua, Simon Good, Matti Ala-Lahti, Adnane Osmane, and Venla Koikkalainen
Ann. Geophys., 42, 163–177, https://doi.org/10.5194/angeo-42-163-2024, 2024
The solar wind is organised into slow and fast streams, interaction regions, and transient structures originating from solar eruptions. Their internal characteristics are not well understood. A more comprehensive understanding of such features can give insight itno physical processes governing their formation and evolution. Using tools from information theory, we find that the solar wind shows universal turbulent properties on smaller scales, while on larger scales, clear differences arise.
GEOMAPLEARN 1.0: Detecting geological structures from geological maps with machine learning
David Oakley, Christelle Loiselet, Thierry Coowar, Vincent Labbe, and Jean-Paul Callot
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-35,2024
Preprint under review for GMD (discussion: open, 0 comments)
In this work, we develop two automated workflows for identifying fold structures on geological maps using machine learning. In one method, we identify map patterns suggestive of folding based on pre-defined rules and apply a clustering algorithm to group those from the same fold together. In the other, we train a convolutional neural network to identify folds based on a set of training examples. We apply both methods to a set of synthetic maps and to real-world maps from two locations in France.
Learning from conceptual models – a study of emergence of cooperation towards resource protection in a social-ecological system
Saeed Harati-Asl, Liliana Perez, and Roberto Molowny-Horas
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-57,2024
Preprint under review for GMD (discussion: open, 0 comments)
Social-ecological systems are the subject of many sustainability problems. Because of the complexity of these systems we must be careful when intervening in them, otherwise we may cause irreversible damage. Using computer models, we can gain insight about these complex systems without harming them. In this paper we describe how we connected an ecological model of forest insect infestation with a social model of cooperation, and simulated an intervention measure to save a forest from infestation.
