Pico-Light H2O: intercomparison of in situ water vapour measurements during the AsA 2022 campaign
Mélanie Ghysels, Georges Durry, Nadir Amarouche, Dale Hurst, Emrys Hall, Kensy Xiong, Jean-Charles Dupont, Jean-Christophe Samake, Fabien Frérot, Raghed Bejjani, and Emmanuel D. Riviere
Atmos. Meas. Tech., 17, 3495–3513, https://doi.org/10.5194/amt-17-3495-2024, 2024
A tunable diode laser hygrometer, “Pico-Light H2O”, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign from Aire-sur-l'Adour (France) in September 2022. A total of 15 balloons were launched within the framework of the EU-funded HEMERA project. Pico-Light H2O has been compared in situ with the NOAA Frost Point Hygrometer in the upper troposphere and stratosphere, as well as with meteorological sondes (iMet-4 and M20) in the troposphere.
A new method for estimating megacity NOx emissions and lifetimes from satellite observations
Steffen Beirle and Thomas Wagner
Atmos. Meas. Tech., 17, 3439–3453, https://doi.org/10.5194/amt-17-3439-2024, 2024
We present a new method for estimating emissions and lifetimes for nitrogen oxides emitted from large cities by using satellite NO2 observations combined with wind fields. The estimate is based on the simultaneous evaluation of the downwind plumes for opposing wind directions. This allows us to derive seasonal mean emissions and lifetimes for 100 cities around the globe.
Using a portable FTIR spectrometer to evaluate the consistency of Total Carbon Column Observing Network (TCCON) measurements on a global scale: the Collaborative Carbon Column Observing Network (COCCON) travel standard
Benedikt Herkommer, Carlos Alberti, Paolo Castracane, Jia Chen, Angelika Dehn, Florian Dietrich, Nicholas M. Deutscher, Matthias Max Frey, Jochen Groß, Lawson Gillespie, Frank Hase, Isamu Morino, Nasrin Mostafavi Pak, Brittany Walker, and Debra Wunch
Atmos. Meas. Tech., 17, 3467–3494, https://doi.org/10.5194/amt-17-3467-2024, 2024
The Total Carbon Column Observing Network is a network of ground-based Fourier transform infrared (FTIR) spectrometers used mainly for satellite validation. To ensure the highest-quality validation data, the network needs to be highly consistent. This is a major challenge, which so far is solved by site comparisons with airborne in situ measurements. In this work, we describe the use of a portable FTIR spectrometer as a travel standard for evaluating the consistency of TCCON sites.
A perspective on the next generation of Earth system model scenarios: towards representative emission pathways (REPs)
Malte Meinshausen, Carl-Friedrich Schleussner, Kathleen Beyer, Greg Bodeker, Olivier Boucher, Josep G. Canadell, John S. Daniel, Aïda Diongue-Niang, Fatima Driouech, Erich Fischer, Piers Forster, Michael Grose, Gerrit Hansen, Zeke Hausfather, Tatiana Ilyina, Jarmo S. Kikstra, Joyce Kimutai, Andrew D. King, June-Yi Lee, Chris Lennard, Tabea Lissner, Alexander Nauels, Glen P. Peters, Anna Pirani, Gian-Kasper Plattner, Hans Pörtner, Joeri Rogelj, Maisa Rojas, Joyashree Roy, Bjørn H. Samset, Benjamin M. Sanderson, Roland Séférian, Sonia Seneviratne, Christopher J. Smith, Sophie Szopa, Adelle Thomas, Diana Urge-Vorsatz, Guus J. M. Velders, Tokuta Yokohata, Tilo Ziehn, and Zebedee Nicholls
Geosci. Model Dev., 17, 4533–4559, https://doi.org/10.5194/gmd-17-4533-2024, 2024
The scientific community is considering new scenarios to succeed RCPs and SSPs for the next generation of Earth system model runs to project future climate change. To contribute to that effort, we reflect on relevant policy and scientific research questions and suggest categories for representative emission pathways. These categories are tailored to the Paris Agreement long-term temperature goal, high-risk outcomes in the absence of further climate policy and worlds “that could have been”.
Remote sensing-based high-resolution mapping of the forest canopy height: some models are useful, but might they be even more if combined?
Nikola Besic, Nicolas Picard, Cédric Vega, Lionel Hertzog, Jean-Pierre Renaud, Fajwel Fogel, Agnès Pellissier-Tanon, Gabriel Destouet, Milena Planells-Rodriguez, and Philippe Ciais
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-95,2024
Preprint under review for GMD (discussion: open, 0 comments)
The creation of advanced mapping models for forest attributes, utilizing remote sensing data and incorporating machine or deep learning methods, has become a key area of interest in the domain of forest observation and monitoring. This paper introduces a method where we blend and collectively interpret five models dedicated to estimating forest canopy height. We achieve this through Bayesian model averaging, offering a comprehensive approach to height estimation in forest ecosystems.
Abstract
Fungal aerosols, as significant biocomponents of inhalable particulate matter, encompass a variety of allergens and pathogens. However, comprehensive knowledge regarding their composition, sources, and opportunistic pathogens present in severe air pollution remains limited. In this study, PM2.5 samples were collected from January to March 2018 in a northern Chinese city, during the winter heating and spring sandstorm seasons. The fungal community characteristics within three distinct haze and haze-dust composite pollution were examined. The concentration of fungal aerosols was found to be significantly higher in dust samples. This was evidenced by a strong positive correlation with Ca2+, temperature, and wind speed (p < 0.05). Human and animal pathogens, such as Candida, were more prevalent in haze samples. Conversely, allergens and plant pathogens, like Alternaria, were found in higher concentration in dust samples. The primary ecological function shifted from being saprophytic to becoming human-animal pathogenic or plant-animal pathogenic. This shift was observed from non-pollution, haze, to haze-dust composite pollution. The dispersion of fungal aerosols was influenced by factors such as dust events and meteorological conditions, including increased temperature and wind speed. In the spring dust episodes, dust-related pollutants, such as soil Ca2+ and PM10, accounted for 51.39% of the variation in the fungal community. This research explored the dynamics of fungal communities, potential pathogens, and factors influencing fungal communities in regional air pollution. The insights garnered from this research provide a robust foundation for subsequent human health exposure assessments.
Abstract
The formation of secondary organic aerosol (SOA) is inextricably linked to the photo-oxidation of aromatic hydrocarbons. However, models still exhibit biases in representing SOA mass and chemical composition. We implemented a box model coupled with a near-explicit photochemical mechanism, the Master Chemical Mechanism (MCMv3.3.1), to simulate a series of chamber studies and assess model biases in simulating SOA from representative monocyclic aromatic hydrocarbons, that is, toluene and three xylene isomers (TX SOA). The box model underpredicted SOA yields of toluene and xylenes by 4.7%–100%, which could be improved by adjusting the saturation vapor pressure (SVP) of their oxidation products. After updating the SVP values, the mass concentration of TX SOA in the Yangtze River Delta region during summer doubled, and there was also an approximate 3% enhancement in the total SOA. Compared to a lumped mechanism used for simulating TX SOA, MCM predicted comparable mass concentrations but exhibited different volatility distributions and oxidation states.
Software sustainability of global impact models
Emmanuel Nyenah, Petra Döll, Daniel S. Katz, and Robert Reinecke
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-97,2024
Preprint under review for GMD (discussion: open, 1 comment)
Research software is crucial for scientific progress but is often developed by scientists with limited training, time, and funding, leading to software that is hard to understand, (re)use, modify, and maintain. Our study across 10 research sectors highlights strengths in version control, open-source licensing, and documentation while emphasizing the need for containerization and code quality. Recommendations include workshops, code quality metrics, funding, and adherence to FAIR standards.
Short-term effects of hurricanes on nitrate-nitrogen runoff loading: a case study of Hurricane Ida using E3SM land model (v2.1)
Yilin Fang, Hoang Viet Tran, and L. Ruby Leung
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-70,2024
Preprint under review for GMD (discussion: open, 0 comments)
Hurricanes may worsen the water quality in the lower Mississippi River Basin (LMRB) by increasing nutrient runoff. We found that runoff parameterizations greatly affect nitrate-nitrogen runoff simulated using an Earth system land model. Our simulations predicted increased nitrogen runoff in LMRB during Hurricane Ida in 2021, but less pronounced than the observations, indicating areas for model improvement to better understand and manage nutrient runoff loss during hurricanes in the region.
Abstract
The capabilities of assimilating the all-sky Fengyun-4A Advanced Geostationary Radiation Imager (AGRI) infrared radiances (IR) are completed by including hydrometers in the observation operator, its adjoint, and tangent linear model. This allows the three-dimensional variational data assimilation model to include cloud-precipitation information from infrared IR observations. Advanced as the all-sky data assimilation methodologies are, the assimilation of cloudy scene IR radiances for tropical cyclone (TC) systems has not led to consistently better results, especially for the intensity of TCs. This work explores the effects of all-sky AGRI radiance assimilation on a Super Typhoon In-Fa (2106) during its stage experiencing abnormal changes in the intensity and the track. It is shown that the all-sky assimilation of AGRI two channels 9–10 brings no obviously better TC forecasts than the all-sky AGRI single-channel assimilation does. Besides, the O − B (observation minus background) bias was corrected to be even larger with the variational bias correction method for the pixels with relatively lower or higher cloud impact. This indicates that traditional bias correction schemes with linear fitting functions are suboptimal if the relations between the predictor and O − B biases are non-linear. When the conventional observation and IR radiances are assimilated in two steps, the wind in the inner-core region is better described to properly capture the changes in the typhoon intensity. Generally, the analyses and forecasts of Typhoon In-Fa from experiments with the all-sky IR observations are enhanced compared to those with only the clear-sky IR observations.
Abstract
Observational evidence has shown that the Earth's tropics have widened since 1980. However, climate models underestimate the observed tropical expansion rate, with a large spread among individual models. The proposal of internal variability to account for model–observation differences is hindered by the limited availability of sufficient realizations from models in the Coupled Model Intercomparison Project (CMIP), restricting the accuracy of quantitative contribution estimation. The emergence of a single model initial-condition large ensemble provides a new opportunity to quantify the role of internal variability. Here, using large-ensemble simulations from two individual models complemented with CMIP Phase 6 (CMIP6) simulations, we show evidence that the recent widening of the tropics is mainly caused by internal variability related to the Interdecadal Pacific Oscillation (IPO). The positive-to-negative phase transition of the IPO from 1980 to 2014 reduced the meridional tropospheric temperature gradient, resulting in poleward shifts in tropical edges. After adjusting the IPO trends simulated by individual realizations to ensure consistency with the observations, the IPO phase transition can account for at least 73% (66%) of the observed tropical expansion rate in the Northern Hemisphere based on the metric of the meridional stream function (surface zonal wind). The IPO is also essential for shaping tropical expansion-related precipitation changes. Our results underscore the significance of considering internal variability when explaining model–observation differences and understanding intermodel uncertainty.
Abstract
Atmospheric gravity waves (GWs) impact the circulation and variability of the atmosphere. Sub-grid scale GWs, which are too small to be resolved, are parameterized in weather and climate models. However, some models are now available at resolutions at which these waves become resolved and it is important to test whether these models do this correctly. In this study, a GW resolving run of the European Center for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS), run with a 1.4 km average grid spacing (TCo7999 resolution), is compared to observations from the Atmospheric Infrared Sounder (AIRS) instrument, on NASA's Aqua satellite, to test how well the model resolves GWs that AIRS can observe. In this analysis, nighttime data are used from the first 10 days of November 2018 over part of Asia and surrounding regions. The IFS run is resampled with AIRS's observational filter using two different methods for comparison. The ECMWF ERA5 reanalysis is also resampled as AIRS, to allow for comparison of how the high resolution IFS run resolves GWs compared to a lower resolution model that uses GW drag parametrizations. Wave properties are found in AIRS and the resampled models using a multi-dimensional S-Transform method. Orographic GWs can be seen in similar locations at similar times in all three data sets. However, wave amplitudes and momentum fluxes in the resampled IFS run are found to be significantly lower than in the observations. This could be a result of horizontal and vertical wavelengths in the IFS run being underestimated.
An evaluation of microphysics in a numerical model using Doppler velocity measured by ground-based radar for application to the EarthCARE satellite
Woosub Roh, Masaki Satoh, Yuichiro Hagihara, Hiroaki Horie, Yuichi Ohno, and Takuji Kubota
Atmos. Meas. Tech., 17, 3455–3466, https://doi.org/10.5194/amt-17-3455-2024, 2024
The advantage of the use of Doppler velocity in the categorization of the hydrometeors is that Doppler velocities suffer less impact from the attenuation of rain and wet attenuation on an antenna. The ground Cloud Profiling Radar observation of the radar reflectivity for the precipitation case is limited because of wet attenuation on an antenna. We found the main contribution to Doppler velocities is the terminal velocity of hydrometeors by analysis of simulation results.
Flood hazard mapping and disaster prevention recommendations based on detailed topographical analysis in Khovd City, Western Mongolia
Narangerel Serdyanjiv, Suzuki Yasuhiro, Hasegawa Tomonori, and Takaichi Yoshiyuki
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-91,2024
Preprint under review for NHESS (discussion: open, 0 comments)
The present study considers the hazard areas of rainfall-derived river floods and flash floods flowing into Khovd City. We consider geomorphological elements such as terrace profiles, floodplains, riverbeds, gullies and depressions to derive detailed topographical and directional hazard maps. This study results provide valuable insights for the Administration of Government and Emergency Department of Khovd to protect citizens from flood hazards.
Abstract
Strengthening aquatic resilience to prevent adverse shifts is critical for preserving global freshwater biodiversity and advancing Sustainable Development Goals. Nonetheless, understanding the long-term trends and underlying causes of lake ecosystem resilience at a global scale remains elusive. Here, we employ an innovative framework, integrating satellite-derived water quality indices with early warning signals and machine learning techniques, to investigate the dynamics of resilience in 1,049 lakes worldwide during 2000–2018. Our results indicate that 46.7% of lakes are experiencing a significant decline in resilience, particularly since the early 2010s, closely associated with higher human population density and anthropogenic eutrophication. In contrast, most lakes situated in alpine regions exhibit an increase in resilience, probably benefiting from climate warming and wetting. Together, this study provides a novel way to monitor lake resilience and predict undesired transitions, and reveals a widespread erosion in the ability of lakes to withstand stressors associated with global change.
Abstract
Variability of ice microphysical properties like crystal size and density in cirrus clouds is important for climate through its impact on radiative forcing, but challenging to represent in models. For the first time, recent laboratory experiments of particle growth (tied to crystal morphology via deposition density) are combined with a state-of-the-art Lagrangian particle-based microphysics model in large-eddy simulations to examine sources of microphysical variability in cirrus. Simulated particle size distributions compare well against balloon-borne observations. Overall, microphysical variability is dominated by variability in the particles' thermodynamic histories. However, diversity in crystal morphology notably increases spatial variability of mean particle size and density, especially at mid-levels in the cloud. Little correlation between instantaneous crystal properties and supersaturation occurs even though the modeled particle morphology is directly tied to supersaturation based on laboratory measurements. Thus, the individual thermodynamic paths of each particle, not the instantaneous conditions, control the evolution of particle properties.
Abstract
Chorus subpackets are the wave packets with modulated amplitudes in chorus waves, commonly observed in the magnetospheres of Earth and other planets. Nonlinear wave-particle interactions have been suggested to play an important role in subpacket formation, yet the corresponding electron dynamics remain not fully understood. In this study, we have investigated the electron trapping through cyclotron resonance with subpackets, using a self-consistent general curvilinear plasma simulation code simulation model in dipole fields. The electron trapping period has been quantified separately through electron dynamic analysis and theoretical derivation. Both methods indicate that the electron trapping period is shorter than the subpacket period/duration. We have further established the relation between electron trapping period and subpacket period through statistical analysis using simulation and observational data. Our study demonstrates that the nonlinear electron trapping through cyclotron resonance is the dominant mechanism responsible for subpacket formation.
Abstract
Satellite laser ranging (SLR) is a well-established geodetic technique for measuring the low-degree time-variable gravity field for decades. However, its application in mass change estimation is limited by low spatial resolution, even for global mean ocean mass (GMOM) change which represents one of the largest spatial scales. After successfully correcting for signal leakage, for the first time, we can infer realistic GMOM changes using SLR-derived gravity fields up to only degree and order 5. Our leakage-corrected SLR GMOM estimates are compared with those from the Gravity Recovery and Climate Experiment (GRACE) for the period 2005 to 2015. Our results show that the GMOM rate estimates from SLR are in remarkable agreement with those from GRACE, at 2.23 versus 2.28 mm/year, respectively. This proof-of-concept study opens the possibility of directly quantifying GMOM change using SLR data prior to the GRACE era.
Abstract
Severe space weather has the potential to cause significant socio-economic impact and it is widely accepted that mitigating this risk requires more comprehensive observations of the Sun and heliosphere, enabling more accurate forecasting of significant events with longer lead-times. In this context, it is now recognized that observations from the L5 Sun-Earth Lagrange point (both remote and in situ) would offer considerable improvements in our ability to monitor and forecast space weather. Remote sensing from L5 allows for the observation of solar features earlier than at L1, providing early monitoring of active region development, as well as tracking of interplanetary coronal mass ejections through the inner heliosphere. In situ measurements at L5 characterize the solar wind's geoeffectiveness (particularly stream interaction regions), and can also be ingested into heliospheric models, improving their performance. The Vigil space weather mission is part of the ESA Space Safety Program and will provide a real-time data stream for space weather services from L5 following its anticipated launch in the early 2030s. The interplanetary magnetic field is a key observational parameter, and here we describe the development of the Vigil magnetometer instrument for operational space weather monitoring at the L5 point. We summarize the baseline instrument capabilities, demonstrating how heritage from science missions has been leveraged to develop a low-risk, high-heritage instrument concept.
