Abstract
Knowledge of the planetary boundary layer height (PBLH) is crucial for various applications in atmospheric and environmental sciences. Lidar measurements are frequently used to monitor the evolution of the PBLH, providing more frequent observations than traditional radiosonde-based methods. However, lidar-derived PBLH estimates have substantial uncertainties, contingent upon the retrieval algorithm used. In addressing this, we applied the Different Thermo-Dynamic Stabilities (DTDS) algorithm to establish a PBLH data set at five separate Department of Energy's Atmospheric Radiation Measurement sites across the globe. Both the PBLH methodology and the products are subject to rigorous assessments in terms of their uncertainties and constraints, juxtaposing them with other products. The DTDS-derived product consistently aligns with radiosonde PBLH estimates, with correlation coefficients exceeding 0.77 across all sites. This study delves into a detailed examination of the strengths and limitations of PBLH data sets with respect to both radiosonde-derived and other lidar-based estimates of the PBLH by exploring their respective errors and uncertainties. It is found that varying techniques and definitions can lead to diverse PBLH retrievals due to the inherent intricacy and variability of the boundary layer. Our DTDS-derived PBLH data set outperforms existing products derived from ceilometer data, offering a more precise representation of the PBLH. This extensive data set paves the way for advanced studies and an improved understanding of boundary-layer dynamics, with valuable applications in weather forecasting, climate modeling, and environmental studies.
Can TROPOMI NO2 satellite data be used to track the drop in and resurgence of NOx emissions in Germany between 2019–2021 using the multi-source plume method (MSPM)?
Enrico Dammers, Janot Tokaya, Christian Mielke, Kevin Hausmann, Debora Griffin, Chris McLinden, Henk Eskes, and Renske Timmermans
Geosci. Model Dev., 17, 4983–5007, https://doi.org/10.5194/gmd-17-4983-2024, 2024
Nitrogen dioxide (NOx) is produced by sources such as industry and traffic and is directly linked to negative impacts on health and the environment. The current construction of emission inventories to keep track of NOx emissions is slow and time-consuming. Satellite measurements provide a way to quickly and independently estimate emissions. In this study, we apply a consistent methodology to derive NOx emissions over Germany and illustrate the value of having such a method for fast projections.
Updates and evaluation of NOAA’s online-coupled air quality model version 7 (AQMv7) within the Unified Forecast System
Wei Li, Beiming Tang, Patrick C. Campbell, Youhua Tang, Barry Baker, Zachary Moon, Daniel Tong, Jianping Huang, Kai Wang, Ivanka Stajner, Raffaele Montuoro, and Robert C. Gilliam
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-107,2024
Preprint under review for GMD (discussion: open, 0 comments)
The study describes the updates of NOAA's current UFS-AQMv7 air quality forecast model by incorporating the latest scientific and structural changes in CMAQv5.4. An evaluation during August 2023 shows that the updated model greatly improves the simulation of MDA8 O3 by reducing the bias by 72 % in the contiguous US. PM2.5 prediction is only enhanced in regions less affected by wildfire, highlighting the need for future refinements.
An updated aerosol simulation in the Community Earth System Model (v2.1.3): dust and marine aerosol emissions and secondary organic aerosol formation
Yujuan Wang, Peng Zhang, Jie Li, Yaman Liu, Yanxu Zhang, Jiawei Li, and Zhiwei Han
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-109,2024
Preprint under review for GMD (discussion: open, 0 comments)
This study updates CESM's aerosol schemes, focusing on dust, marine aerosol emissions, and secondary organic aerosols (SOA) formation. Dust emission modifications make deflation areas more continuous, improving results in North America and the subarctic. Humidity correction to sea-salt emissions has a minor effect. Introducing marine organic aerosol emissions, coupled with ocean biogeochemical processes, and adding aqueous reactions for SOA formation, advance CESM's aerosol modelling results.
Abstract
For the first-time, analysis of a decade long measurement of Black Carbon mass concentration (BC) was carried out at a representative central Indo-Gangetic Plain (IGP) location, Varanasi (25.30°N, 83.03°E, 79 m asl), from 2009 to 2021 to understand its physical, optical, and radiative impacts. During the 13-year study period, the daily BC mass concentration was found to vary between 0.07 and 46.23 μg m−3 (mean 9.18 ± 6.53 μg m−3) and showed a strong inter-annual and intra-annual variations. The inter-annual variability of BC showed a significant decreasing trend (−0.47 μg m−3 yr−1), with a maximum during the post-monsoon (−1.86 μg m−3 yr−1) and minimum during the pre-monsoon season (−0.31 μg m−3 yr−1). The Black Carbon Aerosol Radiative Forcing (BC-ARF) at the top of the atmosphere (BC-ARFT), surface (BC-ARFS), and within the atmosphere (BC-ARFA) was found to be 10.3 ± 6.4, −30.1 ± 18.9, and 40.5 ± 25.2 W m−2, respectively. BC-ARF also showed a strong inter-annual variability with a decreasing trend for BC-ARFT (−0.47 W m−2 yr−1) and BC-ARFA (−1.94 W m−2 yr−1), while it showed an increasing trend for BC-ARFS (1.33 W m−2 yr−1). Concentrated weighted trajectories (CWT) and potential source contribution function (PSCF) analyses were performed at the station to determine the potential source sectors and transport routes of BC aerosols. These analyses revealed that the long-range source of BC at Varanasi originates from the upper and lower IGP, central highlands, southern peninsular region, Pakistan, and even from the Central East Asia region.
Abstract
An improved microwave gaseous absorption scheme based on statistical regression is proposed in this study. In the new scheme, Monochromatic Radiative Transfer Model (MonoRTM) replaces the Millimeter-wave Propagation Model (MPM) to train the new scheme and the effect of real Spectral Response Functions is included in the training process. After the replacement, results of the new scheme are closer to observations from Advanced Technology Microwave Sounder (ATMS) onboard Suomi National Polar-orbiting Partnership satellite in low level channels while MPM has some advantages in upper level channels. Introducing ozone absorption can cause a systematic bias but results in small standard deviations in channels with frequency 183 ± 1.8 GHz and 183 ± 1 GHz. In addition, the new scheme updates the vertical interpolation of water vapor and optimizes the vertical distribution of Planck function. These updates can reduce biases caused by vertical interpolation, especially for water vapor absorption channels. The bias associated to vertical interpolation can reach 0.25 K whereas the new scheme can decrease it to 0.003 K. To further validate the accuracy of the new scheme, we apply the new scheme to Advanced Radiative transfer Modeling System and compare simulated results to RTTOV 13.2 under 37 and 137 level (L) atmosphere (atm). Observations from ATMS onboard NOAA-20 are used as true values. Results show that the new scheme agrees with RTTOV 13.2 well in accuracy and performs even better in upper level channels and water vapor absorption channels.
Abstract
Urbanization alters land surface properties in absorbing, reflecting and emitting radiation as well as infiltrating, evaporating and storing water. This consequently modifies surface energy and water fluxes and, thus, urban climates. Weak synoptic flow, clear sky conditions and higher surface temperatures in cities compared to their rural surroundings create a buoyancy-driven atmospheric circulation, in which surface energy fluxes become the main determinants of urban daytime overheating. Here, we demonstrate the role of surface energy fluxes for warming and cooling processes in the urban canopy layer under buoyancy-driven atmospheric conditions. We improve and apply an integrated CFD-GIS modeling approach to provide a detailed analysis of fine-scale land-atmosphere interactions and assess the surfaces' profound implications on energy and water exchange. We show that variations in the ratios of the surface energy fluxes to the net radiation can be separated from meteorological conditions (wind speed, air temperature and incoming solar radiation) and emissivity values, varying explicitly with changes in land surface type and water availability for vegetated areas. Based on the energy flux ratios, we introduce an approach to assess the surface-induced warming and cooling effect and its contribution to urban overheating in the urban canopy layer, under buoyancy-driven atmospheric conditions, directly applicable to strategic urban planning for climate change adaptation. Independent of meteorological conditions, this approach can be used to evaluate different surface materials (both natural and artificial) and climate adaptation measures, such as urban nature-based solutions and blue-green infrastructures, and to monitor changes in the energy and water balance.
Abstract
The impact of latitudinal variations in the Intertropical Convergence Zone (ITCZ) on northern Andean hydroclimate during the Medieval Climate Anomaly (MCA; 950–1,150 CE) and Little Ice Age (LIA; 1,300–1,850 CE) is uncertain. Synthesis of two new lacustrine paleoclimate records from the Eastern Colombian Andes with existing circum-Andean records shows that effective moisture anomalies were synchronous and in phase across the tropical Andes during the last millennium. During the MCA, when the ITCZ was shifted northward, topographically controlled responses in the northern Andes to vigorous atmospheric convection resulted in low precipitation and high evaporation, while precipitation was also reduced in the southern tropical Andes. During the LIA, precipitation decreased in the northern Andes as the ITCZ migrated southward but was offset by cooling that lowered evaporation, establishing high effective moisture. In the southern tropical Andes, the southward ITCZ position simultaneously strengthened precipitation, increasing effective moisture. MCA-like responses to continued warming trends could similarly reduce northern Andean precipitation while increasing evaporation, thereby lowering effective moisture and possibly reducing water resource availability.
No abstract is available for this article.
Long-term evaluation of commercial air quality sensors: an overview from the QUANT (Quantification of Utility of Atmospheric Network Technologies) study
Sebastian Diez, Stuart Lacy, Hugh Coe, Josefina Urquiza, Max Priestman, Michael Flynn, Nicholas Marsden, Nicholas A. Martin, Stefan Gillott, Thomas Bannan, and Pete M. Edwards
Atmos. Meas. Tech., 17, 3809–3827, https://doi.org/10.5194/amt-17-3809-2024, 2024
In this paper we present an overview of the QUANT project, which to our knowledge is one of the largest evaluations of commercial sensors to date. The objective was to evaluate the performance of a range of commercial products and also to nourish the different applications in which these technologies can offer relevant information.
Abstract
Before large volumes of crystal poor rhyolites are mobilized as melt, they are extracted through the reduction of pore space within their corresponding crystal matrix (compaction). Petrological and mechanical models suggest that a significant fraction of this process occurs at intermediate melt fractions (ca. 0.3–0.6). The timescales associated with such extraction processes have important ramifications for volcanic hazards. However, it remains unclear how melt is redistributed at the grain-scale and whether using continuum scale models for compaction is suitable to estimate extraction timescales at these melt fractions. To explore these issues, we develop and apply a two-phase continuum model of compaction to two suites of analog phase separation experiments—one conducted at low and the other at high temperatures, T, and pressures, P. We characterize the ability of the crystal matrix to resist porosity change using parameterizations of granular phenomena and find that repacking explains both data sets well. A transition between compaction by repacking to melt-enhanced grain boundary diffusion-controlled creep near the maximum packing fraction of the mush may explain the difference in compaction rates inferred from high T + P experiments and measured in previous deformation experiments. When upscaling results to magmatic systems at intermediate melt fractions, repacking may provide an efficient mechanism to redistribute melt. Finally, outside nearly instantaneous force chain disruption events occasionally recorded in the low T + P experiments, melt loss is continuous, and two-phase dynamics can be solved at the continuum scale with an effective matrix viscosity.
Abstract
The Hengill volcano and its associated geothermal fields represent Iceland's most productive harnessed high-temperature geothermal fields, where resources are fueled by cooling magmatic intrusions connected to three volcanic systems. The crustal structure in this area is highly heterogeneous and shaped by the intricate interplay between tectonic forces and magmatic/hydrothermal activities. This complexity makes detailed subsurface characterization challenging. In this study, we aim to push the current resolution limits using a 500-node temporary seismic array and perform an isotropic and, for the first time, radially-anisotropic velocity model of the area. The high-resolution isotropic velocity model reveals the characteristic N30ºE fissure swarm that crosses the area within the top 500 m and outlines a deep-seated low-velocity body composed of cooling magmatic intrusions at 5 km depth. This deeper body is located near the eastern part of the three volcanic centers and connected to a shallower body at 2–3 km depth that strikes westward toward Hengill volcano. Additionally, our study discovered that non-induced earthquakes deeper than 2 km align with velocity contrasts that reflect structural variability, indicating the potential to identify deep permeable pathways using dense array imaging. The anisotropic model indicates that the shallow crust of Hengill within the top 2 km is dominated by vertical fractures or cracks, likely attributed to overall divergent deformation from rifting in the study area. This characteristic is diminished at depths greater than 2–3 km, replaced by a layering pattern where the lava flows and/or subhorizontal intrusions become the primary factors influencing the observed anisotropy.
No abstract is available for this article.
Abstract
Subglacial lakes have been mapped across Antarctica with two methods, radio-echo sounding (RES) and ice-surface deformation. At sites where both are coincident, these methods typically provide conflicting interpretations about the ice-bed interface. With a single exception, active subglacial lakes identified by surface deformation do not display the expected flat, bright, and specular bed reflection in RES data, characteristic of non-active lakes. This observational conundrum suggests that our understanding of Antarctic subglacial hydrology, especially beneath important fast-moving ice streams, remains incomplete. Here, we use an airborne RES campaign that surveyed a well-characterized group of active subglacial lakes on lower Mercer and Whillans ice streams, West Antarctica, to explore inconsistency between the two observational techniques. We test hypotheses of increased scattering and attenuation due to the presence of an active subglacial lake system that could suppress reflected bed-echo power for RES observations in these locations, finding that entrained water is most plausible.
Abstract
The influence of bioturbation induced by bottom-dwelling macrozoobenthos on nitrogen dynamics in lotic stream sediments remains unclear. In this work, we advance the understanding of faunal bioturbation in lotic environments by developing a fully-coupled flow and multicomponent reactive transport model and investigate the influence of sediment reworking and burrow ventilation processes on nitrogenous transformations. The model results indicate that sediment reworking and burrow ventilation significantly increase nitrate (NO3
−) influx, penetration depth, and reaction rates in the streambed. Denitrification rates were observed up to three times higher in beds with U-shaped burrows compared to flatbeds. The ratio of mound height to stream water depth ratio (h/H
0) is a dominant control on determining the relative importance of the sediment reworking and burrow ventilation processes in modulating nitrogenous reactions. A power-law scaling framework is ultimately proposed to predict NO3
− removal efficiency based on the Damköhler number in bioturbated lotic streambeds.
No abstract is available for this article.
A quest for precipitation attractors in weather radar archives
Loris Foresti, Bernat Puigdomènech Treserras, Daniele Nerini, Aitor Atencia, Marco Gabella, Ioannis V. Sideris, Urs Germann, and Isztar Zawadzki
Nonlin. Processes Geophys., 31, 259–286, https://doi.org/10.5194/npg-31-259-2024, 2024
We compared two ways of defining the phase space of low-dimensional attractors describing the evolution of radar precipitation fields. The first defines the phase space by the domain-scale statistics of precipitation fields, such as their mean, spatial and temporal correlations. The second uses principal component analysis to account for the spatial distribution of precipitation. To represent different climates, radar archives over the United States and the Swiss Alpine region were used.
On the relationship between the mesospheric sodium layer and the meteoric input function
Yanlin Li, Tai-Yin Huang, Julio Urbina, Fabio Vargas, and Wuhu Feng
Ann. Geophys., 42, 285–299, https://doi.org/10.5194/angeo-42-285-2024, 2024
This work combines lidar observation data and a new numerical sodium (Na) chemistry model, using data assimilation to study the relation between the mesospheric Na layer and the meteoric input function. Simulation captures the seasonal variability in the Na number density compared with lidar observations over the Colorado State University (CSU) lidar. The estimated global ablated meteoroid material inputs from Andes Lidar Observatory and CSU observations are 83 t d-1 and 53 t d-1, respectively.
Abstract
Electron density irregularities in the ionosphere can give rise to scintillations, affecting radio wave phase and amplitude. While scintillations in the cusp and polar cap regions are commonly associated with mesoscale density inhomogeneities and/or shearing, the auroral regions exhibit a strong correlation between scintillation and density structures generated by electron precipitation (arcs). We aim to examine the impact of electron precipitation on the formation of scintillation-producing density structures using a high-resolution physics-based plasma model, the “Geospace Environment Model of Ion-Neutral Interactions,” coupled with a radio propagation model, the “Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere.” Specifically, we explore the effects of varying spatial and temporal characteristics of the precipitation, including electron total energy flux and their characteristic energies, obtained from the all-sky-imagers and Poker Flat Incoherent Scatter Radar observations, on auroral scintillation. To capture small-scale structures, we incorporate a power-law turbulence spectrum that induces short wavelength features sensitive to scintillation. Finally, we compare our simulated scintillation results with satellite-observed scintillations, along with spectral comparisons.
Abstract
Different from power line harmonic radiation (PLHR) events at high harmonics (∼kHz) in the ionosphere and inner magnetosphere, the wave dynamics of power line emission (PLE) (the fundamental frequency 50/60 Hz or PLHR at low harmonics) can be significantly affected by various ion species. In order to investigate the evolution of the wave properties of PLE from power lines to satellite altitudes in a dipole field, a numerical model is developed to perform full-wave simulations, in which the lithosphere and atmosphere are characterized by electrical conductivity and the ionosphere (inner magnetosphere) is treated as collisional (collisionless) cold plasma consisting of electron, H+, He+, O+, and NO+. Our simulation results show that the spatial distribution and wave properties of PLE are determined by the magnetic latitudes of power lines and plasma densities. PLE from power lines at middle and high magnetic latitudes (|MLAT| > 40°) can propagate to high L shells as whistler waves; PLE from power lines at |MLAT| < 30° usually propagate at low L shells below local He+ cyclotron frequency as left-handedly polarized or right-handedly He+ band electromagnetic ion cyclotron (EMIC) waves. The amplitude of PLE is usually stronger with smaller electron density in the space plasma medium. With power lines at |MLAT| < 30°, the coupling efficiency between different right-handedly polarized EMIC wave modes of PLE decreases significantly with electron density. Wave properties of PLE including Poynting vector direction, wave normal angle and wave polarization obtained from our simulation results are consistent with some of the recent observations using Van Allen Probes.
