Abstract
Sea surface winds influence shipping, fisheries, and coastal projects. However, the current sea surface wind forecast exhibits noticeable biases. This study introduces a deep learning (DL)-based bias correction model, WindNet, to improve the Global Forecast System (GFS) sea surface wind field forecast in the Northwest Pacific Ocean (NWPO). WindNet reduces the Root Mean Squared Errors (RMSEs) of wind speed at lead times of 24, 48, and 72 hr from 1.41–1.95 to 1.11–1.55 m s−1, achieving percentage reductions of 20.51%–21.28%. Simultaneously, the RMSEs of wind direction are reduced from 29.67–41.45° to 25.38–36.81°, demonstrating percentage reductions of 11.19%–14.46%. During typhoon passages, the RMSEs of wind speed and direction at three forecast lead times after using WindNet are reduced from 1.57–2.42 to 1.24–1.95 m s−1 and from 30.31–42.35° to 25.88–37.64°, demonstrating percentage reductions of 19.42%–21.02% and 11.12%–14.62%. By integrating a Squeeze-and-Excitation Network into WindNet, we find that utilizing information from the circulation field, apart from the zonal and meridional wind components at 10 m height, is crucial for the correction of the sea surface wind speed. WindNet can effectively capture the non-linear relationship between other low-level-circulation-related variables and sea surface wind speed. Therefore, WindNet remarkably enhances sea surface wind field forecast accuracy in NWPO.
Abstract
The 10–12 April 2019 thundersnow (i.e., lightning within snowfall) outbreak was examined via ground- and space-based lightning observations and was simulated using a numerical weather prediction model with an explicit electrification parameterization. When compared to observations, the simulation propagated the synoptic snowband two to six hours faster while also exaggerating the 3-D reflectivity structure. Throughout the event, the simulation produced 1,733 thundersnow flashes which was less than what was observed by ground- and space-based lightning sensors. In general, simulated thundersnow flashes were spatially offset from the largest reflectivities within the synoptic snowband and tended to occur within elevated convection that traversed isentropically along the top of mid-level frontogenesis. These simulated thundersnow flashes were associated with a tripole charge structure with ice/snow hydrometeors contributing most to the main negative charge region. Both simulated and observed thundersnow flashes initiated in conditionally unstable environments. Lastly, a conceptual model was developed to explain the spatial separation between the largest reflectivities in the snowband and the occurrence of thundersnow. It is hypothesized that the spatial offset of thundersnow initiation from the reflectivity cores within the synoptic snowband arose from a thermal circulation—induced by mid-level frontogenesis—that advects positively charged ice/snow hydrometeors toward the surface and creates a nearly homogeneous vertical charge structure.
Abstract
Ice nucleating particles (INPs) are rare particles that initiate primary ice formation, a critical step required for subsequent important cloud microphysical processes that ultimately govern cloud phase and cloud radiative properties. Laboratory studies have found that organic-rich dusts, such as those found in soils, are more efficient INPs compared to mineral dust. However, the atmospheric relevance of these organic-rich dusts are not well understood, particularly in regions with significant agricultural activity. The Agricultural Ice nuclei at the Southern Great Plains field campaign (AGINSGP) was conducted in rural Oklahoma to investigate how soil dusts contribute to INP populations in the Great Plains. We present chemical characterization of ambient and ice crystal residual particles from a single day of sampling, using single particle mass spectrometry (SPMS) and scanning microscopy. Ambient particles were primarily carbonaceous or secondary aerosol, while the fraction of dust particles was higher in the residual particles. We also observed an unusual particle type consisting of a carbonaceous core mixed with dust fragments on the surface, which was found in higher proportion in residuals. Dust particles measured during residual sampling contained greater proportions of phosphate (63PO2− ${\text{PO}}_{2}^{-}$ and 79PO3− ${\text{PO}}_{3}^{-}$) and lead (206Pb+). Strong sulfate signals were not seen in the residual dust particles measured by the SPMS, while nitrate was slightly depleted relative to ambient dust. This study shows that organic-rich soils may be important contributors to the ambient INP population in agricultural regions.
Abstract
The objectives of the current study are to carry out soil gas radon (Rn) measurements, to evaluate the total inhalation effective dose, to determine risk levels over the lithological formations of the study area. The behavior investigation of Rn activity concentration distributions in dwellings and soils, and soil Rn mapping were also conducted. Soil gas Rn measurements were made at 102 sampling points by Markus 10 instrument. This data was combined with previously reported results from 140 indoor Rn RADTRAK dosimeters to determine the total inhalation effective dose and to conduct a statistical analysis. Overall, the Rn activity concentrations in soil and dwellings range from 4 to 66 kBq m−3 and from 15 to 140 Bq m−3, with averages of 31 ± 15 kBq m−3 and 41 ± 24 Bq m−3 respectively. The corresponding total inhalation effective dose ranges from 0.35 to 3.53 mSv y−1, with a mean value of 1.37 ± 0.58 mSv y−1. For soil gas Rn, the chlorite schist lithology showed the highest average concentration level. Which could be justified by the possible presence, within chlorite minerals, highly emitting zones of alpha particles, leading to the formation of radioactive halos. Normal and high-risk level of Rn were found for about 82% and 11% of the total area surveyed respectively. These findings highlight the need for preventive measure against Rn exposure in homes within the investigated areas. This study contributes valuable insights into Rn distribution patterns and risk assessment, offering a basis for targeted interventions in the region.
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.
Colossal undersea mountains, towering up to thousands of meters high, stir up deep sea currents: impacting how our ocean stores heat and carbon.
Across Asia, the Pacific Ocean, and the Americas, El Niño Southern Oscillation (ENSO) brings variations in winds, weather, and ocean temperature that can cause droughts, floods, crop failures, and food shortages. Recently, the world has experienced a major El Niño event in 2023–2024, dramatically impacting weather, climate, ecosystems, and economies globally.
For the first time, researchers from UC San Diego's Scripps Institution of Oceanography led an international team that directly measured cold, deep water upwelling via turbulent mixing along the slope of a submarine canyon in the Atlantic Ocean.
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.
In the Earth's subduction zones, water is transported into the deep mantle by nominally anhydrous minerals (NAMs) and water-bearing minerals in oceanic plates that react with seawater. Therefore, determination of the stability field and water content of water-bearing minerals is very important for understanding the water cycle processes in the Earth's deep interior.
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.
