Journal of Geophysical Research Atmospheres

Rehbein, Amanda; Ambrizzi, Tercio; Prein, Andreas F.

doi: 10.1029/2025jd045438pmid: N/A

This study investigates the mesoscale convective systems (MCSs) over South America in a future climate using two distinct modeling approaches: the Weather Research and Forecasting (WRF) regional model with dynamical downscaling and pseudoglobal warming, and the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) global cloud‐resolving model within the Coupled Model Intercomparison Project (CMIP6) High Resolution Model Intercomparison Project (HighResMIP) framework. Results are analyzed in terms of changes in MCS occurrence, precipitation contribution, maximum precipitation rates, and precipitation volume across subregions of South America. MCSs in the future climate tend to exhibit higher maximum precipitation rates and larger precipitation volumes across South America. This tendency toward MCS intensification with increasing temperatures is consistent with previous studies and represents a key aspect of future climate projections. The spatial extent of statistically significant changes is limited, indicating that robust signals common to both models are restricted to specific regions and seasons. Overall, increases in MCS occurrence and precipitation proportion are mainly projected over Northwest South America (NWS) and North South America (NSA), particularly during the austral summer (DJF). Over southern Brazil, they are projected to increase during the austral winter (JJA), suggesting that warmer temperatures may influence the winter climate at the mesoscale level over that region. In contrast, decreases in both variables are found over the South America Monsoon region (SAM), especially during the transition months from dry to wet season (SON) and wet to dry season (MAM).

Farley, Ryan N.; Gorkowski, Kyle; Lee, James E.; Benedict, Katherine B.; Shawon, Abu Sayeed Md; Franco, Nevil A.; Berta, Veronica Z.; Williams, Abigail S.; Robinson, Lauren T.; Chang, Rachel Y.‐W.; Dubey, Manvendra K.; Russell, Lynn M.; Aiken, Allison C.

doi: 10.1029/2025jd045943pmid: N/A

Anthropogenic aerosols influence marine cloud properties in coastal regions, but their impacts remain poorly understood due to the complexity of sources and aerosol‐cloud interactions. To investigate how cloud processing affects aerosol composition, in situ measurements of aerosol properties were performed at Mt. Soledad in La Jolla, CA (251 m asl, 2 km from shore) as part of the Eastern Pacific Cloud Aerosol Precipitation Experiment Partitioning Thrust by Los Alamos National Laboratory from October to December 2023. A ground‐based counterflow virtual impactor coupled with high‐resolution aerosol mass spectrometry was used to directly measure the composition of cloud droplet residuals, which were compared to out of cloud aerosols. Cloud residuals showed a large enhancement of inorganic nitrate and chloride fractions, increasing by up to a factor of 2 and 5 times relative to the out‐of‐cloud periods, respectively, with nitrate mass fraction increasing with cloud liquid water content. Through positive matrix factorization analysis, we identified a factor associated with aqueous‐phase reactions in clouds. The organic material within cloud residuals was not highly oxidized, weakly hygroscopic and showed a similar size distribution to the inorganic species, suggesting that internally mixed inorganic species related to anthropogenic emissions and aged sea salt control cloud condensation nuclei activity in this location. The increase in hygroscopic inorganic components and aerosol size during cloud events could increase the ability of particles to activate into droplets. These results help constrain the role of different aerosol sources and cloud processing in cloud‐forming potential at a coastal site.

Weber, Austin M.; Beaudon, Emilie; Sierra‐Hernández, M. Roxana; Davis, Mary; Kenny, Don; Shutkin, Tal Y.; Thompson, Lonnie G.

doi: 10.1029/2025jd045574pmid: N/A

In addition to warming and hydrological changes, glacier retreat is influenced by mineral dust and other light absorbing impurities. However, very little is known about the presence of mineral dust in the tropical Andes, making it difficult to model the radiative impact of dust on glacial surfaces. We present two 60‐year (1960–2019) ice core dust records from the col and summit of Earth's highest tropical mountain (Nevado Huascarán, Cordillera Blanca, Peru) and use the Snow, Ice, and Aerosol Radiative model (SNICAR) to investigate dust‐driven albedo changes over time. Our results show that, although dust concentrations have trended upward for several decades, mineral dust has only a marginal effect on the albedo of the high‐altitude glaciers at Huascarán. We estimate that by the end of the century, the reduction in surface albedo due to mineral dust will translate to an additional 15–70 mm w.e. of ablation on the col and 16–57 mm w.e. on the summit, or less than ∼5% of the average net accumulation rates of today.

Kolmašová, I.; Soula, S.; Santolík, O.; Defer, E.; Zhu, Y.; Pédeboy, S.; Lán, R.; Kolínská, A.; Uhlíř, L.

doi: 10.1029/2025jd045415pmid: N/A

Narrow bipolar events (NBEs) are brief intracloud discharges that generate the most intense radiation in the high frequency and very high frequency radio bands. Their occurrence is statistically correlated with strong convection and typically takes place in the upper regions of thunderclouds. This study presents the first detailed analysis of NBEs detected in Europe. Thirty‐five positive discharges, with an average peak current of 43 kA, were recorded in 2022 using broadband magnetic loop sensors at two locations in South‐Eastern France. Examination of the NBE pulse waveforms revealed that NBEs with stronger peak currents consistently exhibited narrower pulses. Similarity of pulse shapes of NBEs occurring close in time and space (within a few minutes and a few km apart) might indicate the similarity of the underlying charge structure in the thundercloud. One fourth of the studied NBEs occurred isolated not initiating a lightning flash. Most events occurred over land at the periphery of convective cores near the edges of the coldest thundercloud regions across all analyzed storms. The observed positive NBEs share characteristics with those reported on other continents. However, the severe storm conditions—especially the vertical cloud development required for their occurrence—may be less frequent in midlatitudes in Europe, resulting in a lower probability of NBE detection.

Sun, Rui; Subramanian, Aneesh C.; Wolding, Brandon O.; Hsu, Tien‐Yiao; Mazloff, Matthew R.; Cornuelle, Bruce D.; Sprintall, Janet; Miller, Arthur J.; Gopalakrishnan, Ganesh; Ag, Prajeesh; Hoteit, Ibrahim

doi: 10.1029/2025jd044185

Leguijt, Gijs; Maasakkers, Joannes D.; Denier van der Gon, Hugo A. C.; Segers, Arjo J.; Nesser, Hannah; Aben, Ilse

doi: 10.1029/2025jd044636pmid: N/A

Understanding and independently validating carbon emissions from concentrated point sources is vital to support climate policy. Satellite‐based quantifications of CO2 ${\text{CO}}_{2}$ point source emissions have been limited by the spatial coverage of current satellite instruments. We combine three different satellite instruments to determine carbon monoxide (CO) and carbon dioxide (CO2 ${\text{CO}}_{2}$) emissions of seven large cities and six industrial complexes. We first estimate CO emission rates using TROPOMI CO observations with the Cross‐Sectional Flux method. Subsequently, CO2 ${\text{CO}}_{2}$ emission rates are calculated by multiplying with the ratio of TROPOMI‐observed CO enhancements and CO2 ${\text{CO}}_{2}$ enhancements from OCO‐2 and OCO‐3, also representing the combustion efficiency. We use synthetic observations to validate our approach and show that the inclusion of TROPOMI CO observations increases the number of possible CO2 ${\text{CO}}_{2}$ emission quantifications. Using 2018–2023 observations, we find lower CO emission rates for Delhi and Lahore than the EDGAR emission inventory version 8. In contrast, our CO emission estimates exceed bottom‐up inventory estimates for most industrial sources. This is caused by observed combustion efficiencies that are generally lower than those reported in emission inventories. Our CO2 ${\text{CO}}_{2}$ emission estimates show better agreement with EDGAR than the CO emissions, especially for industrial sources. We find higher CO2 ${\text{CO}}_{2}$ emission rates than EDGAR for Delhi, Lahore, and Cairo that better agree with the ODIAC inventory. Our work shows the importance of CO as a co‐emitted species, and paves the way for a similar approach to be applied to the combination of TROPOMI, its successor Sentinel‐5, and the future CO2M satellites.

Chen, Cong; Su, Mingkun; Gao, Yang; Liu, Tianjun; Wu, Juntao; Pan, Lingsa

doi: 10.1029/2025jd045322pmid: N/A

Rainfall forecasting based on the Global Navigation Satellite System (GNSS) plays an important role in GNSS‐meteorology applications. However, traditional methods that rely on GPS‐ZTD (Zenith Total Delay) are limited by the influence of ZHD (Zenith Hydrostatic Delay), while those based on GPS‐PWV (Precipitable Water Vapor) depend heavily on external meteorological parameters. Moreover, most existing studies have not addressed the forecasting of rainfall duration. In this study, the feasibility of rainfall forecasting using GPS‐ZWD (zenith wet delay) is demonstrated through theoretical analysis and correlation assessment. A new method is proposed for forecasting light, medium, and heavy rainfall events, as well as rainfall duration, directly based on GPS‐ZWD. Data sets collected from 2010 to 2020 in Hong Kong are used to evaluate the accuracy of GPS‐ZWD and establish a forecasting threshold model, while data from 2021 to 2022 are employed to validate the proposed method. Experimental results show that (a) the correlation coefficients between GPS‐ZWD and ERA5‐ZWD, and between GPS‐ZWD and NCEP‐ZWD, are 0.99 and 0.93, respectively; (b) the true rates for light, medium, and heavy rainfall event forecasting are 83.10%, 93.25%, and 100% based on GPS‐ZWD. The average true rate is 88.28%, which is comparable to the methods based on GPS‐PWV and better than GPS‐ZTD methods; (c) for rainfall duration forecasting, the average true rates for light, medium, and heavy rainfall are 74.55%, 85.35%, and 96.29%, respectively. These results indicate that the proposed methods for rainfall event and rainfall duration forecasting based on GPS‐ZWD demonstrate strong performance and hold significant potential for advancing GNSS‐meteorology applications.

Wang, Weiqi; Feng, Juan; Miao, Yujie; Ma, Weihan; Li, Yadi; Li, Xichen

doi: 10.1029/2025jd046200pmid: N/A

The El Niño‐Southern Oscillation (ENSO) exhibits pronounced spatial diversity between its eastern Pacific (EP) and central Pacific expressions, with distinct impacts on the global atmospheric circulation, including the Hadley circulation (HC). However, the traditional zonal‐mean perspective of the HC masks the longitudinal structure of the circulation responses to different ENSO types, thereby concealing basin‐dependent overturning contrasts and their implications for HC‐subtropical jet interactions. In this study, we show that different ENSO types induce distinct three‐dimensional adjustments of the HC. During CP‐type events, Pacific HC cells exhibit a broader meridional extent with centers shifted farther west, resulting in a stronger coupling with the subtropical jet, whereas EP‐type events are characterized by a more zonally broadened HC confined near the equator. These contrasts extend beyond the Pacific basin, with Atlantic HC anomalies during CP‐type events also displaced farther westward than those associated with EP‐type events. The differing HC responses are closely linked to the distinct spatial patterns and seasonal evolution of sea surface temperature and precipitation anomalies associated with different ENSO types. Together, these findings enhance our understanding of ENSO diversity and its climatic impacts, particularly in the context of the projected increase in CP‐type events under global warming.

Zeng, Zixuan; Sun, Jianqi

doi: 10.1029/2025jd045846pmid: N/A

This study investigates the spring monthly drought variations in central‐eastern China (CEC) and the possible synergistic effects of multi‐timescale atmospheric teleconnections. During March, CEC drought conditions are jointly influenced by high‐frequency and low‐frequency variations of the Scandinavian teleconnection (SCA). When these multi‐timescale atmospheric teleconnections align in phase, a reinforced dipole atmospheric circulation anomaly (high‐pressure over Lake Balkhash and low‐pressure over Japan) causes decreased moisture and surface warming in the CEC, favoring less precipitation and more potential evapotranspiration over there and consequently causing pronounced droughts. When these atmospheric teleconnections align out of phase, the above‐mentioned dipole atmospheric circulation anomaly weakens significantly, and there is a normal condition in the CEC. In April and May, the high‐frequency drought variations are associated with both the SCA and the West Pacific teleconnection, whereas the low‐frequency variations are modulated by the SCA and the North Atlantic Oscillation. In‐phase alignment of the above‐mentioned multi‐timescale atmospheric teleconnections could amplify the dipole atmospheric circulation over Lake Balkhash and Japan, which can significantly influence the dry conditions in CEC by modulating local precipitation and evapotranspiration. In comparison, out‐of‐phase alignment cannot affect the drought conditions in the region.

Daley, H. M.; Dickerson, R. R.; Stratton, P.; He, H.; Ren, X.; Koss, A. R.; Brewer, W. A.; Baidar, S.; Hmiel, B.; Bon, D.; Pierce, G.; Weibring, P.; Richter, D.; Walega, J.; Ngulat, M. C.; Santos, A.; Hodshire, A. L.; Vaughn, T. L.; Zimmerle, D.; Fried, A.