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    Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Transmission Spectroscopy
    (AAS, 2024-05-23) Kuzuhara, Masayuki; Fukui, Akihiko; Livingston, John H.; Caballero, José A.; Leon, Jerome P. de; Hirano, Teruyuki; Kasagi, Yui; Murgas, Felipe; Narita, Norio; Omiya, Masashi; Orell-Miquel, Jaume; Palle, Enric; Changeat, Quentin; Esparza-Borges, Emma; Harakawa, Hiroki; Hellier, Coel; Hori, Yasunori; Ikuta, Kai; Ishikawa, Hiroyuki Tako; Kodama, Takanori; Kotani, Takayuki; Kudo, Tomoyuki; Morales, Juan C.; Mori, Mayuko; Nagel, Evangelos; Parviainen, Hannu; Perdelwitz, Volker; Reiners, Ansgar; Ribas, Ignasi; Sanz-Forcada, Jorge; Sato, Bun’ei; Schweitzer, Andreas; Tabernero, Hugo M.; Takarada, Takuya; Uyama, Taichi; Watanabe, Noriharu; Zechmeister, Mathias; García, Néstor Abreu; Aoki, Wako; Beichman, Charles; Béjar, Víctor J. S.; Brandt, Timothy D.; Calatayud-Borras, Yéssica; Carleo, Ilaria; Charbonneau, David; Collins, Karen A.; Currie, Thayne; Doty, John P.; Dreizler, Stefan; Fernández-Rodríguez, Gareb; Fukuda, Izuru; Galán, Daniel; Geraldía-González, Samuel; González-Rodríguez, Josafat; Hayashi, Yuya; Hedges, Christina; Henning, Thomas; Hodapp, Klaus; Ikoma, Masahiro; Isogai, Keisuke; Jacobson, Shane; Janson, Markus; Jenkins, Jon M.; Kagetani, Taiki; Kambe, Eiji; Kawai, Yugo; Kawauchi, Kiyoe; Kokubo, Eiichiro; Konishi, Mihoko; Korth, Judith; Krishnamurthy, Vigneshwaran; Kurokawa, Takashi; Kusakabe, Nobuhiko; Kwon, Jungmi; Laza-Ramos, Andrés; Libotte, Florence; Luque, Rafael; Madrigal-Aguado, Alberto; Matsumoto, Yuji; Mawet, Dimitri; McElwain, Michael W.; Gallardo, Pedro Pablo Meni; Morello, Giuseppe; Torres, Sara Muñoz; Nishikawa, Jun; Nugroho, Stevanus K.; Ogihara, Masahiro; Peláez-Torres, Alberto; Rapetti, David; Sánchez-Benavente, Manuel; Schlecker, Martin; Seager, Sara; Serabyn, Eugene; Serizawa, Takuma; Stangret, Monika; Takahashi, Aoi; Teng, Huan-Yu; Tamura, Motohide; Terada, Yuka; Ueda, Akitoshi; Usuda, Tomonori; Vanderspek, Roland; Vievard, Sébastien; Watanabe, David; Winn, Joshua N.; Osorio, Maria Rosa Zapatero
    Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (P orb) of 12.76 days. The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous P orb from TESS data. We confirmed the transit signal and P orb using ground-based photometry with MuSCAT2 and MuSCAT3, and validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host star is inactive, with an X-ray-to-bolometric luminosity ratio of log Lₓ / L bol ≈ -5.7. Joint analysis of the light curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕, a 3σ mass upper limit of 3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric (TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
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    Sex-specific mechanisms underlie long-term potentiation at hippocampus-medium spiny neuron synapses in the medial shell of the nucleus accumbens
    (Society for Neuroscience, 2024-05-24) Copenhaver, Ashley E.; LeGates, Tara
    Sex differences have complicated our understanding of the neurobiological basis of many behaviors that are key for survival. As such, continued elucidation of the similarities and differences between sexes is necessary to gain insight into brain function and vulnerability. The connection between the hippocampus (Hipp) and nucleus accumbens (NAc) is a crucial site where modulation of neuronal activity mediates reward-related behavior. Our previous work demonstrated that long-term potentiation (LTP) of Hipp→NAc synapses is rewarding, and mice can establish learned associations between LTP of these synapses and the contextual environment in which LTP occurred. Here, we investigated sex differences in the mechanisms underlying Hipp→NAc LTP using whole-cell electrophysiology and pharmacology. We observed similarities in basal synaptic strength between males and females and found that LTP occurs postsynaptically with similar magnitudes in both sexes. However, key sex differences emerged as LTP in males required NMDA receptors (NMDAR) whereas LTP in females utilized an NMDAR-independent mechanism involving L-type voltage-gated Ca²⁺ channels (VGCC) and estrogen receptor α (ERα). We also uncovered sex-similar features as LTP in both sexes depended on CaMKII activity and occurred independently of dopamine-1 receptor (D1R) activation. Our results have elucidated sex-specific molecular mechanisms for LTP in an integral pathway that mediates reward-related behaviors, emphasizing the importance of considering sex as a variable in mechanistic studies. Continued characterization of sex-specific mechanisms underlying plasticity will offer novel insight into the neurophysiological basis of behavior, with significant implications for understanding how diverse processes mediate behavior and contribute to vulnerability to developing psychiatric disorders. Significance statement Strengthening of hippocampus-nucleus accumbens (Hipp-NAc) synapses drives reward-related behaviors. Long-term potentiation (LTP) occurs with a similar magnitude in males and females, and both sexes have a predicted postsynaptic locus of plasticity. Despite these similarities, here we illustrate that sex-specific molecular mechanisms underlie LTP at Hipp-NAc synapses. Given the bidirectional relationship between Hipp-NAc synaptic strength in mediating reward-related behaviors, the use of distinct molecular mechanisms may explain sex differences observed in stress susceptibility or response to rewarding stimuli. Uncovering these latent sex differences offers a deeper understanding of the sex-specific function of this behaviorally-relevant synapse with widespread implications for circuits that underlie learning and reward-related behavior.
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    PropBank-Powered Data Creation: Utilizing Sense-Role Labelling to Generate Disaster Scenario Data
    (ACL, 2024-05-21) Shichman, Mollie Frances; Bonial, Claire; Hudson, Taylor A.; Blodgett, Austin; Ferraro, Francis; Rudinger, Rachel
    For human-robot dialogue in a search-and-rescue scenario, a strong knowledge of the conditions and objects a robot will face is essential for effective interpretation of natural language instructions. In order to utilize the power of large language models without overwhelming the limited storage capacity of a robot, we propose PropBank-Powered Data Creation. PropBank-Powered Data Creation is an expert-in-the-loop data generation pipeline which creates training data for disaster-specific language models. We leverage semantic role labeling and Rich Event Ontology resources to efficiently develop seed sentences for fine-tuning a smaller, targeted model that could operate onboard a robot for disaster relief. We developed 32 sentence templates, which we used to make 2 seed datasets of 175 instructions for earthquake search and rescue and train derailment response. We further leverage our seed datasets as evaluation data to test our baseline fine-tuned models.
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    Rethinking Latency-Aware DNN Design With GPU Tail Effect Analysis
    (IEEE, 2024-05-22) Yu, Fuxun; Xu, Zirui; Shangguan, Longfei; Wang, Di; Stamoulis, Dimitrios; Madhok, Rishi; Karianakis, Nikolaos; Li, Ang; Liu, ChenChen; Chen, Yiran; Chen, Xiang
    As the size of Deep Neural Networks (DNNs) continues to grow, their runtime latency also scales. While model pruning and Neural Architecture Search (NAS) can effectively reduce the computation workload, their effectiveness fails to consistently translate into runtime latency reduction. In this paper, we identify the root cause behind the mismatch between workload reduction and latency reduction is GPU tail effect – a classic system issue caused by resource under-utilization in the last processing wave of the GPU. We conduct detailed DNN workload characterization and demonstrate the prevalence of GPU tail effect across different DNN architectures, and meanwhile reveal that the unique deep structure and the light-weight layer workload of DNNs exacerbate the tail effect for DNN inference. We then propose a tail-awareness design space enhancement and DNN optimization algorithm to optimize existing NAS and pruning designs and achieve better runtime latency and model accuracy performance. Extensive experiments show 11%-27% latency reduction over SOTA DNN pruning and NAS methods.
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    Assimilated ozone from EOS-Aura: Evaluation of the tropopause region and tropospheric columns
    (AGU, 2008-05-29) Stajner, Ivanka; Wargan, Krzysztof; Pawson, Steven; Hayashi, Hiroo; Chang, Lang-Ping; Hudman, Rynda C.; Froidevaux, Lucien; Livesey, Nathaniel; Levelt, Pieternel F.; Thompson, Anne M.; Tarasick, David W.; Stübi, René; Andersen, Signe Bech; Yela, Margarita; König-Langlo, Gert; Schmidlin, F. J.; Witte, Jacquelyn C.
    Retrievals from the Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) on EOS-Aura were included in the Goddard Earth Observing System version 4 (GEOS-4) ozone data assimilation system. The distribution and daily to seasonal evolution of ozone in the stratosphere and troposphere during 2005 are investigated. In the lower stratosphere, where dynamical processes dominate, comparisons with independent ozonesonde and Measurement of Ozone and Water Vapour by Airbus In-Service Aircraft (MOZAIC) data indicate mean agreement within 10%. In the troposphere, OMI and MLS provide constraints on the ozone column, but the ozone profile shape results from the parameterized ozone chemistry and the resolved and parameterized transport. Assimilation of OMI and MLS data improves tropospheric column estimates in the Atlantic region but leads to an overestimation in the tropical Pacific and an underestimation in the northern high and middle latitudes in winter and spring. Transport and data biases are considered in order to understand these discrepancies. Comparisons of assimilated tropospheric ozone columns with ozonesonde data reveal root-mean-square (RMS) differences of 2.9–7.2 Dobson units (DU), which are smaller than the model-sonde RMS differences of 3.2–8.7 DU. Four different definitions of the tropopause using temperature lapse rate, potential vorticity (PV), and isentropic surfaces or ozone isosurfaces are compared with respect to their global impact on the estimated tropospheric ozone column. The largest sensitivity in the tropospheric ozone column is found near the subtropical jet, where the ozone- or PV-determined tropopause typically lies below the lapse rate tropopause.
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    Grounding Stylistic Domain Generalization with Quantitative Domain Shift Measures and Synthetic Scene Images
    (2024-05-24) Luo, Yiran; Feinglass, Joshua; Gokhale, Tejas; Lee, Kuan-Cheng; Baral, Chitta; Yang, Yezhou
    Domain Generalization (DG) is a challenging task in machine learning that requires a coherent ability to comprehend shifts across various domains through extraction of domain-invariant features. DG performance is typically evaluated by performing image classification in domains of various image styles. However, current methodology lacks quantitative understanding about shifts in stylistic domain, and relies on a vast amount of pre-training data, such as ImageNet1K, which are predominantly in photorealistic style with weakly supervised class labels. Such a data-driven practice could potentially result in spurious correlation and inflated performance on DG benchmarks. In this paper, we introduce a new 3-part DG paradigm to address these risks. We first introduce two new quantitative measures ICV and IDD to describe domain shifts in terms of consistency of classes within one domain and similarity between two stylistic domains. We then present SuperMarioDomains (SMD), a novel synthetic multi-domain dataset sampled from video game scenes with more consistent classes and sufficient dissimilarity compared to ImageNet1K. We demonstrate our DG method SMOS. SMOS uses SMD to first train a precursor model, which is then used to ground the training on a DG benchmark. We observe that SMOS+SMD altogether contributes to stateof-the-art performance across five DG benchmarks, gaining large improvements to performances on abstract domains along with on-par or slight improvements to those on photo-realistic domains. Our qualitative analysis suggests that these improvements can be attributed to reduced distributional divergence between originally distant domains. Our data are available at https://github.com/ fpsluozi/SMD-SMOS .
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    Trans-Pacific transport of reactive nitrogen and ozone to Canada during spring
    (EGU, 2010-09-07) Walker, T. W.; Martin, R. V.; van Donkelaar, A.; Leaitch, W. R.; MacDonald, A. M.; Anlauf, K. G.; Cohen, R. C.; Bertram, T. H.; Huey, L. G.; Avery, M. A.; Weinheimer, A. J.; Flocke, F. M.; Tarasick, D. W.; Thompson, Anne M.; Streets, D. G.; Liu, X.
    We interpret observations from the Intercontinental Chemical Transport Experiment, Phase B (INTEX-B) in spring 2006 using a global chemical transport model (GEOS-Chem) to evaluate sensitivities of the free troposphere above the North Pacific Ocean and North America to Asian anthropogenic emissions. We develop a method to use satellite observations of tropospheric NO₂ columns to provide timely estimates of trends in NOx emissions. NOx emissions increased by 33% for China and 29% for East Asia from 2003 to 2006. We examine measurements from three aircraft platforms from the INTEX-B campaign, including a Canadian Cessna taking vertical profiles of ozone near Whistler Peak. The contribution to the mean simulated ozone profiles over Whistler below 5.5 km is at least 7.2 ppbv for Asian anthropogenic emissions and at least 3.5 ppbv for global lightning NOx emissions. Tropospheric ozone columns from OMI exhibit a broad Asian outflow plume across the Pacific, which is reproduced by simulation. Mean modelled sensitivities of Pacific (30° N–60° N) tropospheric ozone columns are at least 4.6 DU for Asian anthropogenic emissions and at least 3.3 DU for lightning, as determined by simulations excluding either source. Enhancements of ozone over Canada from Asian anthropogenic emissions reflect a combination of trans-Pacific transport of ozone produced over Asia, and ozone produced in the eastern Pacific through decomposition of peroxyacetyl nitrates (PANs). A sensitivity study decoupling PANs globally from the model's chemical mechanism establishes that PANs increase ozone production by removing NOx from regions of low ozone production efficiency (OPE) and injecting it into regions with higher OPE, resulting in a global increase in ozone production by 2% in spring 2006. PANs contribute up to 4 ppbv to surface springtime ozone concentrations in western Canada. Ozone production due to PAN transport is greatest in the eastern Pacific; commonly occurring transport patterns advect this ozone northeastward into Canada. Transport events observed by the aircraft confirm that polluted airmasses were advected in this way.
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    Convective distribution of tropospheric ozone and tracers in the Central American ITCZ region: Evidence from observations during TC4
    (AGU, 2010-10-13) Avery, Melody; Twohy, Cynthia; McCabe, David; Joiner, Joanna; Severance, Kurt; Atlas, Eliot; Blake, Donald; Bui, T. P.; Crounse, John; Dibb, Jack; Diskin, Glenn; Lawson, Paul; McGill, Matthew; Rogers, David; Sachse, Glen; Scheuer, Eric; Thompson, Anne M.; Trepte, Charles; Wennberg, Paul; Ziemke, Jerald
    During the Tropical Composition, Clouds and Climate Coupling (TC4) experiment that occurred in July and August of 2007, extensive sampling of active convection in the ITCZ region near Central America was performed from multiple aircraft and satellite sensors. As part of a sampling strategy designed to study cloud processes, the NASA ER-2, WB-57 and DC-8 flew in stacked “racetrack patterns” in convective cells. On July 24, 2007, the ER-2 and DC-8 probed an actively developing storm and the DC-8 was hit by lightning. Case studies of this flight, and of convective outflow on August 5, 2007 reveal a significant anti-correlation between ozone and condensed cloud water content. With little variability in the boundary layer and a vertical gradient, low ozone in the upper troposphere indicates convective transport. Because of the large spatial and temporal variability in surface CO and other pollutants in this region, low ozone is a better convective indicator. Lower tropospheric tracers methyl hydrogen peroxide, total organic bromine and calcium substantiate the ozone results. OMI measurements of mean upper tropospheric ozone near convection show lower ozone in convective outflow. A mass balance estimation of the amount of convective turnover below the tropical tropopause transition layer (TTL) is 50%, with an altitude of maximum convective outflow located between 10 and 11 km, 4 km below the cirrus anvil tops. It appears that convective lofting in this region of the ITCZ is either a two-stage or a rapid mixing process, because undiluted boundary layer air is never sampled in the convective outflow.
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    High-resolution tropospheric ozone fields for INTEX and ARCTAS from IONS ozonesondes
    (AGU, 2010-10-19) Tarasick, D. W.; Jin, J. J.; Fioletov, V. E.; Liu, G.; Thompson, Anne M.; Oltmans, S. J.; Liu, J.; Sioris, C. E.; Liu, X.; Cooper, O. R.; Dann, T.; Thouret, V.
    The IONS-04, IONS-06, and ARC-IONS ozone sounding campaigns over North America in 2004, 2006, and 2008 obtained approximately 1400 profiles, in five series of coordinated and closely spaced (typically daily) launches. Although this coverage is unprecedented, it is still somewhat sparse in its geographical spacing. Here we use forward and back trajectory calculations for each sounding to map ozone measurements to a number of other locations and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Comparisons with MOZAIC profiles and surface station data show generally good agreement. A variable-length smoothing algorithm is used to fill data gaps: for each point on the map, the smoothing radius is such that a minimum of 10 data points are included in the average. The total tropospheric ozone column maps calculated by integrating the smoothed fields agree well with similar maps derived from TOMS and OMI/MLS measurements. The resulting three-dimensional picture of the tropospheric ozone field for the INTEX and ARCTAS periods facilitates visualization and comparison of different years and seasons and will be useful to other researchers.
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    Convective and wave signatures in ozone profiles over the equatorial Americas: Views from TC4 2007 and SHADOZ
    (AGU, 2010-11-06) Thompson, Anne M.; MacFarlane, Alaina M.; Morris, Gary A.; Yorks, John E.; Miller, Sonya K.; Taubman, Brett F.; Verver, Gé; Vömel, Holger; Avery, Melody A.; Hair, Johnathan W.; Diskin, Glenn S.; Browell, Edward V.; Canossa, Jéssica Valverde; Kucsera, Tom L.; Klich, Christopher A.; Hlavka, Dennis L.
    During the TC4 (Tropical Composition, Clouds, and Climate Coupling) campaign in July–August 2007, daily ozonesondes were launched over coastal Las Tablas, Panamá (7.8°N, 80°W) and several times per week at Alajuela, Costa Rica (10°N, 84°W). Wave activity, detected most prominently in 100–300 m thick ozone laminae in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves (GW, possibly Kelvin waves) by laminar identification, occur with similar structure and frequency over the Paramaribo (5.8°N, 55°W) and San Cristóbal (0.92°S, 90°W) Southern Hemisphere Additional Ozonesondes (SHADOZ) sites. GW-labeled laminae in individual soundings correspond to cloud outflow as indicated by DC-8 tracers and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi-horizontal displacements, referred to as Rossby waves by the laminar technique, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extratropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999–2007 Paramaribo and San Cristóbal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated waves appear to dominate ozone transport in the tropical tropopause layer; intrusions from the extratropics occur throughout the free troposphere.
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    Impact of electric and clean-fuel vehicles on future PM₂.₅ and ozone pollution over Delhi
    (IOP, 2024) Mogno, Caterina; Wallington, Timothy J.; Palmer, Paul; Hakkim, Haseeb; Sinha, Baerbel; Sinha, Vinayak; Steiner, Allison; Sharma, Sumit
    We investigate the impact of adoption of electric vehicles and cleaner fuels on future surface levels of PM₂.₅ and ozone over Delhi for two contrasting seasons, pre-monsoon and post-monsoon. We run the WRF-Chem atmospheric transport model at high resolution (4 km) with two transport emission scenarios for year 2030: 1) a scenario with electrification of two- and three-wheelers and light commercial vehicles, and 2) a scenario which also includes conversion of diesel vehicles to compressed natural gas (CNG). Compared to the baseline values in 2019, the scenario with both electrification and conversion of diesel vehicles to CNG has a greater reduction in PM₂.₅ concentrations (up to 5%) than the electrification of two- and three-wheelers and light commercial vehicles alone (within 1%), mainly due to the the greater reduction in primary emissions of PM₂.₅ and black carbon from diesel conversion to CNG. Vehicles electrification could result in an increase in the daily maximum 8-hours ozone concentrations, which are partially offset by additionally converting to CNG - by -1.9% and +2.4% during pre-monsoon and post-monsoon seasons. This reflects higher NOx emissions from the CNG vehicle scenario compared to electrification-alone scenario, which limits the increase of surface ozone in the VOC-limited chemical environment over Delhi. Our findings highlight the importance of a coordinated strategy for PM₂.₅ and ozone when considering traffic emission controls, and highlight that the transition to electric vehicles should be accompanied by the conversion of diesel vehicles to CNG to limit surface ozone increase and achieve greater reduction in PM₂.₅ concentrations over Delhi. However, the small changes in PM₂.₅ and in ozone compared to the baseline scenario highlight the importance of joint emissions reduction from other sectors to achieve substantial progress in PM₂.₅ and ozone air quality in Delhi.
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    Technical Note: Ozonesonde climatology between 1995 and 2011: description, evaluation and applications
    (EGU, 2012-08-17) Tilmes, S.; Lamarque, J.-F.; Emmons, L. K.; Conley, A.; Schultz, M. G.; Saunois, M.; Thouret, V.; Thompson, Anne M.; Oltmans, S. J.; Johnson, B.; Tarasick, D.
    An ozone climatology based on ozonesonde measurements taken over the last 17 yr has been constructed for model evaluation and comparisons to other observations. Vertical ozone profiles for 42 stations around the globe have been compiled for the period 1995–2011, in pressure and tropopause-referenced altitudes. For each profile, the mean, standard deviation, median, the half-width are provided, as well as information about interannual variability. Regional aggregates are formed in combining stations with similar ozone characteristics. The Hellinger distance is introduced as a new diagnostic to identify stations that describe similar shapes of ozone probability distribution functions (PDFs). In this way, 12 regions were selected covering at least 2 stations and the variability among those stations is discussed. Significant variability with longitude of ozone distributions in the troposphere and lower stratosphere in the northern mid- and high latitudes is found. The representativeness of regional aggregates is discussed for high northern latitudes, Western Europe, Eastern US, and Japan, using independent observations from surface stations and MOZAIC aircraft data. Good agreement exists between ozonesondes and aircraft observations in the mid-troposphere and between ozonesondes and surface observations for Western Europe. For Eastern US and high northern latitudes, surface ozone values from ozonesondes are biased 10 ppb high compared to independent measurements. An application of the climatology is presented using the NCAR CAM-Chem model. The climatology allows evaluation of the model performance regarding ozone averages, seasonality, interannual variability, and the shape of ozone distributions. The new assessment of the key features of ozone distributions gives deeper insights into the performance of models.
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    Look Angle Correction for SMAP L-Band Radiometer Using Geolocation Measurements
    (IEEE, 2024-05-29) Le Vine, David M.; Dinnat, Emmanuel P.; De Matthaeis, Paolo; Peng, Jinzheng
    Geolocation of the radiometer footprint in scanning instruments such as SMAP has been successfully demonstrated using the change in antenna temperature as the radiometer scans across land/water boundaries (coastlines). This measurement provides the distance of the footprint from the nominal coastline, but it does not provide information about the error in look angle and azimuth of the antenna boresight vector needed to correct for the geolocation error. A method for doing this is reported using fore and aft crossings of the boundary. The approach is demonstrated using the SMAP radiometer simulator and then applied to SMAP data over the west coast of Madagascar. The error estimates of 0.3 degrees for look angle and 0.15 degrees for azimuth are consistent with independent estimates.
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    Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming
    (Springer Nature, 2024-05-30) Yuan, Tianle; Song, Hua; Oreopoulos, Lazaros; Wood, Robert; Bian, Huisheng; Breen, Katherine; Chin, Mian; Yu, Hongbin; Barahona, Donifan; Meyer, Kerry; Platnick, Steven
    Human activities affect the Earth’s climate through modifying the composition of the atmosphere, which then creates radiative forcing that drives climate change. The warming effect of anthropogenic greenhouse gases has been partially balanced by the cooling effect of anthropogenic aerosols. In 2020, fuel regulations abruptly reduced the emission of sulfur dioxide from international shipping by about 80% and created an inadvertent geoengineering termination shock with global impact. Here we estimate the regulation leads to a radiative forcing of +0.2 ± 0.11Wm⁻² averaged over the global ocean. The amount of radiative forcing could lead to a doubling (or more) of the warming rate in the 2020 s compared with the rate since 1980 with strong spatiotemporal heterogeneity. The warming effect is consistent with the recent observed strong warming in 2023 and expected to make the 2020 s anomalously warm. The forcing is equivalent in magnitude to 80% of the measured increase in planetary heat uptake since 2020. The radiative forcing also has strong hemispheric contrast, which has important implications for precipitation pattern changes. Our result suggests marine cloud brightening may be a viable geoengineering method in temporarily cooling the climate that has its unique challenges due to inherent spatiotemporal heterogeneity.
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    The Water Vapor Variability - Satellite/Sondes (WAVES) Field Campaigns
    (2008-07-07) Whiteman, D. N.; Adam, M.; Barnet, C.; Bojkov, B.; Delgado, Ruben; Demoz, B.; Fitzgibbon, J.; Forno, R.; Herman, R.; Hoff, Raymond; Joseph, E.; Landulfo, E.; McCann, K.; McGee, T.; Miloshevich, L.; Restrepo, I.; Schmidlin, F. J.; Taubman, B.; Thompson, Anne M.; Twigg, L.; Venable, D.; Vomel, H.; Walthall, C.
    Three NASA-funded field campaigns have been hosted at the Howard University Research Campus in Beltsville, MD. In each of the years 2006, 2007 and 2008, WAVES field campaigns have coordinated ozonesonde launches, lidar operations and other measurements with A-train satellite overpasses for the purposes of satellite validation. The unique mix of measurement systems, physical location and the interagency, international group of researchers and students has permitted other objectives, such as mesoscale meteorological studies, to be addressed as well. We review the goals and accomplishments of the three WAVES missions with the emphasis on the nonsatellite validation component of WAVES, as the satellite validation activities have been reported elsewhere.
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    Bay Breeze Impact on Surface Ozone at Edgewood, Maryland During July 201
    (2012-09-19) Stauffer, Ryan M.; Thompson, Anne M.; Martins, Douglas K.; Clark, Richard D.; Goldberg, Daniel L.; Loughner, Christopher P.; Delgado, Ruben; Dickerson, Russell R.; Stehr, Jeffrey W.; Tzortziou, Maria A.
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    Radial Variations in Solar Type III Radio Bursts
    (AAS, 2024-05-28) Krupar, Vratislav; Kruparova, Oksana; Szabo, Adam; Wilson, Lynn B.; Nemec, Frantisek; Santolik, Ondrej; Pulupa, Marc; Issautier, Karine; Bale, Stuart D.; Maksimovic, Milan
    Type III radio bursts are generated by electron beams accelerated at reconnection sites in the corona. This study, utilizing data from the Parker Solar Probe’s first 17 encounters, closely examines these bursts down to 13 solar radii. A focal point of our analysis is the near-radial alignment (within 5°) of the Parker Solar Probe, STEREO-A, and Wind spacecraft relative to the Sun. This alignment, facilitating simultaneous observations of 52 and 27 bursts by STEREO-A and Wind respectively, allows for a detailed differentiation of radial and longitudinal burst variations. Our observations reveal no significant radial variations in electron beam speeds, radio fluxes, or exponential decay times for events below 50 solar radii. In contrast, closer to the Sun we noted a decrease in beam speeds and radio fluxes. This suggests potential effects of radio beaming or alterations in radio source sizes in this region. Importantly, our results underscore the necessity of considering spacecraft distance in multispacecraft observations for accurate radio burst analysis. A critical threshold of 50 solar radii emerges, beyond which beaming effects and changes in beam speeds and radio fluxes become significant. Furthermore, the consistent decay times across varying radial distances point toward a stable trend extending from 13 solar radii into the inner heliosphere. Our statistical results provide valuable insights into the propagation mechanisms of type III radio bursts, particularly highlighting the role of scattering near the radio source when the frequency aligns with the local electron plasma frequency.
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    Environment Canada cuts threaten the future of science and international agreements
    (AGU, 2012-02-14) Thompson, Anne M.; Salawitch, Ross J.; Hoff, Raymond; Logan, Jennifer A.; Einaudi, Franco
    In August 2011, 300 Environment Canada scientists and staff working on environmental monitoring and protection learned that their jobs would be terminated, and an additional 400-plus Environment Canada employees received notice that their positions were targeted for elimination. These notices received widespread coverage in the Canadian media and international attention in Nature News. Environment Canada is a government agency responsible for meteorological services as well as environmental research. We are concerned that research and observations related to ozone depletion, tropospheric pollution, and atmospheric transport of toxic chemicals in the northern latitudes may be seriously imperiled by the budget cuts that led to these job terminations. Further, we raise the questions being asked by the international community, scientists, and policy makers alike: First, will Canada be able to meet its obligations to the monitoring and assessment studies that support the various international agreements inTable 1? Second, will Canada continue to be a leader in Arctic research.
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    Transpacific transport of ozone pollution and the effect of recent Asian emission increases on air quality in North America: an integrated analysis using satellite, aircraft, ozonesonde, and surface observations
    (EGU, 2008-10-22) Zhang, L.; Jacob, D. J.; Boersma, K. F.; Jaffe, D. A.; Olson, J. R.; Bowman, K. W.; Worden, J. R.; Thompson, Anne M.; Avery, M. A.; Cohen, R. C.; Dibb, J. E.; Flock, F. M.; Fuelberg, H. E.; Huey, L. G.; McMillan, W. W.; Singh, H. B.; Weinheimer, A. J.
    We use an ensemble of aircraft, satellite, sonde, and surface observations for April–May 2006 (NASA/INTEX-B aircraft campaign) to better understand the mechanisms for transpacific ozone pollution and its implications for North American air quality. The observations are interpreted with a global 3-D chemical transport model (GEOS-Chem). OMI NO₂ satellite observations constrain Asian anthropogenic NOx emissions and indicate a factor of 2 increase from 2000 to 2006 in China. Satellite observations of CO from AIRS and TES indicate two major events of Asian transpacific pollution during INTEX-B. Correlation between TES CO and ozone observations shows evidence for transpacific ozone pollution. The semi-permanent Pacific High and Aleutian Low cause splitting of transpacific pollution plumes over the Northeast Pacific. The northern branch circulates around the Aleutian Low and has little impact on North America. The southern branch circulates around the Pacific High and some of that air impacts western North America. Both aircraft measurements and model results show sustained ozone production driven by peroxyacetylnitrate (PAN) decomposition in the southern branch, roughly doubling the transpacific influence from ozone produced in the Asian boundary layer. Model simulation of ozone observations at Mt. Bachelor Observatory in Oregon (2.7 km altitude) indicates a mean Asian ozone pollution contribution of 9±3 ppbv to the mean observed concentration of 54 ppbv, reflecting mostly an enhancement in background ozone rather than episodic Asian plumes. Asian pollution enhanced surface ozone concentrations by 5–7 ppbv over western North America in spring 2006. The 2000–2006 rise in Asian anthropogenic emissions increased this influence by 1–2 ppbv.
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    I Hate the News May 21
    (I Hate Politics Podcast, 2024-05-21) Dasgupta, Sunil
    The weekly news analysis from I Hate Politics: Montgomery County Council President Andrew Friedson on criticism of the new 2024-25 budget passed last week. Maryland Public Service Commission Chair Fred Hoover on getting tough with retail energy suppliers. Primary election numbers with Gilberto Zelaya of the County Board of Elections. Canine flu outbreak continues in the local animal shelter. Music from Doogie Whittaker and the Lonesome Mile.