By collocating 10 years (1999–2009) of remotely sensed surface turbulent heat fluxes with satellite altimetry data, we investigate the impact of oceanic mesoscale eddies on the latent and sensible ...heat fluxes in the South Atlantic Ocean. In strongly energetic regions, such as the Brazil–Malvinas confluence and the Agulhas Current Retroflection, eddies explain up to 20% of the total variance in the surface turbulent heat fluxes with averaged anomalies of ± (10–20) W/m2. Cyclonic (anticyclonic, respectively) eddies are associated with negative (positive) heat flux anomalies that tend to cool (warm) the marine atmospheric boundary layer. A composite analysis of the turbulent heat flux anomalies inside the eddies reveals a direct relationship between eddy amplitude and the intensity of such anomalies. In addition, these anomalies are stronger near the eddy center, decaying radially to reach minimum values outside the eddies.
Key Points
Eddies can significantly impact the surface turbulent heat fluxes
Stronger heat flux anomalies are associated with large‐amplitude eddies
Cyclonic eddies contribute to ocean heat gain, while anticyclonic with heat loss
Abstract
Atomic oxygen is a key oxidant for greenhouse gases such as H
2
O, CH
4
, and N
2
O whose amounts are currently increasing in the stratosphere. Ozone photolysis is a major source of atomic ...oxygen generation. We found, for the first time, that the ozone photolysis of
48
O
3
and
18
O
16
O
16
O generated a sharp diurnal variation of
δ
18
OOO in the middle stratosphere (37 km), in contrast to the temporal variation of
48
O
3
. The average isotopic enrichment
δ
18
OOO derived from the Superconducting Submillimeter‐Wave Limb‐Emission Sounder (SMILES) observation was higher during daytime (16.2 ± 3.3%) than at night (13.7 ± 3.6%). Isotopic fractionation effects were simulated for both ozone formation reaction and ozone photolysis with the ozone photolysis contribution estimated to be 80% of the daytime
δ
18
OOO enhancement. Significant solar radiation dependence was observed in the isotopic fractionation of ozone photolysis derived from the SMILES observation and theoretical calculations. These results show that
δ
18
O can be a powerful tool to investigate oxidant chemistry.
Key Points
Diurnal variation of the oxygen isotopic ratio of asymmetric‐18 ozone (
δ
18
OOO) was derived from spaceborne SMILES observation for the first time
The
δ
18
OOO diurnal behavior was observed to be different from those of
48
O
3
and
18
O
16
O
16
O concentrations
Significant solar radiation dependence was observed in the isotopic fractionation of ozone photolysis derived from our analysis
Five pigs experimentally infected with Actinobacillus pleuropneumoniae serovar 15 isolated in our previous study were pathologically examined. One pig died at 2 days post inoculation (dpi) and four ...pigs were euthanized at 7 dpi. Autopsy revealed fibrinohemorrhagic pleuropneumonia in all pigs. Histopathologically, the lesions were characterized by extensive hemorrhage and necrosis, fibrin deposition, and multifocal abscesses composed of numerous neutrophils including oat cells and numerous Gram-negative bacilli. In one survived pig, asteroid body formation was confirmed in the lung. The bacteria within the abscesses and asteroid bodies were immunohistochemically positive for antiserum raised against A. pleuropneumoniae serovar 15. This is the first report describing porcine pleuropneumonia with asteroid bodies in a pig experimentally infected with A. pleuropneumoniae serovar 15.
We examined the changes in the ocean’s upper layer structure involved in the formation of the subtropical mode water in the South Atlantic. Here we present the results from a survey done in the ...region of formation between 37°W and 32°W and 34°S and 37°S from July–October 2018, using high‐resolution measurements obtained from an underwater glider. From its records, the mode water development was observed for the first time in the South Atlantic as localized chimney‐like patterns in the temperature, salinity, and potential vorticity (PV) measurements with a horizontal scale of (7 ± 2) km, associated with wintertime oceanic convective processes. Over time, these submesoscale structures tend to expand and dominate the region as a large volume of mode water. These vertical structures present highly homogeneous temperature and salinity values. The observed PV was on the order of 5.0 × 10−11 m−1 s−1, which is one order of magnitude smaller than the pre‐existent mode water at the lower layers; negative values were observed, indicating active convection. A 1‐D vertical model was used to predict the depth of the mixed layer conditioned by the surface fluxes and triggered by its changes in winter to late spring. Comparisons of the sea surface temperature measured from satellite collocated with the glider’s measurements showed a very good agreement. From this analysis, we were able to establish the decorrelation scales that characterize mode water formation. Further inspection of the glider data yielded temporal decorrelation scales indicative of convection modified by planetary rotation.
Plain Language Summary
Subtropical mode waters are a uniform volume of water found at the edges of subtropical gyres. The South Atlantic Subtropical Mode Water (SASTMW) is no exception. It is found between 30°S and 40°S, from the surface to a depth of 200–350 m. It forms when the mixed layer deepens in winter to early spring; it does not mix with the surrounding water and remains homogeneous. It sinks after the surface waters become stratified again at the end of spring. The properties of the water (such as oxygen concentration or potential vorticity) change while it is in contact with the atmosphere. When the water sinks, it preserves a memory of these changes. We used in situ, satellite, and glider data to understand the physics of its formation and to describe its main characteristics in unprecedented detail. The formation takes the shape of chimney‐like structures that extend down from the surface to about 350 m, with spatial scales of 7 km and temporal of 3 days. From the satellite data, we noticed that these structures occur where the temperature falls between 14.1°C and 15.9°C. These structures are mainly due to convection and are modified by the Earth’s rotation.
Key Points
Chimney‐like structures revealed in high resolution glider data are associated with mode water formation
Newly formed mode waters are distinguished by extremely low values of PV
A 1‐D vertical mixed layer model forced by surface fluxes predicts the mode water formation
No direct observational evidence of sprite‐produced active radicals has been presented owing to the difficulty of observing a small event area in the nighttime mesosphere, whereas sprite chemical ...models have indicated that sprite discharge locally affects the atmospheric composition. We present the first observational evidence of a HO2 production above sprite‐producing thunderstorms from the coincidence of temporal‐spatial observations of HO2 spectra, sprite events, and thunderstorms by two space instruments, a submillimeter‐wave limb spectrometer and ultraviolet/visible Imager and a ground‐based very low frequency radiation lightning detection network. A total of three areas was identified with enhanced HO2 levels of approximately 1025 molecules. A chemical sprite model indicates an increase in HO2 in the considered altitude region; however, the predicted production due to a single sprite event is smaller than the observed enhancement. Our observational results suggest that sprites potentially contribute 1% of nighttime background HO2 generation at altitudes of 75–80 km globally.
Distal transradial approach (dTRA) for neuroendovascular procedures has received much attention in recent years as a newer and less invasive alternative to the conventional transfemoral or ...transradial approaches. We present the case of an 89-year-old woman with a basilar artery aneurysm requiring simultaneous catheterization of the bilateral vertebral arteries who was successfully embolized using bilateral dTRA. The aneurysm was accessed from the right vertebral artery using the right dTRA. Control angiograms during the procedure were performed from the left vertebral artery via the left dTRA. The operator's posture was ergonomically comfortable, and the catheters were easy to handle during the procedure. To the best of our knowledge, this is the first case of a bilateral dTRA used for neuroendovascular procedures. Bilateral dTRA is a safe and minimally invasive method for patients and ergonomically comfortable for operators.
Background/Aim: The aim of this study was to evaluate the efficacy of preoperative chemotherapy for stage II-III esophageal squamous cell carcinoma based on an objective computed tomography method. ...Patients and Methods: A total of 82 patients who underwent preoperative chemotherapy followed by surgery for advanced esophageal squamous cell carcinoma from January 2006 to June 2019 were included. Treatment effect was evaluated by measuring the esophageal wall thickness before and after neoadjuvant chemotherapy using contrast-enhanced thoracoabdominal computed tomography. The percentage decrease in esophageal wall thickness was calculated using the following formula: reduction (%)=(wall thickness before preoperative chemotherapy − wall thickness after preoperative chemotherapy)/(wall thickness before preoperative chemotherapy)×100. We demonstrated the efficacy of this measurement method and then analyzed which patient factors might affect the treatment effect. Results: Receiver operating characteristic analysis showed the percentage tumor reduction to be a good predictor of histological therapeutic effect (grade ≥2) (area under the curve=0.727). In the multivariate analysis, tumor location (lower versus upper esophagus) was identified as an independent factor associated with tumor reduction (odds ratio=0.15; 95% confidence interval=0.03-0.79; p=0.025). Conclusion: We demonstrated an association between the reduction of esophageal wall thickness in the tumoral area and the histological therapeutic effect of chemotherapy. Secondary analysis showed poorer tumor reduction in patients with lower esophageal cancer than in those with upper esophageal cancer.
Abstract No direct observational evidence of sprite‐produced active radicals has been presented owing to the difficulty of observing a small event area in the nighttime mesosphere, whereas sprite ...chemical models have indicated that sprite discharge locally affects the atmospheric composition. We present the first observational evidence of a HO production above sprite‐producing thunderstorms from the coincidence of temporal‐spatial observations of HO spectra, sprite events, and thunderstorms by two space instruments, a submillimeter‐wave limb spectrometer and ultraviolet/visible Imager and a ground‐based very low frequency radiation lightning detection network. A total of three areas was identified with enhanced HO levels of approximately 10 molecules. A chemical sprite model indicates an increase in HO in the considered altitude region; however, the predicted production due to a single sprite event is smaller than the observed enhancement. Our observational results suggest that sprites potentially contribute 1% of nighttime background HO generation at altitudes of 75–80 km globally.
Plain Language Summary HO radical, a key atmospheric oxidant in the mechanisms that influence the atmospheric composition of our planet, has been predicted to be generated by lightning‐induced upper atmospheric discharge, called sprites, from water vapor. However, there has been no observational evidence of sprite‐producing active radicals due to the difficulty in specific observations that identify these radical productions by sprite, caused by factors such as a very small molecular abundance and narrow event area in the upper atmosphere. For the first time, we present observational evidence of a rise in HO amount above sprite‐producing thunderstorms by using a unique method that combined observations between HO detection by a super‐high‐sensitive space spectrometer, sprite emission detection using a satellite imager and ground‐based lightning detection using expand radio frequency receivers. The amount of HO generated in the sprite event area can be approximated to be 40–190 times greater than the background values. Sprite chemical model simulations reproduced HO enhancement by sprite events. These pieces of evidence suggest that sprites potentially contribute about 1% increase of background level of global HO generation during nighttime at altitudes of 75–80 km, which can contribute to a change in the Earth's atmospheric composition.
Key Points Clear HO enhancements above sprite‐producing thunderstorms were identified by coincidence of space and ground‐based observations Enhanced HO amounts in a sprite event area were estimated to be 10 molecules Sprites potentially contribute about 1% of nighttime background HO generations at 75–80 km globally
Diurnal variations of ClO, HO2, and HOCl were simultaneously observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) between 12 October 2009 and 21 April 2010. These were ...the first global observations of the diurnal variation of HOCl in the upper atmosphere. A major reaction for the production of HOCl is ClO + HO2 arrow right HOCl + O2 (Reaction (R1)) in extra-polar regions. A model study suggested that in the mesosphere, this is the only reaction influencing the amount of HOCl during the night. The evaluation of the pure reaction period, when only Reaction (R1) occurred in the Cly chemical system, was performed by checking the consistency of the HOCl production rate with the ClO loss rate from SMILES observation data. It turned out that the SMILES data at the pressure level of 0.28 hPa (about 58 km) in the autumn mid-latitude region (20-40 degree , February-April 2010) during night (between modified local time 18:30 and 04:00) were suitable for the estimation of the rate constant, k1. The rate constant obtained from SMILES observations was k1(245 K) = (7.75 plus or minus 0.25) 10-12 cm3 molecule-1 s-1. This result is consistent with results from a laboratory experiment and ab initio calculations for similar low-pressure conditions.
Cloud masking is a critical step in the estimation of Sea Surface Temperature (SST) from satellite observations. It can affect the validation statistics of SST on synoptic scales but also on ...long-term climatologies. One of the main challenges in cloud masking is the discrimination between clouds and ocean sharp fronts as both of these are associated with high spatial variability. In this study, we investigate the impact of cloud masking on the climatology of SST gradient magnitudes. Using night-time Level 2 SST derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua for almost the entire mission, i.e. 2003 to 2018 over the Southwestern Atlantic Ocean (SAO), we show that misclassification of sharp ocean thermal fronts as clouds leads to (1) significant underestimation of thermal frontal activity in monthly and longer-term climatologies and (2) different spatial distributions and temporal variability of SST gradient magnitudes.
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