Surface ozone trends at El Arenosillo observatory from a new perspective.

Surface ozone trends observed at El Arenosillo observatory for the last 22 years (2000-2021) were investigated. The trends for daily averages and daily 5th and 95th percentiles were 1.2 ± 0.3 ppb decade-1, 2.2 ± 0.3 ppb decade-1 and -0.03 ± 0.43 ppb decade-1, respectively, thus showing a significant increase of background ozone. The surface temperature trends were also explored, obtaining trends of 0.5 ± 0.2 °C decade-1, 1.1 ± 0.2 °C decade-1 and -0.3 ± 0.2 °C decade-1 for daily averages, 5th and 95th percentiles, respectively. To identify potential changes in the ozone drivers, the weather pattern shifts were analyzed through the horizontal distribution trends of temperature at 2 m and geopotential height at 850 hPa. A strengthening of the Azores anticyclone and a regional warming were detected, which could contribute to the ozone trends obtained. The surface ozone trend in every month was explored, identifying a monthly pattern, with remarkable opposite trends in December-January (2.4 ± 0.9 ppb decade-1) vs July-August (-0.5 ± 1.1 ppb decade-1). The surface ozone trends for every hour of the day were also explored, identifying two clear patterns. The first pattern occurred from spring to autumn and was characterized by a behavior opposite to the typical daily ozone cycle. The second pattern was observed in winter, and it shows two relative peaks in the ozone trends (around 13:00 and 19:00 UTC). In a context of ozone precursor's depletion, changes in the weather conditions and warmer climate, to improve our knowledge of the ozone trends, we suggest exploring them based on daily and hourly averages.

Ground-based and OMI-TROPOMI NO2 measurements at El Arenosillo observatory: Unexpected upward trends.

Eleven years, January 2008 to June 2019, of hourly nitrogen dioxide (NO2) levels recorded at El Arenosillo observatory (Southwestern Europe) were analyzed. Annual averages ranged between 4 µg m-3 and 6 µg m-3 with peaks exceeding 40 µg m-3. A slight monthly variation was observed with maximum and minimum values in the cold (∼6 µg m-3) and warm (∼4 µg m-3) seasons respectively. A diurnal pattern was found with a weak amplitude (∼3 µg m-3). The monthly trends were investigated using surface observations and OMI (Ozone Monitoring instrument) satellite measurements. An unexpected upward trend was obtained in the last five years. The periods with elevated NO2 concentrations in the last years were analyzed, showing an increase in its frequency and concentrations, linked with the upward trend observed. The weather conditions in these NO2 peaks were studied using local surface meteorology, mean sea level pressure and wind fields from the data reanalysis of ERA5. The transport of NO2 was explored using TROPOMI (Tropospheric Monitoring Instrument) measurements. The events occurred under conditions governed by high-pressure systems, which induced weak synoptic airflows or the development of mesoscale processes. Four scenarios of NO2 transport were identified, associated with weak synoptic flows from inland or Southern Portugal and with mesoscale processes. The gulf of Cadiz plays an important role as a reservoir where the NO2 coming from the south of Portugal, the Western Mediterranean Basin and urban-industrial areas can be accumulated and later transported inland. A strong correlation was found between the increase of NO2 observed in the last years and positive anomalies of the temperature and geopotential height at 850 and 500 hPa levels. These findings could indicate that the causes of the changes in the NO2 would be attributed to alterations in the weather patterns associated with a warmer climate.

SO2 measurements in a clean coastal environment of the southwestern Europe: Sources, transport and influence in the formation of secondary aerosols.

Two years of SO2 measurements at El Arenosillo observatory located in the Gulf of Cadiz (Atlantic Ocean) were investigated. Annual hourly averages of 1.9 ± 1.5 µg m-3 and p95 between 3 and 4.4 µg m-3 were recorded, showing clean and background environments. Monthly means vary between 1.5 and 2.4 µg m-3, a monthly evolution was not found. SO2 fields from the MERRA2 model were used to identify SO2 sources and its transport, which could be affecting the studied region. Although SO2 records were low, major conductive for SO2 increases were observed in specific periods. A selection methodology was applied to extract these events, which showed a mean of ~11 µg m-3. Surface meteorological observations and ERA5 meteorological fields from the ECMWF model were used to assess the weather conditions. SO2 increases, in cold months occurred under conditions governed by synoptic-scale. Two types of transport scenarios were identified: SO2 transport defined as direct impact, which is the sum of the plumes from Portugal and the Huelva area; and indirect impact, where SO2 and sulphate particle emissions from Portugal were transported and accumulated in the Gulf of Cadiz and then carried inland, where new particle formation were observed. Episodes with high SO2 concentrations were also reported in warm periods associated with pure sea-land breezes. The SO2 peaks under sea-land breezes were associated with the transport of SO2 from the south of Portugal to the Gulf of Cadiz, whereas SO2 from the east of the Iberian Peninsula and north of Africa reached the Mediterranean Sea and were then transported to the Atlantic Ocean following the Strait of Gibraltar. Blocking of the airflows from the Mediterranean Sea to the Atlantic Ocean turns the Gulf of Cadiz into a chemical reservoir, where chemical species such as SO2 can accumulate, triggering new particle formation processes.

Recent increase in NO2 levels in the southeast of the Iberian Peninsula.

We report the evolution of tropospheric NO2 over the south-east of the Iberian Peninsula from 2005 to 2017. We have used hourly NO2 levels measured at air-quality stations in urban and suburban environments. Annual averages ranged between 14 and 45 µg m-3, with peaks above 200 µg m-3. A monthly variation was observed, with higher concentrations in cold months (40-60 µg m-3) and lower levels in the warm season (13-17 µg m-3). A diurnal pattern was found in urban and suburban areas. The upward trend in NO2 observed during the whole period contrasts with the upward trend reported in 2013-2017. The NO2 tropospheric column levels measured by the Ozone Monitoring Instrument over the Iberian Peninsula indicated a similar behaviour; nevertheless, the largest Spanish metropolitan areas did not show this increase. The mean sea level pressure and wind field data of ERA5 (European Centre for Medium-Range Weather Forecasts) were used to investigate the weather conditions, the NO2 outputs of the Copernicus Monitoring Services being used for the assessment of the NO2 spatial distribution. NO2 regional events, with concentrations in the range 140-150 µg m-3, and which occurred both in the winter and summer season under anticyclonic conditions, are also described. A local origin is identified in winter, whereas in summer, they are associated with a high-pressure system that blocks Mediterranean outflows towards the Atlantic Ocean. The high NO2 levels are attributed mainly to two factors: i) local emissions, rather than contributions from the western Mediterranean (or even North Africa), and ii) an increase in the pressure gradient between the Atlantic and the Mediterranean pressure systems, associated with a decrease in wind speed, was found during the last five years compared with the previous eight. Meteorological and chemical changes in mid-latitudes associated with global warming should also be investigated in the future.

Study of the exceptional meteorological conditions, trace gases and particulate matter measured during the 2017 forest fire in Doñana Natural Park, Spain.

In late June 2017, a forest fire occurred in Doñana Natural Park, which is located in southwestern Europe. Many animal and plant species, some of which are threatened, suffered from the impact of this fire, and important ecosystems in the European Union were seriously affected. This forest fire occurred under exceptional weather conditions. The meteorological situation was studied at both the synoptic scale and the local scale using meteorological fields in the ERA-Interim global model from ECMWF (European Centre for Medium Range Weather Forecasts), the WRF (Weather Research and Forecasting) mesoscale model and ground observations collected at El Arenosillo observatory. Anomalies were obtained using records (observations and simulations) over the last two decades (1996-2016). An anticyclonic system dominated the synoptic meteorological conditions, but a strong pressure gradient was present; positive high pressure anomalies and negative low pressure anomalies resulted in intense NW flows. At the surface, wind gusts of 80 km h-1, temperatures up to 35 °C and relative humidity values <20% were observed. In terms of anomalies, these observations corresponded to positive temperature anomalies (differences of 12 °C), positive wind speed anomalies (>29 km h-1) and negative relative humidity anomalies (differences of 40%). The forest fire reached El Arenosillo observatory approximately 8 h after it began. When the fire started, record-setting maximum values were measured for all gases monitored at this site (specifically, peaks of 99,995 µg m-3 for CO, 951 µg m-3 for O3, 478 µg m-3 for NO2, 116 µg m-3 for SO2 and 1000 µg m-3 for PM10). According to the temporal evolution patterns of these species, the atmosphere over a burnt area can recover to initial atmospheric levels between 48 and 96 h after an event. The impact of the Doñana plume was studied using hourly forward trajectories computed with the HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model to analyse the emission source for the burnt area. The Doñana fire plume affected large metropolitan areas near the Mediterranean coast. Air quality stations located in the cities of Seville and Cadiz registered the arrival of the plume based on increases in CO and PM10. Using CO as a tracer, measurements from the AIRS and MOPITT instruments allowed us to observe the transport of the Doñana plume from the Strait of Gibraltar to the Mediterranean. Finally, after two days, the Doñana forest fire plume reached the western Mediterranean basin.

An anomalous African dust event and its impact on aerosol radiative forcing on the Southwest Atlantic coast of Europe in February 2016.

A desert dust (DD) event that had its origin in North Africa occurred on the 20th-23rd of February 2016. The dust transport phenomenon was exceptional because of its unusual intensity during the coldest season. A historical dataset (2006-2015) of February meteorological scenarios using ECMWF fields, meteorological parameters, aerosol optical properties, surface O3 and AOD retrieved from MODIS at the El Arenosillo observatory (southwestern Spain) were analysed and compared with the levels during the DD event to highlight its exceptionality. Associated with a low-pressure system in western North Africa, flows transported air from the Sahel to Algeria and consequently increased temperatures from the surface to 700hPa by up to 7-9°C relative to the last decade. These conditions favoured the formation of a Saharan air layer. Dust was transported to the north and reached the Western Mediterranean Basin and the Iberian Peninsula. The arrival of the DD event at El Arenosillo did not affect the surface weather conditions or ozone but did impact the aerosol radiative forcing at the top of atmosphere (RFTOA). Aerosol radiative properties did not change relative to historical; however, the particle size and the amount of the aerosol were significantly higher. The DD event caused an increase (in absolute terms) of the mean aerosol RFTOA to a value of -8.1Wm-2 (long-term climatological value ~-1.5Wm-2). The aerosol RFTOA was not very large relative other DD episodes; however, our analysis of the historical data concluded that the importance of this DD event lay in the month of occurrence. European phenological datasets related to extreme atmospheric events predominantly reflect changes that are probably associated with climate change. This work is an example of this phenomenon, showing an event that occurred in a hotspot, the Saharan desert, and its impact two thousand km away.

[Gaucher's disease suspected by abdominal echography findings]. / Enfermedad de Gaucher sospechada por los hallazgos de la ecografía abdominal.

Abdominal ultrasonographic findings of Gaucher's disease had been reported, but a specific pattern has not been described. We report here a patient with an abdominal sonographic pattern which was concluded to be strongly suggestive of Gaucher's disease: solid focal splenic lesions with different patterns (hypoechoic, hiperechoic and mixed nodules associated with hypoechoic irregular areas) and bright liver and spleen echo pattern with posterior beam attenuation. Gaucher's disease was subsequently confirmed by determination of leukocyte beta-glucosidase activity and mutations of glucocerebrosidase gene.

Assessment of the usefulness of endoscopic signs in Helicobacter pylori associated gastritis.

OBJECTIVE: To determine whether endoscopic signs exist to establish the presence of Helicobacter pylori, which may be used markers of infection in the absence of gastroduodenal peptic lesions. METHODS: A prospective study was carried out in 150 consecutive patients, all symptomatic, who presented endoscopic evidence of gastritis and in whom the absence or presence of H. pylori was undetermined at the time of the study. A quantitative assessment was made of the three types of lesions previously associated with the presence of H. pylori on endoscopy: nodules, erosions, and red patches in the antrum. Biopsy samples were taken for the microbiological and histological studies; a positive result in either study was considered to indicate infection by H. pylori. RESULTS: Of the 150 patients studied, 115 (76%) presented H. pylori infection. No significant differences existed with respect to the clinical findings or the distribution according to sex. The mean age of infected patients was 49 years, being lower in the nodular group (p = 0.008) and higher in the group presenting erosions (p < 0.05); this fact suggests that the endoscopic findings may differ depending on the moment of infection. Evidence of antral nodules was observed in 15 patients, 11 of whom (73%) showed positively for H. pylori; the sensitivity was 9.5% and the positive predictive value was 0.73. Of the 17 patients presenting erosions, 16 were positive for H. pylori (93.8%); the sensitivity was 13% and the positive predictive value was 0.94. Red patches were detected in 63 patients, 48 of whom (76%) were positive for H. pylori; the sensitivity was 48% and the positive predictive value was 0.76. These three patterns did not coincide in any of the patients, for an overall sensitivity and specificity of 70.5% and 80.6%, respectively (p < 0.05). CONCLUSION: The sensitivity and specificity of the set of lesions assessed were high as no two overlapped; when the lesions were dealt with individually, however, the sensitivity was low, showing a low negative predictive value, making it necessary the use of standard detection measures, although in the presence of nodules and/ or erosions the existence of H. pylori infection is practically the norm.