Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better ...understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI) and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere.
An increase in global surface temperature of between 1.4 K and 5.8 K is expected to occur by 2100 due to a doubling of the global concentration of CO
2
. Associated with this predicted surface ...warming will be an increase in the downwards longwave (3-100 µm) radiation (F↓) at the Earth's surface. Observations of this quantity on a global scale are almost non-existent. Clear-sky estimates of F↓ can be obtained from radiative transfer calculations using temperature and moisture profiles from radiosoundings. Here long-term (more than 25 years) mean monthly profiles obtained from globally distributed land-based radiosonde stations are subjected to detailed radiative transfer computations and Fourier time-series analysis. The results indicate that over the period 1964-1990, there has been a global increase in the clear-sky longwave flux at the surface. The global trend is approximately +1.7 W m
−2
per decade, and there is a strong latitudinal pattern, with greater increases occurring in the tropics and smaller increases at both poles. There are also concomitant increases in precipitable water and the patterns appear to be highly correlated with increases in F↓. Increases in CO
2
with time were not included in the calculations and it is estimated that the radiative impact of changes in CO
2
on the F↓ trend is ∼20% per decade. A simple model of the dependence of surface air temperature and precipitable water on the downwards clear-sky flux supports the notion that both variables are contributing to increases in F↓. It is suggested that increases in precipitable water represent a positive feedback on F↓.
Volcanic eruptions emit plumes of ash and gases into the atmosphere, potentially at very high altitudes. Ash-rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside ...their engines. With more than 50 active volcanoes per year and the ever-increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be), which is a free online service initiated by the European Space Agency (ESA) for the near-real-time (NRT) satellite monitoring of volcanic plumes of SO2 and ash. It combines data from three ultraviolet (UV)-visible and three infrared (IR) spectrometers. The UV-vis sensors are the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the two polar orbiting meteorological satellites (MetOp-A & MetOp-B) operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The IR sensors are the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on-board MetOp-A & MetOp-B. This new multi-sensor warning system of volcanic emissions is based on the selective detection of SO2 and ash. This system is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. A successful rate with more than 95% of notifications corresponding to true volcanic activity is obtained by the SACS system.
This study explored the association between family cohesion and self-perceived need for dental treatment among adolescents. A school-based representative cross-sectional study was conducted with 746 ...students aged 15 to 19 randomly selected from schools in Campina Grande, Brazil. Parents/guardians provided information on sociodemographic data, and students completed questionnaires about the self-perceived need for dental treatment, dental pain, and family cohesion and adaptability (FACES III). Two dentists were trained (kappa >0.80) to diagnosis dental caries using the Nyvad criteria and assess adolescents’ level of functional oral health literacy (BREALD-30). Descriptive analysis was performed, followed by nonadjusted and adjusted robust binary logistic regression for complex samples (α=5%). The prevalence of self-perceived need for dental treatment was 88.6%. The presence of dental caries (OR=2.10; IC 95%: 1.22–3.61), tooth loss (OR=15.81; IC 95%: 2.14–116.56), dental pain in the last six months (OR=1.87; IC 95%: 1.06–3.31), and enmeshed family cohesion type (OR=10.23; IC 95%: 3.96–26.4) remained associated with the self-perceived need for dental treatment in the final model. In conclusion, dental caries, dental pain, tooth loss, and family cohesion influenced the self-perceived need for dental treatment in adolescents.
Abstract We present a case report of a four-year-old boy with torcicollis and trismus after acute otitis media. Grisel Syndrome diagnosis in association with temporo-mandibular reactive arthritis was ...admitted, leading to early conservative treatment. GS should be suspected in a child presenting with torticollis after an upper respiratory tract infection or an ENT surgical procedure. The association with temporo-mandibular reactive findings is somehow rarer but not impossible, due to the close vascular communication between retropharyngeal and pterigoid spaces.
Meteosat second generation (MSG) provides multispectral data with a high temporal resolution of 15 min. On the basis of these data, the Land Surface Analysis-Satellite Applications facility ...(LSA-SAF), patronized by Eumetsat, generates and distributes many MSG products. The land surface temperature (LST) is one of its main products. It is generated from the MSG spinning enhanced visible and infra red imager (SEVIRI) data with a split-window algorithm, using 10.8 and 12.0 µm channels. Based on the accuracy of the parameters used in the LST algorithm, the SAF-LST quality is estimated to be ±2°C. However, this estimation must be proven with ground-truth data. This article presents the concept of the first LST validation station for the MSG in Evora, Portugal. The validation results calculated for cloud-free days during 2006 reveal very good agreement of the satellite- and ground-based LST at night (average difference of 1.0±1.5°C). During the day, however the average bias reaches 3.0±1.5°C. The largest disagreements take place on hot summer days with very intense direct solar radiation. This systematical bias reveals that the algorithm overestimates LST at high surface temperatures.
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