High Spectral Resolution Lidar using Spherical Fabry-Perot to measure Aerosol and Atmospheric Molecular Density in the upper troposphere and lower stratosphere

International audienceMeasurement of the vertical temperature profile within the UTLS presents a major challenge in geophysics to study microphysical phenomena and dynamic processes in particular to detect gravity waves between 2 km and 30 km of altitude. Theoretically, the use of an HSRL method should enable the validity range for the molecular density and temperature profiles from Rayleigh LIDAR to be extended to below 30 km by eliminating the particle contribution. In practice, a spectral separation of a few picometres requires a special filtering system. In the context of this work, we tested the use of a Spherical Fabry-Perot which achieves these performances while maintaining a high level of flexibility in terms of optical alignment. However, the first tests have shown that this filtering device has some technical limitations (thermal drift and possibly partial depolarization of the backscattered signal)

Rotational Raman Lidar to measure the Atmospheric Temperature in the upper troposphere and lower stratosphere

International audienceMeasurement of the vertical temperature profile within the UTLS presents a major challenge in geophysics to study microphysical phenomena and dynamic processes in particular to detect gravity waves between 2 km and 30 km of altitude. Theoretically, a Lidar method using the anti-Stokes rotational lines of N2 and 02 Raman spectrum should enable the validity range for the temperature profile to be extended to below 30 km by eliminating the particle contribution. In practice, this method uses the variation with the temperature of the envelop of the intensities of the backscattered rotational Raman spectrum, or more precisely the variations of the ratio of the intensities at two lines close-by wavelengths. For each temperature of the gas, the ratio of the fluxes through two narrow and close-by filters takes a definite value directly related to the temperature. The difficulty of eliminating the near-by contribution of the Mie backscattering was solved by adding a Notch filter to produce a rejection factor of 108 at the central wavelength. The theoretical calculation of the method led to an analytic calibration function which, once adjusted, can provide the temperature profile in the upper troposphere and lower stratosphere. We will also consider the technical evolutions of this optical device with a Fabry-Perot interferometer, a diffraction grating and a new detector

High spectral resolution lidar using spherical Fabry-Perot to measure aerosol and atmospheric molecular density

The 28th International Laser Radar Conference (ILRC 28)International audienceIn theory, the HSRL method should expand the domain of validity of the atmospheric molecular density and temperature profiles of the Rayleigh LIDAR. This, in the UTLS under 30 km with the accuracy of 1 K, while suppressing the particulate contribution. We tested a Spherical Fabry-Perot which achieves these performances while keeping a big flexibility in optical alignment. Performances and limitations of this device will be shown

An innovative rotational Raman lidar to measure the temperature profile from the surface to 30 km altitude

International audienceThe temperature is a fundamental parameter for meteorology and climatology. It is measured firstly twice a day using radiosondes with good vertical resolution but in a limited number of stations in the world and secondly from space but often with a vertical resolution limited by the weighting function of the instrument. Lidars provide a good vertical resolution and continuity of measurements. Currently the temperature is measured by lidar Rayeigh from NDACC ground stations but only above 30 km due to the presence of aerosols below this altitude. There is currently no space lidar in flight or in project measuring the temperature. The rotational Raman lidar technology allows access to the evolution of the temperature profile in the troposphere and lower stratosphere. It requires developing an efficient optical system with separation between the Rayleigh and the rotational Raman signal, the first being 2 to 3 orders of magnitude stronger than the second. It requires acquiring the full rotational Raman spectrum of molecular nitrogen, the temperature being deduced from the evolution of the relationship between the spectral lines. We are developing at LATMOS a prototype rotational Raman lidar with daylight measurement capability that will be implemented in the NDACC station at Haute-Provence Observatory to benefit from the facilities available on site (laser source, telescopes, ...). The Rayleigh-Mie line is attenuated using a Fabry-Pérot etalon with a line spacing exactly equal to the line spacing of the N2 rotational Raman spectrum Such a system will perform a continuous survey of the temperature profile from the surface to the middle stratosphere and could serve as a reference to define a future space lidar for measuring the temperature in the troposphere and lower stratosphere

BeCOOL: A Balloon-Borne Microlidar System Designed for Cirrus and Convective Overshoot Monitoring

International audienceA balloon-borne microlidar has been built at LATMOS to monitor cirrus optical properties and convective overshoot topography during long duration flights in the lower tropical stratosphere. Weighting less than 7 kg in a reduced volume and consuming less than 10 W, it will be involved in the CNES-Strateole2 campaign. This instrument paves the way to the use of microlidar technology for planetary missions

EVALUATION OF CIRCUMSPOROZOITE PROTEIN OF Plasmodium vivax TO ESTIMATE ITS PREVALENCE IN OIAPOQUE , AMAPÁ STATE, BRAZIL, BORDERING FRENCH GUIANA

International audienceMalaria is a major health problem for people who live on the border between Brazil and French Guiana. Here we discuss Plasmodium vivax distribution pattern in the town of Oiapoque, Amapá State using the circumsporozoite (CS) gene as a marker. Ninety-one peripheral blood samples from P. vivax patients have been studied. Of these, 64 individuals were from the municipality of Oiapoque (Amapá State, Brazil) and 27 patients from French Guiana (August to December 2011). DNA extraction was performed, and a fragment of the P. vivax CS gene was subsequently analyzed using PCR/RFLP. The VK210 genotype was the most common in both countries (48.36% in Brazil and 14.28% in French Guiana), followed by the P. vivax-like (1.10% in both Brazil and French Guiana) and VK247 (1.10% only in Brazil) in single infections. We were able to detect all three CS genotypes simultaneously in mixed infections. There were no statistically significant differences either regarding infection site or parasitaemia among individuals with different genotypes. These results suggest that the same genotypes circulating in French Guiana are found in the municipality of Oiapoque in Brazil. These findings suggest that there may be a dispersion of parasitic populations occurring between the two countries. Most likely, this distribution is associated with prolonged and/or more complex transmission patterns of these genotypes in Brazil, bordering French Guiana

Ground-based Rayleigh-Mie Doppler liar for wind measurements in the middle atmosphere

International audienceA unique Rayleigh-Mie Doppler wind lidar, measuring Doppler shift between the emitted and backscattered light using directdetection technique is deployed at Observatory of Haute Provence Southern France) and at Reunion island (tropical Indian Ocean). The instrument was shown capable of wind measurements between 5 and 50 km with accuracy better than 1 m/s up to 30 km. The system consists of a monomode Nd:Yag laser operating at 532 nm, three telescopes and a double-edge Fabry-Perot interferometer. The laser light is sent alternatively in the vertical as well as zonal and meridional directions at 40° from the zenith using a rotating mirror. The two components of the horizontal wind are obtained from the measurement of the Doppler shift of the return signal spectrally filtered by the Fabry-Perot etalon. After demonstration of the method in 1989 the measurements were used for studying stratospheric dynamics as well as for constructing wind climatology up to 50 km altitude. A new system, featuring a more compact design was installed at Maïdo observatory at Reunion Island (21° S). The design of the instrument, results of observations and comparison against GPS radiosondes are presented. Application of Doppler lidar for validation of the future ADM-Aeolus satellite mission is discussed as well

Micro-Ares, An electric field sensor for ExoMars 2016

International audienceFor the past few years, LATMOS has been involved in the development of Micro-ARES, an electric field sensor part of the science payload (DREAMS) of the ExoMars 2016 Schiaparelli entry, descent and landing demonstrator module (EDM). It is dedicated to the very first measurement and characterization of the Martian atmospheric electricity