High spectral resolution lidar (HSRL) are known to offer capabilities of separating attenuated aerosol and molecular backscattering so that particle extinction and backscattering can be separately retrieved. UV operation provides high energy in eye-safety conditions. Further to that, it could be important for most meteorological or environmental studies to get wind measurements at the same time. LNG is now the only HSR Doppler Lidar (HSRDL) system capable of this. Results obtained during ground-based and airborne measurements show that the backscatter and extinction coefficients at 355 nm can be measured with a relative precision better than 10% (adjusting altitude and time resolution from 60 m to 240 m and 30s to 2mn, respectively) in aerosol layers of 0.5 10−6 m−1 sr−1 backscatter coefficient from ground and aircraft. The same relative precision is obtained in cirrus clouds of a 10−5 m−1 sr−1 backscatter coefficient. The capacity of the system to perform wind velocity measurements has also been demonstrated with precisions in the range of 1 to 2 ms−1 in same conditions. We present the main characteristics and illustrate observational capabilities from ground-based and airborne measurements.

We present the design of a differential absorption LIDAR targeting HDO/H216O isotopic ratio measurement with high vertical resolution. This approach is enabled by infrared water vapor spectroscopy and recent high power multi-species parametric emitter developments.

We present the measurement principle and the optical design of a Quad Mach Zehnder (QMZ) interferometer as HSRL technique, allowing simultaneous measurements of particle backscattering and wind velocity. Key features of this concept is to operate with a multimodal laser and do not require any frequency stabilization. These features are relevant especially for space applications for which high technical readiness level is required.

We will present airborne wind profile measurements performed during the NAWDEX-EPATAN campaign held in Iceland on September 21 to October 18, 2016. The airborne high spectral resolution LNG LIDAR was taking measurements onboard the French SAFIRE falcon 20 (F20) along with the cloud Doppler radar RASTA. LNG line-of-sight can be oriented nadir/zenith and side looking with an angle of 37 degrees off vertical on request. Wind profile retrievals are possible thanks to backscattering signals incoming from thin ice clouds and aerosols. This 37° pointing configuration allows similar measurements to ALADIN onboard the ADM-Aeolus satellite to be launched end 2018. In addition to the LIDAR and radar wind measurements, in situ wind measurements were also obtained from dropsondes launched from the F20. We will give an overview of the instruments onboard the French falcon. Then we will present the principle of estimations of the horizontal wind components with the HSR LNG LIDAR operating in the ADM ALADIN mode (37°). The LIDAR measurements obtained during several flights of the NAWDEX-EPATAN campaign will be compared against measurements given by dropsondes and the combination of the three antennas of Doppler cloud radar.

The in situ tests of first ever autonomous aerosol and cloud backscatter LIDAR (light detection and ranging) systems implemented on buoys for Arctic observations has been achieved in 2015 within the French EQUIPEX IAOOS project. The environmental and operational constraints were met by adopting a concept of a fibered microjoule lidar system using a laser diode. Two systems have been developed with and without polarization analysis capability. A specific optical design was used for polarization discrimination. These systems were integrated in buoys and tested in the Arctic in 2014 and 2015 at latitudes higher than 80°N. Data were transmitted through an Iridium space link. Measurements have been obtained 90% of the time from the non-polarized system in 2014 over 8 months as the first fully equipped buoy drifted from the Barneo Russian camp close to the North Pole toward Svalbard. A polarized system was then tested over a short period in winter 2015 north of Svalbard during the Norwegian campaign N-ICE. In April and May 2014, the unattended lidar measurements showed a large occurrence of aerosols and haze. The average attenuated scattering ratio for non-cloudy profiles during this period was about 2.2. Aerosols could reach an altitude of 5km on average, whereas over the rest of the period low level clouds (below 1000 m) were prevailing with an average attenuated scattering ratio of about 103. The main features of the developed lidar instruments and first results are presented here.

The development of a first ever autonomous aerosol and cloud backscatter lidar system for on-buoy arctic observations has been achieved in 2014, within the French EQUIPEX IAOOS project developed in collaboration with LOCEAN at UPMC. This development is part of a larger set-up designed for integrated ocean-ice-atmosphere observations. First results have been obtained from spring to autumn 2014 after the system was installed at the North Pole at the Barneo Russian camp, and in winter-spring 2015 during the Norwegian campaign N-ICE 2015. The buoys were taking observations as drifting in the high arctic region where very few measurements have been made so far. This project required the design and the conception of an all-new lidar system to fit with the numerous constraints of such a deployment. We describe here the prototype and its performance. First analyzes are presented.

Better understanding of atmosphere-ice-ocean interactions and in particular of the role of aerosols and clouds in this Earth system is of prime importance in the Arctic. In the frame of the French IAOOS Equipex project, a new observational network is planned to be developed for ocean-ice-atmosphere climate survey over the Arctic, starting in 2015, to complement satellite observations. Eye-safe lidar measurements will allow us to profile aerosols and clouds for the atmospheric part, with the objective to perform regular measurements and characterize the vertical structure and optical properties. Radiation and meteorological parameters will be measured at the surface. A first buoy has been prototyped and deployed in April 2014 at the Barneo site set by the Russian teams at the North Pole. Measurements with the first autonomous backscatter lidar ever deployed in the arctic have been taken from April to end of November 2014 before the buoy was lost. Four profiles a day have been performed allowing a good sampling of cloud variability. Observations have shown that the occurrence of low level clouds was higher than 90% during summer. The project is presented, instrument performance is described and first results are discussed.

In the frame of the French IAOOS Equipex project, a new observational network is to be developed for the ocean-ice-atmosphere survey over the Arctic starting in 2015 to better understand interactions and in particular the role of aerosols and clouds in the Arctic. Eye-safe lidar measurements will allow to profile aerosols and clouds for the atmospheric part, with the objective to perform regular measurements and characterize their vertical structure and optical properties complementing satellite observations. Radiation and meteorological parameters will simultaneously be measured at the surface. A first buoy has been prototyped and deployed in April 2014 at the Barneo site set by the Russian teams at the North Pole. Measurements with the first autonomous backscatter lidar ever deployed in the arctic have been taken from April to end of November 2014 before the buoy was lost. A second set of data were acquired during the N-ICE campaign north of Svalbard during winter 2015. Up to four profiles a day (10 mn sequence each) have been performed allowing a good sampling with respect to meteorological analyses. Observations have shown that the occurrence of low level clouds was higher than 90% during summer. New deployments are planned in summer 2015 as the start of the IAOOS network. The project is presented, instruments are described and first results are discussed.

A high spectral resolution (HSR) measurement capability in the ultraviolet has been added to the 3-wavelength-2-polarization-backscatter lidar LNG (lidar aerosols nouvelle génération) and tested during several flights. The system includes a Mach-Zehnder interferometer (MZI) as a spectral discriminator and does not require any frequency locking between the emitter and the interferometer. Results obtained during test flights show that the backscatter and extinction coefficients at 355 nm can be measured with a relative precision of 10% for 60 m and 240 m vertical resolution, respectively, in aerosol layers of 10-6  m-1 sr-1 backscatter coefficient with a 30-km horizontal resolution. The same relative precision is obtained in cirrus clouds of a 2×10-5  m-1 sr-1 backscatter coefficient for the same vertical resolution and a horizontal resolution reduced to 5 km. The capacity of the system to perform wind velocity measurements is also demonstrated with precisions in the range of 1 to 2  ms-1. Particle-to-total backscatter ratio and line-of-sight speed measurements have been performed on ground echoes; averaged data show biases less than 1% and 0.15  ms-1, respectively.

It is quite clear that for studying Arctic climate changes, and better understand interacting processes it is essential to follow an integrated approach for observing and modeling the whole Arctic system encompassing the atmosphere, the ocean and sea-ice at once. Due to the difficulties in retrieving key parameters, satellite observations alone are not the right answer. The project we are developing, is an attempt to tackle this challenge by providing and maintaining a new integrated observing network of instrumented buoys over the Arctic Ocean in order to collect simultaneously and in real time information related to the state of the upper Ocean, the lower Atmosphere and the Arctic sea-ice/snow. It is planned to operate several autonomous platforms in a network in the Arctic Ocean for a period of at least 5 years. Each platform is equipped to vertically sense and profile key variables in the ocean, sea-ice and atmosphere using - CTD (conductivity, temperature, depth) vertical profilers sensors collecting ocean temperature and salinity down to 800m depth, - Temperature and heat conductivity in snow and ice from ice-mass-balance systems - Cloud and aerosol lidar profiling of the lower atmosphere - Diffuse and direct solar flux using wide angle radiometer - Meteorological standard parameters at the surface Platforms allow measurements to be transmitted in near real time via Iridium satellites. As they will be drifting, it is planned to replace part of them every year. Major tests were performed deploying progressively fully equipped IAOOS platform at the North Pole in April 2012, 2013 and 2014. These platforms drifted from the North Pole in April to Fram Strait (September, October) providing spring summer and fall field data. Important fieldwork for IAOOS was also taking place within the Norwegian ice camp on board R/V Lance organized by the Norsk Polar Institute from January to June 2015, as part of the Norwegian young ICE (N-ICE 2015) cruise project. These intensive tests were very timely. The first IAOOS array deployment will start in August 2015 from R/V Araon during the Korean cruise organized by the KOPRI in the Canadian Basin and from R/V Polarstern during the German cruise TRANSARC II organized by the Alfred Wegener Institute in the Eurasian Basin. First results obtained in the frame of IAOOS will be presented and discussed.

A direct-detection wind lidar that operates with a multimode laser has been developed and tested. The instrument exploits the light backscattered by particles using a Mach-Zehnder interferometer with an optical path difference matched to the free spectral range of the laser longitudinal modes. In addition to requiring no monomodal emission, the system requires no frequency locking between the interferometer and the laser. We report laboratory and atmospheric measurements that show that the lidar is capable of measuring the radial wind velocity with a systematic error lower than 1 ms(-1) and a random error lower than 2 ms(-1) for a signal-to-noise ratio of 100. The development is motivated by the possibility to probe wind with a compact system in planetary atmospheres.

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The electronic system developed for the SpaCal lead/scintillating-fibre calorimeters of the H1 detector in operation at the HERA ep collider is described in detail and the performance achieved during H1 data-taking is presented. The 10 MHz bunch crossing rate of HERA puts severe constraints on the requirements of the electronics. The energy and time readout are performed respectively with a 14-bit dynamic range and with a resolution of about 0.4 ns. The trigger branch consists of a nanosecond-resolution calorimetric time-of-flight for background rejection and an electron trigger based on analog `sliding windows'. The on-line background rejection currently achieved is o(10**6). The electron trigger allows a low energy trigger threshold to be set at about 0.50 +/- 0.08 (RMS) GeV with an efficiency >99.9%. The energy and time performance of the readout and trigger electronics is based on a newly-developed low noise (sigma_noise ca. 0.4 MeV) wideband (f < 200 MHz) preamplifier located at the output of the photomultipliers which are used for the fibre light readout in the ca. 1 Tesla magnetic field of H1.

Technical aspects of the three major components of the H1 detector at the electron-proton storage ring HERA are described. This paper covers the detector status up to the end of 1994 when a major upgrading of some of its elements was undertaken. A description of the other elements of the detector and some performance figures from luminosity runs at HERA during 1993 and 1994 are given in a paper previously published in this journal.

We describe the digital filter section of the FERMI readout microsystem. The filter section, consisting of two separate filter blocks, extracts the pulse amplitude and time information for the first-level trigger process and performs a highly accurate energy measurement for higher-level triggering and data readout purposes. An FIR-order statistic hybrid filter structure is used to improve the amplitude extraction performance. Using a training procedure the filters are optimized to produce a precise and accurate output in the presence of electronics and pile-up noise, sample timing jitter and the superposition of high-energy pulses. As the FERMI system resides inside the detector where accessibility is limited, the filter implementations are presented together with fault tolerance considerations. The filter section is modelled with the VHDL hardware descriptive language and the subsystems are further optimized to minimize the system latency and circuit area.

The Front-End Read-out MIcrosystem (FERMI) for calorimeters at LHC presented last year has been further developed with the aim to achieve a full silicon implementation early 1994. Each microsystem will, as before, contain 9 channels with 15-16 bits dynamic range using IO-bit AD converters sampled every 15 ns. The function is accomplished by using a non-linear amplifier in front of the ADC to compress high amplitude signals, reversing the transformation to obtain overall linearity in a look-up table after the digitisation. The direct first-level trigger output for digitally filtered energy data is equipped with pulse recognition capability. The main data flow enters a pipeline memory from which relevant portions are extracted to second and third-level triggers via an adaptive 7-tap digital filter. The module is presently developed as 14 ASICs to be