This PDF file contains the front matter associated with SPIE Proceedings Volume 8182, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

This paper describes a robust technology investment program to improve Earth observation capabilities. Four key challenges are identified, along with a brief overview of technologies addressing each of these challenges. The remainder of the paper focuses upon active remote sensing technology developments, including both lidar and radar advancements, supporting priority Earth science measurements. Technology advancements for each of these measurements - such as aerosols, altimetry, and 3D winds -- are highlighted.

At NASA's Goddard Space Flight Center we are developing next generation laser transmitters for future spaceflight, remote instruments including a micropulse altimeter for ice-sheet and sea ice monitoring, laser spectroscopic measurements of atmospheric CO2 and an imaging lidar for high resolution mapping of the Earth's surface. These laser transmitters also have applicability to potential missions to other solar-system bodies for trace gas measurements and surface mapping. In this paper we review NASA spaceflight laser transmitters used to acquire measurements in orbit around Mars, Mercury, Earth and the Moon. We then present an overview of our current spaceflight laser programs and describe their intended uses for remote sensing science and exploration applications.

Carbon dioxide (CO2) and methane (CH4) are the most important of the greenhouse gases that are directly influenced by human activities. The Integrated Path Differential Absorption (IPDA) lidar technique using hard target reflection in the near IR (1.57μm and 1.64μm) to measure the column-averaged dry air mixing ratio of CO2 and CH4 with high precision and low bias has the potential to deliver measurements from space and air that are needed to understand the sources and sinks of these greenhouse gases. CO2 and CH4 IPDA require tunable laser sources at 1.57 μm and 1.64 μm that coincide with appropriate absorption lines of these species having high pulse energy and average power as well as excellent spectral and spatial properties. Within this study we have realized more than 50mJ of pulse energy in the near IR coincident with appropriate absorption lines using an injection-seeded optical parametric oscillator-amplifier system pumped at 100 Hz. At the same time this device showed excellent spectral and spatial properties. Bandwidths of less than 100 MHz with a high degree of spectral purity (> 99.9 %) have been achieved. The frequency stability was likewise excellent. The M2-factor was better than 2.3. Owing to these outstanding properties optical parametric devices are currently under investigation for the CH4 lidar instrument on the projected French-German climate satellite MERLIN. A similar device is under development at DLR for the lidar demonstrator CHARM-F which will enable the simultaneous measurement of CO2 and CH4 from an airborne platform.

In this paper we will discuss our development effort of an airborne instrument as a pathfinder for the LIdar Surface Technology (LIST) mission. This paper will discuss the system approach, enabling technologies, instrument concept, final assembly and the preparation for flight with this new multi-beam non-scanning, swath mapping laser altimeter system.

In this paper we present the final configuration of the space flight laser transmitter as delivered to the Lunar Orbiter Laser Altimeter (LOLA) instrument along with some in-space operation performance data. The LOLA instrument is designed to map the lunar surface and provide unprecedented data products in anticipation of future manned flight missions. The laser transmitter has been operating on orbit at the Moon continuously since July 2009 and accumulated over 1.8 billion laser shots in space. The LOLA laser transmitter design has heritage dated back to the MOLA laser transmitter launched more than 10 years ago and incorporates lessons learned from previous laser altimeter missions at NASA Goddard Space Flight Center.

In this paper the possible synergy between advanced lidars and ceilometers for the monitoring of atmospheric aerosols is evaluated. The advanced measurement capabilities of the multi-wavelength Raman lidar are used to investigate the capability of ceilometers to provide reliable information about the atmospheric aerosol content. At the CNR-IMAA Atmospheric Observatory (CIAO), a ceilometer is operational since September 2009 providing vertical profiles of atmospheric backscatter at 1064nm up to 15km; at the same location, the Potenza EArlinet Raman Lidar (PEARL), a quality-assured, multi-wavelength Raman lidar operates in the framework of EARLINET and performs regular measurements plus measurements of special events (Sahara dust outbreaks, volcanic eruptions etc.). Using the PEARL data products as a reference, the capability of ceilometers to detect aerosol layers and provide quantitative information about the atmospheric aerosol load is investigated. The variation of ceilometers' performance in different atmospheric conditions is analysed. A procedure for obtaining backscatter coefficient profiles from ceilometer signals is proposed and its limitations are discussed.

Obtaining high resolution vertical profiles of water vapor is crucially important to understand short and long term global climate changes. Raman lidar technique is widely recognized as the most effective tool to study water vapor and aerosols profiles in the lower atmosphere. The Great lakes area is one of the ideal areas to study the environmental impact of water vapor and aerosols profiles on air quality due to its dynamic ecological system, and proximity to most North American industrial centers. Latest results of a newly developed water vapor Raman lidar instrument at the Environment Canada's Centre for Atmospheric Research Experiments (CARE) (44°14'02" North, 79°45'40" West) will be presented. In this study, the instrument is described and its capabilities are illustrated along with preliminary measurements. The CARE Raman lidar setup utilizes third harmonic (355 nm) output of employed YAG laser to probe aerosols, water vapor, and nitrogen profiles. By manipulating inelastic backscattering lidar signals of the Raman nitrogen channel (386.7 nm) and Raman water vapor channel (407.5 nm), a vertical profile of water vapor mixing ratio from the near ground up to 12 km geometrical altitude is deduced. Vertical profile of the backscattering ratio obtained at 1064 nm using another elastic lidar will be shown and related to the Raman lidar results.

The development of the Global Position System (GPS) satellite network provides new opportunities to characterize atmospheric parameters using innovative techniques. The GPS Radio Occultation Technique (GPS RO) is one of the most recent and promising atmospheric remote sensing technique applied to GPS measurements. The GPS RO technique allows obtaining profiles of refractivity, temperature, pressure and water vapor in the neutral atmosphere and electron density in the ionosphere. In the last years, other missions confirmed the RO efficiency, like GPS/MET, COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate), Formosa Satellite Mission 3 and the last Radio Occultation Sounder Antenna for the Atmosphere. In this work, water vapor mixing ratio profiles retrieved from COSMIC observations are presented and validated using ground based water vapor Raman lidar profiles. As far as we know, this is the first time water vapor mixing ratio profiles provided by COSMIC are compared with a ground based Raman lidar. COSMIC profiles used in this study are retrieved applying a one-dimensional variational method that make use of ECMWF low resolution analysis data as a guess of atmospheric water vapor. Raman lidar measurements of the water vapor mixing ratio profiles are provided by PEARL (Potenza EArlinet Raman Lidar) system running at CIAO, located in Potenza, South Italy. Performance of COSMIC retrieval are studied over a period of one year (2008) of systematic water vapor Raman lidar measurements. A possible strategy for reducing the impact of the co-location mismatch between satellite footprint and the lidar station is presented and the problem of the vertical resolution of COSMIC profiles respect to the Raman lidar is also discussed. The statistical analysis for the selected cases shows good performance of COSMIC in the identification of the vertical gradients of the water vapor field, even though the average difference between the Raman lidar and the COSMIC profiles suggests that caution should be taken in using COSMIC data as an absolute or reference measurement of water vapor, in particular in the low and middle troposphere.

Data of one year (January to December 2010) has been analyzed regarding aerosol layers in the free troposphere. In total, 120 layers were observed above the boundary layer during 56 out of 78 performed measurements. The investigated aerosol types were anthropogenic (15% of all layers), forest fire plumes (10%), volcanic from Eyjafjallajokull (6%), desert dust (17%) and aerosol transported over the sea below an altitude of 2 km (18%). The remaining 35% of the layers could not be assigned to one aerosol type unambiguously. The seasonal variability was investigated as well. In winter, only 8% of the aerosol layers were detected. Most layers were observed during spring (40%) and summer (34%). The aerosol layer mean height, layer depth, lidar ratios, Angstrom exponents and aerosol optical depths as well as relative humidity were investigated with the aim of a characterization of the individual aerosol types. The variations of most of the analyzed properties within one cluster were high. This is partly due to differences in, aerosol mixing close to the source, aging processes or different transport paths of the aerosol layers in one cluster. Lidar ratios at 355 nm and extinction-related Angstrom exponents from 355 to 532 nm were (51 ± 17) sr and 1.7 ± 0.7, respectively, for anthropogenic aerosol, (43 ± 13) sr and 1.4 ± 0.5 for forest fire aerosol, (50 ± 11) sr and 1.9 ± 1.0 for volcanic aerosol, (58 ± 20) sr and 0.5 ± 0.3 for desert dust, (52 ± 20) sr and 1.8 ± 0.8 for aerosol transported over the sea below 2 km and (54 ± 21) sr and 1.8 ± 1.0 for all layers, which could not be assigned to any of the types.

A 1.57-μm laser remote sensor using differential absorption spectrometory is being developed as a candidate for the next space-based mission to observe atmospheric CO₂ and/or other trace gases. In a previous study, the performance of a proto-type system with sinusoidal modulation was evaluated based on ground and airborne measurements. The airborne measurements showed that the LAS with sinusoidal modulation could detect strong CO₂ plume, and suppress the impact of an aerosol layer over high surface reflectivity. Based on those results, an outline of LAS system on the space platform such as the International Space Station Japan Experimental Module (ISS-JEM) was desined. However, an elevated layer in the observation path is still remain, which leads to reduce effective observed data as long as current sinusoidal modulation is employed. In order to prevent the impact of elevated layer, different modulation schemes such as random or frequency modulation are capable. We are currently improving the LAS system with a chirp modulation scheme for the purpose. Some of recent airborne measurements using sinusoidal modulation and ground-based measurements using chirp modulation in progress will be shown in this meeting.

Inverse techniques using atmospheric transport models are developed to estimate the CO₂ sources and sinks based on the observed data. In comparison with the ground-based monitoring network, CO₂ measurements for vertical profiles in the troposphere have been due to the limited observations by using campaign-style aircrafts and the commercial airlines with limited spatial and temporal coverage. The differential absorption lidar (DIAL) with the range resolution is expected to bring several advantages over passive measurements, for example, daytime coverage and neglecting influences of aerosol and cirrus layers. We have succeeded to develop the 1.6 μm DIAL technique using direct detection method for measurement of CO₂ concentration profiles in the atmosphere. This paper describes the advanced CO₂ 1.6 μm DIAL technique consisting of the optical parametric generator (OPG) transmitter (10mJ/pulse) that excited by the LD pumped Nd:YAG laser with high repetition rate (500Hz) and the receiving optics that included the large telescope with 60cm diameter and the photomultiplier tube with high quantum efficiency (~8%) operating at the photon counting mode and the narrowband interference filter (0.5nm bandwidth) for daytime observations. The CO₂ concentration profiles from ground to an altitude of 12km are conducted to measure with better than 1% standard deviation using 500m bins by this CO₂ DIAL.

We present airborne measurements of a novel eye-safe spectrally broadband LIDAR capable of dealing with the atmospherically-induced variations in CO2 absorption using a Fabry-Perot based detector. The Fabry-Perot solid etalon in the receiver part is tuned to match the wavelength of several CO₂ absorption lines simultaneously. The broadband technique tremendously reduces the requirement for source wavelength stability, instead putting this responsibility on the Fabry- Perot based receiver. The instrument technology we are developing has a clear pathway to space and realistic potential to become a robust, low risk space measurement system.

The Aeolus mission of the European Space Agency (ESA) will send the first wind lidar to space to fulfill the utmost need for global wind profile observations. Before the scheduled launch in late 2013, pre-launch campaigns have to be performed to validate the measurement principle and to optimize retrieval algorithms. Therefore, an airborne prototype instrument has been developed, the ALADIN Airborne Demonstrator (A2D). In September 2009 an airborne campaign over Greenland, Iceland and the Atlantic Ocean was conducted using two instruments: the A2D and a well established coherent 2-μm lidar for aerosol and cloud backscatter. Thus, two wind lidar instruments measuring Mie and Rayleigh backscatter in parallel were operated on the same aircraft. This paper describes the analysis of wind measurement data gathered during a flight segment on 26.09.2009. A dedicated aerial interpolation algorithm is introduced taking into account the different resolution grids of the two lidar systems. Via a statistical comparison of line of sight (LOS) winds the systematic and random error of the direct-detection wind lidar A2D was assessed, yielding -0.7 m/s and 1.9 m/s for the Rayleigh and 1.1 m/s and 1.3 m/s for the Mie channel, respectively.

A field deployable all-fiber eye-safe Coherent Doppler LIDAR is being developed at the Optical Remote Sensing Lab at the City College of New York (CCNY) and is designed to monitor wind fields autonomously and continuously in urban settings. Data acquisition is accomplished by sampling lidar return signals at 400 MHz and performing onboard processing using field programmable gate arrays (FPGAs). The FPGA is programmed to accumulate signal information that is used to calculate the power spectrum of the atmospherically back scattered signal. The advantage of using FPGA is that signal processing will be performed at the hardware level, reducing the load on the host computer and allowing for 100% return signal processing. An experimental setup measured wind speeds at ranges of up to 3 km.

Prediction of weather disaster such as heavy rain and light strike is an earnest desire. Successive monitoring of the low altitude atmosphere is important to predict it. In this study, high precision polarization lidar was developed to observe the low altitude atmosphere. This lidar has the high extinction ratio of polarization of >30dB to detect the small polarization change of the atmosphere. The change of the polarization in the atmosphere leads to the detection of the depolarization effect and the Faraday effect, which are caused by ice-crystals and lightning discharge, respectively. The long-term observation was accomplished at low elevation angle. It aims to monitor the low altitude atmosphere under the cloud base and capture its spatial distribution and convection process. The observation has been continued in the cloudy and rainy days. The thunder cloud is also a target.

In this paper, the simulations of the Weather Research and Forecast (WRF) and Community Multiscale Air Quality (CMAQ) Models applied to the New York City (NYC) area are assessed with the aid of vertical profiling and column integrated remote sensing measurements. First, we find that when turbulent mixing processes are dominant, the WRFderived planetary boundary layer (PBL) height exhibits a strong linear correlation (R>0.85) with lidar-derived PBL height. In these comparisons, we estimate the PBL height from the lidar measurements using a Wavelet Covariance Transform (WCT) approach that is modified to better isolate the convective layer from the residual layer (RL). Furthermore, the WRF-Lidar PBL height comparisons are made using different PBL parameterization schemes, including the Asymmetric Convective Model-version2 (ACM2) and the Modified Blackadar (BLK) scheme (which are both runs using hindcast data), as well as the Mellor-Yamada-Janjic (MYJ) scheme run in forecast mode. Our findings show that the correlations for these runs are high (>0.8), but the hindcast runs exhibit smaller overall dispersion (≈0.1) than the forecast runs. We also apply continuous 24-hour/7-day vertical ceilometer measurements to assess WRFCMAQ model forecasts of surface PM_2.5 (particulate matter has aerodynamic diameter <2.5μm). Strong overestimations in the surface PM_2.5 mass that are observed in the summer prior to sunrise are particularly shown to be strongly connected to underestimations of the PBL height and less to enhanced emissions. This interpretation is consistent with observations that TEOM (Tapered Element Oscillating MicroBalance) PM_2.5 measurements are better correlated to pathintegrated CMAQ PM_2.5 than the near-surface measurements during these periods.

The determination of the depth of daytime and nighttime Planetary Boundary Layer Height (PBLH) must be known very accurately to relate boundary layer concentrations of gases or particles to upstream fluxes. Moreover, the air quality forecasts rely upon semi-empirical parameterizations within numerical models for the description of dispersion, formation and fate of pollutants influenced by the spatial and temporal distribution of emissions in cities, topography, and weather. The particulate matter (PM) mass measured at the ground level is a common way to quantify the amount of aerosol particles in the atmosphere and is the standard used to evaluate air quality. Remote sensing of atmospheric aerosols in the lower troposphere that affect air quality is done at the University of Maryland, Baltimore County (UMBC) by the Atmospheric Lidar Group, that supported the joint NOAA/ARL and NCEP ad hoc field study. These campaigns launched radiosondes from Howard University (HU) (26.6km south of UMBC) and RFK Stadium (29.15 km south of UMBC) during September 14-22, 2009 to develop a database to investigate the evolution and spatial variability of the PBLH. In this paper, we examined the potential for continual observation of PBLH by performing a statistical comparison of the spatial and temporal resolution of PBLH from lidars, wind profiler, and radiosonde measurements

A lidar-based method was used to separate profiles of optical parameters due to different aerosol types over different European Aerosol Research LIdar NETwork (EARLINET) stations. The method makes uses of particle backscatter profiles at 532 nm and vertically resolved linear particle depolarization ratio measurements at the same wavelength. Values of particle depolarization ratio of 'pure' aerosol types (Saharan dust, biomass burning aerosols, anthropogenic aerosols, Volcanic ash aerosols) were taken from literature. Cases of CALIPSO space-borne lidar system were selected on the basis of different mixing state of the atmosphere over EARLINET stations. To identify the origin of air-masses four-day air mass back trajectories were computed using HYbrid Single-Particle Langrangian Integrated Trajectory (HYSPLIT) model, for different arrival heights, for the location and time under study was used. Also, the Dust REgional Atmospheric Modeling (DREAM) model was used to identify cases where dust from Saharan region was affecting the place under study. For our analysis we have used Atmospheric Volume Description (AVD), Cloud-Aerosol Discrimination (CAD) and extinction Quality Control (QC) flags to screen out CALIOP data. The method was applied for different horizontal resolution of 5, 25, 45 and 105 km. The height-resolved lidar results were finally compared with column-integrated products obtained with Aerosol Robotic Network Sun photometer (AERONET) in order to see to what extent Sun photometer columnar data are representative when different aerosol layers are present in the atmosphere.

Atmospheric aerosol particles have received much attention in recent years due to their importance in climate change. The influence of these particles on Earth's radiative budget depends on a number of factors, including their size distribution and chemical composition. This work addresses a particular property of aerosols, namely, the extent to which they have affinity for water vapor. The size increase of aerosol particles resulting from water vapor uptake has important implications for the direct scattering of radiation and cloud droplets formation. We used a single-wavelength backscatter LIDAR (532 nm), and relative humidity profiles obtained from radiosounding to assess the hygroscopic growing factor of aerosols over Sao Paulo metropolitan region, for five days altogether on March and September 2007 and August 2009. In these days we had a breeze onset over the metropolitan area, potentially bringing marine aerosols and humidity from the Atlantic Ocean. In this way we were able to detect a change in the boundary layer aerosol optical properties during these onsets using range corrected backscattering signal from LIDAR and a detailed analysis on the changes in backscattering coefficient profiles by a Klett analysis. In order to infer the hygroscopic growing factor, we developed a fitting model algorithm, proposed in the literature, calculating the backscattering coefficient at 532 nm for periods before and during the breeze and comparing the same profiles at various altitude levels with a reference profile at the lowest relative humidity level whithin the mixing layer. In addition, we performed a comparison between the thirty minutes backscattering profiles inside the breeze with a reference thirty minutes backscattering profile before the breeze.

In this paper, we first report the recent achievement of a mid-infrared supercontinuum fiber laser source in our laboratory. Using fluoride fibers, we have generated a wavelength supercontinuum covering the whole 2-3.5μm range, and delivering a power spectral density of 0.3 mW/nm on a large spectral range. Experimental results are presented. This source can open opportunities for broadband remote sensing of multiple gas species in the atmosphere, especially above 3 μm, where numerous organic compounds have strong absorption signatures. Therefore, we consider a simple Supercontinuum Laser Absorption Spectroscopy (SLAS) experiment, and we develop a numerical case study above 3 μm, involving a multi-component gas mixture. We first describe a method for modelling noisy spectroscopic signals. Then we consider the inverse problem, and attempt to perform identification and quantitative estimation of the gas mixture. After showing the inapplicability of a direct multi-linear regression, we focus on processing methods that use complexity penalization principles, and show that they can address efficiently the identification/estimation problem. Among various penalization criteria, those based on Minimum Description Length (MDL) approaches are shown to perform particularly well. Finally, we apply these methods to preliminary experimental spectroscopic signals obtained with supercontinuum sources in our laboratory.

A 6-channel dichroic-based polychromator is presented as the spectrally selective unit for the U.P.C. elastic/Raman lidar. Light emission is made at 355-nm (ultraviolet, UV), 532-nm (visible, VIS) and 1064-nm (near infrared, NIR) wavelengths. In reception, the polychromator is the spectral separation unit that separates the laser backscattered composite return into 3 elastic (355, 532, 1064-nm wavelengths) and 3 Raman channels (386.7, 607.4 and 407.5-nm (water-vapor) wavelengths). The polychromator houses photo-multiplier tubes (PMT) for all the channels except for the NIR one, which is avalanche photodiode (APD) based. The optomechanical design uses 1-inch optics and Eurorack standards. The APD-based receiver uses a XY-axis translation/elevation micro-positioning stage due to its comparatively small active area and motorised neutral density filters are used in all PMT-based channels to avoid detector saturation. The design has been specially optimized to provide homogeneous spatial light distribution onto the photodetectors and good mechanical repeatability. All channels are acquired in mixed analog and photon-counting mode using Licel® transient recorders, which are controlled by means of a user friendly LabVIEW^TM interface. The paper focuses on the main polychromator optical design parameters, that is, light collimation trade-offs, end-to-end transmissivity, net channel responsivity, light distribution and spot size onto the photodetectors. The polychromator along with the rest of the U.P.C. lidar system has successfully been tested during a recent lidar system intercomparison campaign carried out in Madrid (Spain) during Oct. 2010.

We have been developing white light lidar using a terawatt laser system at 800 nm, which generates a coherent white light continuum in the wavelength range from 300 nm to more than 2200 nm. The white light lidar has the advantage of performing the simultaneous multi-wavelength measurements at preferred spectral lines for various applications. In addition, the white light generated in Kr gas keeps the linear polarization of the original laser. The white light lidar can be applied to sensing the polarization of multi-wavelength backscattered light capable of determining the degree of nonsphericity of the particles. Also, a new approach, called channeled spectropolarimetry, is developed that provides a complete polarization description of clouds and aerosols. The complete set of Stokes parameters from 450 to 700 nm are reconstructed from one spectral measurement. We demonstrated this approach capable of characterizing the spectrally resolved polarization state of a linearly polarized beam transmitted by a birefringent sample and the weak scattered light from the Cu plate 20 m away. This remarkable experiment opens new prospective in remote sensing by using the polarization.

Characterization of atmospheric emissions from industrial flare stacks represents a challenge in measurement techniques because it is extremely difficult to determine the real-time concentrations of combustion products by in situ sampling, due to stack height, sensor calibration difficulties, and the dynamics of oscillations in the emission patterns. A ground based laser remote sensing (LIDAR) system has been developed for continuous and real-time monitoring of atmospheric emissions from an oil refinery located approximately 400 m from the instrument. The system is able to perform 3D scanning and profiling around the emission point. Tests were carried out using a scanning system pointed to the refinery flare. The mapping was obtained from a sequence of measurements at different zenithal and azimuthal angles resulting in a 3D image of the flare shape plus the flame itself. The measurements can be used to estimate the aerosol size distribution based on the ratios of the backscattering signal at three distinct wavelengths: 1064/532 nm, 1064/355 nm, and 532/355 nm. The method can be used in real time monitoring of industrial aerosol emissions and in the control of industrial processes. Preliminary results indicate a calibration procedure to assess the refining process efficiency based on the particle size distribution within and around the flare.

Optical remote sensing techniques have obvious advantages for monitoring gas and aerosol emissions, since they enable the operation over large distances, far from hostile environments, and fast processing of the measured signal. In this study two remote sensing devices, namely a Lidar (Light Detection and Ranging) for monitoring the vertical profile of backscattered light intensity, and a Sodar (Acoustic Radar, Sound Detection and Ranging) for monitoring the vertical profile of the wind vector were operated during specific periods. The acquired data were processed and compared with data of air quality obtained from ground level monitoring stations, in order to verify the possibility of using the remote sensing techniques to monitor industrial emissions. The campaigns were carried out in the area of the Environmental Research Center (Cepema) of the University of Sao Paulo, in the city of Cubatao, Brazil, a large industrial site, where numerous different industries are located, including an oil refinery, a steel plant, as well as fertilizer, cement and chemical/petrochemical plants. The local environmental problems caused by the industrial activities are aggravated by the climate and topography of the site, unfavorable to pollutant dispersion. Results of a campaign are presented for a 24- hour period, showing data of a Lidar, an air quality monitoring station and a Sodar.

Affordable coherent wind lidars based on modern telecom components have recently emerged on the wind energy market spurred by high demand of the industry for compact and accurate remote sensing wind and turbulence profilers. Today, hundreds of ground based wind lidars that achieve the range resolution by either focusing a continuous-wave laser beam or by gating a pulsed laser beam are used for measuring mean wind and turbulence profiles in the lower atmospheric boundary-layer. However, detailed understanding of the influence of the spatial filtering of the lidars on their precise assessment of turbulence is still a challenge. For assessment of the fine structure turbulence, and in particular for the easy and fast assessment of the dissipation rate of turbulent kinetic energy from measurements in the Kolmogorov inertial subrange, we havemodeled the atmospheric velocity structure functions and spectra obtainable from fixed-orientation along-beam wind measurements by these lidars. The dissipation rate retrieval model is experimentally evaluated with data obtained with a pulsed lidar pointing horizontally into horizontally homogeneous turbulence encountered at the top level of a 125 m tall meteorological tower, equipped with an in-situ turbulence measurement device (a three-dimensional sonic anemometer) for intercomparison. Our experimental study has revealed that the easily manageable analytical model accounts well for the observed fine structure turbulent spectra and their dependence on the pointing direction of the lidar beam relative to the mean wind direction. The results demonstrate that turbulence dissipation rates, and hence boundary-layer turbulence, can easily be obtained from wind lidar-based fine structure measurements.

Lidar and dial are well established methods to explore the atmosphere. Different groups have already shown experimentally the possibility to measure the density variation of aerosol and particulate in the atmosphere due to plumes emitted in forest fires with this kind of systems. The aim of the present work is to demonstrate the capabilities of our mobile Lidar system, based on a CO2 laser, to detect forest fires and minimizing false alarms. For this purpose, our system can be operated in both lidar and dial configurations in sequence. The first Lidar measurement is performed to evaluate the variation of the local density into the atmosphere, using a nonabsorption water wavelength 10R18 (10.571 μm). If the returned signal reports a backscattering peak, the presence of a fire is probable. To confirm this hypothesis, a second dial measurement is carried out to reveal a second component emitted during the combustion process. The chosen second component is water vapour, which is, as it is well-known, largely produced during the first combustion stage. Measuring the water concentration peak after the detection of the aerosol density increment (referred to the standard mean atmospheric value) represents a good method to reduce false alarms with a dial system. In order to test this methodology, a first set of measurements has been performed in a field near the Engineering Faculty of the University of Rome "Tor Vergata". A quite small controlled-fire has been lighted into a box at a distance of about one kilometre from the system. The data acquired at the two wavelengths (10R18 and 10R20) have been averaged on 100 elastic backscattered Lidar signals. The first results confirm the effectiveness of the measurement strategy for reducing the number of false alarm preserving the early detection.

The central and western portion of the Sao Paulo State has large areas of sugar cane plantations, and due to the growing demand for biofuels, the production is increasing every year. During the harvest period some plantation areas are burnt a few hours before the manual cutting, causing significant quantities of biomass burning aerosol to be injected into the atmosphere. During August 2010, a field campaign has been carried out in Ourinhos, situated in the south-western region of Sao Paulo State. A 2-channel Raman Lidar system and two meteorological S-Band Doppler Radars are used to indentify and quantify the biomass burning plumes. In addiction, CALIPSO Satellite observations were used to compare the aerosol optical properties detected in that region with those retrieved by Raman Lidar system. Although the campaign yielded 30 days of measurements, this paper will be focusing only one case study, when aerosols released from nearby sugar cane fires were detected by the Lidar system during a CALIPSO overpass. The meteorological radar, installed in Bauru, approximately 110 km northeast from the experimental site, had recorded "echoes" (dense smoke comprising aerosols) from several fires occurring close to the Raman Lidar system, which also detected an intense load of aerosol in the atmosphere. HYSPLIT model forward trajectories presented a strong indication that both instruments have measured the same air masss parcels, corroborated with the Lidar Ratio values from the 532 nm elastic and 607 nm Raman N₂ channel analyses and data retrieved from CALIPSO have indicated the predominance of aerosol from biomass burning sources.

We present initial aerosol validation results of the space-borne lidar CALIOP -onboard the CALIPSO satellite - Level 2 extinction coefficient profiles, using coincident observations performed with a ground-based lidar in Thessaloniki, Greece (40.5° N, 22.9° E, 50m above sea level). A ground-based backscatter/Raman lidar system is operating since 2000 at the Laboratory of Atmospheric Physics (LAP) in the framework of the European Aerosol Research LIdar NETwork (EARLINET), the first lidar network for tropospheric aerosol studies on a continental scale. Since July 2006, a total of 150 coincidental aerosol ground-based lidar measurements were performed over Thessaloniki during CALIPSO overpasses. The ground-based measurements were performed each time CALIPSO overpasses the station location within a maximum distance of 100 km. The duration of the ground-based lidar measurements was approximately two hours, centred on the satellite overpass time. The analysis was performed for 4 different horizontal resolutions of 5, 25, 45 and 105 km. For our analysis we have used Atmospheric Volume Description (AVD) array to screen out everything that is not an aerosol. Also, the cloud-aerosol discrimination (CAD) score, which provides a numerical confidence level for the classification of layers by the CALIOP cloud-aerosol discrimination algorithm was set between -80 and -100. CALIPSO extinction QC flags, which summarize the final state of the extinction retrieval, was also used. In our analysis we have used those measurements where the lidar ratio is unchanged (extinction QC = 0) during the extinction retrieval or it the retrieval is constrained (extinction QC = 1). The comparison was performed both for extinction and backscater coefficient profiles. For clear sky conditions, the comparison shows good performances of the CALIPSO on-board lidar.

Multiwavelength micropulse lidar (MML) designed for continuous optical sounding of the atmosphere is presented. A specific signal processing technique applying two directional Kalman filtering is introduced in order to enhance signal to noise ratio. Application of this technique is illustrated with profiles collected in course of COAST 2009 and WRNP 2010 research campaigns.

Daily Aerosol Optical Depth (AOD) values from MODIS satellite instrument may be useful to predict Particulate Matter (PM) values in local scale in accordance with vertical profile of the atmosphere and meteorological data. In the frame of 'AIRSPACE' project, correlations between the AOD retrieved from MODIS to sun photometer data from both hand-held MICROTOPS II and ground-based CIMEL from the AERONET network were applied with good correlation coefficients. This permits to use MODIS retrievals as a reliable tool for assessing PM whereas the relationship between these two quantities is not lucid. The main study area is the centre of Limassol in Cyprus. Results concerning the relation between AOD and PM are presented. In cases where high AOD values corresponded to low PM surface values, the vertical distribution of aerosols from Lidar allows the AOD to be quantified within the boundary layer as this fraction best represents the PM measurements in a well-mixed layer.