Dual-FOV Raman and Doppler lidar studies of aerosol-cloud interactions : Simultaneous profiling of aerosols, warm-cloud properties, and vertical wind

Date of Acceptance: 24/04/2014 This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are madeFor the first time, colocated dual-field of view (dual-FOV) Raman lidar and Doppler lidar observations (case studies) of aerosol and cloud optical and microphysical properties below and within thin layered liquid water clouds are presented together with an updraft and downdraft characterization at cloud base. The goal of this work is to investigate the relationship between aerosol load close to cloud base and cloud characteristics of warm (purely liquid) clouds and the study of the influence of vertical motions and turbulent mixing on this relationship. We further use this opportunity to illustrate the applicability of the novel dual-FOV Raman lidar in this field of research. The dual-FOV lidar combines the well-established multiwavelength Raman lidar technique for aerosol retrievals and the multiple-scattering Raman lidar technique for profiling of the single-scattering extinction coefficient, effective radius, number concentration of the cloud droplets, and liquid water content. Key findings of our 3 year observations are presented in several case studies of optically thin altocumulus layers occurring in the lower free troposphere between 2.5 and 4 km height over Leipzig, Germany, during clean and polluted situations. For the clouds that we observed, the most direct link between aerosol proxy (particle extinction coefficient) and cloud proxy (cloud droplet number concentration) was found at cloud base during updraft periods. Above cloud base, additional processes resulting from turbulent mixing and entrainment of dry air make it difficult to determine the direct impact of aerosols on cloud processes.Peer reviewedFinal Published versio

Utjecaj visokog hidrostatskog tlaka na viskozitet otopina β-laktoglobulina

In this research new experimental data for the pressure dependence of the viscosity of β-lactoglobulin solution are presented. The experimental investigation is based on in-situ viscometric measurement technique which provides an observation of the high-pressure-induced changes of β-lactoglobulin solution during the treatment. This method refers to a rolling ball viscometer that is adapted for the use at high pressures and has a variable inclination angle. The estimation of the viscosity has been done in order to detect reversible and irreversible conformational changes of β-lactoglobulin. For investigation protein solutions concentration 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 g/g were used. The sample solutions are exposed to pressure of 0.1-600 MPa. The results showed that there is no significant effect of 100 MPa pressure on the viscosity of β-lactoglobulin solutions. With increasing pressure, between 100 and 300 MPa, the viscosity of β-lactoglobulin solutions increase. Pressure above 300 MPa causes further increase of the viscosity due to nonreversible and more extensive effects on protein, e.g. unfolding of monomeric proteins and aggregation. The structural changes of the β-lactoglobulin under high pressure affect the hydration of the β-lactoglobulin molecules. At pressure between 100 and 300 MPa there is a significant increase in relative hydration due to structural changes and increase in number of water molecules which are associated with protein molecules. Higher pressure cause protein aggregation due to formation of intermolecular disulfide bonds and irreversible denaturation and aggregation occurs. Because of that, there is no changes in protein hydration, moreover, the hydration of β-lactoglobulin molecules have a small decreases at pressure between 400 and 600 MPa.U radu su prikazani novi eksperimentalni podaci o viskozitetu vodene otopine β-laktoglobulina na visokim tlakovima. Eksperimentalno ispitivanje temeljeno je na primjeni in-situ tehnike mjerenja viskoziteta otopine. Za mjerenja korišten je Rolling ball viskozimetar s različitim kutovima nagiba koji je prilagođen radu na visokim tlakovima. Određivanje viskoziteta otopine vršeno je s ciljem utvrđivanja reverzibilnih i ireverzibilnih promjena strukture molekula β-laktoglobulina. Za eksperimentalna mjerenja korištene su otopine koncentracije 0.01, 0.02, 0.03, 0.04, 0.05 i 0.06 g/g, a izložene su tlakovima od 0.1 do 600 MPa. Rezultati ispitivanja pokazuju da tlakovi do 100 MPa ne utječu bitnije na viskozitet otopine β-laktoglobulina. S povišenjem tlaka, između 100 i 300 MPa, viskozitet otopine značajno raste ukazujući na promjene strukture molekula β-laktoglobulina. Daljnji porast tlaka iznad 300 MPa dovodi do daljnjeg povećanja viskoziteta uslijed nereverzibilnih i izraženijih promjena proteina, denaturacije i agregacije. Strukturne promjene β-laktoglobulina koje su izazvane visokim tlakovima utječu i na hidrataciju molekula β-laktoglobulina. Na tlakovima između 100 i 300 MPa zapaženo je značajno povećanje relativne hidratacije, što može biti posljedica strukturnih promjena s jedne, i povećanja broja molekula vode koje su asocirane s molekulama proteina - s druge strane. Na višim tlakovima javljaju se ireverzibilna denaturacija i agregacija proteina, koja nastaje kao posljedica uspostavljanja intermolekularnih disulfidnih veza. Uslijed toga ne dolazi do povećanja hidratacije molekula β-laktoglobulina, naprotiv na tlakovima između 400 i 600 MPa hidratacija proteina blago se smanjuje

Utjecaj visokog hidrostatskog tlaka na viskozitet otopina β-laktoglobulina

In this research new experimental data for the pressure dependence of the viscosity of β-lactoglobulin solution are presented. The experimental investigation is based on in-situ viscometric measurement technique which provides an observation of the high-pressure-induced changes of β-lactoglobulin solution during the treatment. This method refers to a rolling ball viscometer that is adapted for the use at high pressures and has a variable inclination angle. The estimation of the viscosity has been done in order to detect reversible and irreversible conformational changes of β-lactoglobulin. For investigation protein solutions concentration 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 g/g were used. The sample solutions are exposed to pressure of 0.1-600 MPa. The results showed that there is no significant effect of 100 MPa pressure on the viscosity of β-lactoglobulin solutions. With increasing pressure, between 100 and 300 MPa, the viscosity of β-lactoglobulin solutions increase. Pressure above 300 MPa causes further increase of the viscosity due to nonreversible and more extensive effects on protein, e.g. unfolding of monomeric proteins and aggregation. The structural changes of the β-lactoglobulin under high pressure affect the hydration of the β-lactoglobulin molecules. At pressure between 100 and 300 MPa there is a significant increase in relative hydration due to structural changes and increase in number of water molecules which are associated with protein molecules. Higher pressure cause protein aggregation due to formation of intermolecular disulfide bonds and irreversible denaturation and aggregation occurs. Because of that, there is no changes in protein hydration, moreover, the hydration of β-lactoglobulin molecules have a small decreases at pressure between 400 and 600 MPa.U radu su prikazani novi eksperimentalni podaci o viskozitetu vodene otopine β-laktoglobulina na visokim tlakovima. Eksperimentalno ispitivanje temeljeno je na primjeni in-situ tehnike mjerenja viskoziteta otopine. Za mjerenja korišten je Rolling ball viskozimetar s različitim kutovima nagiba koji je prilagođen radu na visokim tlakovima. Određivanje viskoziteta otopine vršeno je s ciljem utvrđivanja reverzibilnih i ireverzibilnih promjena strukture molekula β-laktoglobulina. Za eksperimentalna mjerenja korištene su otopine koncentracije 0.01, 0.02, 0.03, 0.04, 0.05 i 0.06 g/g, a izložene su tlakovima od 0.1 do 600 MPa. Rezultati ispitivanja pokazuju da tlakovi do 100 MPa ne utječu bitnije na viskozitet otopine β-laktoglobulina. S povišenjem tlaka, između 100 i 300 MPa, viskozitet otopine značajno raste ukazujući na promjene strukture molekula β-laktoglobulina. Daljnji porast tlaka iznad 300 MPa dovodi do daljnjeg povećanja viskoziteta uslijed nereverzibilnih i izraženijih promjena proteina, denaturacije i agregacije. Strukturne promjene β-laktoglobulina koje su izazvane visokim tlakovima utječu i na hidrataciju molekula β-laktoglobulina. Na tlakovima između 100 i 300 MPa zapaženo je značajno povećanje relativne hidratacije, što može biti posljedica strukturnih promjena s jedne, i povećanja broja molekula vode koje su asocirane s molekulama proteina - s druge strane. Na višim tlakovima javljaju se ireverzibilna denaturacija i agregacija proteina, koja nastaje kao posljedica uspostavljanja intermolekularnih disulfidnih veza. Uslijed toga ne dolazi do povećanja hidratacije molekula β-laktoglobulina, naprotiv na tlakovima između 400 i 600 MPa hidratacija proteina blago se smanjuje

Vertical separation of the atmospheric aerosol components by sign POLIPHON retrieval in polarized micro pulse lidar (P-MPL) measurements: case studies of specific climate-relevant aerosol types

POLIPHON (POlarization-LIdar PHOtometer Networking) retrieval consists in the vertical separation of two/three particle components in aerosol mixtures, highlighting their relative contributions in terms of the optical properties and mass concentrations. This method is based on the specific particle linear depolarization ratio given for different types of aerosols, and is applied to the new polarized Micro-Pulse Lidar (P-MPL). Case studies of specific climate-relevant aerosols (dust particles, fire smoke, and pollen aerosols, including a clean case as reference) observed over Barcelona (Spain) are presented in order to evaluate firstly the potential of P-MPLs measurements in combination with POLIPHON for retrieving the vertical separation of those particle components forming aerosol mixtures and their properties.Peer ReviewedPostprint (published version

Evaluation of the ALMA Prototype Antennas

The ALMA North American and European prototype antennas have been evaluated by a variety of measurement systems to quantify the major performance specifications. Nearfield holography was used to set the reflector surfaces to 17 microns RMS. Pointing and fast switching performance was determined with an optical telescope and by millimeter wavelength radiometry, yielding 2 arcsec absolute and 0.6 arcsec offset pointing accuracies. Path length stability was measured to be less than or approximately equal to 20 microns over 10 minute time periods using optical measurement devices. Dynamical performance was studied with a set of accelerometers, providing data on wind induced tracking errors and structural deformation. Considering all measurements made during this evaluation, both prototype antennas meet the major ALMA antenna performance specifications.Comment: 83 pages, 36 figures, AASTex format, to appear in PASP September 2006 issu

Separation of the optical and mass features of particle components in different aerosol mixtures by using POLIPHON retrievals in synergy with continuous polarized Micro-Pulse Lidar (P-MPL) measurements

The application of the POLIPHON (POlarization-LIdar PHOtometer Networking) method is presented for the first time in synergy with continuous 24/7 polarized Micro-Pulse Lidar (P-MPL) measurements to derive the vertical separation of two or three particle components in different aerosol mixtures, and the retrieval of their particular optical properties. The procedure of extinction-to-mass conversion, together with an analysis of the mass extinction efficiency (MEE) parameter, is described, and the relative mass contribution of each aerosol component is also derived in a further step. The general POLIPHON algorithm is based on the specific particle linear depolarization ratio given for different types of aerosols and can be run in either 1-step (POL-1) or 2 steps (POL-2) versions with dependence on either the 2- or 3-component separation. In order to illustrate this procedure, aerosol mixing cases observed over Barcelona (NE Spain) are selected: a dust event on 5 July 2016, smoke plumes detected on 23 May 2016 and a pollination episode observed on 23 March 2016. In particular, the 3-component separation is just applied for the dust case: a combined POL-1 with POL-2 procedure (POL-1/2) is used, and additionally the fine-dust contribution to the total fine mode (fine dust plus non-dust aerosols) is estimated. The high dust impact before 12:00 UTC yields a mean mass loading of 0.6±0.1 g m'2 due to the prevalence of Saharan coarse-dust particles. After that time, the mean mass loading is reduced by two-thirds, showing a rather weak dust incidence. In the smoke case, the arrival of fine biomass-burning particles is detected at altitudes as high as 7 km. The smoke particles, probably mixed with less depolarizing non-smoke aerosols, are observed in air masses, having their origin from either North American fires or the Arctic area, as reported by HYSPLIT back-trajectory analysis. The particle linear depolarization ratio for smoke shows values in the 0.10-0.15 range and even higher at given times, and the daily mean smoke mass loading is 0.017±0.008 g m'2, around 3 % of that found for the dust event. Pollen particles are detected up to 1.5 km in height from 10:00 UTC during an intense pollination event with a particle linear depolarization ratio ranging between 0.10 and 0.15. The maximal mass loading of Platanus pollen particles is 0.011±0.003 g m'2, representing around 2 % of the dust loading during the higher dust incidence. Regarding the MEE derived for each aerosol component, their values are in agreement with others referenced in the literature for the specific aerosol types examined in this work: 0.5±0.1 and 1.7±0.2 m2 g'1 are found for coarse and fine dust particles, 4.5±1.4 m2 g'1 is derived for smoke and 2.4±0.5 m2 g'1 for non-smoke aerosols with Arctic origin, and a MEE of 2.4±0.8 m2 g'1 is obtained for pollen particles, though it can reach higher or lower values depending on predominantly smaller or larger pollen grain sizes. Results reveal the high potential of the P-MPL system, a simple polarization-sensitive elastic backscatter lidar working in a 24/7 operation mode, to retrieve the relative optical and mass contributions of each aerosol component throughout the day, reflecting the daily variability of their properties. In fact, this procedure can be simply implemented in other P-MPLs that also operate within the worldwide Micro-Pulse Lidar Network (MPLNET), thus extending the aerosol discrimination at a global scale. Moreover, the method has the advantage of also being relatively easily applicable to space-borne lidars with an equivalent configuration such as the ongoing Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) on board NASA CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) and the forthcoming Atmospheric Lidar (ATLID) on board the ESA EarthCARE mission

A Model of the Spectral Evolution of Pulsar Wind Nebulae

Recent observations suggest that many old pulsar wind nebulae (PWNe) are bright TeV gamma-ray sources without a strong X-ray counterpart. In this paper, we study the spectral evolution of PWNe taking into account the energy which was injected when they were young for old PWNe. We model the evolution of the magnetic field and solve for the particle distribution inside a uniformly expanding PWN. The model is calibrated by fitting the calculated spectrum to the observations of the Crab Nebula at an age of a thousand years. We find that only a small fraction of the injected energy from the Crab Pulsar goes to the magnetic field, consistent with previous studies. The spectral evolution model of the Crab Nebula shows that the flux ratio of TeV gamma-rays to X-rays increases with time, which implies that old PWNe are faint at X-rays, but not at TeV gamma-rays. The increase of this ratio is primarily because the magnetic field decreases with time and is not because the X-ray emitting particles are cooled more rapidly than the TeV gamma-ray emitting particles. Our spectral evolution model matches the observed rate of the radio flux decrease of the Crab Nebula.Comment: 5 pages, 3 figures. Proc. of the 2009 Fermi Symposium, Washington, DC, Nov 2-5; eConf Proceedings C09112

Experimental assessment of a micro-pulse lidar system in comparison with reference lidar measurements for aerosol optical properties retrieval

Simultaneous observations of a polarized micro-pulse lidar (P-MPL) system and two reference European Aerosol Research Lidar Network lidars running at the Leipzig site Germany, 51.4g gN, 12.4g gE; 125gmga.s.l.) were performed during a comprehensive 2-month field intercomparison campaign in summer 2019. An experimental assessment regarding both the overlap (OVP) correction of the P-MPL signal profiles and the volume linear depolarization ratio (VLDR) analysis, together with its impact on the retrieval of the aerosol optical properties, is achieved; the experimental procedure used is also described. The optimal lidar-specific OVP function is experimentally determined, highlighting that the one delivered by the P-MPL manufacturer cannot be used long. Among the OVP functions examined, the averaged function between those obtained from the comparison of the P-MPL observations with those of the other two reference lidars seems to be the best proxy at both near- and far-field ranges. In addition, the impact of the OVP function on the accuracy of the retrieved profiles of the total particle backscatter coefficient (PBC) and the particle linear depolarization ratio (PLDR) is examined. The VLDR profile is obtained and compared with that derived from the reference lidar, showing that it needs to be corrected by a small offset value with good accuracy. Once P-MPL measurements are optimally (OVP, VLDR) corrected, both the PBC and PLDR profiles can be accurately derived and are in good agreement with reference aerosol retrievals. Overall, as a systematic requirement for lidar systems, an adequate OVP function determination and VLDR testing analysis needs to be performed on a regular basis to correct the P-MPL measurements in order to derive suitable aerosol products. A dust event observed in Leipzig in June 2019 is used for illustration

Inhibition of influenza virus replication by nitric oxide

Nitric oxide (NO) has been shown to contribute to the pathogenesis of influenza virus-induced pneumonia in mouse models. Here we show that replication of influenza A and B viruses in Mabin Darby canine kidney cells is severely impaired by the NO donor, S-nitroso-N-acetylpenicillamine. Reduction of productively infected cells and virus production proved to correlate with inhibition of viral RNA synthesis, indicating that NO affects an early step in the replication cycle of influenza viruses

Measurement of the linear depolarization ratio of aged dust of three wavelengths (355, 532 and 1064 nm) simultaneously over Barbados

A ground-based polarization Raman lidar is presented, that is able to measure the depolarization ratio at three wavelengths (355, 532 and 1064 nm) simultaneously. This new feature is implemented for the first time in a Raman lidar. It provides a full dataset of 3 backscatter coefficients, two extinction coefficients and 3 depolarization ratios (3+2+3 lidar system). To ensure the data quality, it has been compared to the well characterized two wavelength polarization lidar POLIS. Measurements of long-range transported dust have been performed in the framework of the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the Caribbean