Download or read book Aerosols and Boundary Layer Structure Over Arctic Sea Ice Based on Airborne Lidar and Dropsonde Measurements written by and published by . This book was released on 2014 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmosphere over the Arctic Ocean is strongly influenced by the distribution of sea ice and open water. Leads in the sea ice produce strong convective fluxes of sensible and latent heat and release aerosol particles into the atmosphere. They increase the occurrence of clouds and modify the structure and characteristics of the atmospheric boundary layer (ABL) and thereby influence the Arctic climate. In the course of this study aircraft measurements were performed over the western Arctic Ocean as part of the campaign PAMARCMIP 2012 of the Alfred Wegener Institute for Polar and Marine Research (AWI). Backscatter from aerosols and clouds within the lower troposphere and the ABL were measured with the nadir pointing Airborne Mobile Aerosol Lidar (AMALi) and dropsondes were launched to obtain profiles of meteorological variables. Furthermore, in situ measurements of aerosol properties, meteorological variables and turbulence were part of the campaign. The measurements covered a broad range of atmospheric and sea ice conditions. In th...

Download or read book Springer Handbook of Atmospheric Measurements written by Thomas Foken and published by Springer Nature. This book was released on 2021-11-09 with total page 1761 pages. Available in PDF, EPUB and Kindle. Book excerpt: This practical handbook provides a clearly structured, concise and comprehensive account of the huge variety of atmospheric and related measurements relevant to meteorologists and for the purpose of weather forecasting and climate research, but also to the practitioner in the wider field of environmental physics and ecology. The Springer Handbook of Atmospheric Measurements is divided into six parts: The first part offers instructive descriptions of the basics of atmospheric measurements and the multitude of their influencing factors, fundamentals of quality control and standardization, as well as equations and tables of atmospheric, water, and soil quantities. The subsequent parts present classical in-situ measurements as well as remote sensing techniques from both ground-based as well as airborn or satellite-based methods. The next part focusses on complex measurements and methods that integrate different techniques to establish more holistic data. Brief discussions of measurements in soils and water, at plants, in urban and rural environments and for renewable energies demonstrate the potential of such applications. The final part provides an overview of atmospheric and ecological networks. Written by distinguished experts from academia and industry, each of the 64 chapters provides in-depth discussions of the available devices with their specifications, aspects of quality control, maintenance as well as their potential for the future. A large number of thoroughly compiled tables of physical quantities, sensors and system characteristics make this handbook a unique, universal and useful reference for the practitioner and absolutely essential for researchers, students, and technicians.

Download or read book Comparative Aerosol Studies Based on Multi wavelength Raman LIDAR at Ny lesund Spitsbergen written by Anne Hoffmann and published by . This book was released on 2011 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Arctic is a particularly sensitive area with respect to climate change due to the high surface albedo of snow and ice and the extreme radiative conditions. Clouds and aerosols as parts of the Arctic atmosphere play an important role in the radiation budget, which is, as yet, poorly quantified and understood. The LIDAR (Light Detection And Ranging) measurements presented in this PhD thesis contribute with continuous altitude resolved aerosol profiles to the understanding of occurrence and characteristics of aerosol layers above Ny-Ålesund, Spitsbergen. The attention was turned to the analysis of periods with high aerosol load. As the Arctic spring troposphere exhibits maximum aerosol optical depths (AODs) each year, March and April of both the years 2007 and 2009 were analyzed. Furthermore, stratospheric aerosol layers of volcanic origin were analyzed for several months, subsequently to the eruptions of the Kasatochi and Sarychev volcanoes in summer 2008 and 2009, respectively. The Koldewey Aerosol Raman LIDAR (KARL) is an instrument for the active remote sensing of atmospheric parameters using pulsed laser radiation. It is operated at the AWIPEV research base and was fundamentally upgraded within the framework of this PhD project. It is now equipped with a new telescope mirror and new detection optics, which facilitate atmospheric profiling from 450m above sea level up to the mid-stratosphere. KARL provides highly resolved profiles of the scattering characteristics of aerosol and cloud particles (backscattering, extinction and depolarization) as well as water vapor profiles within the lower troposphere. Combination of KARL data with data from other instruments on site, namely radiosondes, sun photometer, Micro Pulse LIDAR, and tethersonde system, resulted in a comprehensive data set of scattering phenomena in the Arctic atmosphere. The two spring periods March and April 2007 and 2009 were at first analyzed based on meteorological parameters, like local temperature and relative humidity profiles as well as large scale pressure patterns and air mass origin regions. Here, it was not possible to find a clear correlation between enhanced AOD and air mass origin. However, in a comparison of two cloud free periods in March 2007 and April 2009, large AOD values in 2009 coincided with air mass transport through the central Arctic. This suggests the occurrence of aerosol transformation processes during the aerosol transport to Ny-Ålesund. Measurements on 4 April 2009 revealed maximum AOD values of up to 0.12 and aerosol size distributions changing with altitude. This and other performed case studies suggest the differentiation between three aerosol event types and their origin: Vertically limited aerosol layers in dry air, highly variable hygroscopic boundary layer aerosols and enhanced aerosol load across wide portions of the troposphere. For the spring period 2007, the available KARL data were statistically analyzed using a characterization scheme, which is based on optical characteristics of the scattering particles. The scheme was validated using several case studies. Volcanic eruptions in the northern hemisphere in August 2008 and June 2009 arose the opportunity to analyze volcanic aerosol layers within the stratosphere. The rate of stratospheric AOD change was similar within both years with maximum values above 0.1 about three to five weeks after the respective eruption. In both years, the stratospheric AOD persisted at higher rates than usual until the measurements were stopped in late September due to technical reasons. In 2008, up to three aerosol layers were detected, the layer structure in 2009 was characterized by up to six distinct and thin layers which smeared out to one broad layer after about two months. The lowermost aerosol layer was continuously detected at the tropopause altitude. Three case studies were performed, all revealed rather large indices of refraction of m = (1.531.55) - 0.02i, suggesting the presence of an absorbing carbonaceous component. The particle radius, derived with inversion calculations, was also similar in both years with values ranging from 0.16 to 0.19 æm. However, in 2009, a second mode in the size distribution was detected at about 0.5 æm. The long term measurements with the Koldewey Aerosol Raman LIDAR in Ny-Ålesund provide the opportunity to study Arctic aerosols in the troposphere and the stratosphere not only in case studies but on longer time scales. In this PhD thesis, both, tropospheric aerosols in the Arctic spring and stratospheric aerosols following volcanic eruptions have been described qualitatively and quantitatively. Case studies and comparative studies with data of other instruments on site allowed for the analysis of microphysical aerosol characteristics and their temporal evolution.

Download or read book Lidar Investigations of Aerosol Cloud and Boundary Layer Properties Over the ARM ACRF Sites written by and published by . This book was released on 2015 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The systematic and routine measurements of aerosol, water vapor, and clouds in the vertical column above the Atmospheric Radiation Measurement (ARM) sites from surface-based remote sensing systems provides a unique and comprehensive data source that can be used to characterize the boundary layer (i.e., the lowest 3 km of the atmosphere) and its evolution. New algorithms have been developed to provide critical datasets from ARM instruments, and these datasets have been used in long-term analyses to better understand the climatology of water vapor and aerosol over Darwin, the turbulent structure of the boundary layer and its statistical properties over Oklahoma, and to better determine the distribution of ice and aerosol particles over northern Alaska.

Download or read book Characterizing Environmental Boundary Layer Conditions Around Nocturnal Convective Storms with Airborne Compact Ramam Lidar During PECAN written by Guo Lin and published by . This book was released on 2017 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of environmental conditions around severe local storms are important in advancing our understanding of these severe local storms. These measurements are, however, difficult to collect. During the PECAN (Plains Elevated Convection at Night) field campaign on the Great Plains, a Compact Raman Lidar (CRL) system deployed on the University of Wyoming King Air (UWKA) uniquely characterized structures of rapidly changing water vapor, temperature and aerosols in the Atmospheric Boundary Layer (ABL) around a nocturnal Mesoscale Convective System (MCS) on July 1st, and a Convection Initiation (CI) on June 8th, 2015. For the MCS case, the CRL initially sampled a region impacted by early precipitation, where two reversed flows, a southern environmental flow and a flow from a previous convective cell, generated two distinct layers of water vapor and aerosols. Later a cold pool outflow boundary was also sampled on July 1st. The flight level vertical wind and temperature transect depicted a quick transition from up to 1.5 m/s updraft out of the cold pool boundary to a 1.5 m/s downdraft. Water vapor and aerosol transects revealed an inflow that was pushed upward by the slanted cold pool outflow. An inversion layer was formed by a warm southwestern flow on the top of a cool southeastern flow on the leading edge of a density current. The 2D aerosol distributions above the inversion layer captured the wave motions triggered by the outflow, which had a similar energy distribution for wavelengths from 1.8 to 18 km as that of the in-situ flight level vertical velocity. This result indicates that the CRL 2D aerosol structure can be used to derive wave structures in the ABL. The UWKA also sampled an ABL structure associated with a CI on June 8th, 2015. The collision by the environmental inflow and outflow in a transition with high CAPE and low CIN environment initiated a strong uplift of water vapor as indicated by the CRL observed a narrow water vapor plume above the ABL, which led a CI quickly. An intense surface observation network, including PISA sites, mobile mesonet vehicles and radars, served as additional measurements were integrated with CRL measurements to better understand ABL structures around the MCS and leading to the CI.

Download or read book Measurement and Identification of Aerosols Collected Near Barrow Alaska written by Motoi Kumai and published by . This book was released on 1978 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric Boundary Layer Structure and Drag Coefficients Over Sea Ice written by James E. Overland and published by . This book was released on 1985 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions Between Arctic Sea Ice and Atmospheric Boundary Layer in the Presence of Leads written by and published by . This book was released on 1993 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Theory for the Scalar Roughness and the Scalar Transfer Coefficients Over Snow and Sea Ice written by Edgar L. Andreas and published by . This book was released on 1986 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The bulk aerodynamic transfer coefficients for sensible (C sub H) and latent (C sub E) heat over snow and sea ice surfaces are necessary for accurately modeling the surface energy budget but are very difficult to measure. This report therefore presents a theory that predicts C sub H and C sub E as functions of the wind speed and a surface roughness parameter. The crux of the model is establishing the interfacial sublayer profiles of the scalars, temperature and water vapor, over aerodynamically smooth and rough surfaces. These interfacial sublayer profiles are delivered from surface-renewal model in which turbulent eddies continually sweep down to the surface, transfer scalar contaminants across the interface by molecular diffusion, and then burst away. Matching the interfacial sublayer profiles with the usual semilogarithmic inertial sublayer profiles yields the roughness lengths for temperature and water vapor. With these and a model for the drag coefficient over snow and sea ice based on actual measurements, the transfer coefficients are predicted. C sub E is always a few percent larger than C and H. Both decrease monotonically with increasing wind speed for speeds above 1 m/s, both increase at all winds speeds as the surface gets rougher. Both, nevertheless, are almost between 0.0010 and 0.0015.

Download or read book Radiative Interactions Between Arctic Sea Ice and Boundary Layer Stratus Clouds written by Elizabeth Eby Ebert and published by . This book was released on 1984 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds written by and published by . This book was released on 2011 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

Download or read book Sea Ice Sources of Sea Salt Aerosols in Polar Regions written by Jiayue Huang and published by . This book was released on 2018 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blowing briny snow and frost flowers have been suggested as important sources of sea salt aerosols (SSA) over sea ice covered regions, where they can affect radiation, cloud formation, and boundary layer chemistry. During polar spring, observations show periodic near total ozone depletion events (ODEs) in the boundary layer. These ODEs are initiated by the release of reactive bromine gases, however the origin of the reactive bromine has been subject to debate. In particular, saline surface snow, blowing snow SSA and frost flowers SSA have been proposed as potential sources releasing bromine. My Ph.D. research aims to provide new constraints on blowing snow and frost flower sources of SSA and assess their impact on tropospheric chemistry by using satellite observations together with a chemical transport model (CTM). In the first part of my Ph.D. project (Chapter 2), I interpreted observations of aerosol extinction coefficients from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud-Aerosol Lidar and Intrared Pathfinder Satellite Observations (CALIPSO) with the GEOS-Chem CTM to evaluate the role of sea ice sources of SSA in the Arctic and Antarctic boundary layer. I find that the inclusion of blowing snow SSA emissions is necessary for the GEOS-Chem model to reproduce the CALIOP aerosol extinctions over sea ice regions during cold months, but that frost flower SSA fail to do so. Using the CALIOP aerosol extinction coefficients, I derived monthly-varying surface snow salinities, which further improves the performance of the blowing snow GEOS-Chem simulation. In the second part of my Ph.D. project (Chapter 3), I implemented bromine release from SSA generated via blowing snow events, and evaluated the model against tropospheric BrO columns retrieved from the Second Global Ozone Monitoring Experiment (GOME-2) onboard the MetOp-A satellite and the Ozone Monitoring Instrument (OMI) onboard the Aura satellite, as well as in-situ observations of surface ozone over the Arctic. I find that bromine release from blowing snow SSA in GEOS-Chem allows the model to capture the timing and locations of the observed bromine explosion events and some of the observed ODEs in the springtime Arctic. I estimated that the halogen chemistry from blowing snow SSA increases the Br[subscript]y abundance by a factor of 2.6 and decreases the O3 abundance by 10% in the Arctic lower troposphere (0–2 km) during spring (March–May).

Download or read book Chemical Composition and Origin of Aerosol Particles Involved in Summertime Arctic Cloud Processes written by Oliver Eppers and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Arctic climate is warming rapidly compared to other regions of the globe with drastic implications for its environment (e.g. sea ice loss). Aerosol particles are an important factor for the energy budget in this polar region as they interact directly or indirectly via cloud formation and processing with solar and terrestrial radiation. However, the interaction between aerosol and clouds in the Arctic is still not fully understood. This study focuses on the occurrence of different aerosol species and their influence on cloud processes in the summertime Arctic. Airborne in-situ measurements of particle composition were conducted in the European Arctic using the single particle mass spectrometer ALABAMA. Ambient aerosol particles and cloud particle residues in the diameter range between 250 nm and 1.6 μm were chemically analyzed. More than 240000 single particle mass spectra were obtained in total during the flights, almost 45000 of them from cloud residuals sampled in clouds. Different particle types were identified by detection of characteristic ion signal markers. This chemical particle analysis was complemented by further measurements of aerosol and cloud properties, trace gases as well as air mass history simulations. This study has found that Arctic cloud residual composition was dominated by triethyl- and/or diethylamine, which were observed for the first time in Arctic aerosol particles. In addition to amines, also sea spray, dicarboxylic acids, nitrate, iodine and elemental carbon were enriched inside the cloud residuals. In contrast, particles in ambient air contained mainly trimethylamine and sea spray inside the boundary layer and ammonium sulfate in the free troposphere. Only little contribution of triethyl- and/or diethylamine to particle composition in ambient air was observed, suggesting these amines were taken up by the cloud droplets from the gas-phase. This hypothesis was further supported by the observed correlation between the ethylated amine fraction and cloud liquid water content indicating their high solubility. Outside the Arctic, a significant contribution of these amines was found in clouds at mid-latitudes as well, suggesting a general importance of amines for cloud processes. Moreover, the cloud residual composition of clouds, which were thermodynamically decoupled from the surface, showed similarities to above-cloud particle composition. Thus, the thermodynamic structure of the clouds seems to play a critical role for the contribution of surface-related aerosol species to Arctic clouds.

Download or read book Spatial Distribution of Aerosol Particles in and Above the Planetary Boundary Layer Studied by Scanning LIDAR Measurements written by Hengheng Zhang and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Ice Crystals on Radiative Forcing and Remote Sensing of Arctic Boundary layer Mixed phase Clouds written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This PhD thesis is embedded into the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) and investigates the radiative transfer through Arctic boundary-layer mixed-phase (ABM) clouds. For this purpose airborne spectral solar radiation measurements and simulations of the solar and thermal infrared radiative transfer have been performed. This work reports on measurements with the Spectral Modular Airborne Radiation measurement sysTem (SMART-Albedometer) conducted in the framework of ASTAR in April 2007 close to Svalbard. For ASTAR the SMART-Albedometer was extended to measure spectral radiance. The development and calibration of the radiance measurements are described in this work. In combination with in situ measurements of cloud particle properties provided by the Laboratoire de M¶et¶eorologie Physique (LaMP) and simultaneous airborne lidar measurements by the Alfred Wegener Institute for Polar and Marine Research (AWI) ABM clouds were sampled. The SMART-Albedometer measurements were used to retrieve the cloud thermodynamic phase by three different approaches. A comparison of these results with the in situ and lidar measurements is presented in two case studies. Beside the dominating mixed-phase clouds pure ice clouds were found in cloud gaps and at the edge of a large cloud field. Furthermore the vertical distribution of ice crystals within ABM clouds was investigated. It was found that ice crystals at cloud top are necessary to describe the observed SMART-Albedometer measurements. The impact of ice crystals on the radiative forcing of ABM clouds is in vestigated by extensive radiative transfer simulations. The solar and net radiative forcing was found to depend on the ice crystal size, shape and the mixing ratio of ice crystals and liquid water droplets.

Download or read book Modeling of the Arctic Boundary Layer written by and published by . This book was released on 1997 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the recent 3 month Arctic Ocean Expedition (AOE-96) to the North Pole during the summer of 1996 an enormous amount of data collected on the Arctic planetary boundary layer. In preparation for the expedition, the authors have developed an expanded and quite flexible 1-D computer code based on the successful work of ReVelle and of ReVelle and Coulter on modeling of boundary layer ''bursting''. This new code, BLMARC (Boundary Layer, Mixing, Aerosols, Radiation and Clouds), explicitly includes the physical and chemical effects due to the presence of clouds, aerosols and associated air chemistry. Using data from AOE-96 and the model BLMARC, the authors have begun a systematic effort to compare observations of the high Arctic boundary layer against numerical modeling results. The preliminary results for case963 and case964 are quite promising. The second period exhibits what appears to be bursting effects in the temperature, the winds and in the aerosol concentration and the modeling efforts have shown a similar set of features as well. Current work also includes model experiments with BLMARC on the aerosol nucleation and growth in the Arctic PBL and cloud and fog formation.

Download or read book The Atmospheric Boundary Layer Over Sea Ice written by Timo Vihma and published by . This book was released on 2005 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: