scholarly journals The Backscatter Cloud Probe – a compact low-profile autonomous optical spectrometer

2013 ◽  
Vol 6 (4) ◽  
pp. 7379-7424
Author(s):  
K. Beswick ◽  
D. Baumgardner ◽  
M. Gallagher ◽  
R. Newton
Keyword(s):  
Climate Models ◽  
The Other ◽  
Equivalent Diameter ◽  
Size Distributions ◽  
The European Union ◽  
Cloud Particle ◽  
Airborne Measurements ◽  
Cloud Properties ◽  
Wide Range ◽  
Research Aircraft

Abstract. A compact (500 cm3), lightweight (500 g), near-field, single particle backscattering optical spectrometer is described that mounts flush with the skin of an aircraft and measures the concentration and optical equivalent diameter of particles from 5 to 75 μm. The Backscatter Cloud Probe (BCP) was designed as a real-time qualitative cloud detector primarily for data quality control of trace gas instruments developed for the climate monitoring instrument packages that are being installed on commercial passenger aircraft as part of the European Union In-Service Aircraft for a Global Observing System (IAGOS) program (http://www.iagos.org/). Subsequent evaluations of the BCP measurements on a number of research aircraft, however, have revealed it capable of delivering quantitative particle data products including size distributions, liquid water content and other information on cloud properties. We demonstrate the instrument's capability for delivering useful long-term climatological information, across a wide range of environmental conditions. The BCP has been evaluated by comparing its measurements with those from other cloud particle spectrometers on research aircraft and several BCPs are currently flying on commercial A340/A330 Airbus passenger airliners. The design and calibration of the BCP is described in this presentation, along with an evaluation of measurements made on the research and commercial aircraft. Comparisons of the BCP with two other cloud spectrometers, the Cloud Droplet Probe (CDP) and the Cloud and Aerosol Spectrometer (CAS), show that the BCP size distributions agree well with those from the other two, given the intrinsic limitations and uncertainties related to the three instruments. Preliminary results from more than 7000 h of airborne measurements by the BCP on two Airbus A-340s operating on routine global traffic routes (one Lufthansa, the other China Airlines) show that more than 340 h of cloud data have been recorded at normal cruise altitudes (> 10 km) and more than 40% of the > 1200 flights were through clouds at some point between takeoff and landing. These data are a valuable contribution to data bases of cloud properties, including sub-visible cirrus, in the upper troposphere and useful for validating satellite retrievals of cloud water and effective radius as well as providing a broader, geographically and climatologically relevant view of cloud microphysical variability useful for improving parameterizations of clouds in climate models. They are also useful for monitoring the vertical climatology of clouds over airports, especially those over mega-cities where pollution emissions may be impacting local and regional climate.

scholarly journals The backscatter cloud probe – a compact low-profile autonomous optical spectrometer

2014 ◽  
Vol 7 (5) ◽  
pp. 1443-1457 ◽  
Author(s):  
K. Beswick ◽  
D. Baumgardner ◽  
M. Gallagher ◽  
A. Volz-Thomas ◽  
P. Nedelec ◽  
...  
Keyword(s):  
Climate Models ◽  
Equivalent Diameter ◽  
The European Union ◽  
Data Quality Control ◽  
Cloud Particle ◽  
Cloud Data ◽  
Airborne Measurements ◽  
Cloud Properties ◽  
Wide Range ◽  
Research Aircraft

Abstract. A compact (500 cm3), lightweight (500 g), near-field, single particle backscattering optical spectrometer is described that mounts flush with the skin of an aircraft and measures the concentration and optical equivalent diameter of particles from 5 to 75 μm. The backscatter cloud probe (BCP) was designed as a real-time qualitative cloud detector primarily for data quality control of trace gas instruments developed for the climate monitoring instrument packages that are being installed on commercial passenger aircraft as part of the European Union In-Service Aircraft for a Global Observing System (IAGOS) program (http://www.iagos.org/). Subsequent evaluations of the BCP measurements on a number of research aircraft, however, have revealed it capable of delivering quantitative particle data products including size distributions, liquid-water content and other information on cloud properties. We demonstrate the instrument's capability for delivering useful long-term climatological, as well as aviation performance information, across a wide range of environmental conditions. The BCP has been evaluated by comparing its measurements with those from other cloud particle spectrometers on research aircraft and several BCPs are currently flying on commercial A340/A330 Airbus passenger airliners. The design and calibration of the BCP is described in this article, along with an evaluation of measurements made on the research and commercial aircraft. Preliminary results from more than 7000 h of airborne measurements by the BCP on two Airbus A340s operating on routine global traffic routes (one Lufthansa, the other China Airlines) show that more than 340 h of cloud data have been recorded at normal cruise altitudes (> 10 km) and more than 40% of the > 1200 flights were through clouds at some point between takeoff and landing. These data are a valuable contribution to databases of cloud properties, including sub-visible cirrus, in the upper troposphere and useful for validating satellite retrievals of cloud water and effective radius; in addition, providing a broader, geographically and climatologically relevant view of cloud microphysical variability that is useful for improving parameterizations of clouds in climate models. Moreover, they are also useful for monitoring the vertical climatology of clouds over airports, especially those over megacities where pollution emissions may be impacting local and regional climate.

Refinements to Ice Particle Mass Dimensional and Terminal Velocity Relationships for Ice Clouds. Part II: Evaluation and Parameterizations of Ensemble Ice Particle Sedimentation Velocities

2007 ◽  
Vol 64 (4) ◽  
pp. 1068-1088 ◽  
Author(s):  
Andrew J. Heymsfield ◽  
Gerd-Jan van Zadelhoff ◽  
David P. Donovan ◽  
Frederic Fabry ◽  
Robin J. Hogan ◽  
...  
Keyword(s):  
Climate Models ◽  
Doppler Radar ◽  
Terminal Velocity ◽  
Fall Velocity ◽  
Particle Sedimentation ◽  
Cloud Properties ◽  
Wide Range ◽  
Single Moment ◽  
Ice Water Content ◽  
Ice Water

Abstract This two-part study addresses the development of reliable estimates of the mass and fall speed of single ice particles and ensembles. Part I of the study reports temperature-dependent coefficients for the mass-dimensional relationship, m = aDb, where D is particle maximum dimension. The fall velocity relationship, Vt = ADB, is developed from observations in synoptic and low-latitude, convectively generated, ice cloud layers, sampled over a wide range of temperatures using an assumed range for the exponent b. Values for a, A, and B were found that were consistent with the measured particle size distributions (PSD) and the ice water content (IWC). To refine the estimates of coefficients a and b to fit both lower and higher moments of the PSD and the associated values for A and B, Part II uses the PSD from Part I plus coincident, vertically pointing Doppler radar returns. The observations and derived coefficients are used to evaluate earlier, single-moment, bulk ice microphysical parameterization schemes as well as to develop improved, statistically based, microphysical relationships. They may be used in cloud and climate models, and to retrieve cloud properties from ground-based Doppler radar and spaceborne, conventional radar returns.

scholarly journals Performance of WVSS-II hygrometers on the FAAM research aircraft

2015 ◽  
Vol 8 (3) ◽  
pp. 1617-1625 ◽  
Author(s):  
A. K. Vance ◽  
S. J. Abel ◽  
R. J. Cotton ◽  
A. M. Woolley
Keyword(s):  
Liquid Water ◽  
The Other ◽  
Optimal Conditions ◽  
Statistical Assessment ◽  
Free Data ◽  
Variable Nature ◽  
Wide Range ◽  
Research Aircraft ◽  
Using Data ◽  
Good Agreement

Abstract. We compare the performance of five hygrometers fitted to the Facility for Airborne Atmospheric Measurement's (FAAM) BAe 146-301 research aircraft using data from approximately 100 flights executed over the course of 2 years under a wide range of conditions. Bulk comparison of cloud free data show good agreement between chilled mirror hygrometers and a WVSS-II fed from a modified Rosemount inlet, but that a WVSS-II fed from the standard flush inlet appears to over-read compared to the other instruments, except at higher humidities. Statistical assessment of hygrometer performance in cloudy conditions is problematic due to the variable nature of clouds, so a number of case studies are used instead to investigate the performance of the hygrometers in sub-optimal conditions. It is found that the flush inlet is not susceptible to either liquid or solid water but that the Rosemount inlet has a significant susceptibility to liquid water and may also be susceptible to ice. In all conditions the WVSS-II responds much more rapidly than the chilled mirror devices, with the flush inlet-fed WVSS-II being more rapid than that connected to the Rosemount.

POLISH AND RUSSIAN BORDER ON THE ROAD TO SCHENGEN

2011 ◽  
Vol 161 (3) ◽  
pp. 97-122
Author(s):  
Halina ŁACH
Keyword(s):  
Central Europe ◽  
Action Plan ◽  
Migration Policy ◽  
Buffer Zone ◽  
The Other ◽  
The European Union ◽  
Illegal Migration ◽  
Wide Range ◽  
On The Road ◽  
The Eu

After the collapse of communism, the countries of Central Europe, including Poland, be-came a “buffer zone” for the European Union. This was not the result of a deliberate policy by the EU; Poland and the other countries in Central Europe wanted to begin cooperation with the EU as soon as possible, hoping to become its members.Future membership in the Union required Poland to adopt and implement the regulations of the Schengen legal order, which included control on its external borders, a common visa regime, combating cross-border crime, migration policy, infrastructure for border protection, as well as cooperation of border, customs and police services. Adopting the EU standards formed the basis for drawing up and implementing strategic governmental projects: The Action Plan for the Implementation of the Schengen Legal Heritage in Poland as well as the Strategy for the Integrated Border Management.Membership in the EU entailed a wide range of legal, institutional and infrastructural adjustments along the Polish and Russian border, as Poland came to be responsible for the safety of each specific section of the external border. In order to meet the Schengen regulations on the Polish and Russian border, the authorities of the Province of Warmia and Mazury began implementing projects and plans for managing the national border with respect to modernising its infrastructure and construction of border crossings. On the other hand, The Warmia and Mazury Division of the Border Guard took action in border protection consisting in adjusting border protection standards to the border crime threats, illegal migration as well as the intro-duction of regulations to allow for free transfer of persons and objects across the border.

Radiative Properties of Aerosols and Clouds from Observations and Models over the Southeast Atlantic

2020 ◽  
Author(s):  
Ian Chang ◽  
Keyword(s):  
Climate Models ◽  
Current Model ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Radiative Properties ◽  
High Spectral Resolution ◽  
Airborne Measurements ◽  
Cloud Properties ◽  
Satellite Retrievals ◽  
Aerosol Radiative Effects

<p>The southeast Atlantic serves as a natural laboratory for studying aerosol-cloud-radiation interactions due to the abundant presence of quasi-permanent stratocumulus and overlying biomass burning smoke aerosols during austral winters. Aerosol and cloud properties from the Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) and Solar Spectral Flux Radiometer (SSFR) on board NASA P-3 and High Spectral Resolution Lidar (HSRL) on board NASA ER-2 during the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign are used to compare with satellite retrievals. Aerosol and cloud properties from regional climate models such as WRF-Chem, WRF-Chem (with CAM5), ALADIN, GEOS-CHEM, EAM-E3SM, MERRA-2, and GEOS-5 with aerosol schemes are also compared against airborne measurements and satellite retrievals to evaluate and address the current model deficiencies in the southeast Atlantic. A preliminary estimate of the direct aerosol radiative effects over the southeast Atlantic will be presented.</p>

Kosovo

2008 ◽  
Author(s):  
Tim Judah
Keyword(s):  
European Union ◽  
The Other ◽  
Self Determination ◽  
The European Union ◽  
Western Balkans ◽  
National Pride ◽  
Wide Range ◽  
The World ◽  
The Right ◽  
Accessible Format

On February 17, 2008, Kosovo declared its independence, becoming the seventh state to emerge from the break-up of the former Yugoslavia. A tiny country of just two million people, 90% of whom are ethnic Albanians, Kosovo is central - geographically, historically, and politically - to the future of the Western Balkans and, in turn, its potential future within the European Union. But the fate of both Kosovo, condemned by Serbian leaders as a “fake state” and the region as a whole, remains uncertain. In Kosovo: What Everyone Needs to Know, Tim Judah provides a straight-forward guide to the complicated place that is Kosovo. Judah, who has spent years covering the region, offers succinct, penetrating answers to a wide range of questions: Why is Kosovo important? Who are the Albanians? Who are the Serbs? Why is Kosovo so important to Serbs? What role does Kosovo play in the region and in the world? Judah reveals how things stand now and presents the history and geopolitical dynamics that have led to it. The most important of these is the question of the right to self-determination, invoked by the Kosovo Albanians, as opposed to right of territorial integrity invoked by the Serbs. For many Serbs, Kosovo's declaration of independence and subsequent recognition has been traumatic, a savage blow to national pride. Albanians, on the other hand, believe their independence rights an historical wrong: the Serbian conquest (Serbs say “liberation”) of Kosovo in 1912. For anyone wishing to understand both the history and possible future of Kosovo at this pivotal moment in its history, this book offers a wealth of insight and information in a uniquely accessible format.

scholarly journals Assessment of Global Cloud Datasets from Satellites: Project and Database Initiated by the GEWEX Radiation Panel

2013 ◽  
Vol 94 (7) ◽  
pp. 1031-1049 ◽  
Author(s):  
C. J. Stubenrauch ◽  
W. B. Rossow ◽  
S. Kinne ◽  
S. Ackerman ◽  
G. Cesana ◽  
...  
Keyword(s):  
Climate Models ◽  
Water Cycle ◽  
Dominant Role ◽  
Cloud Amount ◽  
Climate Data ◽  
Cloud Data ◽  
Measurement Capability ◽  
Spatial And Temporal Scales ◽  
Cloud Properties ◽  
Wide Range

Clouds cover about 70% of Earth's surface and play a dominant role in the energy and water cycle of our planet. Only satellite observations provide a continuous survey of the state of the atmosphere over the entire globe and across the wide range of spatial and temporal scales that compose weather and climate variability. Satellite cloud data records now exceed more than 25 years; however, climate data records must be compiled from different satellite datasets and can exhibit systematic biases. Questions therefore arise as to the accuracy and limitations of the various sensors and retrieval methods. The Global Energy and Water Cycle Experiment (GEWEX) Cloud Assessment, initiated in 2005 by the GEWEX Radiation Panel (GEWEX Data and Assessment Panel since 2011), provides the first coordinated intercomparison of publicly available, standard global cloud products (gridded monthly statistics) retrieved from measurements of multispectral imagers (some with multiangle view and polarization capabilities), IR sounders, and lidar. Cloud properties under study include cloud amount, cloud height (in terms of pressure, temperature, or altitude), cloud thermodynamic phase, and cloud radiative and bulk microphysical properties (optical depth or emissivity, effective particle radius, and water path). Differences in average cloud properties, especially in the amount of high-level clouds, are mostly explained by the inherent instrument measurement capability for detecting and/or identifying optically thin cirrus, especially when overlying low-level clouds. The study of long-term variations with these datasets requires consideration of many factors. The monthly gridded database presented here facilitates further assessments, climate studies, and the evaluation of climate models.

scholarly journals What Is the Maximum Entropy Principle? Comments on “Statistical Theory on the Functional Form of Cloud Particle Size Distributions”

2019 ◽  
Vol 76 (12) ◽  
pp. 3955-3960 ◽  
Author(s):  
Jun-Ichi Yano
Keyword(s):  
Maximum Entropy ◽  
Relative Entropy ◽  
Functional Form ◽  
Maximum Entropy Principle ◽  
The Other ◽  
Standard Entropy ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Cloud Particle ◽  
Entropy Principle

Abstract The basic idea of the maximum entropy principle is presented in a succinct, self-contained manner. The presentation points out some misunderstandings on this principle by Wu and McFarquhar. Namely, the principle does not suffer from the problem of a lack of invariance by change of the dependent variable; thus, it does not lead to a need to introduce the relative entropy as suggested by Wu and McFarquhar. The principle is valid only with a proper choice of a dependent variable, called a restriction variable, for a distribution. Although different results may be obtained with the other variables obtained by transforming the restriction variable, these results are simply meaningless. A relative entropy may be used instead of a standard entropy. However, the former does not lead to any new results unobtainable by the latter.

scholarly journals A unified data set of airborne cloud remote sensing using the HALO Microwave Package (HAMP)

2018 ◽  
Author(s):  
Heike Konow ◽  
Marek Jacob ◽  
Felix Ament ◽  
Susanne Crewell ◽  
Florian Ewald ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Microwave Remote Sensing ◽  
Joint Analysis ◽  
Wet Season ◽  
Data Set ◽  
Cloud Radar ◽  
Cloud Properties ◽  
Wide Range ◽  
Research Aircraft ◽  
Microwave Radiometers

Abstract. Cloud properties and their environmental conditions were observed during four aircraft campaigns over the North Atlantic on 37 flights. The Halo Microwave Package (HAMP) was deployed on the German research aircraft HALO (High Altitude LOng range research aircraft) during these four campaigns. HAMP comprises microwave radiometers with 26 channels in the frequency range between 20 and 183 GHz and a 35 GHz cloud radar. The four campaigns took place between December 2013 and October 2016 out of Barbados and Iceland. Measured situations cover a wide range of conditions including the dry and wet season over the tropical Atlantic and the cold and warm sectors of mid-latitude cyclones. The data set we present here contains measurements of the radar reflectivity factor and linear depolarization ratio from cloud radar, brightness temperatures from microwave radiometers, and atmospheric profiles from dropsondes. It represents a unique combination of active and passive microwave remote sensing measurements and 525 in-situ measured dropsonde profiles. The data from these different instruments are quality controlled and unified into one common format for easy combination of data and joint analysis. The data are available from the CERA database for the four campaigns individually (https://doi.org/10.1594/WDCC/HALO_measurements_1, https://doi.org/10.1594/WDCC/HALO_measurements_2, https://doi.org/10.1594/WDCC/HALO_measurements_3, https://doi.org/10.1594/WDCC/HALO_measurements_4). This data set allows for analyses to get insight into cloud properties and atmospheric state in remote regions over the tropical and mid-latitude Atlantic. In this paper, we describe the four campaigns, the data, and the quality control applied to the data.

scholarly journals EUREC<sup>4</sup>A

2021 ◽  
Vol 13 (8) ◽  
pp. 4067-4119
Author(s):  
Bjorn Stevens ◽  
Sandrine Bony ◽  
David Farrell ◽  
Felix Ament ◽  
Alan Blyth ◽  
...  
Keyword(s):  
Climate Models ◽  
Scientific Practice ◽  
Lower Atmosphere ◽  
Upper Ocean ◽  
Cloud Droplets ◽  
The North ◽  
Brazil Current ◽  
North Brazil ◽  
Wide Range ◽  
Research Aircraft

Abstract. The science guiding the EUREC4A campaign and its measurements is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement.

Sign in / Sign up

Export Citation Format

Share Document