The Experts below are selected from a list of 86721 Experts worldwide ranked by ideXlab platform
Christiane Voigt - One of the best experts on this subject based on the ideXlab platform.
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ml cirrus the airborne experiment on natural cirrus and contrail cirrus with the high altitude long range Research Aircraft halo
Bulletin of the American Meteorological Society, 2017Co-Authors: Christiane Voigt, Maxi Boettcher, Armin Afchine, Luca Bugliaro, Ulrich Schumann, Andreas Minikin, Ahmed Abdelmonem, Stephan Borrmann, Bernhard Buchholz, Anja CostaAbstract:AbstractThe Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and Aircraft-induced contrail cirrus. Direct observations of cirrus properties and their variability are still incomplete, currently limiting our understanding of the clouds’ impact on climate. Also, dynamical effects on clouds and feedbacks are not adequately represented in today’s weather prediction models.Here, we present the rationale, objectives, and selected scientific highlights of ML-CIRRUS using the G-550 Aircraft of the German atmospheric science community. The first combined in situ–remote sensing cloud mission with HALO united state-of-the-art cloud probes, a lidar and novel ice residual, aerosol, trace gas, and radiation instrumentation. The Aircraft observations were accompanied by remote sensing from satellite and ground and by numerical simulations.In spring 2014, HALO performed 16 f...
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vertical distribution of the phase state of particles in tropical deep convective clouds as derived from cloud side reflected solar radiation measurements
Atmospheric Chemistry and Physics, 2017Co-Authors: Evelyn Jakel, Christiane Voigt, Tina Jurkat, Manfred Wendisch, Trismono Krisna, Florian Ewald, Tobias Kolling, Micael A Cecchini, Luiz A T MachadoAbstract:Vertical profiles of cloud particle phase in tropical deep convective clouds (DCCs) were investigated using airborne solar spectral radiation data collected by the German High Altitude and Long Range Research Aircraft (HALO) during the ACRIDICON-CHUVA campaign, which was conducted over the Brazilian rainforest in September 2014. A phase discrimination retrieval based on imaging spectroradiometer measurements of DCC side spectral reflectivity was applied to clouds formed in different aerosol conditions. From the retrieval results the height of the mixed-phase layer of the DCCs was determined. The retrieved profiles were compared with in situ measurements and satellite observations.
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chemical ionization mass spectrometric measurements of atmospheric trace gases
Atmospheric Physics: Background - Methods - Trends, 2012Co-Authors: Heinfried Aufmhoff, F Arnold, Anke Roiger, Christiane Voigt, Dominik Schauble, Tina Jurkat, Hans SchlagerAbstract:Chemical Ionization Mass Spectrometry (CIMS) is a versatile, fast and sensitive method for the detection of atmospheric trace gases, which play key roles in atmospheric chemistry and climate. A combination of different types of mass spectrometers, ion sources and inlet configurations are deployed by IPA. Sophisticated calibration techniques and in-flight calibration systems are developed to ensure high data quality. The CIMS instruments are employed preferably on Research Aircraft; in addition, observations are performed on ships, ground based sites and in laboratory scenarios including atmospheric chambers.
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nitric acid trihydrate nat formation at low nat supersaturation in polar stratospheric clouds pscs
Atmospheric Chemistry and Physics, 2005Co-Authors: Christiane Voigt, Hans Schlager, Anke Roiger, Stephan Borrmann, B P Luo, A Dornbrack, Paul Stock, Joachim Curtius, H VossingAbstract:Abstract. A PSC was detected on 6 February 2003 in the Arctic stratosphere by in-situ measurements onboard the high-altitude Research Aircraft Geophysica. Low number densities (~10-4cm-3) of small nitric acid (HNO3) containing particles (d TNAT-3.1K). This unique measurement of PSC formation at extremely low NAT saturation ratios (SNAT≤10) constrains current NAT nucleation theories. We suggest, that the NAT particles have formed heterogeneously, but for certain not on ice. Conversely, meteoritic particles may be favorable candidates for triggering NAT nucleation at the observed low number densities.
Stephan Borrmann - One of the best experts on this subject based on the ideXlab platform.
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ml cirrus the airborne experiment on natural cirrus and contrail cirrus with the high altitude long range Research Aircraft halo
Bulletin of the American Meteorological Society, 2017Co-Authors: Christiane Voigt, Maxi Boettcher, Armin Afchine, Luca Bugliaro, Ulrich Schumann, Andreas Minikin, Ahmed Abdelmonem, Stephan Borrmann, Bernhard Buchholz, Anja CostaAbstract:AbstractThe Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and Aircraft-induced contrail cirrus. Direct observations of cirrus properties and their variability are still incomplete, currently limiting our understanding of the clouds’ impact on climate. Also, dynamical effects on clouds and feedbacks are not adequately represented in today’s weather prediction models.Here, we present the rationale, objectives, and selected scientific highlights of ML-CIRRUS using the G-550 Aircraft of the German atmospheric science community. The first combined in situ–remote sensing cloud mission with HALO united state-of-the-art cloud probes, a lidar and novel ice residual, aerosol, trace gas, and radiation instrumentation. The Aircraft observations were accompanied by remote sensing from satellite and ground and by numerical simulations.In spring 2014, HALO performed 16 f...
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aerosol characteristics and particle production in the upper troposphere over the amazon basin
HASH(0x7fc5f17c5a18), 2017Co-Authors: Meinrat O Andreae, Armin Afchine, Stephan Borrmann, Micael A Cecchini, Rachel I Albrecht, Bruna Holanda, Paulo Artaxo, Henrique M J Barbosa, Anja CostaAbstract:Observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by one or two orders of magnitude. The measurements were made during the German-Brazilian cooperative Aircraft campaign ACRIDICON-CHUVA on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place over the Amazon Basin in September/October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation.
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nitric acid trihydrate nat formation at low nat supersaturation in polar stratospheric clouds pscs
Atmospheric Chemistry and Physics, 2005Co-Authors: Christiane Voigt, Hans Schlager, Anke Roiger, Stephan Borrmann, B P Luo, A Dornbrack, Paul Stock, Joachim Curtius, H VossingAbstract:Abstract. A PSC was detected on 6 February 2003 in the Arctic stratosphere by in-situ measurements onboard the high-altitude Research Aircraft Geophysica. Low number densities (~10-4cm-3) of small nitric acid (HNO3) containing particles (d TNAT-3.1K). This unique measurement of PSC formation at extremely low NAT saturation ratios (SNAT≤10) constrains current NAT nucleation theories. We suggest, that the NAT particles have formed heterogeneously, but for certain not on ice. Conversely, meteoritic particles may be favorable candidates for triggering NAT nucleation at the observed low number densities.
Anja Costa - One of the best experts on this subject based on the ideXlab platform.
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ml cirrus the airborne experiment on natural cirrus and contrail cirrus with the high altitude long range Research Aircraft halo
Bulletin of the American Meteorological Society, 2017Co-Authors: Christiane Voigt, Maxi Boettcher, Armin Afchine, Luca Bugliaro, Ulrich Schumann, Andreas Minikin, Ahmed Abdelmonem, Stephan Borrmann, Bernhard Buchholz, Anja CostaAbstract:AbstractThe Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and Aircraft-induced contrail cirrus. Direct observations of cirrus properties and their variability are still incomplete, currently limiting our understanding of the clouds’ impact on climate. Also, dynamical effects on clouds and feedbacks are not adequately represented in today’s weather prediction models.Here, we present the rationale, objectives, and selected scientific highlights of ML-CIRRUS using the G-550 Aircraft of the German atmospheric science community. The first combined in situ–remote sensing cloud mission with HALO united state-of-the-art cloud probes, a lidar and novel ice residual, aerosol, trace gas, and radiation instrumentation. The Aircraft observations were accompanied by remote sensing from satellite and ground and by numerical simulations.In spring 2014, HALO performed 16 f...
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aerosol characteristics and particle production in the upper troposphere over the amazon basin
HASH(0x7fc5f17c5a18), 2017Co-Authors: Meinrat O Andreae, Armin Afchine, Stephan Borrmann, Micael A Cecchini, Rachel I Albrecht, Bruna Holanda, Paulo Artaxo, Henrique M J Barbosa, Anja CostaAbstract:Observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by one or two orders of magnitude. The measurements were made during the German-Brazilian cooperative Aircraft campaign ACRIDICON-CHUVA on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place over the Amazon Basin in September/October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation.
Bjorn Stevens - One of the best experts on this subject based on the ideXlab platform.
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hamp the microwave package on the high altitude and long range Research Aircraft halo
Atmospheric Measurement Techniques, 2014Co-Authors: Mario Mech, Emiliano Orlandi, Susanne Crewell, Felix Ament, Lutz Hirsch, Martin Hagen, Gerhard Peters, Bjorn StevensAbstract:Abstract. An advanced package of microwave remote sensing instrumentation has been developed for the operation on the new German High Altitude LOng range Research Aircraft (HALO). The HALO Microwave Package, HAMP, consists of two nadir-looking instruments: a cloud radar at 36 GHz and a suite of passive microwave radiometers with 26 frequencies in different bands between 22.24 and 183.31 ± 12.5 GHz. We present a description of HAMP's instrumentation together with an illustration of its potential. To demonstrate this potential, synthetic measurements for the implemented passive microwave frequencies and the cloud radar based on cloud-resolving and radiative transfer model calculations were performed. These illustrate the advantage of HAMP's chosen frequency coverage, which allows for improved detection of hydrometeors both via the emission and scattering of radiation. Regression algorithms compare HAMP retrieval with standard satellite instruments from polar orbiters and show its advantages particularly for the lower atmosphere with a root-mean-square error reduced by 5 and 15% for temperature and humidity, respectively. HAMP's main advantage is the high spatial resolution of about 1 km, which is illustrated by first measurements from test flights. Together these qualities make it an exciting tool for gaining a better understanding of cloud processes, testing retrieval algorithms, defining future satellite instrument specifications, and validating platforms after they have been placed in orbit.
G W Sachse - One of the best experts on this subject based on the ideXlab platform.
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nonmethane hydrocarbon measurements in the north atlantic flight corridor during the subsonic assessment ozone and nitrogen oxide experiment
Journal of Geophysical Research, 2000Co-Authors: Isobel J Simpson, D R Blake, N J Blake, Taiyih Chen, B C Sive, Jimena P Lopez, Bruce E Anderson, G W SachseAbstract:Mixing ratios of nonmethane hydrocarbons (NMHCs) were not enhanced in whole air samples collected within the North Atlantic Flight Corridor (NAFC) during the fall of 1997. The investigation was conducted aboard NASA's DC-8 Research Aircraft, as part of the Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX). NMHC enhancements were not detected within the general organized tracking system of the NAFC, nor during two tail chases of the DC-8's own exhaust. Because positive evidence of Aircraft emissions was demonstrated by enhancements in both nitrogen oxides and condensation nuclei during SONEX, the NMHC results suggest that the commercial air traffic fleet operating in the North Atlantic region does not contribute at all or contributes negligibly to NMHCs in the NAFC.
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nonmethane hydrocarbon measurements on the north atlantic flight corridor during sonex
1999Co-Authors: Isobel J Simpson, D R Blake, N J Blake, B C Sive, T Y Chen, Jimena P Lopez, G W Sachse, S A Vay, Henry E Fuelberg, Y KondoAbstract:Mixing ratios of nonmethane hydrocarbons (NMHCS) were not enhanced in whole air samples collected within the North Atlantic Flight Corridor (NAFC) during the fall of 1997. The investigation was conducted aboard NASA's DC-8 Research Aircraft, as part of the Subsonic Assessment-Ozone and Nitrogen Experiment (SONEX). NMHC enhancements were not detected within the general Organized Tracking System (OTS) of the NAFC, nor during two tail-chases of the DC-8's own exhaust. Because positive evidence of Aircraft emissions was demonstrated by enhancements in both nitrogen oxides and condensation nuclei during SONEX, the NMHC results suggest that the commercial air traffic fleet operating in the North Atlantic region does not contribute significantly to NMHCs in the NAFC.
