scholarly journals A High-Altitude Long-Range Aircraft Configured as a Cloud Observatory: The NARVAL Expeditions

2019 ◽  
Vol 100 (6) ◽  
pp. 1061-1077 ◽  
Author(s):  
Bjorn Stevens ◽  
Felix Ament ◽  
Sandrine Bony ◽  
Susanne Crewell ◽  
Florian Ewald ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Altitude ◽  
Long Range ◽  
Large Scale ◽  
Radiant Energy ◽  
Vertical Component ◽  
Field Studies ◽  
Meteorological Conditions ◽  
Research Aircraft ◽  
New Generation

AbstractA configuration of the High-Altitude Long-Range Research Aircraft (HALO) as a remote sensing cloud observatory is described, and its use is illustrated with results from the first and second Next-Generation Aircraft Remote Sensing for Validation (NARVAL) field studies. Measurements from the second NARVAL (NARVAL2) are used to highlight the ability of HALO, when configured in this fashion, to characterize not only the distribution of water condensate in the atmosphere, but also its impact on radiant energy transfer and the covarying large-scale meteorological conditions—including the large-scale velocity field and its vertical component. The NARVAL campaigns with HALO demonstrate the potential of airborne cloud observatories to address long-standing riddles in studies of the coupling between clouds and circulation and are helping to motivate a new generation of field studies.

scholarly journals ML-CIRRUS: The Airborne Experiment on Natural Cirrus and Contrail Cirrus with the High-Altitude Long-Range Research Aircraft HALO

2017 ◽  
Vol 98 (2) ◽  
pp. 271-288 ◽  
Author(s):  
Christiane Voigt ◽  
Ulrich Schumann ◽  
Andreas Minikin ◽  
Ahmed Abdelmonem ◽  
Armin Afchine ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Altitude ◽  
Long Range ◽  
Prediction Models ◽  
Weather Prediction ◽  
Climate Impact ◽  
Jet Streams ◽  
Direct Observations ◽  
Research Aircraft

Abstract The 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 flights above Europe with a focus on anthropogenic contrail cirrus and midlatitude cirrus induced by frontal systems including warm conveyor belts and other dynamical regimes (jet streams, mountain waves, and convection). Highlights from ML-CIRRUS include 1) new observations of microphysical and radiative cirrus properties and their variability in meteorological regimes typical for midlatitudes, 2) insights into occurrence of in situ–formed and lifted liquid-origin cirrus, 3) validation of cloud forecasts and satellite products, 4) assessment of contrail predictability, and 5) direct observations of contrail cirrus and their distinction from natural cirrus. Hence, ML-CIRRUS provides a comprehensive dataset on cirrus in the densely populated European midlatitudes with the scope to enhance our understanding of cirrus clouds and their role for climate and weather.

scholarly journals POLSTRACC: Airborne Experiment for Studying the Polar Stratosphere in a Changing Climate with the High Altitude and Long Range Research Aircraft (HALO)

2019 ◽  
Vol 100 (12) ◽  
pp. 2634-2664 ◽  
Author(s):  
Hermann Oelhaf ◽  
Björn-Martin Sinnhuber ◽  
Wolfgang Woiwode ◽  
Harald Bönisch ◽  
Heiko Bozem ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Altitude ◽  
Long Range ◽  
Potential Temperature ◽  
The Arctic ◽  
Ozone Loss ◽  
Changing Climate ◽  
Research Aircraft ◽  
Polar Stratosphere

Abstract The Polar Stratosphere in a Changing Climate (POLSTRACC) mission employed the German High Altitude and Long Range Research Aircraft (HALO). The payload comprised an innovative combination of remote sensing and in situ instruments. The in situ instruments provided high-resolution observations of cirrus and polar stratospheric clouds (PSCs), a large number of reactive and long-lived trace gases, and temperature at the aircraft level. Information above and underneath the aircraft level was achieved by remote sensing instruments as well as dropsondes. The mission took place from 8 December 2015 to 18 March 2016, covering the extremely cold late December to early February period and the time around the major warming in the beginning of March. In 18 scientific deployments, 156 flight hours were conducted, covering latitudes from 25° to 87°N and maximum altitudes of almost 15 km, and reaching potential temperature levels of up to 410 K. Highlights of results include 1) new aspects of transport and mixing in the Arctic upper troposphere–lower stratosphere (UTLS), 2) detailed analyses of special dynamical features such as tropopause folds, 3) observations of extended PSCs reaching sometimes down to HALO flight levels at 13–14 km, 4) observations of particulate NOy and vertical redistribution of gas-phase NOy in the lowermost stratosphere (LMS), 5) significant chlorine activation and deactivation in the LMS along with halogen source gas observations, and 6) the partitioning and budgets of reactive chlorine and bromine along with a detailed study of the efficiency of ClOx/BrOx ozone loss cycle. Finally, we quantify—based on our results—the ozone loss in the 2015/16 winter and address the question of how extraordinary this Arctic winter was.

scholarly journals HAMP – the microwave package on the High Altitude and LOng range research aircraft HALO

2014 ◽  
Vol 7 (5) ◽  
pp. 4623-4657
Author(s):  
M. Mech ◽  
E. Orlandi ◽  
S. Crewell ◽  
F. Ament ◽  
L. Hirsch ◽  
...  
Keyword(s):  
High Altitude ◽  
Long Range ◽  
Microwave Remote Sensing ◽  
Passive Microwave ◽  
Lower Atmosphere ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Model Calculations ◽  
Cloud Radar ◽  
Research Aircraft

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 reduced root mean square error 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 better understanding of cloud processes, testing retrieval algorithms, defining future satellite instrument specifications, and validating platforms after they have been placed in orbit.

Numerical modeling of mesospheric mountain wave propagation observed in Southern Argentina during the SOUTHTRAC campaign

2020 ◽  
Author(s):  
Tyler Mixa ◽  
Andreas Dörnbrack ◽  
Bernd Kaifler ◽  
Markus Rapp
Keyword(s):  
Remote Sensing ◽  
Large Scale ◽  
Numerical Models ◽  
Airborne Lidar ◽  
Tierra Del Fuego ◽  
Polar Night ◽  
Research Aircraft ◽  
Complex Propagation ◽  
The Antarctic

<p>We present numerical simulations of a deep orographic gravity wave (GW) event observed by the ALIMA airborne lidar on 11-12 September 2019 over Southern Argentina. The measurements are taken from the 2019 SOUTHTRAC Campaign, employing a comprehensive suite of remote sensing and in-situ instruments onboard the HALO research aircraft to study the stratospheric GW hotspot over Tierra del Fuego and the Antarctic Peninsula. Wind conditions on 11-12 September exhibit local and large-scale directional shear from the ground to the polar night jet, creating a complex propagation environment supporting multiple orientations of GW propagation and strong potential for local GW breaking and secondary GW generation. Using high resolution numerical models, we simulate the 3D evolution of the orographic GW field to analyze<span> the remote sensing and in-situ measurements from the event.</span></p>

scholarly journals Vertical structure of Antarctic tropospheric ozone depletion events: characteristics and broader implications

2010 ◽  
Vol 10 (3) ◽  
pp. 8189-8246 ◽  
Author(s):  
A. E. Jones ◽  
P. S. Anderson ◽  
E. W. Wolff ◽  
H. K. Roscoe ◽  
G. J. Marshall ◽  
...  
Keyword(s):  
High Altitude ◽  
Ozone Depletion ◽  
Tropospheric Ozone ◽  
Large Scale ◽  
Field Experiments ◽  
Strong Association ◽  
Vertical Component ◽  
Low Pressure ◽  
The Arctic ◽  
Low Pressure Systems

Abstract. The majority of tropospheric ozone depletion event (ODE) studies have focussed on time-series measurements, with comparatively few studies of the vertical component. Those that exist have almost exclusively used free-flying balloon-borne ozonesondes and almost all have been conducted in the Arctic. Here we use measurements from two separate Antarctic field experiments to examine the vertical profile of ozone during Antarctic ODEs. We use tethersonde data to probe details in the lowest few hundred meters and find considerable structure in the profiles associated with complex atmospheric layering. The profiles were all measured at wind speeds less than 7 ms−1, and on each occasion the lowest inversion height lay between 10 m and 40 m. We also use data from a free-flying ozonesonde study to select events where ozone depletion was recorded at altitudes >1 km above ground level. Using ERA-40 meteorological charts, we find that on every occasion the high altitude depletion was preceded by an atmospheric low pressure system. An examination of limited published ozonesonde data from other Antarctic stations shows this to be a consistent feature. Given the link between BrO and ODEs, we also examine ground-based and satellite BrO measurements, and find a strong association between enhanced BrO and atmospheric low pressure systems. The results suggest that, in Antarctica, such depressions are responsible for driving high altitude ODEs and for generating the large-scale BrO clouds observed from satellites. In the Arctic, the prevailing meteorology differs from that in Antarctica, but we show that major low pressure systems in the Arctic, when they occur, can also generate BrO clouds. Such depressions thus appear to be fundamental when considering the broader influence of ODEs, particularly in Antarctica, such as halogen export and the radiative influence of ozone-depleted air masses.

scholarly journals HAMP – the microwave package on the High Altitude and LOng range research aircraft (HALO)

2014 ◽  
Vol 7 (12) ◽  
pp. 4539-4553 ◽  
Author(s):  
M. Mech ◽  
E. Orlandi ◽  
S. Crewell ◽  
F. Ament ◽  
L. Hirsch ◽  
...  
Keyword(s):  
High Altitude ◽  
Long Range ◽  
Microwave Remote Sensing ◽  
Passive Microwave ◽  
Lower Atmosphere ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Model Calculations ◽  
Cloud Radar ◽  
Research Aircraft

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.

scholarly journals Methods for studying the morphology of abrasion-accumulative coast of the West coast of the Crimea using UAV and GNSS (on the example of a land of the territory of Great Sevastopol)

2021 ◽  
Vol 27 (1) ◽  
pp. 351-363
Author(s):  
Aleksandr Suchilin ◽  
Nadezhda Belay ◽  
Ivan Voskresensky ◽  
Svetlana Mikheeva ◽  
Victoria Zorina ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Large Scale ◽  
Geodetic Network ◽  
Field Studies ◽  
Research Area ◽  
Global Navigation Satellite Systems ◽  
The Black Sea ◽  
Western Coast ◽  
Satellite Systems ◽  
Global Navigation Satellite

The method of studying the abrasion-accumulative coast of the Western coast of Crimea within the urban area of Sevastopol includes remote sensing using unmanned aerial vehicles (UAVs) and field studies of the morphology and structure of abrasion and landslide landforms of the coast. As a result of the research, the morphological zoning of the abrasion-accumulative coast was established. The formation of the morphological zoning of the abrasion-accumulative coast (according to I.S. Shchukin) during the last 150 years took place at a constant level of the Black Sea. Analysis of the coast from previously published multi-temporal maps and aerospace photographs revealed different stages in the movement of the coastline and landslide scarp. Since 1966, the coastal area has been used for low-rise residential development, which may have influenced the activity of landslide processes in the coastal strip. Remote sensing using UAVs consists of aerial photography of the research area along the planned flight route at altitudes of 20–100 m, with further compilation of a large-scale orthophotomap from a mosaic of images with geospatial fixation of images to the signs of the reference long-term local geodetic network, previously measured by the methods of global navigation satellite systems (GNSS ), as well as the formation of a digital elevation model (DEM) and the compilation of derived maps and plans on its basis in the environment of geographic information systems (GIS), for the analysis of the morphometry of the relief and modeling. The developed method of remote sensing of the Earth with the use of UAVs and simultaneous field studies makes it possible to organize operational monitoring of dynamically developing abrasion-accumulative shores.

scholarly journals Long-range pollution transport during the MILAGRO-2006 campaign: a case study of a major Mexico City outflow event using free-floating altitude-controlled balloons

2010 ◽  
Vol 10 (2) ◽  
pp. 3347-3399 ◽  
Author(s):  
P. B. Voss ◽  
R. A. Zaveri ◽  
F. M. Flocke ◽  
H. Mao ◽  
T. P. Hartley ◽  
...  
Keyword(s):  
High Altitude ◽  
Mexico City ◽  
Long Range ◽  
State Variables ◽  
Pollution Transport ◽  
Transport Pathways ◽  
Westerly Jet ◽  
Time Period ◽  
Research Aircraft ◽  
Wind Profiles

Abstract. One of the major objectives of the Megacities Initiative: Local And Global Research Observations (MILAGRO-2006) campaign was to investigate the long-range transport of polluted Mexico City Metropolitan Area (MCMA) outflow and determine its downwind impacts on air quality and climate. Six research aircraft, including the National Center for Atmospheric Research (NCAR) C-130, made extensive chemical, aerosol, and radiation measurements above MCMA and more than 1000 km downwind in order to characterize the evolution of the outflow as it aged and dispersed over the Mesa Alta and Gulf of Mexico. As part of this effort, free-floating Controlled-Meteorological (CMET) balloons, commanded to change altitude via satellite, made repeated profile measurements of winds and state variables within the advecting outflow. In this paper, we present an analysis based on the data from two CMET balloons that were launched near Mexico City on the afternoon of 18 March 2006 and floated downwind with the MCMA pollution for nearly 30 h. The repeating profile measurements show the evolving structure of the outflow in considerable detail: its stability and stratification, interaction with other air masses, mixing episodes, and dispersion into the regional background. Air parcel trajectories, computed directly from the balloon wind profiles, show three different transport pathways on 18–19 March: (a) high-altitude advection of the top of the MCMA mixed layer, (b) mid-level outflow over the Sierra Madre Oriental followed by decoupling and isolated transport over the Gulf, and (c) low-altitude outflow with entrainment into a cleaner westerly jet below the plateau. The C-130 aircraft intercepted the balloon-based trajectories three times on 19 March, once along each of these pathways. In all three cases, distinct peaks in the urban tracer signatures and LIDAR backscatter imagery were consistent with MCMA pollution. The coherence of the high-altitude outflow was well preserved after one day whereas that lower in the atmosphere was more widely dispersed over the same time period. Other C-130 intercepts of polluted air are shown to have likely originated outside of MCMA. These findings, and the aircraft intercepts in particular, should prove useful in answering a range of scientific questions pertaining to the transport, transformation, and downwind impacts of megacity air pollution.

scholarly journals Vertical structure of Antarctic tropospheric ozone depletion events: characteristics and broader implications

2010 ◽  
Vol 10 (16) ◽  
pp. 7775-7794 ◽  
Author(s):  
A. E. Jones ◽  
P. S. Anderson ◽  
E. W. Wolff ◽  
H. K. Roscoe ◽  
G. J. Marshall ◽  
...  
Keyword(s):  
High Altitude ◽  
Ozone Depletion ◽  
Tropospheric Ozone ◽  
Large Scale ◽  
Field Experiments ◽  
Strong Association ◽  
Vertical Component ◽  
Low Pressure ◽  
The Arctic ◽  
Low Pressure Systems

Abstract. The majority of tropospheric ozone depletion event (ODE) studies have focussed on time-series measurements, with comparatively few studies of the vertical component. Those that exist have almost exclusively used free-flying balloon-borne ozonesondes and almost all have been conducted in the Arctic. Here we use measurements from two separate Antarctic field experiments to examine the vertical profile of ozone during Antarctic ODEs. We use tethersonde data to probe details in the lowest few hundred meters and find considerable structure in the profiles associated with complex atmospheric layering. The profiles were all measured at wind speeds less than 7 ms−1, and on each occasion the lowest inversion height lay between 10 m and 40 m. We also use data from a free-flying ozonesonde study to select events where ozone depletion was recorded at altitudes >1 km above ground level. Using ERA-40 meteorological charts, we find that on every occasion the high altitude depletion was preceded by an atmospheric low pressure system. An examination of limited published ozonesonde data from other Antarctic stations shows this to be a consistent feature. Given the link between BrO and ODEs, we also examine ground-based and satellite BrO measurements and find a strong association between atmospheric low pressure systems and enhanced BrO that must arise in the troposphere. The results suggest that, in Antarctica, such depressions are responsible for driving high altitude ODEs and for generating the large-scale BrO clouds observed from satellites. In the Arctic, the prevailing meteorology differs from that in Antarctica, but, while a less common effect, major low pressure systems in the Arctic can also generate BrO clouds. Such depressions thus appear to be fundamental when considering the broader influence of ODEs, certainly in Antarctica, such as halogen export and the radiative influence of ozone-depleted air masses.

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