Total Eclipse Aircraft Mission (TEAM)

A unique opportunity exists during the 2017 total solar eclipse that traverses the United States to study atmospheric chemistry by obtaining high altitude aircraft and balloon based measurements during this once-in-a-lifetime event. The Total Eclipse Aircraft Mission (TEAM) is a high altitude aircraft mission concept that is intended to acquire complementary measurements to those taken from high-altitude balloon platforms along the eclipse path using the University of North Dakota\u27s Citation Research Aircraft. Initial plans are to accurately measure temperature, O3, OH-, and NOX as a function of eclipse obscuration. One of the mission architectures under consideration includes a flight that begins and ends in Grand Forks, North Dakota. The research jet would ascend to its mission altitude in the lower stratosphere at an altitude of approximately 13 km, and begin gathering data while total eclipse is still over the Pacific Ocean. The aircraft would then intercept the eclipse line over Nebraska just before totality in that region, and be overtaken by the eclipse. The jet would return to its base in Grand Forks as total eclipse proceeds toward the southeastern portion of the United States, all the while collecting atmospheric data within the stratosphere. This paper will present the TEAM mission objectives, mission architecture, and outline the schedule, cost, and risk associated with this mission, along with tentative high-level functional and operational performance requirements

Remote sensing of volcanic ash clouds using special sensor microwave imager data

Measurements from the satellite-based special sensor microwave imager (SSM/I) were used to collect passive microwave radiation (19–85 GHz) for the August 19, 1992 (UT date), Crater Peak/Spurr volcanic cloud. This eruption was also imaged by a ground-based C-band radar system at Kenai, Alaska, 80 km away, and by the thermal infrared channels of the polar-orbiting advanced very high resolution radiometer (AVHRR). The SSM/I sensor detects scattering of Earth-emitted radiation by millimeter size volcanic ash particles. The size of ash particles in a volcanic ash cloud can be estimated by comparing the scattering at different microwave frequencies. The mass of particles in the volcanic ash cloud can be estimated by using a theoretical method based on Mie theory or by adapting the empirical methods used for estimating rainfall rates and accounting for the different dielectric constants of volcanic ash and raindrops. For the August 19, 1992, Crater Peak/Spurr eruption, the SSM/I-based estimate of ash fallout mass (1.3 × 109 − 3 × 1010 kg) was 4%–85% of the mass fallout measured in the field. Like weather radar systems, the SSM/I offers the ability to sense young volcanic ash clouds during and immediately following (within 30 min) actual eruptions. Because most volcanoes are out of range of weather radar systems, the SSM/I may be an important tool for determining the magnitude, initial trajectory, and potential fallout mass of eruptions. The SSM/I may therefore play a role in mitigating volcanic cloud hazards for aircraft, determining masses where ground sampling is not possible, and in issuing fallout warnings for communities downwind of volcanic eruptions

A Balloon-Borne Cloud Condensation Nuclei Counter

A balloon-borne instrument was constructed for observations of vertical profiles of cloud condensation nucleus (CCN) concentrations, active at 1% supersaturation. Droplet concentration in the static thermal-gradient diffusion chamber is deduced from the amount of scattered laser light detected by a photodetector. The photodetector is calibrated using a video camera and computer system to count the number of droplets produced from NaCl aerosol. Preliminary data are available from nine early morning profiles obtained at Laramie, Wyoming, between June 1995 and January 1997. To complement the CCN measurements, instruments that measure condensation nuclei (CN) and aerosols with diameter greater than 0.30 micrometers (D(sub 0.3) were also included on the balloon package. CCN concentrations exhibited a general decrease from the surface to the top of the boundary layers, were generally uniform through well-mixed layers, and show variability above well-mixed layers. In general, the structure of the CCN profile appears to be closely related to the structure in the CN and D(sub 0.3) profiles. Summer profiles generally have CCN concentration greater than 200/cu cm up to 500 mbar, whereas winter profiles are less than 200/cu cm at all levels

An assessment of aerosol‐cloud interactions in marine stratus clouds based on surface remote sensing

An assessment of aerosol-cloud interactions (ACI) from ground-based remote sensing under coastal stratiform clouds is presented. The assessment utilizes a long-term, high temporal resolution data set from the Atmospheric Radiation Measurement (ARM) Program deployment at Pt. Reyes, California, United States, in 2005 to provide statistically robust measures of ACI and to characterize the variability of the measures based on variability in environmental conditions and observational approaches. The average ACIN (= dlnNd/dlna, the change in cloud drop number concentration with aerosol concentration) is 0.48, within a physically plausible range of 0–1.0. Values vary between 0.18 and 0.69 with dependence on (1) the assumption of constant cloud liquid water path (LWP), (2) the relative value of cloud LWP, (3) methods for retrieving Nd, (4) aerosol size distribution, (5) updraft velocity, and (6) the scale and resolution of observations. The sensitivity of the local, diurnally averaged radiative forcing to this variability in ACIN values, assuming an aerosol perturbation of 500 c-3 relative to a background concentration of 100 cm-3, ranges betwee-4 and -9 W -2. Further characterization of ACI and its variability is required to reduce uncertainties in global radiative forcing estimates

Multi-campaign ship and aircraft observations of marine cloud condensation nuclei and droplet concentrations

In-situ marine cloud droplet number concentrations (CDNCs), cloud condensation nuclei (CCN), and CCN proxies, based on particle sizes and optical properties, are accumulated from seven field campaigns: ACTIVATE; NAAMES; CAMP2EX; ORACLES; SOCRATES; MARCUS; and CAPRICORN2. Each campaign involves aircraft measurements, ship-based measurements, or both. Measurements collected over the North and Central Atlantic, Indo-Pacific, and Southern Oceans, represent a range of clean to polluted conditions in various climate regimes. With the extensive range of environmental conditions sampled, this data collection is ideal for testing satellite remote detection methods of CDNC and CCN in marine environments. Remote measurement methods are vital to expanding the available data in these difficult-to-reach regions of the Earth and improving our understanding of aerosol-cloud interactions. The data collection includes particle composition and continental tracers to identify potential contributing CCN sources. Several of these campaigns include High Spectral Resolution Lidar (HSRL) and polarimetric imaging measurements and retrievals that will be the basis for the next generation of space-based remote sensors and, thus, can be utilized as satellite surrogates

Intercomparison of airborne and surface-based measurements during the CLARIFY, ORACLES and LASIC field experiments

This is the final version. Available on open access from the European Geosciences Union via the DOI in this recordCode availability: Processing code for the FAAM core measurements suite is available from GitHub (Sproson et al., 2020).Data availability Airborne data for the CLARIFY campaign are available from the Centre for Environmental Data Analysis (Facility for Airborne Atmospheric Measurements et al., 2017) and for the ORACLES campaign from NASA Earth Science Project Office (ORACLES Science Team, 2020). The LASIC ground-based data sets are publicly available from the Atmospheric Radiation Measurement Climate Research Facility (Zuidema et al., 2017) with specialist data sets available for the following: SP2 – https://iop.archive.arm.gov/arm-iop/2016/ (last access: 25 October 2022, Sedlacek, 2017), CO – https://doi.org/10.5439/1046183 (Springston, 2018b), CAPS PMSSA – https://adc.arm.gov/discovery/#/results/s::caps-ssa (Onasch et al., 2015), ACSM – https://doi.org/10.5439/1763029 (Zawadowicz and Howie, 2021).Data are presented from intercomparisons between two research aircraft, the FAAM BAe-146 and the NASA Lockheed P3, and between the BAe-146 and the surface-based DOE (Department of Energy) ARM (Atmospheric Radiation Measurement) Mobile Facility at Ascension Island (8∘ S, 14.5∘ W; a remote island in the mid-Atlantic). These took place from 17 August to 5 September 2017, during the African biomass burning (BB) season. The primary motivation was to give confidence in the use of data from multiple platforms with which to evaluate numerical climate models. The three platforms were involved in the CLouds–Aerosol–Radiation Interaction and Forcing for Year 2017 (CLARIFY-2017), ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES), and Layered Atlantic Smoke and Interactions with Clouds (LASIC) field experiments. Comparisons from flight segments on 6 d where the BAe-146 flew alongside the ARM facility on Ascension Island are presented, along with comparisons from the wing-tip-to-wing-tip flight of the P3 and BAe-146 on 18 August 2017. The intercomparison flight sampled a relatively clean atmosphere overlying a moderately polluted boundary layer, while the six fly-bys of the ARM site sampled both clean and polluted conditions 2–4 km upwind. We compare and validate characterisations of aerosol physical, chemical and optical properties as well as atmospheric radiation and cloud microphysics between platforms. We assess the performance of measurement instrumentation in the field, under conditions where sampling conditions are not as tightly controlled as in laboratory measurements where calibrations are performed. Solar radiation measurements compared well enough to permit radiative closure studies. Optical absorption coefficient measurements from all three platforms were within uncertainty limits, although absolute magnitudes were too low (<10 Mm−1) to fully support a comparison of the absorption Ångström exponents. Aerosol optical absorption measurements from airborne platforms were more comparable than aircraft-to-ground observations. Scattering coefficient observations compared adequately between airborne platforms, but agreement with ground-based measurements was worse, potentially caused by small differences in sampling conditions or actual aerosol population differences over land. Chemical composition measurements followed a similar pattern, with better comparisons between the airborne platforms. Thermodynamics, aerosol and cloud microphysical properties generally agreed given uncertainties.Natural Environment Research Council (NERC)NERC/Met Office Industrial Case studentshipResearch Council of NorwayUS Department of Energy, Office of ScienceNASAUS Department of Energy Atmospheric Systems Research (ASR) programm

Total Eclipse Aircraft Mission (TEAM)

A unique opportunity exists during the 2017 total solar eclipse that traverses the United States to study atmospheric chemistry by obtaining high altitude aircraft and balloon based measurements during this once-in-a-lifetime event. The Total Eclipse Aircraft Mission (TEAM) is a high altitude aircraft mission concept that is intended to acquire complementary measurements to those taken from high-altitude balloon platforms along the eclipse path using the University of North Dakota\u27s Citation Research Aircraft. Initial plans are to accurately measure temperature, O3, OH-, and NOX as a function of eclipse obscuration. One of the mission architectures under consideration includes a flight that begins and ends in Grand Forks, North Dakota. The research jet would ascend to its mission altitude in the lower stratosphere at an altitude of approximately 13 km, and begin gathering data while total eclipse is still over the Pacific Ocean. The aircraft would then intercept the eclipse line over Nebraska just before totality in that region, and be overtaken by the eclipse. The jet would return to its base in Grand Forks as total eclipse proceeds toward the southeastern portion of the United States, all the while collecting atmospheric data within the stratosphere. This paper will present the TEAM mission objectives, mission architecture, and outline the schedule, cost, and risk associated with this mission, along with tentative high-level functional and operational performance requirements

Comparison of Concurrent Radar and Aircraft Measurements of Cirrus Clouds

The instrumented North Dakota Citation Research Aircraft and the Navy’s Mid-Course Radar (MCR), a high-resolution radar, obtained concurrent measurements of anvil cirrus clouds during seven research flights over Cape Canaveral, Florida in the summer of 2015 (CAPE2015). The Citation Research Aircraft is equipped with instruments for measuring GPS location and altitude, pressure, temperature, dew point temperature, and wind velocity, as well as set of cloud physics instruments. The MCR is a C-band, dual-polarization, Doppler radar with the capability of switching between two waveforms, a low-resolution beam and a high-resolution beam. Two radar reflectivity data sets are included: an observed radar reflectivity factor data set from the MCR and a derived equivalent radar reflectivity factor data set obtained from microphysical probes onboard the Citation Research Aircraft