Abstract

Abstract. The Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC), part of the larger experiment known as Elucidating the Role of Clouds-Circulation Coupling in Climate (EUREC4A), was held in the western Atlantic during the period 17 January–11 February 2020. This paper describes observations made during ATOMIC by the US National Oceanic and Atmospheric Administration's (NOAA) Lockheed WP-3D Orion research aircraft based on the island of Barbados. The aircraft obtained 95 h of observations over 11 flights, many of which were coordinated with the NOAA research ship R/V Ronald H. Brown and autonomous platforms deployed from the ship. Each flight contained a mixture of sampling strategies including high-altitude circles with frequent dropsonde deployment to characterize the large-scale environment, slow descents and ascents to measure the distribution of water vapor and its isotopic composition, stacked legs aimed at sampling the microphysical and thermodynamic state of the boundary layer, and offset straight flight legs for observing clouds and the ocean surface with remote sensing instruments and the thermal structure of the ocean with in situ sensors dropped from the plane. The characteristics of the in situ observations, expendable devices, and remote sensing instrumentation are described, as is the processing used in deriving estimates of physical quantities. Data archived at the National Center for Environmental Information include flight-level data such as aircraft navigation and basic thermodynamic information (NOAA Aircraft Operations Center and NOAA Physical Sciences Laboratory, 2020, https://doi.org/10.25921/7jf5-wv54); high-accuracy measurements of water vapor concentration from an isotope analyzer (National Center for Atmospheric Research, 2020, https://doi.org/10.25921/c5yx-7w29); in situ observations of aerosol, cloud, and precipitation size distributions (Leandro and Chuang, 2020, https://doi.org/10.25921/vwvq-5015); profiles of seawater temperature made with Airborne eXpendable BathyThermographs (AXBTs; NOAA Physical Sciences Laboratory, 2020a, https://doi.org/10.25921/pe39-sx75); radar reflectivity, Doppler velocity, and spectrum width from a nadir-looking W-band radar (NOAA Physical Sciences Laboratory, 2020c, https://doi.org/10.25921/n1hc-dc30); estimates of cloud presence, the cloud-top location, and the cloud-top radar reflectivity and temperature, along with estimates of 10 m wind speed obtained from remote sensing instruments operating in the microwave and thermal infrared spectral regions (NOAA Physical Sciences Laboratory, 2020b, https://doi.org/10.25921/x9q5-9745); and ocean surface wave characteristics from a Wide Swath Radar Altimeter (Prosensing, Inc., 2020, https://doi.org/10.25921/qm06-qx04). Data are provided as netCDF files following Climate and Forecast conventions.

Highlights

  • As part of the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) the US National Oceanic and Atmospheric Administration (NOAA) operated a Lockheed WP-3D Orion research aircraft from the island of Barbados during the period 17 January–11 February 2020

  • This paper describes observations made during ATOMIC by the US National Oceanic and Atmospheric Administration’s (NOAA) Lockheed WP-3D Orion research aircraft based on the island of Barbados

  • Some quantities are measured by multiple sensors; such values are denoted within files prepared by NOAA’s Aircraft Operations Center (AOC) with a trailing integer for each independent measurement (e.g., TDM.1, TDM.2, and TDM.3 denote dew point temperature measurements from three independent sensors)

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Summary

Observing the atmosphere and ocean in the wintertime trades

As part of the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) the US National Oceanic and Atmospheric Administration (NOAA) operated a Lockheed WP-3D Orion research aircraft from the island of Barbados during the period 17 January–11 February 2020. Measurements from the ocean platforms are described in Quinn et al (2021). Many of the 11 P-3 flights included excursions to the location of the RHB and sampling of atmospheric and oceanic conditions around the ship and other ocean vehicles. Because of its large size and long endurance (most flights were 8–9 h long) the P-3 was tasked with obtaining a wide array of observations including remote sensing of clouds and the ocean surface, in situ measurements within and below clouds and of isotopic composition throughout the lower troposphere, and the deployment of expendable profiling instruments in the atmosphere and ocean. Some measurements obtained from the P-3 are or will be included in cross-experiment datasets described elsewhere

Sampling strategy
Instrumentation and initial data processing
Flight level data
Water vapor stable isotope analyzer
February
16 GHz radar reflectivity
Microphysics
Dropsondes
Physical Sciences Laboratory W-band radar
Wide Swath Radar Altimeter
Stepped Frequency Microwave Radiometer
Infrared radiometer
Post-processed and derived quantities
Isotope analyzer
Remote sensing
WSRA: sea state and rain rate information
Code and data availability
Findings
Conclusions
Full Text
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