Design of an instrument stabilising system for in-situ measurements on a research vesse

Filisetti, Andrew; Marouchos, Andreas; McRobert, Ian M.; Baldwinson, Ben; Protat, Alain; Atkinson, Brad

doi:10.1109/oceanse.2017.8084695

Cited by 3 publications

(4 citation statements)

References 16 publications

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“…Hallet and Mossop, 1984) as the ice crystals interacted with supercooled liquid water in updrafts. 7) that was on a stabilized platform (Filisetti et al, 2017). Ascending W-Band Doppler velocities exceeding 3 m s -1 are seen near the tops of several cells between 10 and 12 UTC (not corrected for particle motion).…”

Section: Methodsmentioning

confidence: 99%

Inferring the Properties of Snow in Southern Ocean Shallow Convection and Frontal Systems Using Dual-Polarization C-Band Radar

Mace

Protat

Benson

et al. 2023

Journal of Applied Meteorology and Climatology

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We use dual polarization C-Band data collected in the Southern Ocean to examine the properties of snow observed during a voyage in the Austral Summer of 2018. Using existing forward modeling formalisms based on an assumption of Rayleigh scattering by soft spheroids, an optimal estimation algorithm is implemented to infer snow properties from horizontally polarized radar reflectivity, the differential radar reflectivity, and the specific differential phase. From the dual polarization observables, we estimate ice water content (𝑞𝑖), the mass-mean particle size (Dm), and the exponent of the mass-dimensional relationship (bm) that, with several assumptions, allow for evaluation of snow bulk density, and snow number concentration. Upon evaluating the uncertainties associated with measurement and forward model errors, we determine that the algorithm can retrieve 𝑞𝑖, Dm, and bm within single-pixel uncertainties conservatively estimated in the range 120%, 60%, and 40%, respectively. Applying the algorithm to open cellular convection in the Southern Ocean, we find evidence for secondary ice formation processes within multi-cellular complexes. In stratiform precipitation systems we find snow properties and infer processes that are distinctly different from the shallow convective systems with evidence for riming and aggregation being common. We also find that embedded convection within the frontal system produces precipitation properties consistent with graupel. Examining 5 weeks of data, we show that snow in open cellular cumulus has higher overall bulk density than snow in stratiform precipitation systems with implications for interpreting measurements from space-based active remote sensors.

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Section: Methodsmentioning

confidence: 99%

Inferring the Properties of Snow in Southern Ocean Shallow Convection and Frontal Systems Using Dual-Polarization C-Band Radar

Mace

Protat

Benson

et al. 2023

Journal of Applied Meteorology and Climatology

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“…When used on RV Investigator, the BASTA cloud radar is mounted on a stabilized platform inside an air-conditioned container, ensuring resilient operations in harsh environments such as the Southern Ocean, Antarctica, and the trop-ics. The stabilized platform design is described in detail in Filisetti et al (2017) and follows the design from Moran et al (2012). It has been recently demonstrated that vertical stabilization to better than 0.2 • can be achieved with this platform for sea states up to 6.…”

Section: The Rv Investigator Stabilized Platform and Sampling Strategiesmentioning

confidence: 99%

“…Matrosov et al, 2002;Mace et al, 2002;Delanoë et al, 2007), lidars (e.g. Heymsfield et al, 2005), or cloud radar-lidar combination (Wang and Sassen, 2002;Okamoto et al, 2003;Tinel et al, 2005;Delanoë and Hogan, 2008;Deng et al, 2010). The next challenge to better understand the interactions between dynamics and cloud microphysics is to characterize the dynamical context of these cloud microphysical observations, including horizontal winds, vertical wind shear, and entrainment processes within and at the boundaries of clouds.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional wind profiles using a stabilized shipborne cloud radar in wind profiler mode

Protat

McRobert

2020

Atmos. Meas. Tech.

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Abstract. In this study, a shipborne 95 GHz Doppler cloud radar mounted on a stabilized platform is used to retrieve vertical profiles of three-dimensional (3D) winds by sequentially pointing the stabilized platform in different directions. A specific challenge is that the maximum angle off zenith is 8∘, which implies that the projection of the horizontal wind components onto the radar beam directions is a small component of Doppler velocity in most cases. A variational 3D wind retrieval technique is then described, allowing for 1 min 3D wind profiles to be retrieved. Statistical comparisons with 3-hourly radiosonde launches from the ship indicate that horizontal wind profiles can be obtained from such cloud radar observations at small off-zenith angles with biases less than 0.2 m s−1 and standard deviations of differences with radiosonde winds less than 2.5 m s−1.

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“…When used on RV Investigator, the BASTA cloud radar is mounted on a stabilized platform inside an air-conditioned container, making operations in harsh environments such as the Southern Ocean, Antarctica and the Tropics a smooth experience. The stabilized platform design is described in detail in Filisetti et al (2017) and follows the design from Moran et al (2012). It has been recently demonstrated that vertical stabilization to better than 0.2° can be achieved with this platform for sea states up to 6.…”

Section: The Rv Investigator Stabilized Platform and Sampling Strategiesmentioning

confidence: 99%

Three-dimensional wind profiles using a stabilized shipborne cloud radar in wind profiler mode

Protat¹,

McRobert²

2020

Preprint

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Abstract. In this study, a shipborne 95 GHz Doppler cloud radar mounted on a stabilized platform is used to retrieve vertical profiles of three-dimensional (3D) winds by sequentially pointing the stabilized platform in different directions. A specific challenge is that the maximum angle off zenith is 8°, which implies that the projection of the horizontal wind components onto the radar beam directions is a small component of Doppler velocity in most cases. A variational 3D wind retrieval technique is then described, allowing for 1-minute resolution 3D wind profiles to be retrieved. Statistical comparisons with 3-hourly radiosonde launches and qualitative comparisons with ship-level horizontal winds demonstrate that accurate 3D wind profiles can be obtained from such cloud radar observations at small off-zenith angles.

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Design of an instrument stabilising system for in-situ measurements on a research vesse

Cited by 3 publications

References 16 publications

Inferring the Properties of Snow in Southern Ocean Shallow Convection and Frontal Systems Using Dual-Polarization C-Band Radar

Inferring the Properties of Snow in Southern Ocean Shallow Convection and Frontal Systems Using Dual-Polarization C-Band Radar

Three-dimensional wind profiles using a stabilized shipborne cloud radar in wind profiler mode

Three-dimensional wind profiles using a stabilized shipborne cloud radar in wind profiler mode

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