Data from: Turbulence characteristics of ice-free radiatively driven convection in a deep, unstratified lake
Data files
Mar 11, 2025 version files 30.35 MB
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buoyancy_flux.csv
16.56 KB
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glider_data.csv
30.28 MB
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heat_budget.csv
52.04 KB
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README.md
2.42 KB
Abstract
This study examines data collected with an autonomous underwater glider during a period of vigorous radiatively driven convection (RDC) and low winds in deep, unstratified Lake Superior. Conductivity, temperature and depth (CTD) measurements reveal distinct convective plumes of warm downwelling water with temperature anomalies of ~0.1 °C and width scales on the order of 10-100 m, consistent with theoretical scalings for the unstratified convective regime. Shear and temperature microstructure measurements indicate turbulent kinetic energy (TKE) dissipation (ε) and temperature variance dissipation rates (ΧT) orders of magnitude greater in thermal plumes than laterally adjacent waters. Decay timescales of ε indicate highly efficient mixing is sustained throughout the night. Energetics, mixing efficiency, and constraints on convective plume scales are also discussed. These observations demonstrate that RDC can dominate vertical mixing dynamics even in deep ice-free systems, and these systems can serve as a real-scale laboratory for investigation of convective dynamics.
https://doi.org/10.5061/dryad.z8w9ghxp3
Description of the data and file structure
Files and variables
File: heat_budget.csv
Description:
Variables
- datetime: datetime formatted string of time in local timezone (UTC - 5:00)
- datenum: matlab formatted datenum
- SW_Avg: incident shortwave radiation (W/m^2)
- LW_net: net longwave radiation (W/m^2)
- sensible_heat_flux: sensible heat flux (W/m^2)
- latent_heat_flux: latent heat flux (W/m^2)
File: buoyancy_flux.csv
Description:
Variables
- datetime: datetime formatted string of time in local timezone (UTC - 5:00)
- datenum: matlab formatted datenum
- B*: radiative buoyancy flux, as defined in the manuscript (W/kg)
File: glider_data.csv
Description:
Variables
- ctd_date: datetime formatted string of time from CTD clock in local timezone (UTC - 5:00)
- ctd_datenum: matlab formatted datenum from CTD clock
- depth: glider depth (m)
- latitude: glider location latitude (decimal degrees)
- longitude: glider location longitude (decimal degrees)
- m_pitch: measured glider pitch (degrees)
- ww: water vertical velocity, derived from the flight model (m/s). Entires with a 'null' value are present where the glider flight is not steady-state and vertical velocity estimates are invalid.
- conservative_temperature: conservative temperature derived from glider CTD with TEOS-10 (deg C)
- conservative_temperature_anomaly: conservative temperature difference relative to median for each dive/climb segment (deg C)
- potential density: potential density, calculated with TEOS-10 (sigma units, kg/m^3)
- epsilon: TKE dissipation rate derived from MicroRider microstructure data (W/kg). Entries with a 'null' value indicate no valid estimate is available from the glider's microstructure profile window.
- chi_t: Temperature variance dissipation rate derived from MicroRider microstructure data (K^2/s). Entries with a 'null' value indicate where no valid estimate is available from the glider's microstructure profile window.
Access information
Data was derived from the following sources:
- Meteorological data used to calculate the heat budget are available at: https://doi.org/10.13020/1XFM-MW95