From May to July 2019, an array of moored equipment was deployed in Lake Superior to characterize the spatial and temporal scales of radiatively driven convection (RDC). Previous work suggested that convective plumes have horizontal scales on the order of tens of meters, posing a significant observational challenge. The centerpiece of the deployment was a large, two-dimensional (2D) array of thermistors that provided resolution on the order of 10 meters in both the vertical and a single horizontal dimension. This was augmented by an acoustic Doppler current meter mooring and a meteorology buoy capable of estimating surface heat and momentum fluxes. Instantaneous temperature variability at a given location is dominated by a lateral background flow advecting strong horizontal temperature gradients. By combining velocity data with temperature data, this fact can be used to examine horizontal structure at centimeter scales, and can produce 2D images of instantaneous temperature distribution on a horizontal surface, revealing multiple patterns of temperature anomaly distribution. The walls of convective structures are very sharp, with horizontal gradients on the order of 1°C m−1; horizontal scales of convective structures themselves are on the order of many tens of meters. Finally, convection is shown to strongly control the vertical distribution of water quality parameters.
|Original language||English (US)|
|Number of pages||13|
|Journal||Limnology and Oceanography|
|State||Published - Oct 2022|
Bibliographical noteFunding Information:
The authors would like to thank Samuel Kelly, Alberto Scotti, and Stefan Llewellyn‐Smith for fruitful conversations during the preparation of this manuscript, as well as the hard work of the crew of the R/V . Three anonymous reviews resulted in a significantly improved manuscript. Funding for the fieldwork and analysis was provided by NSF‐OCE‐1829895. Blue Heron
© 2022 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography.