Measurement and Scaling of Lake Surface Skin Temperatures

• Published in: Geophysical research letters 2022-03, Vol.49 (6), p.n/a
• Main Authors: Hondzo, Miki, You, Jiaqi, Taylor, Jackie, Bartlet, Garret, Voller, Vaughan R.
• Format: Article
• Language: English
• Subjects: Air temperature; Air-water interface; Convection; Convection cooling; cool skin; Cooling; Free convection; Greenhouse gases; Heat flux; Heat transfer; Inland waters; Integration; lake surface temperatures; Lakes; natural convection; Ocean surface; Ocean temperature; Oceans; Parameterization; Satellites; Scaling; Sea surface temperature; Skin; Skin effect; Skin temperature; Subsurface water; Surface temperature; Surface water; Temperature differences; Temperature effects; Temperature gradients; Temperature profile; Temperature profiles; Thermometers; Thickness; Water temperature; Wind speed
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2021GL093226

Water temperature microprofiles at the air‐water interface of a stratified lake were measured concurrently with moderate wind speeds of 0.8–8.2 ms−1 above the lake surface. The day‐time measurements revealed the cool skin effect of water surface temperatures that triggers the cooling of the lake surface and the occurrence of natural convection. Natural convection velocity scale mediates the thickness of the diffusive thermal sublayer and the corresponding net heat flux at the interface. The diffusive thermal sublayer thickness ranged from 0.7 to 3.6 mm. The temperature microprofiles and proposed parameterization of skin‐to‐bulk temperatures enable similarity scaling of temperature microprofiles over the diffusive thermal sublayer thickness. The proposed parameterizations allow for the estimation of diffusive thermal sublayer thickness and skin‐to‐bulk temperature difference in the presence of natural convection. Our results have the potential to facilitate the validation and integration of satellite‐derived lake surface temperatures. Plain Language Summary Inland water and ocean surface temperatures are a “global thermometer” of the planet. These water surface temperatures provide an important coupling channel between water and atmosphere environments and mediate the exchange of energy and chemicals between the two. We measured and analyzed temperature profiles in the proximity of air‐water interface in a small stratified lake. These measurements revealed a “cool skin” effect—colder water temperatures at the lake surface than those just below it. This cool skin effect triggers the convective cooling of the subsurface water. We propose a model to quantify the cool skin effect in the presence of natural convection. The proposed model can potentially facilitate verification and integration of large‐scale measurements of satellite‐derived surface water temperatures and may assist the estimation of greenhouse gas transport across lake and ocean surfaces. Key Points Natural convection velocity mediate the thickness of diffusive thermal sublayer and the corresponding net heat flux at the interface Proposed parameterization of skin‐to‐bulk temperatures Similarity scaling of temperature microprofiles over the diffusive thermal sublayer thickness