Impacts of Precipitation on Ice Cover and Water Temperature in the Great Lakes

Session: Physical Processes in Lakes (4)

Ayumi Fujisaki-Manome, University of Michigan, ayumif@umich.edu
Eric Anderson, NOAA/GLERL, eric.j.anderson@noaa.gov
James Kessler, University of Michigan, jamkessl@umich.edu
Gregory Lang, Great Lakes Environmental Research Laboratory, Gregory.Lang@noaa.gov
Jia Wang, NOAA, GLERL, jia.wang@noaa.gov
Philip Chu, NOAA/GLERL, philip.chu@noaa.gov
Andrew Gronewold, University of Michigan, drewgron@umich.edu

Abstract

Heat from precipitation to lakes and ice cover has been often overlooked yet can play a significant role in the energy budget. In the Great Lakes, the quantification of this process is relatively important among other detail processes in numerical models because 1) the large air-water temperature difference in fall and winter can cause significant sensible heat flux from precipitation (H_sp), and 2) winter-spring precipitation often falls as snow, which cools the lake surface by latent heat flux due to snow melting (H_lp). Snowfall also has two opposite effects on the energy and mass budget of ice; 1) one being increased surface albedo leading to delayed melting and promoted growth of ice, and 2) the other being insulation of cold air by low thermal conductivity of snow, leading to slowed ice growth. This study evaluates the precipitation impacts on water temperature and ice cover in the Great Lakes based on a simple time series analysis of  H_spand H_lpand complexthree-dimensional coupled ice-hydrodynamic modeling using the unstructured grid Finite-Volume Community Ocean Model (FVCOM).