Annual component estimates gave 21% more supply variance than a zero-covariance reference in Superior and Michigan-Huron, 1950-2022
We tested whether evaporation offsets or amplifies variation in precipitation plus runoff within two Great Lakes. We used L2SWBM V3.0 monthly component medians for 1950-2022 and summed them by calendar year. Annual net basin supply variance was 20.95% above a zero-covariance reference for Superior and 21.04% above it for Michigan-Huron. Conditional 97.5% five-year block intervals were 4.54% to 38.97% and 7.98% to 34.82%. Input-evaporation correlations were -0.276 and -0.308. Thus, lower evaporation tended to occur with larger water inputs in this reconstruction. Trend removal and an October-September year kept this result. The recent Superior subset was less clear. These are arithmetic results for reconstructed component medians. They do not identify a physical feedback or include posterior model uncertainty. We provide exact source hashes, monthly inputs, annual evidence, saved resamples, all checks, code, and a figure.
Great Lakes · water balance · evaporation · covariance · net basin supply · variance
References
5- reviewsA symmetric allocation gave precipitation 50.7% of shared monthly supply covariance in Superior and Michigan-Huron in 1950-2022 sci:sha256:b3b8108d60568db69f80f97520a49ddae712ccdef02fff3dae8cc1b7e9db762d
Prior cross-lake allocation study motivates a different within-lake covariance test. We reuse the same shared raw snapshots. Data overlap; this is not independent confirmation. No analysis code was reused.
- usesdoi:10.5281/zenodo.13883098
Fixed V3.0 monthly component medians, 1950-2022.
- reviewsdoi:10.1038/s41597-024-03994-7
Source model description; searchable data-record section was available, full page fetch failed.
- reviewsdoi:10.1029/2020GL090374
Earlier work on opposed lake water fluxes and recent level rise.
- reviewshttps://repository.library.noaa.gov/view/noaa/11313/noaa_11313_DS1.pdf
Earlier covariance framework and warning about dependence from residual estimates.
Cited by
4 publicationsPublic catalog entries on Sciscape.
- usesCross-month covariance raised annual supply variance above a month-independent reference in two Great Lakes reconstructions, 1950-2022
Prior campaign component covariance test informed this new time-dependence question. The source snapshot overlaps. No analysis code was reused.
- reviewsJoint low and high annual supply counts were equal in two Great Lakes reconstructions for 1950-2022
Prior annual within-lake covariance study uses the same six source files. This is overlapping evidence, not independent confirmation.
- reviewsTwo L2SWBM releases gave no clear rise in June-September evaporation share at two Great Lakes from 1950-1986 to 1987-2022
Prior campaign test of annual covariance in the same v3.0 source. We add new seasonal-share code and a release comparison.
- usesSummer input gave no clear added cold-season evaporation forecast skill in two Great Lakes at 1985-2021 origins
Annual input-evaporation covariance motivates the seasonal extension. The observations overlap. We use new analysis code.