USGS - Graph Of The Day - Ice-Out Dates For New England Lakes 1850 - 2000

[hatrack]

Key Findings

Ice-out dates from 29 lakes in New England with 64 to 163 years of record were assembled and analyzed for this study (Hodgkins and James, 2002; Hodgkins and others, 2002). Twenty-two of these lakes are in Maine, four are in New Hampshire, and three are in Massachusetts.

Ice-out dates have become significantly earlier in New England since the 1800's. Ice-out dates changed between 1850 and 2000 by 9 days in northern and mountainous areas of New England (primarily northern and western Maine) and by 16 days in more southerly locations (figs. 1 and 2). Changes in the ice-out dates over time were very consistent between lakes within each of these two areas of New England.


Figure 1. Ice-out dates over time for Damariscotta Lake, Maine, and a smoothed line through the dates.


Figure 2. Smoothed lines of ice-out dates over time for the eight lakes in New England with the longest periods of record. The top four lines represent lakes in northern and western Maine and the bottom four lines represent lakes in southern Maine.

About half of the year-to-year variability in the lake ice-out dates is explained by historical March-April air temperatures. The ice-out dates of the two areas have a different response to changes in air temperature though. The ice-out dates in the northern/mountainous areas are less sensitive to changes in air temperatures than the ice-out dates in the more southerly areas. This may be due to the typically higher amounts of snow on the lake ice in the northern/ mountainous areas in late winter/early spring. The estimated late winter/early spring air-temperature warming in both areas of New England since 1850, based on the relation between lake ice-out dates and air temperatures, is about 2.6oF. Changes in lake ice-out dates over time can affect important characteristics of lakes, such as the rate of change of summer oxygen levels (Stewart, 1976), and the health of important parts of the food chain (Maeda and Ichimura, 1973; Porter and others, 1996).


References

Hodgkins, G.A., and James, I.C. II, 2002, Historical ice-out dates for 29 lakes in New England: U.S. Geological Survey Open-File Report 02-34, 32 p.

Hodgkins, G.A., James, I.C., and Huntington, T.G., 2002, Historical changes in lake ice-out dates as indicators of climate change in New England, 1850-2000: International Journal of Climatology, v. 22, p. 1819-1827.

Maeda, O., and Ichimura, S.E., 1973, On the high density of a phytoplankton population found in a lake under ice: Internationale Revue der Gesamten Hydrobiologie, v. 58, p. 673-685.

Porter K.G., Saunders, P.A., Haberyan, K.A., Macubbin, A.E., Jacobsen, T.R., and Hodson, R.E., 1996, Annual cycle of autotrophic and heterotrophic production in a small, monomictic Piedmont Lake (Lake Oglethorpe)—Analog for the effects of climatic warming on dimictic lakes: Limnology and Oceanography, v. 41, p. 1041-1051.

Stewart, K.M., 1976, Oxygen deficits, clarity and eutrophication in some Madison Lakes: Internationale Revue der Gesamten Hydrobiologie, v. 61, p. 563-579.

—By Glenn A. Hodgkins, Ivan C. James II, and Thomas G. Huntington

EDIT/END

http://pubs.usgs.gov/fs/2005/3002/

[lapfog_1]

1. But but but...

he fudged the data!!!

Where is the raw data? This is just graphs and charts and stuff.

He probably used some sort of trick in drawing those curves.

Isn't a lower number better?

We don't want ice on our lakes anyway.

BTW... :sarcasm: