Evidence of recent warming and El Niño‐related variations in ice breakup of Wisconsin lakes

Abstract

Ice breakup dates from 196 8 to 19 8 8 were examined for 20 Wisconsin lakes to determine whether consistent interannual and long-term changes exist. Each ice record had a trend toward earlier breakup dates, as demonstrated by a negative slope with time, indicating a recent warming trend. The average change in breakup dates was 0.82 d earlier per year for the lakes in southern Wisconsin, which was more extreme than that for the northern Wisconsin lakes (0.45 d yr-I). Interannual variation in breakup dates was related to the warm phase of El Nina/Southern Oscillation (ENSO) episodes. El Niiio events occurred five times during this period (1965, 1972, 1976, 1982, and 1986). Average breakup dates were significantly earlier than average (5-14 d) during the mature phase of El Nifio. This variability was affected by the location of the lake: El Nine-related variation was more evident for the southern lakes than the northern lakes. This difference was caused by the average date of breakup for the southern lakes being in late March directly following the period when air temperatures were strongly related to El Nifio events, whereas the average dates of breakup of the northern lakes was in mid-to late April following a period when air temperatures were not significantly related to El Nina events. Overall, the interannual and long-term patterns across Wisconsin were relatively consistent, indicating that recent warming and El Nina-related variation are regional climatic responses.

Determinants of temporal coherence in the satellite‐derived 1987–1994 ice breakup dates of lakes on the Laurentian Shield

“…Numerous investigators (e.g. Anderson et al 1996;Assel and Robertson 1995;Palecki and Barry 1986;Robertson et al 1992) have noted that the breakup date is primarily a reflection of the climatic conditions in the preceding month or so. The temporal coherence of any parameter is primarily a measure of synchronicity of response over time-not a measure of the relative degree of response.…”

“…Assel and Robertson 1995;Palecki and Barry 1986;Schindler et al 1990;Wynne and Lillesand 1993), suggestion of a trend toward decreased ice duration (primarily due to earlier breakup dates) on several inland lakes and Great Lakes bays (e.g. Anderson et al 1996;Assel and Robertson 1995;Comb 1990;Hanson et al 1992;Robertson et al 1992), ability to be detected from the spaceborne sensors for which substantial archival data are available (e.g. Maslanik and Barry 1987;Wynne and Lillesand 1993), and utility as a climate proxy in the high latitude areas of North America and Eurasia-areas characterized by a relative paucity of meteorological stations (Palecki and Barry 1986;Robertson et al 1992;Wynne and Lillesand 1993).…”

Measuring the sensitivity of southern Wisconsin lake ice to climate variations and lake depth using a numerical model

“…Palecki and Barry 1986;Schindler et al 1990;Wynne and Lillesand 1993), the suggestion of a trend toward decreased ice duration (primarily due to earlier breakup dates) on several inland lakes and Great Lakes bays (e.g. Comb 1990; Robertson et al 1992;Assel and Robertson 1995;Anderson et al 1996); its ability to be detected from the spaceborne sensors from which substantial archival data are available (e.g. Wynne and Lillesand 1993), and its utility as a climate proxy in the high-latitude areas of North America and Eurasia-regions characterized by a relative paucity of meteorological stations (Palecki and Barry 1986;Robertson et al 1992;Wynne and Lillesand 1993).…”

Meteorological forcing of plankton dynamics in a large and deep continental European lake

“…Many long-term time series show a close coupling between large-scale meteorological phenomena and changes in population densities. For example, effects of the El Niño Southern Oscillation (ENSO) are apparent in oceanic and limnetic time series from Lake Tahoe (USA) to Tasmania (Barber and Chavez 1983;Strub et al 1985;Harris et al 1988;Karl et al 1995;Anderson et al 1996). Although there may be some linkages between the ENSO and weather patterns in Europe (Fraedrich and Müller 1992), it has become increasingly clear during recent years that the North Atlantic Oscillation (NAO) drives the weather patterns in the region of the northern hemisphere north of 20°N (Lamb and Peppler 1987;Hurrell 1995;Davies et al 1998).…”