Impact of large-scale climate oscillations on ice in New Brunswick and Maine



by LORENZO CIOTTI

Impact of large-scale climate oscillations on ice in New Brunswick and Maine

Regional impact of large-scale climate oscillations on ice out variability in New Brunswick and Maine, a study published on the PeerJ, did a retrospective evaluating the impact of this factor in these two countries on the north Atlantic coast.

The researchers explained: "Four relatively closely spaced lakes in southwestern New Brunswick (Harvey, Oromocto, Skiff) and eastern Maine (West Grand Lake), with the longest set of available observations being for Oromocto Lake starting in 1876.

Results of a coherence analysis carried out on the ice out data from the four lakes indicates that there is regional coherence and correspondingly, that regional drivers influence ice out. These results also indicate that ice out dates for lakes from the region where records have not been kept can also be interpolated from these results.

As the ice out record was coherent, further analysis was done for only Oromocto Lake on the basis of it having the longest ice out record.Cross-wavelet analysis was carried out between the ice out record and a variety of cyclic climate teleconnections and the sunspot record to identify which phenomena best explain the observed ice out trends.

The most important observed contributors to ice out were the North Atlantic Oscillation (NAO) and the El Niño Southern Oscillation (ENSO), with observed periodicities at the interannual scale . At the decadal scale the Pacific Decadal Oscillation (PDO) and the 11-year solar cycle were the only patterns observed to significantly contribute to ice out." The climate of Maine (which straddles the 45th parallel) is distinctly continental but also influenced by the Atlantic Ocean which washes its coasts to the south.

The Köppen climate classification places this state, the easternmost of the USA and on the border with Canada, in the Dfb climate belt, i.e. among the cold climates of the middle latitudes, i.e. with the coldest month with average temperatures below -3 °C but with averages of the hottest month with values above 10 °C, with abundant rainfall in all months and with a hot but not very hot summer and therefore with no month with average values above 22 °C.

More generally, the position of Maine, between the extensive North American continental mass to the west and the vast ocean to the east, produces a hybrid climate: strong temperature variations between summer and winter, accentuated absolute thermal extremes, abundant snowfalls and rains, sustained ventilation, frequent storms-storms, frequent weather variability.

Maine experiences heavy snowfall during the colder months but snow is also not uncommon in late fall and early spring. Despite the higher temperatures, the snowpack tends to be more abundant, due to the higher rainfall, along the coastal areas.

(Portland on the sea has an annual average of 283 cm while the inland Caribou stops at 179 cm) but in the latter regions of Maine the snow on the ground lasts more days arrives earlier and melts later than in the coastal areas.

The region is often affected by violent storms and Atlantic blizzards with winds that can exceed 100 km/h (rarely some hurricanes or tropical storms coming from the southern areas of the USA can hit or graze this northern state) while in winter they are not rare, especially inside, blizzards, rains and freezing fogs and ice storms that block traffic, leave some communities in the dark and slow down commercial activities. Fogs are frequent especially in summer and along the coastal areas.