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Multiyear trends in snowpack ion accumulation and loss, northern Michigan
Author(s) -
Stottlemyer Robert,
Rutkowski Darcy
Publication year - 1990
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr026i004p00721
Subject(s) - snowpack , snow , precipitation , snowmelt , meltwater , environmental science , hydrology (agriculture) , atmospheric sciences , geology , meteorology , geography , geomorphology , geotechnical engineering
From December 1982 to May 1987 the quality and quantity of snowfall and snowpack were measured at four stations in a small (176 ha) gauged watershed adjacent to Lake Superior's south shore. Annual precipitation was less than and winter precipitation greater than observed east and south of the Lake Superior basin. Snowfall averaged 37% of annual precipitation but was quite variable. Snowfall significantly increased (from 21.1 to 35.7 cm, P < 0.001) with 150 m increase in elevation. Hydrogen and SO 4 2− were the dominant ions in precipitation and snowpack while Ca 2+ and HCO 3 − dominated stream water. No significant time trends in winter precipitation chemistry were found. Snowpack ionic retention rarely matched precipitation input. Generally, midwinter freeze‐thaw periods resulted in elevated concentrations of solutes in snow meltwater and greatly reduced snowpack ion loads prior to peak stream water discharge. All ions exhibited pulses in snowmelt each year. Preferential elution from the snowpack of SO 4 2− and K + was observed. Stream water H + , NH 4 + and most NO 3 − pulses were associated with midwinter thaws. Stream water SO 4 2− pulses were rare. For those years exhibiting the most pronounced spring increase in stream H + , NO 3 − and SO 4 2− concentration, the magnitude and rate of concentration change was as great in a year of small peak snowpack ion load as it was following a more rapid ion loss from a larger snowpack load. This suggests that the pattern of snowpack melt and especially the pathway the meltwater follows to the stream may be important factors in determining whether stream water chemical pulses occur.