in Biogeochemistry of Seasonally Snow-Covered Catchments,
ed. Tonnessen, KA, MW Williams, and M Tranter, IAHS 228, 207-220
SNOW AND WATER CHEMISTRY OF A
HEADWATER ALPINE BASIN, URUMQI RIVER,
TIAN SHAN, PR CHINA
Fengjing Liu
Lanzhou Institute of Glaciology and Geocryology
Lanzhou, Gansu, PR China 730000
Mark W. Williams
Department of Geography and
Institute of Arctic and Alpine Research
University of Colorado
Boulder, Colorado 80309
Daqing Yang
Lanzhou Institute of Glaciology and Geocryology
Lanzhou, Gansu, PR China 730000
John Melack
Department of Biological Sciences
University of California
Santa Barbara, CA
Abstract:
Hydrologic and hydrochemical measurements were conducted from May to
September 1991 in the Dry Cirque, a seasonally
snow-covered alpine basin at the headwaters of the Urumqi River.
The snowpack was sampled for chemical content during maximum
snow accumulation in May.
At the initiation of snowmelt,
ionic concentrations in snow were generally higher by a factor
of four close to
the ground compared to the top of the snowpack,
suggesting that solutes were released from the snowpack
in the form of an ionic pulse.
Furthermore,
maximum concentrations of
HCO3 and CA in the snowpack were near 400 ueq/L
and associated with visibly dirty ice lens,
indicating that dissolution of aeolian particles
in snow was a major source of these solutes.
Solute concentrations in streamwater were generally highest
at the initiation of snowmelt and then declined
through the melt season and into summer,
also indicating that the release of solutes from the snowpack
in an ionic pulse influenced streamwater chemistry.