Monday, 10 January 2005: 5:15 PM
Discharge and water chemistry of streams in NW Greenland (76°N, 68°W) (Formerly Paper Number JP1.7)
The amount, temperature, and quality of freshwater runoff from high latitude areas ultimately affect water stratification, nutrient cycle and formation of deep water current in the ocean. Freshwater is conveyed from Greenland to the ocean in a multitude of medium sized rivers for which little is known about discharge and water quality. Records of high resolved river runoff in connection with weather records from a typical high Arctic area in NW Greenland will increase the understanding of the interaction between climate, landscape processes and river runoff. The study site extends from the western edge of the Greenland Ice Sheet to Baffin Bay; it covers an area ranging between 10-20 km in E-W and 10-15 km in N-S direction, and the elevations reach 700 m. It is a typical high Arctic environment with sparse vegetation and pervasive active patterned ground. Most of the area is covered by glacial drift that resembles the underlying sedimentary and igneous Archean and Proterozoic bedrock. Complete climate records from pre-1978 to the present; indicate increases in mean annual air temperature from -12.0° C to -10.7° C and precipitation from 65 mm to 120 mm weq. between 1993 and 2002. To address how seasonal weather pattern and landscape processes affect runoff and water quality, as well as examine weathering and carbon budgets in the drainage, we monitor water discharge, water temperature, water chemistry (cation, anion, dissolved organic and inorganic carbon) of three rivers. Two of these rivers originate as melt water runoff from the Greenland Ice Sheet. The third stream is fed by local snowmelt and summer rain events. In addition, weather data along with soil moisture and temperature are recorded with automated stations at two locations. The potential sources of river water are thawing permafrost, local snowmelt, rain, and melting of glacial ice that have a discriminative isotopic signature of water (δD and δ18O). Stable isotopes therefore, are used to separate the hydrograph into these sources to help us relate discharge pattern and water quality to climate (precipitation, temperature) and landscape processes (thawing of permafrost, weathering, decomposition of organic matter). Our presentation will discuss results of the first data set collected from June to September 2004.