Variations in suspended and dissolved matter fluxes from glacial and non-glacial catchments during a melt season at Urumqi River, eastern Tianshan, central Asia.

摘要

The effects of climatic conditions on the delivery patterns of suspended solid and dissolved matter are evaluated by examining their correlation with air temperature, precipitation and runoff from glacial and non-glacial catchments at the headwaters of Urumqi River in eastern Tianshan, central Asia. The results show that the physical and chemical weathering fluxes (168 and 23 t km -2 yr -1, respectively) associated with the glacial catchment are higher than those of the non-glacial catchment (34 and 12 t km -2 yr -1, respectively). Significant linear correlations are found between river fluxes and air temperature in both catchments. For each degree of temperature increase, the runoff, physical weathering flux and chemical weathering flux from the glacial catchment increase by 12%, 16% and 5%, respectively. On the other hand, in the non-glacial catchment, these values are 9%, 13% and 15%, respectively, if the temperature is below 4degreesC; the variations in runoff, physical and chemical weathering fluxes are irregular when the temperature exceeds 4degreesC. Such a pattern for the non-glacial catchment during the melt season may be due to the influence of multiple water sources. In contrast, the relation to precipitation is relatively weak in both catchments. Furthermore, although the glacial catchment has a higher increasing rate of physical weathering flux in response to temperature increase than the non-glacial catchment, this is not the case for the chemical weathering flux, suggesting that glaciers play an important role in the effect of air temperature change on physical weathering flux.