Meteorological and climatological feature around Potanin glacier, Mongolian Altai

第33回極域気水圏シンポジウムポスター発

Stable isotopic and geochemical characteristics of groundwater in Kherlen River basin, a semi-arid region in eastern Mongolia

Inorganic solute ion concentrations and stable isotopes of oxygen and hydrogen ingroundwater, river water and precipitation were investigated to gain insight into thegroundwater recharge process in the Kherlen River basin, a semi-arid region in easternMongolia. The solute constituents in the river water (main stream) were of Ca-HCO3 type,spatially invariant and low in concentration. Groundwater in the upstream region was alsocharacterized by a Ca-HCO3 type, though all ion concentrations were higher than in the riverwater. On the other hand, the chemical composition of the groundwater in the midstreamregion (southern and eastern) was spatially variable and the Na+, Mg2+, Cl- and HCO3-concentrations were considerably higher than in the river water and upstream groundwater.The stable isotopic compositions showed an evaporation effect on the groundwater and river water, as well as an altitude effect in the precipitation and river water. Preferential rechargeby relatively large rainfall events is thought to have caused the depleted isotopic ratio in thegroundwater in the dry regions. The stable isotope, chemical and hydrological data suggestthat the main stream water of the Kherlen River is recharged by precipitation that falls in aheadwater region at an altitude of more than 1650 m, and that the interaction between thegroundwater and river water is not dominant in the midstream and downstream regions ofthe river basin

Mass balance of Potanin glacier, Mongolian Altai

第33回極域気水圏シンポジウム11月30日（火） 国立極地研究所 ２階大会議