地球温暖化等の気象変動が河川・湖沼水質に及ぼす影響の統計的解析

Abstract

河川・湖沼水質に及ぼす地球温暖化等の気象変動の影響を定量的に予測することを目的に, 既往の河川・湖沼水質と気象観測データの統計解析を行った。統計的手法を用いる場合の問題点として, 1)流域特性の変化, 2)気象要素の相互作用, 3)地球温暖化により変化する気象過程, 4)気象変動の時間スケール, 5)非線形性等の影響, を取り上げ, それらの予測への影響を議論した。最後に, 水質変化を予測し, 地球温暖化後に水質悪化が生じることを示した。

In order to forcast the influences of global warming on the water environment, the relationship between meteorological conditions and lake water quality was investigated statistically using long-term monitoring data on river and lake water quality. Several analytical problems I. E. 1) change in watershed characteristics, 2) influence due to the interference between air temperature and precipitation, 3) difference of the meteorological processes and time scales between before and after global changes, 4) non-linearity, delay and irreversibility of the relationship, were discussed and solved. Through the quantitative analyses, we have confirmed that an increase in air temperature possibly caused by global warming will result in the deterioration of river and lake water quality such as increase in COD, BOD, decrease in DO, transparency.