衛星リモートセンシングによる中海・宍道湖の水質濃度マッピング(その1) : アオコ発生時の透明度,懸濁物質濃度およびクロロフィルa濃度の面的把握

Simultaneous water quality research with satellite observation were carried out in Lake Shinji and Lake Nakaumi from June to November, 1997. The objective of this report is to know horizontal distributions of Secchi depth (SD), suspended substance concentration (SSC) and chlorophyll a (C) in Lake Shinji and Lake Nakaumi 1997. Average SD ranges 1.0-1.3 m, average SS ranges 5-8mg/1, average C ranges 25-42 μg/l in Lake Shinji. C is the most variable of the three water quality parameters in Lake Shinji. Honjo area water located in the northern part of Lake Nakaumi, showed higher SD, lower SS and lower C than the Nakaumi area water. Under algal bloom condition, Lake Shinji water showed lower SD, higher SS and much higher C than Lake Nakaumi water. An empirical approach of relating SPOT2/HRV data with simultaneous C data through simple linear regression analysis was employed. Highly significant relationships (r=0.79) were identified between HRV bandl (Green) and C. With the linear regression model (C=3.864+HRV bandlx8.64), C map in Lake Shinji and Lake Nakaumi was displayed. The C map in Lake Shinji showed wholly high concentration, especially in the northern parts of the lake.