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Study on Monitoring System of Chlorophyll-a Concentration and Water Temperature in Lake using NOAA/AVHRR Observed Data

利用NOAA/AVHRR观测数据监测湖泊叶绿素a浓度和水温的系统研究

基本信息

批准号：
12555146
负责人：
SADO Kimiteru
金额：
$ 4.03万
依托单位：
Kitami Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The Abashiri Lake consists of two strong stable layers of upper Oligohaline water and lower Polyhaline water, which is entirely a brackish lake. The boundary depth of two layers has gradually decreased with time. At the same time, this has led to an increase in salinity and eutrophication in upper layer and to an acceleration of deoxygenating of lower layer, attributed to the occurrence of algal bloom and the upwelling of bluish water. It is pointed out that the algal bloom occurs in the Abashiri Lake on condition that the water temperature is larger than 18 ℃ and the chlorophyll-a concentration is larger than 30 μg/l.At first, the vertical and seasonal variations of one dimensional water tempera in the Abashiri Lake were calculated using a surface boundary condition described by observed values, a bottom boundary condition with no-heat conduction and a vertical initial condition described by estimated values for January 1^<st>. The surface temperature can be estimated using the software, MCSST (Multi Channel Sea Surface Temperature) for NOAA/AVHRR data received on the condition of no-cloud.In the next, the spectral reflectance of Abashiri Lake surface was formulated by using NOAA/AVHRR data received in Kitami Institute of Technology, horizontal global and scattered solar radiation at the shore. In order to correlate the spectral radiance of NOAA/AVHRR Ch.1 with the spectral radiance emitted from water surface, transmittance and path radiance were calculated approximately by using the horizontal global and the scattered solar radiation. Then, the chlorophyll-a concentration in the center of the Abashiri Lake was estimated by the regression line of the chlorophyll-a concentration on the difference of spectral reflectance between fluorescence and absorption zone of phytoplankton.

网走湖由两个坚固稳定的上层寡盐水和下层多盐水组成，完全是一个半咸水湖。随着时间的推移，两层的边界深度逐渐减小。与此同时，由于赤潮的发生和微蓝水体的上涌，导致上层盐度和富营养化程度的增加，下层缺氧加速。指出网走湖水华发生的条件是水温大于18 ℃，叶绿素a浓度大于30 μ g/l。首先，利用观测值描述的水面边界条件，计算了网走湖一维水温的垂直变化和季节变化，无热传导的底部边界条件和由1月1日的估计值描述的垂直初始条件。<st>利用NOAA/AVHRR数据，利用MCSST（Multi Channel Sea Surface Temperature）软件，在无云条件下估算了网走湖表面温度，并利用北见工业大学的NOAA/AVHRR数据、海岸的水平总辐射和散射太阳辐射，计算了网走湖表面的光谱反射率。为了将NOAA/AVHRR Ch.1的光谱辐亮度与水面辐射光谱辐亮度进行关联，利用水平总辐射和散射太阳辐射近似计算了透过率和路径辐亮度。然后，利用网走湖中心叶绿素a浓度与浮游植物荧光光谱反射率和吸收光谱反射率之差的回归线，估算网走湖中心叶绿素a浓度。