Estimating Chlorophyll-a Concentration in Laizhou Bay Using HJ-1A Hyperspectral Image Data

Chengkun Zhang, Min Han

Tuesday 30 june 2015

12:33 - 12:36h at Asia (level 0)

Themes: (T) Managing deltas, (ST) Impacts of urbanization and land reclamation, Poster pitches

Parallel session: Poster pitches: 5C. Deltas - Impacts

Recent years, the increasing human activities such as the sea aquaculture, industrial production, contribute to the water eutrophication of Laizhou Bay. The concentration of chlorophyll-a, an important index of water quality status, can reflect the extent of eutrophication. With the characteristics of rapidity, cyclicity, large-scale and low-cost, the technique of remote sensing plays a crucial role in quantitatively monitoring the status of water quality. MODIS is designed specifically for ocean color, and its Chlorophyll-a inversion models for case_water were already widely used. But for its lower spatial resolution, MODIS cannot satisfy the needs of monitoring the water quality in coastal case _ waters, such as Laizhou Bay. The short cycle, the higher spatial and spectral resolution of HJ-1A hyperspectral data offered great promise for case _ water status quality monitoring. This paper first investigates the performance of the existing models for the remote estimation of chlorophyll-a concentrations in turbid productive waters. And then by analyzing the relation between the spectral reflectance measured by SVC GER 1500 and the simultaneous chlorophyll-a concentration, a kind of chlorophyll-a inversion model applicable to HJ-1A hyperspectral image data is put forward, which is established based on the wavelength character of chlorophyll-a reflection peak in 570 nm, fluorescence peak in 685 nm and another reflection peak in 835 nm. Through applying the model, the chlorophyll-a concentration distribution map of the Laizhou Bay in the summer of 2014 was given. The results show that chlorophyll-a concentration retrieved on the basis of HJ-1A hyperspectral image data is more similar to the in-situ reference data compared with empirical MODIS algorithms. According to the chlorophyll-a concentration distribution map, the water quality of the border of ocean and land in Laizhou Bay is in a certain degree of eutrophication.