Characteristics of the spectral irradiance in the sea and coastal area of Moquegua and Tacna in September 2017

Abstract

An analysis of the spectral signatures collected at sea, samples of marine bottom sediments and exposed rocks on the beach with the Apogee PS-100 spectroradiometer, was carried out. The purpose was to identify the spectral characteristics of the marine environment. It was evidenced that the spectral response of marine stations was related to the content of suspended particles such as sediments, biological organisms (microalgae) and intensity of solar radiation at the moment of recording the information. Higher irradiance values occurred at stations M-03 (0.069), M-04 (0.122) and M-05 (0.197) watts/m2, which coincided with an increase in the satellite chlorophyll-a concentration in each station. The spectral response of the composition of the exposed rocks and small stones that characterize the Escoria beach in Ilo was identified. The black rocks showed high absorption and low irradiance (<0.04 watts/m2) over the entire spectrum range, the ocher-colored ones showed higher irradiance between 600 and 800 nm (0.14 watts/m2) indicating mineral content. Rocks containing green algal organisms showed higher irradiance 485 nm (0.30 watts/m2) and a maximum absorbance at 550 nm. The spectral signatures of the bottom sediment samples have a similar spectral response because they contain different percentages of the same content of sediments and biological organisms.