Mirosław Darecki, Piotr Kowalczuk, Sławomir Sagan
Institute
of Oceanology, Polish Academy of Sciences, Sopot
Adam Krężel
Institute of Oceanography, Gdansk University, Gdynia
Clorophyll vs AVHRR satellite data during Skagex Experiment.
Studia i Matriały Oceanologiczne 1993, No.64 pp. 49-59.
Keywords: Skagerrak, AVHRR data, Surface chlorophyll concetration, Beam attenuation.
Manuscript received November 17, 1992, in final form October 1, 1993.
Abstract
During Skagex Experiment (May 1990) measurements of hydrophysical, optical, chemical and biological
(including chlorophyll a concentration) parameters were carried out simultaneously by several ships
covering the Skagerrak area. The mesurements were synchronized with with NOAA satellite passes. The satellite
data in red and near-IR light (1st and 2nd channels of AVHRR) were processed and compared with chlorophyll
content.
The results show that at least qualitative desription of some spatial structures is possible. However, there is
lack of theoretical premises for using the AVHRR's channels 1 and 2 for detection of optical parameters of
relatively clean sea waters ( CS < mg m-3, suspended matter < 3 mg dm-3).
Therefore, it seems that further development of processing algorithms is a promising line of research.
Mirosław Darecki, Jerzy Olszewski, Piotr Kowalczuk
Institute
of Oceanology, Polish Academy of Sciences, Sopot
A preliminary study of the spectral characteristics of the
upward radiance field in the surface layer of the Baltic. An empirical algorithm for the remote detection of chlorophyll conentration.
Studia i Matriały Oceanologiczne 1995, No.68 pp. 27-49.
Keywords: Apparent optical properties, Spectral reflectance, Remote Sensing, Chlorophyll a
Manuscript received April 18, 1994, in final form Novenber 5, 1995.
Abstract
The first results of experimental research into the relation between the
diffuse reflectance spectra of seawater and the concentration of chlorophyll
and total suspended matter in the surface layer are presented. The
measurements were conducted in the southern Baltic during summer 1992 and
spring and autumn 1993. The results allowed preliminary classification of these
waters into two basic groups, which differ from each other in the maximum
reflectance and in the concentration ranges of total suspended matter.
Each of the basic groups can be divided into two sub-groups, differing in shape
of the reflectace spectrum (defining the water colour), chlorophyll concetration
and the level of correlation between concetrations of chlorophyll and total
suspended matter.
On the basis of the above data a local algorithm for the radiometric
estimation of chlorophyll content in the surface layer of the Baltic is also
developed and presented. The use of the algorithm requires the reflectance
just above or below the sea surface to be measured at three wavelenghts
(490, 550, 620 nm) at least in order to specify the water's spectral
classification group, and at two of them (490, 620 nm) to compute the
chlorophyll concentration. The empirically determined choice of the 490 nm
band rather than that of the chlorophyll absorption maximum (443 nm) suggests
a high contribution of yellow substances to the optically active components
of Baltic waters.
Jerzy Olszewski, Piotr Kowalczuk, Mirosław Darecki
Institute
of Oceanology, Polish Academy of Sciences, Sopot
On the usefulness of NOAA-AVHRR
satellite data for estimating the component content in Baltic Sea water.
Studia i Matriały Oceanologiczne 1995, No.68 pp. 51-60.
Keywords: Spectral reflectance, Remote Sensing, NOAA-AVHRR, Baltic Sea
Manuscript received April 21, 1994, in final form December 4, 1995.
Abstract
The hypothetical response of the visible channel of the NOAA satellite AVHRR
detector is discussed in order to discover to what extent the content of Baltic
water can be distinguished. The experimental data from the spring of 1993
shows that, the application of the detector has been proven only in the direct
evaluation of totak suspended matter (TSM) concentration. The limitation ranges
of TSM concetration for good and poor AVHRR detection are given. The results
are illustrated with some AVHRR images, processed into spatial distribution
of total suspended matter in the Baltic's surface layer.