HEATING RATE WITHIN THE UPPER OCEAN IN RELATION TO ITS BIOOPTICAL STATE

Solar radiation absorption and local heating within the upper layers of the open ocean are strongly in by the abundance of phytoplankton as depicted by the chlorophyll concentration. According to whether this concentration is high or low, the heat deposition occurs within a layer that may vary in thickness from less than 10 m to more than 100 m. A simple parameterization, accounting for this dependence, is developed. It allows the vertical profiles of heating rate to be predicted from the phytoplanktonic pigment concentration, as it can (and will) be remotely detected from space, by using ocean color sensors. This computationally efficient parameterization has been validated in reference to the results of a full spectral model. In the simplified computation, the solar spectrum is partitioned into two domains, below and above the wavelength 0.75 mum. For the infrared waveband, not influenced by biological materials, the irradiance profile is described by a single exponential function. For the ultraviolet and visible (