Retrieval of IPAR & PAR flam OCM-2 irregular basis and validation with measurements for different regions of tropical, sub tropical and Polar areas
Ocean colour remote sensing is a useful tool and it provides quantitative information of seawater constituents on synoptic scale. ISRO’s ocean colour missions namely OCEANSAT-1 and OCEANSAT-2 OCM have been extensively used for various societal and scientific applications like Potential Fishing Zone identification, ocean primary productivity estimation, algal bloom detection and studying the coastal processes etc. Photosynthetically available radiation (PAR) is one of the key parameter along with spatially invariant and uniform aerosol optical depth under clear sky condition has been used for estimating the ocean primary productivity models using OCM data. Thus, modeling PAR from OCM under variable aerosol loading and cloud conditions is a desirable input parameter to estimate ocean primary production from OCM more accurately. The Instantaneous Photosynthetically Available Radiation (IPAR) is used as one of the input for estimating the PAR (400-700 nm) in some of the models.
Retrieval of sea surface salinity from satellite data and validation
Sea Surface salinity (SSS) is an essential climate variable. It is a key component of the water cycle, as a tracer of precipitation and evaporation, river outflow and ice melt/ freeze. It is a key driver of the oceanic circulation through its role on the ocean density. It is also a critical parameter for understanding the variability of the ocean carbon fluxes, providing information on water masses and of their chemical properties. Salinity dominates seawater density and directly affects physical and biochemical processes. Having a reliable retrieval model is essential to provide frequent and accurate sea surface salinity (SSS) data for marine research. Remote-sensing techniques provide alternatives for SSS data retrieval with its advantages of wide area surveys and real-time monitoring. The past, present and the future ocean colour missions of ISRO can be used for addressing some of the key climate change issues like ocean acidification and carbon dynamics along with it’s contemporary sensors like SST and altimeters. |Hence, there is a need to develop the new algorithms or to evaluate and fine tune the SSS algorithms to address the above issues. 1. Ocean Surface salinity is one of the Essential Climate Variable (ECV) 2. L-Band Passive Microwave radiometers such as SMOS, Aquarius and SMAP have demonstrated the capability to retrieve salinity from brightness temperature data 3. Development of algorithms for retrieval of salinity using passive microwave radiative transfer models 4. Validation of the retrieved salinity using Moored buoy, RAMA buoy and other in-situ observations.
