Potential Applications of HyspIRI for the Observation of Sea-Margin Processes

Abstract

The Hyperspectral Infrared Imager (HyspIRI) mission will observe the effects of future environmental changes upon the world's ecosystems. Among other applications, this paper reviews three different sea-margin processes that can be monitored by the HyspIRI spectrometer, i.e. groundwater and surface-water discharge, meltwater-pond formation, and shoreline delineation. Groundwater and surface-water discharge to coastal regions affects local ecological conditions through changes in the local temperature, salinity, and nutrient load. Water-quality changes and temperature variability resulting from such discharge can be estimated from observation in the visible-to-shortwave-infrared (VSWIR) and the mid- and thermal-infrared (TIR) regions, respectively. The processes of meltwater forming ponds and entering the sea have unique ecological characteristics and are of additional interest because they are also highly subject to climate change. HyspIRI can use TIR to observe the spatial distribution of meltwater, whereas its VSWIR spectrometer can be used to quantify the changes of phytoplankton pigments (e.g., chlorophyll a). Quantifying seamargin changes requires accurate delineation of margin positions wherein tidal influence is minimal. Since the HyspIRI VSWIR data cover a wide spectral range and offer high spatial resolution, they are particularly suitable for shoreline delineation/change detection, as well as flood mapping. The signal-to-noise ratio of HyspIRI is expected to be comparable to that of the Hyperspectral Imager for the Coastal Ocean and much higher than that of Hyperion and Landsat Enhanced Thermal Mapper Plus, making it suitable for studying optically complex coastal aquatic environments. Herein, using examples from existing satellite sensors, HyspIRI's potential to study these complex sea-margin processes is presented and discussed.