Twin Otter International

The coastal zone is home to a high fraction of humanity and increasingly affected by natural and human-induced events from tsunamis to toxic tidal blooms. Current satellite data provide a broad overview of these events but do not have the necessary spectral, spatial and temporal, resolution to characterize and understand these events.

To address this gap, a compact, lightweight, airborne Portable Remote Imaging SpectroMeter (PRISM) compatible with a wide range of piloted and Uninhabited Aerial Vehicle (UAV) platforms are curently being developed at the Jet Propulsion Laboratory. Operating between the spectral range of 350 nm and 1050 nm, PRISM will offer high temporal resolution and below cloud flight altitudes to resolve spatial features as small as 30 cm. The sensor performance exceeds the state of the art in light throughput, spectral and spatial uniformity, and polarization insensitivity by factors of 2-10, while at the same time extending the spectral range into the ultraviolet. PRISM will also have a two-channel spot radiometer at short-wave infrared (SWIR) band (1240 nm and 1640 nm). It will be in co-alignment with the spectrometer in order to provide accurate atmospheric correction of the ocean color measurements.

The development of the PRISM instrument is supported by NASA Earth Science Division’s the Ocean Biology and Biogeochemistry, Earth Science Technology, and Airborne Sciences programs within NASA’s Earth Science Division.

AATS-14 measures direct solar beam transmission at 14 wavelengths between 354 and 2139 nm in narrow channels with bandwidths between 2 and 5.6 nm for the wavelengths less than 1640 nm and 17.3 nm for the 2139 nm channel. The transmission measurements at all channels except 940 nm are used to retrieve spectra of aerosol optical depth (AOD). In addition, the transmission at 940 nm and surrounding channels is used to derive columnar water vapor (CWV) [Livingston et al., 2008]. Methods for AATS-14 data reduction, calibration, and error analysis have been described extensively, for example, by Russell et al. [2007] and Shinozuka et al. [2011]. AATS-14 measurements of spectral AOD and CWV obtained during aircraft vertical profiles can be differentiated to determine corresponding vertical profiles of spectral aerosol extinction and water vapor density. Such measurements have been used extensively in the characterization of the horizontal and vertical distribution of aerosol optical properties and in the validation of satellite aerosol sensors. For example, in the Aerosol Characterization Experiment-Asia (ACE-Asia), AATS measurements were used for closure (consistency) studies with in situ aerosol samplers aboard the NCAR C-130 and the CIRPAS Twin-Otter aircraft, and with ground-based lidar systems. In ACE-Asia, CLAMS (Chesapeake Lighthouse & Aircraft Measurements for Satellites, 2001), the Extended-MODIS-λ Validation Experiment (EVE), INTEX-A, INTEX-B, and ARCTAS, AATS results have been used in the validation of satellite sensors aboard various EOS platforms, providing important aerosol information used in the improvement of retrieval algorithms for the MISR and MODIS sensors among others.