The Modular Aerial Sensing System

Abstract

Satellite remote sensing has enabled remarkable progress in the ocean, earth, atmospheric, and environmental sciences through its ability to provide global coverage with ever-increasing spatial resolution. While exceptions exist for geostationary ocean color satellites, the temporal coverage of low-Earth-orbiting satellites is not optimal for oceanographic processes that evolve over time scales of hours to days. In hydrology, time scales can range from hours for flash floods, to days for snowfall, to months for the snowmelt into river systems. On even smaller scales, remote sensing of the built environment requires a building-resolving resolution of a few meters or better. For this broad range of phenomena, satellite data need to be supplemented with higher-resolution airborne data that are not tied to the strict schedule of a satellite orbit. To address some of these needs, a novel, portable, high-resolution airborne topographic lidar with video, infrared, and hyperspectral imaging systems was integrated. The system is coupled to a highly accurate GPS-aided inertial measurement unit (GPS IMU), permitting airborne measurements of the sea surface displacement, temperature, and kinematics with swath widths of up to 800 m under the aircraft, and horizontal spatial resolution as low as 0.2 m. These data are used to measure ocean waves, currents, Stokes drift, sea surface height (SSH), ocean transport and dispersion, and biological activity. Hydrological and terrestrial applications include measurements of snow cover and the built environment. This paper describes the system, its performance, and present results from recent oceanographic, hydrological, and terrestrial measurements.

Airborne Remote Sensing of Wave Propagation in the Marginal Ice Zone

“…A reoccurring theme in this work is that small‐scale ice features with high horizontal variability affect the development and attenuation of surface waves dramatically. Airborne scanning lidar is an excellent tool for capturing the wave field at the relevant scales, and would benefit, in the future from the inclusion of additional video and infrared sensors (e.g., Melville et al, ) for measuring, for example surface temperature and floe sizes.…”

Observations and modeling of a tidal inlet dye tracer plume

“…Hyperspectral and long‐wave infrared imagery were recorded on 7 May using the Modular Aerial Sensing System (MASS) developed at Scripps Institution of Oceanography [ Melville et al ., ]. Aerial‐based near‐surface dye was estimated following the instruments and methods described in Clark et al .…”

“…[], as summarized below. Dye was imaged using the SIO MASS nadir‐looking hyperspectral imager [ Melville et al ., ] installed on a Partenavia P68‐obs aircraft. The imager is a pushbroom hyperspectral system (SPECIM AisaEagle) in the 400–970 nm range (visible and near infrared), with 5 nm spectral resolution.…”

Air entrainment by breaking waves

“…Figure a shows an example of a wave spectrum ϕ ( k ) measured during the HIRES 2010 experiment, from an aircraft, using a topographic lidar as described in Lenain and Melville [], together with the associated saturation spectrum, B ( k ), both extrapolated at higher frequencies (following Romero et al [] and consistent with recent observations from Melville et al []). The spectrum shows a power law at low wave numbers, before a transition to saturation, , at higher wave numbers (see Melville et al [] for a complete discussion on the transition from equilibrium to saturation spectra).…”