SBIR-STTR Award

Satellite microphysics retrievals rely on in situ measurements to tune and validate their algorithms. Particle imaging probes have been the most reliable in situ instruments for identifying the shapes of cloud particles, thereby distinguishing (non-spherical) ice particles from (spherical) water drops. However, improvements in the pixel resolution, number of gray-levels and software processing of the particle images are required to take these measurements to the next level. Here we describe a new optical probe that vastly improves the ability to automatically identify and classify ice particles and water drops in mixed-phase clouds. The Particle Phase Spectrometer that SPEC will design and test in the laboratory in Phase I will integrate three optical instruments into a single package: 1) a very high-resolution (1-?m pixel resolution) digital camera imaging system, 2) a 10-?m 2D-Gray optical array probe and 3) a forward scattering probe that sizes particles from 2 to 50 ?m. The Particle Phase Spectrometer will provide unprecedented, high-resolution digital images that will be capable of distinguishing spherical from non-spherical cloud particles as small as 10 microns. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The Particle Phase Spectrometer will provide vastly improved ice particle and water drop size distributions in mixed-phase clouds, which constitute about 40% of clouds globally. The Particle Phase Spectrometer will also distinguish spherical from non-spherical particles in cirrus and sub-visible cirrus clouds. The improved microphysics retrievals from satellites will aid NASA in monitoring our changing climate. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): The microphysical measurements will be used to validate satellite retrievals and improve calculations of radiative forcing by clouds, a critical factor in monitoring climate change. There will be a substantial benefit to both industry and society from an improved understanding of climate change. Duration: 6

The 2021 IPCC report on the physical basis of climate change confirms that the Arctic is warming at nearly twice the rate of the global average. The 2021 IPCC report reconfirms previous IPCC reports since 2001 that clouds represent the largest uncertainty in climate models. Arctic mixed-phase clouds have a major impact on surface radiative fluxes and energy balance, which are critical to understanding climate change. The objective of the proposed research is the development and flight-testing of a new airborne instrument, a Particle Phase Spectrometer (PPS), which will provide measurements of the ice and water phases in mixed-phase clouds. These in situ measurements can be used to validate spaceborne microphysical retrievals and provide data that can be parameterized to improve climate prediction models. The PPS will discriminate small (~ 20 to 30 micron) water drops from ice particles in mixed-phase clouds. The airborne PPS will be adapted from SPEC’s commercial 3V-CPI, which combines a cloud particle imager (CPI) with 2.3 micron pixels and a 2D-S optical array probe with 10-micron resolution. The PPS will have 1-micron resolution and the 2D-S will be replaced with a 4-level 2D-Gray probe with 5-micron resolution. To achieve these goals requires substantial engineering and meticulous fabrication of components. The 1-micron resolution CPI is near the diffraction wavelength limit and requires precision optics that were developed in Phase I. It also requires a high-power (200 W) pulsed laser with a 10 ns pulse length. The 5-micron 2D-Gray probe requires ultra-low noise amplification and FPGA (field programmable gate array) compression of large, high-rate data streams. The two airborne subsystems will be designed using solid modeling, fabricated and tested in the laboratory before being packaged into an airborne instrument and test-flown on the company’s Learjet research aircraft. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The prototype PPS will be made available for installation on the NASA P-3B research aircraft that will participate in the NASA Arctic Radiation-Cloud-Aerosol-Surface-Interaction Experiment (ARCSIX) field campaign in the summer of 2024. It will also be available for additional NASA projects and can be installed on the NASA DC-8 and WB-57 research aircraft. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): Research aircraft continue to be a rich market for SPEC Inc., plus spin-off markets such as improved airborne measurements of ice and water content required for certification of commercial aircraft in mixed-phase icing conditions; and identification of smoke from wildfires and other airborne pollutants that cause human health concerns. Duration: 24