Design of a direct-detection wind and aerosol lidar for mars orbit

Abstract

The present knowledge of the Mars atmosphere is greatly limited by a lack of global measurements of winds and aerosols. Hence, measurements of height-resolved wind and aerosol profiles are a priority for new Mars orbiting missions. We have designed a direct-detection lidar (MARLI) to provide global measurements of dust, winds and water ice profiles from Mars orbit. From a 400-km polar orbit, the instrument is designed to provide wind and backscatter measurements with a vertical resolution of 2 km and with resolution of 2° in latitude along track. The instrument uses a single-frequency, seeded Nd:YAG laser that emits 4 mJ pulses at 1064 nm at a 250 Hz pulse rate. The receiver utilizes a 50-cm diameter telescope and a doubleedge Fabry-Pérot etalon as a frequency discriminator to measure the Doppler shift of the aerosol-backscatter profiles. The receiver also includes a polarization-sensitive channel to detect the cross-polarized backscatter profiles from water ice. The receiver uses a sensitive 4 × 4 pixel HgCdTe avalanche photodiode array as a detector for all signals. Here we describe the measurement concept, instrument design, and calculate its performance for several cases of Mars atmospheric conditions. The calculations show that under a range of atmospheric conditions MARLI is capable of measuring wind speed profiles with random error of 2-4 m/s within the first three scale heights, enabling vertically resolved mapping of transport processes in this important region of the atmosphere.

Low‐Level Jets and the Convergence of Mars Data Assimilation Algorithms

“…Studies of low‐level circulations in the Martian atmosphere would thus benefit from collection of additional data more sensitive to near‐surface wind or pressure fields. Technological options for collecting such data include lander networks (e.g., Harri et al., 2017), radio occultation constellations (e.g., Kursinski et al., 2012), and orbiting wind lidars (e.g., Cremons et al., 2020). Alternatively, it may be possible to derive improved constraints on low‐level zonal geostrophic winds from existing radio occultation and/or lander data.…”

Low-level jets and the convergence of Mars data assimilation algorithms

“…Studies of low-level circulations in the Martian atmosphere would thus benefit from collection of additional data more sensitive to near-surface wind or pressure fields. Technological options for collecting such data include lander networks (e.g., Harri et al, 2017), radio occultation constellations (e.g., Kursinski et al, 2012), and orbiting wind lidars (e.g., Cremons et al, 2020). Alternatively, it may be possible to derive improved constraints on low-level zonal geostrophic winds from existing radio occultation and/or lander data.…”

Measuring Mars Atmospheric Winds from Orbit

“…It is most sensitive to the lowest ~40 km of atmosphere and insensitive above 60 km. The Mars lidar for global climate studies from orbit (MARLI) is a directdetection Doppler wind lidar that measures the wind speed along the laser's line-of-sight in addition to dust and water ice extinction [59]. MARLI has been developed through PICASSO and MATISSE program funding to NASA GSFC and was planned to reach TRL 6 in June 2020, prior to the COVID-19 reduction in work.…”