We report the first observation of the largest Martian lee wave and its atmospheric characteristics over Arsia Mons Elongated Cloud (AMEC). We analyze the wavelength, the cloud’s height, and wind speed from the lee wave structure. The estimated wind speed is 86±4.9 m/s, with a wavelength of 60± 0.3 km at the height of 55±7 km. This is the largest lee wave structure that appears during dust storm season (Ls=230 to Ls=300) and strongly contributes to the planet’s Aerosol Optical Depth (AOD) level. Estimated AOD varies from 1.7 (Red channel) to 2.5 (Blue channel), and indicates the maximum contribution from the water ice crystal. The estimated angstrom exponent (α) value signifies coarse mode particle presence in the cloud with an effective radius of 3.2μm. The presence of water ice crystal contributes to the albedo level’s increment to 0.8 and signifies the formation temperature for AMEC to be around 190 K.