Remote sensing of desert dust over Kuwait: long–term variation

Aerosol optical measurements acquired with satellite–borne TERRA/Moderate Resolution Imaging Spectro–radiometer (MODIS) sensor were analyzed over Kuwait. The study focuses on the seasonal variation of aerosol optical thickness (AOT) and their relationship with meteorological parameters during the 7–year period from 2000 through 2007. The mean values of AOT, wind speed (V), air temperatures (T), diurnal temperature range (AT) and water vapor content (WVC) in the near-infrared (NIR) region were high during spring (April–May), while those of the Angstrom wavelength exponent α were low. These low values of α indicate the presence of large aerosol particles (dust). Spectral analysis shows a significant annual variation in the AOT and meteorological parameters. The second (semi–annual), third (4–month) and fourth (3–month) harmonics of the annual variation are also evident. The fourth harmonic is well defined in WVC (NIR) spectra. The power spectral densities of the exponent α, ΔT and RH have a similar spectral power ~1.9. The cross–correlation functions between the time series of the wavelength exponent and each of the meteorological parameters exhibit annual and biennial cycles. The atmosphere over Kuwait is relatively dust free 3 months after WVC (NIR) peaks.