Two Satellite Remote Sensing Applications:
(i) MISR Cloud/Aerosol and Their Variability Through ENSO, and
(ii) MLS Diagnosis of CO and H2O Transport

ABSTRACT

I will present two satellite remote sensing applications: one is the MISR (Multiangle Imaging SpectroRadiometer) observations of cloud/aerosol and their variability through ENSO; and the other is Microwave Limb Sounder diagnosis of carbon monoxide (CO) and water vapor (H2O) transport.

First, decadal observations of cloud/Aerosol from Terra MISR are investigated to characterize tropical low cloud amount and Asian dust and their responses to ENSO (El Nińo Southern Oscillation). The MISR stereo technique has been unique with little dependence on atmospheric thermal structure and surface type in measuring cloud and aerosol. Despite a similar morphology of low cloud cover in the Pacific basin among MISR, MODIS (MOderate Resolution Imaging Spectroradiometer), and ISCCP (International Satellite Cloud Climatology Project), MISR cloud fraction shows the sharpest trade cumulus pattern along the equatorial Pacific. During the warm phase of ENSO, the observed low cloud cover generally decreases in the central Pacific near equator and increases in the subtropics and in the Southeastern (SE) Pacific. To characterize the Asian Dust distribution, three different areas, Taklimakan, Central Gobi, and East Gobi, are chosen as major Asian dust source regions. Despite differences, the ENSO driven aerosol optical thickness (AOT) anomalies from MISR, MODIS Deep Blue-Aqua and OMI (Ozone Monitoring Instrument)-Aqua are physically consistent in three independent satellite-based AOT observations. Asian dust loading is increased during La Nina years, and relatively cold and dry winters are suggested as a favorable condition for the dust production.

Second, the vertical structure and evolution of the carbon monoxide (CO) and water vapor (H2O) transports are diagnosed from Aura Microwave Limb Sounder (MLS) observations. CO is a good tracer throughout the middle atmosphere, while H2O is a good tracer in the tropical tropopause layer. The maximum of the CO Northern Angular Mode and Southern Angular Mode (CNAM and CSAM) indices is used to characterize the vertical descent within the polar vortex as a function of time and height. There is a significant anti-correlation between the mesospheric and stratospheric CNAM indices during 2005-2010 winters, supporting the hypothesis of mesosphere-stratosphere coupling through planetary-gravity wave interactions. The tropical mode indices of H2O show the QBO (Quasi Biennial Oscillation) modulated ascent signals of tropospheric water vapor up to 40km.