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Baranowski, DB, Flatau MK, Flatau PJ, Matthews AJ.  2016.  Impact of atmospheric convectively coupled equatorial Kelvin waves on upper ocean variability. Journal of Geophysical Research: Atmospheres. 121:2045-2059.   10.1002/2015JD024150   Abstract

Convectively coupled Kelvin waves (CCKWs) are atmospheric weather systems that propagate eastward along the equatorial wave guide with phase speeds between 11 and 14 m s−1. They are an important constituent of the convective envelope of the Madden-Julian oscillation (MJO), for which ocean-atmosphere interactions play a vital role. Hence, ocean-atmosphere interactions within CCKWs may be important for MJO development and prediction and for tropical climate, in general. Although the atmospheric structure of CCKWs has been well studied, their impact on the underlying ocean is unknown. In this paper, the ocean-atmosphere interactions in CCKWs are investigated by a case study from November 2011 during the CINDY/DYNAMO field experiment, using in situ oceanographic measurements from an ocean glider. The analysis is then extended to a 15 year period using precipitation data from the Tropical Rainfall Measuring Mission and surface fluxes from the TropFlux analysis. A methodology is developed to calculate trajectories of CCKWs. CCKW events are strongly controlled by the MJO, with twice as many CCKWs observed during the convectively active phase of the MJO compared to the suppressed phase. Coherent ocean-atmosphere interaction is observed during the passage of a CCKW, which lasts approximately 4 days at any given longitude. Surface wind speed and latent heat flux are enhanced, leading to a transient suppression of the diurnal cycle of sea surface temperature (SST) and a sustained decrease in bulk SST of 0.1°C. Given that a typical composite mean MJO SST anomaly is of the order of 0.3°C, and more than one CCKW can occur during the active phase of a single MJO event, the oceanographic impact of CCKWs is of major importance to the MJO cycle.

Flatau, PJ.  1997.  Improvements in the discrete-dipole approximation method of computing scattering and absorption. Optics Letters. 22:1205-1207.   10.1364/ol.22.001205   AbstractWebsite

Improvements in complex-conjugate gradient algorithms applied to the discrete-dipole approximation are reported. It is shown that computational time is reduced by use of the stabilized version of the biconjugate gratings algorithm, with diagonal left preconditioning. (C) 1997 Optical Society of America.

Markowicz, KM, Flatau PJ, Quinn PK, Carrico CM, Flatau MK, Vogelmann AM, Bates D, Liu M, Rood MJ.  2003.  Influence of relative humidity on aerosol radiative forcing: An ACE-Asia experiment perspective. Journal of Geophysical Research-Atmospheres. 108   10.1029/2002jd003066   AbstractWebsite

We present direct radiometric observations of aerosol radiative forcing during the ACE-Asia experiment (March and April of 2001). The observational analysis is based on radiometer data obtained from the NOAA ship Ronald H. Brown, and shipboard measurements of the aerosol chemical and scattering properties are used to construct a model of the aerosol optical properties for use in radiative transfer calculations. The model is validated against the radiometric observations and is used to diagnose the aerosol and environmental factors that contribute to the observed forcings. The mean value of aerosol optical thickness observed during the ACE-Asia cruise over the Sea of Japan was 0.43 (+/-0.25) at 500 nm, while the single-scattering albedo was 0.95 (+/-0.03) at ambient relative humidity. We find a large correlation (r(2) = 0.69) between single-scattering albedo and relative humidity. Aerosols caused a mean decrease in the diurnally averaged solar radiation of 26.1 W m(-2) at the surface, while increasing the atmospheric solar absorption and top of atmosphere reflected solar radiation by 13.4 W m(-2) and 12.7 W m(-2), respectively. The mean surface aerosol forcing efficiency (forcing per unit optical depth) over the Sea of Japan was -60 W m(-2) and is influenced by high values of relative humidity. We show that decreasing the relative humidity to 55% enhances the aerosol forcing efficiency by as much as 6-10 W m(-2). This dependency on relative humidity has implications for comparisons of aerosol forcing efficiencies between different geographical locations.