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  • Author or Editor: J. E. Hansen x
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Steven R. Hanna, Michael J. Brown, Fernando E. Camelli, Stevens T. Chan, William J. Coirier, Olav R. Hansen, Alan H. Huber, Sura Kim, and R. Michael Reynolds

Computational fluid dynamics (CFD) model simulations of urban boundary layers have improved in speed and accuracy so that they are useful in assisting in planning emergency response activities related to releases of chemical or biological agents into the atmosphere in large cities such as New York, New York. In this paper, five CFD models [CFD-Urban, Finite Element Flow (FEFLO), Finite Element Model in 3D and Massively-Parallel version (FEM3MP), FLACS, and FLUENT–Environmental Protection Agency (FLUENT-EPA)] have been applied to the same 3D building data and geographic domain in Manhattan, using approximately the same wind input conditions. Wind flow observations are available from the Madison Square Garden 2005 (MSG05) field experiment. Plots of the CFD models' simulations and the observations of near-surface wind fields lead to the qualitative conclusion that the models generally agree with each other and with field observations over most parts of the computational domain, within typical atmospheric uncertainties of a factor of 2. The results are useful to emergency responders, suggesting, for example, that transport of a release at street level in a large city could extend for a few blocks in the upwind and crosswind directions. There are still key differences among the models for certain parts of the domain. Further examination of the differences among the models and the observations are necessary in order to understand the causal relationships.

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Michael I. Mishchenko, Brian Cairns, Greg Kopp, Carl F. Schueler, Bryan A. Fafaul, James E. Hansen, Ronald J. Hooker, Tom Itchkawich, Hal B. Maring, and Larry D. Travis

The NASA Glory mission is intended to facilitate and improve upon long-term monitoring of two key forcings influencing global climate. One of the mission's principal objectives is to determine the global distribution of detailed aerosol and cloud properties with unprecedented accuracy, thereby facilitating the quantification of the aerosol direct and indirect radiative forcings. The other is to continue the 28-yr record of satellite-based measurements of total solar irradiance from which the effect of solar variability on the Earth's climate is quantified. These objectives will be met by flying two state-of-the-art science instruments on an Earth-orbiting platform. Based on a proven technique demonstrated with an aircraft-based prototype, the Aerosol Polarimetry Sensor (APS) will collect accurate multiangle photopolarimetric measurements of the Earth along the satellite ground track within a wide spectral range extending from the visible to the shortwave infrared. The Total Irradiance Monitor (TIM) is an improved version of an instrument currently flying on the Solar Radiation and Climate Experiment (SORCE) and will provide accurate and precise measurements of spectrally integrated sunlight illuminating the Earth. Because Glory is expected to fly as part of the A-Train constellation of Earth-orbiting spacecraft, the APS data will also be used to improve retrievals of aerosol climate forcing parameters and global aerosol assessments with other A-Train instruments. In this paper, we detail the scientific rationale and objectives of the Glory mission, explain how these scientific objectives dictate the specific measurement strategy, describe how the measurement strategy will be implemented by the APS and TIM, and briefly outline the overall structure of the mission. It is expected that the Glory results will be used extensively by members of the climate, solar, atmospheric, oceanic, and environmental research communities as well as in education and outreach activities.

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William L. Smith Jr., Christy Hansen, Anthony Bucholtz, Bruce E. Anderson, Matthew Beckley, Joseph G. Corbett, Richard I. Cullather, Keith M. Hines, Michelle Hofton, Seiji Kato, Dan Lubin, Richard H. Moore, Michal Segal Rosenhaimer, Jens Redemann, Sebastian Schmidt, Ryan Scott, Shi Song, John D. Barrick, J. Bryan Blair, David H. Bromwich, Colleen Brooks, Gao Chen, Helen Cornejo, Chelsea A. Corr, Seung-Hee Ham, A. Scott Kittelman, Scott Knappmiller, Samuel LeBlanc, Norman G. Loeb, Colin Miller, Louis Nguyen, Rabindra Palikonda, David Rabine, Elizabeth A. Reid, Jacqueline A. Richter-Menge, Peter Pilewskie, Yohei Shinozuka, Douglas Spangenberg, Paul Stackhouse, Patrick Taylor, K. Lee Thornhill, David van Gilst, and Edward Winstead

Abstract

The National Aeronautics and Space Administration (NASA)’s Arctic Radiation-IceBridge Sea and Ice Experiment (ARISE) acquired unique aircraft data on atmospheric radiation and sea ice properties during the critical late summer to autumn sea ice minimum and commencement of refreezing. The C-130 aircraft flew 15 missions over the Beaufort Sea between 4 and 24 September 2014. ARISE deployed a shortwave and longwave broadband radiometer (BBR) system from the Naval Research Laboratory; a Solar Spectral Flux Radiometer (SSFR) from the University of Colorado Boulder; the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) from the NASA Ames Research Center; cloud microprobes from the NASA Langley Research Center; and the Land, Vegetation and Ice Sensor (LVIS) laser altimeter system from the NASA Goddard Space Flight Center. These instruments sampled the radiant energy exchange between clouds and a variety of sea ice scenarios, including prior to and after refreezing began. The most critical and unique aspect of ARISE mission planning was to coordinate the flight tracks with NASA Cloud and the Earth’s Radiant Energy System (CERES) satellite sensor observations in such a way that satellite sensor angular dependence models and derived top-of-atmosphere fluxes could be validated against the aircraft data over large gridbox domains of order 100–200 km. This was accomplished over open ocean, over the marginal ice zone (MIZ), and over a region of heavy sea ice concentration, in cloudy and clear skies. ARISE data will be valuable to the community for providing better interpretation of satellite energy budget measurements in the Arctic and for process studies involving ice–cloud–atmosphere energy exchange during the sea ice transition period.

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