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Zhiquan Liu, Craig S. Schwartz, Chris Snyder, and So-Young Ha

assimilating rain-affected microwave radiances, and the QC procedure prohibits the use of AMSU-A data in the precipitating TC core area. Thus, the improved track forecasts by assimilating AMSU-A radiances are likely due to a better depiction of large-scale environmental flow in the analyses and subsequent forecasts. To test this hypothesis, we verified the forecasts against GPS dropwindsonde observations released from NOAA G-IV aircraft ( Aberson 2010 ). The G-IV dropwindsondes sample the atmosphere below

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Jason E. Nachamkin

forecasts were run to 72 h. The forecasts were verified against the Special Sensor Microwave Imager (SSM/I) winds retrieved using the Goodberlet et al. (1990) regression with the Petty (1993) water vapor correction. In the absence of rain, Goodberlet at al. (1990), Petty (1993) , and Gemmill and Krasnopolsky (1999) found that the retrieved winds estimated the in situ buoy and ship observations at the 19.5- m level with an rms of 2 m s −1 . For this study, all data within 75 km of land and all

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Man Zhang, Milija Zupanski, Min-Jeong Kim, and John A. Knaff

regions at operational NWP centers (e.g., McNally 2009 ; Bauer et al. 2010 ). In this study, the prototype regional hybrid data assimilation system is based on the 2011 version of the NOAA operational HWRF model ( Gopalakrishnan et al. 2011 ), and the maximum likelihood ensemble filter (MLEF; Zupanski 2005 ; Zupanski et al. 2008 ). Specifically, observations from the Advanced Microwave Sounding Unit-A (AMSU-A) ( Robel 2009 ) on board the NOAA-18 satellite and the European Organization for the

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John E. Janowiak, Phillip A. Arkin, and Mark Morrissey

diurnal character of tropicalrainfall (convective and stratiform, collectively), as inferred from microwave data from polar-orbiting satellites, are also discussed. In situ observations of precipitation from ship reports and from optical rain gaugesaboard buoys that are moored in the tropical Pacific arealso analyzed.b. Background The characteristics of the diurnal cycle in tropicalconvective rainfall over land surfaces makes sensefrom atmospheric stability considerations. Intense surface heating

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Jason P. Dunion, Samuel H. Houston, Christopher S. Velden, and Mark D. Powell

Automated Network (C-MAN) stations, ships, meteorological aviation reports (METAR) stations, Global Positioning System (GPS) dropwindsondes (dropsondes), and aircraft flight-level data adjusted to the surface (10 m) based on Powell et al. (1996) . Remotely sensed observations include the Step Frequency Microwave Radiometer (SFMR) aboard NOAA research aircraft and data from polar orbiting microwave satellites [the Special Sensor Microwave/Imager (SSM/I), the Quick Scatterometer (QuikScat), and the TRMM

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Daniel C. Hartung, Jason A. Otkin, Ralph A. Petersen, David D. Turner, and Wayne F. Feltz

1. Introduction A 2009 report issued by the National Research Council (NRC) stressed the importance of establishing a comprehensive and adaptive national strategy for surface-based observations of the planetary boundary layer (PBL). This report concluded that the current observation networks are too sparse and unevenly distributed to adequately detail the thermodynamic structure of the boundary layer at high spatial and temporal resolution, which is needed for a wide variety of applications

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William F. Campbell, Craig H. Bishop, and Daniel Hodyss

microwave temperature sounders such as the Advanced Microwave Sounding Unit-A (AMSU-A).] Understanding some of the limitations of current satellite ensemble DA techniques should aid in the search for techniques that are superior for satellite observations. The theoretical basis for radiance space localization is explored in section 2 , and a conceptual 1D model that exposes its essential limitations is presented in section 3 . In section 4 , a more realistic 1D model is presented, with levels

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Ting-Chi Wu, Milija Zupanski, Lewis D. Grasso, Christian D. Kummerow, and Sid-Ahmed Boukabara

is an advanced microwave sounder on board both the SNPP and NOAA-20 satellites. In this study, ATMS on board the nonoperational SNPP satellite is used. Similar to its two predecessors, AMSU-A and the Microwave Humidity Sounder (MHS), ATMS provides observations of the surface and atmosphere of Earth. ATMS has 22 channels with frequencies ranging from 23.8 to 183.31 GHz. Channels 1–16 have frequencies ranging from 23.8 to 87.9 GHz and are primarily used for temperature soundings. In contrast

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Kozo Okamoto and John C. Derber

on the scattering index from Ferraro (1997) . The thinning distance is set to 160 km, accounting for the observation’s spatial resolution (from 15 km × 13 km at 85.5 GHz to 69 km × 43 km at 19.35 GHz), operational model resolution (approximately 50 km), and the thinning distance of other instruments [145 km for Advanced Microwave Sounding Unit-A (AMSU-A), 240 km for AMSU-B, and 180 km for High Resolution Infrared Radiation Sounder (HIRS)]. In addition, a reduced weight is given to a pixel when

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Rosanne Polkinghorne and Tomislava Vukicevic

the assimilation of precipitation observations because more quantitative precipitation data are available from surface networks and satellite retrieval algorithms. Several works have been undertaken to investigate the impacts of assimilating microwave brightness temperatures versus rainfall ( Moreau et al. 2004 ) as well as to examine the sensitivity of the precipitation to the initial conditions ( Mahfouf and Bilodeau 2007 ). A few studies have been carried out to define the error covariances of

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