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Levinson D.H.,National Oceanic and Atmospheric Administration | Diamond H.J.,National Oceanic and Atmospheric Administration | Knapp K.R.,National Oceanic and Atmospheric Administration | Kruk M.C.,STG Inc | Gibney E.J.,IMSG Inc.
Bulletin of the American Meteorological Society

The International Best Track Archive for Climate Stewardship (IBTrACS) project was formed under the leadership of the World Data Center for Meteorology-Asheville (WDC-Asheville) to address the best-track accessibility issue by combining TC best-track data from all agencies into an integrated dataset readily available to the user community. The new IBTrACS dataset provides the original TC intensities in a uniform format and catalogs the full range of reported values for pressure, wind speed, and position for each 6-hour time step from each agency. The final dataset is available in a varity of formats in use by the TC community, which includes the original unedited data as received from each of the RSMCs (Regional Specialized Meteorological Centers). The purpose of the IBTrACS workshop was to begin a dialog with representatives from the RSMCs and TCWCs, as well as from other organizations to accurately combine the disparate data to better understand the global climatology of TCs. Source

MacWilliams B.A.,Motion Analysis Laboratory | MacWilliams B.A.,University of Utah | Shuckra A.L.,Motion Analysis Laboratory | Mavor T.P.,National Oceanic and Atmospheric Administration | Mavor T.P.,IMSG Inc.
Gait and Posture

A method to estimate means and variance of strength based on anthropometric data is presented. The method is applied using a database of 10 lower extremity strength measures recorded from 48 typically developing children with a handheld dynamometer. Seven anthropometric variables are considered, and the combination of height and BMI is determined as a set of variables best suited to model these muscle groups. This regression scheme accounts for 45-58% of the observed variance. A clinical example illustrating the utility of the method is presented. © 2010 Elsevier B.V. Source

Key J.R.,National Oceanic and Atmospheric Administration | Mahoney R.,Northrop Grumman | Liu Y.,University of Wisconsin - Madison | Romanov P.,City University of New York | And 6 more authors.
Journal of Geophysical Research: Atmospheres

The Visible Infrared Imager Radiometer Suite (VIIRS) instrument was launched in October 2011 on the satellite now known as the Suomi National Polar-orbiting Partnership. VIIRS was designed to improve upon the capabilities of the operational Advanced Very High Resolution Radiometer and provide observation continuity with NASA's Earth Observing System's Moderate Resolution Imaging Spectroradiometer (MODIS). VIIRS snow and ice products include sea ice surface temperature, sea ice concentration, sea ice characterization, a binary snow map, and fractional snow cover. Validation results with these "provisional" level maturity products show that ice surface temperature has a root-mean-square error of 0.6-1.0 K when compared to aircraft data and a similar MODIS product, the measurement accuracy and precision of ice concentration are approximately 5% and 15% when compared to passive microwave retrievals, and the accuracy of the binary snow cover (snow/no-snow) maps is generally above 90% when compared to station data. The ice surface temperature and snow cover products meet their accuracy requirements with respect to the Joint Polar Satellite System Level 1 Requirements Document. Sea Ice Characterization, which consists of two age categories, has not been observed to meet the 70% accuracy requirements of ice classification. Given their current performance, the ice surface temperature, snow cover, and sea ice concentration products should be useful for both research and operational applications, while improvements to the sea ice characterization product are needed before it can be used for these applications. Key Points VIIRS snow and ice products generally meet accuracy requirements ©2013. American Geophysical Union. All Rights Reserved. Source

Park S.-H.,New Jersey Institute of Technology | Park S.-H.,Korea Astronomy and Space Science Institute | Chae J.,Seoul National University | Jing J.,New Jersey Institute of Technology | And 3 more authors.
Astrophysical Journal

To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through the surface. (2) The coronal helicity of the AR is estimated to be-4.3 × 1043 Mx2 just before the X3.4 flare. (3) This flare is preceded not only by a large increase of negative helicity,-3.2 × 1043 Mx2, in the corona over ∼1.5 days but also by noticeable injections of positive helicity through the photospheric surface around the flaring magnetic polarity inversion line during the time period of the channel structure development. We conjecture that the occurrence of the X3.4 flare is involved with the positive helicity injection into an existing system of negative helicity. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. Source

Chen Y.,The Interdisciplinary Center | Han Y.,The Center for Satellite Applications and Research | Delst P.V.,IMSG Inc. | Delst P.V.,Joint Center for Satellite Data Assimilation | Weng F.,The Center for Satellite Applications and Research
Journal of Atmospheric and Oceanic Technology

The nadir-viewing satellite radiances at shortwave infrared channels from 3.5 to 4.6 mm are not currently assimilated in operational numerical weather prediction data assimilation systems and are not adequately corrected for applications of temperature retrieval at daytime. For satellite observations over the ocean during the daytime, the radiance in the surface-sensitive shortwave infrared is strongly affected by the reflected solar radiance, which can contribute as much as 20.0K to the measured brightness temperatures (BT). The nonlocal thermodynamic equilibrium (NLTE) emission in the 4.3-μm CO2 band can add a further 10K to the measured BT. In this study, a bidirectional reflectance distribution function (BRDF) is developed for the ocean surface and an NLTE radiance correction scheme is investigated for the hyperspectral sensors. Both effects are implemented in the Community Radiative Transfer Model (CRTM). The biases of CRTM simulations to Infrared Atmospheric Sounding Interferometer (IASI) observations and the standard deviations of the biases are greatly improved during daytime (about a 1.5-K bias for NLTE channels and a 0.3-Kbias for surface-sensitive shortwave channels) and are very close to the values obtained during the night. These improved capabilities in CRTM allow for effective uses of satellite data at short infrared wavelengths in data assimilation systems and in atmospheric soundings throughout the day and night. © 2013 American Meteorological Society. Source

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