DiNapoli, S. (2010). Determining the Error Characteristics of H*WIND. Master's thesis, Florida State University, Tallahassee, FL.
Abstract: The HRD Real-time Hurricane Wind Analysis System (H*Wind) is a software application used by NOAA's Hurricane Research Division to create a gridded tropical cyclone wind analysis based on a wide range of observations. One application of H*Wind fields is calibration of scatterometers for high wind speed environments. Unfortunately, the accuracy of the H*Wind product has not been studied extensively, and therefore the accuracy of scatterometer calibrations in these environments is also unknown. This investigation seeks to determine the uncertainty in the H*Wind product and estimate the contributions of several potential error sources. These error sources include random observation errors, relative bias between different data types, temporal drift resulting from combining non-simultaneous measurements, and smoothing and interpolation errors in the H*Wind software. The effects of relative bias between different data types and random observation errors are determined by performing statistical calculations on the observed wind speeds. We show that in the absence of large biases, the total contribution of all error sources results in an uncertainty of approximately 7% near the storm center, which increases to nearly 15% near the tropical storm force wind radius. The H*Wind analysis algorithm is found to introduce a positive bias to the wind speeds near the storm center, where the analyzed wind speeds are enhanced to match the highest observations. In addition, spectral analyses are performed to ensure that the filter wavelength of the final analysis product matches user specifications. With increased knowledge of these error sources and their effects, researchers will have a better understanding of the uncertainty in the H*Wind product, and can then judge the suitability of H*Wind for various research applications
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Domingues, R., Kuwano-Yoshida, A., Chardon-Maldonado, P., Todd, R. E., Halliwell, G., Kim, H. - S., et al. (2019). Ocean Observations in Support of Studies and Forecasts of Tropical and Extratropical Cyclones. Front. Mar. Sci., 6, 446.
Abstract: Over the past decade, measurements from the climate-oriented ocean observing system have been key to advancing the understanding of extreme weather events that originate and intensify over the ocean, such as tropical cyclones (TCs) and extratropical bomb cyclones (ECs). In order to foster further advancements to predict and better understand these extreme weather events, a need for a dedicated observing system component specifically to support studies and forecasts of TCs and ECs has been identified, but such a system has not yet been implemented. New technologies, pilot networks, targeted deployments of instruments, and state-of-the art coupled numerical models have enabled advances in research and forecast capabilities and illustrate a potential framework for future development. Here, applications and key results made possible by the different ocean observing efforts in support of studies and forecasts of TCs and ECs, as well as recent advances in observing technologies and strategies are reviewed. Then a vision and specific recommendations for the next decade are discussed.
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Dukhovskoy, D., Johnson, M., & Proshutinsky, A. (2006). Arctic decadal variability from an idealized atmosphere-ice-ocean model: 1. Model description, calibration, and validation. J. Geophys. Res., 111(C6).
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Dukhovskoy, D. S. (2004). Arctic decadal variability: An auto-oscillatory system of heat and fresh water exchange. Geophys. Res. Lett., 31(3).
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Dukhovskoy, D. S., Morey, S. L., & O'Brien, J. J. (2005). Topographic Rossby Waves in a Z-Level Ocean Model (J. Cote, Ed.). Research Activities in Atmospheric and Ocean Modeling, Report No. 35. Geneva, Switzerland: World Meteorological Organization.
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Dukhovskoy, D. S., Morey, S. L., & O'Brien, J. J. (2005). Topographic Rossby waves in a z-level ocean model. Eos Trans. AGU, 86(18), Jt. Assem. Suppl., Abstract OS22A–06.
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Dukhovskoy, D. S., Morey, S. L., & O'Brien, J. J. (2006). Baroclinic topographic waves on the Nicaragua Shelf generated by tropical cyclones (J. Cote, Ed.). Research Activities in Atmospheric and Ocean Modeling, Report No. 36. Geneva, Switzerland: World Meteorological Organization.
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Dukhovskoy, D. S., Morey, S. L., & O'Brien, J. J. (2006). Influence of multi-step topography on barotropic waves and consequences for numerical modeling. Ocean Modelling, 14(1-2), 45–60.
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Dukhovskoy, D. S., Morey, S. L., & O'Brien, J. J. (2009). Generation of baroclinic topographic waves by a tropical cyclone impacting a low-latitude continental shelf. Continental Shelf Research, 29(1), 333–351.
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Dukhovskoy, D. S., Yashayaev, I., Proshutinsky, A., Bamber, J. L., Bashmachnikov, I. L., Chassignet, E. P., et al. (2019). Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic. J. Geophys. Res. Oceans, 124(5), 3333–3360.
Abstract: The cumulative Greenland freshwater flux anomaly has exceeded 5000 km3 since the 1990s. The volume of this surplus fresh water is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveal freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50�100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of fresh water have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
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