Download or read book Improving Hurricane Intensity Forecasts Using 4DVAR Data Assimilation of Airborne Doppler Radar Winds written by Patricia Sánchez-Rodríguez and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decades, researchers have focused on improving tropical cyclone (TC) forecasts. Accurate TC predictions are very important in order to protect life and property. Scientists examine two important pieces regarding TC prediction: where the storm is going and how strong it will be in the future. These are referred as track and intensity forecasts. TC track forecast has improved tremendously over the last several decades. However, hurricane intensity forecasts continue to be a great challenge in operational and research communities. Previous studies have found that the lack of progress in intensity forecasts is partly due to the lag in the ability to specify the initial vortex in the numerical weather prediction (NWP) model, in addition to the lag in representing the observed inner-core storm intensity, structure and internal dynamics. Researches have introduced various data assimilation (DA) techniques to address the problem of determining the initial vortex. However, in order to better represent these features, there must be sufficient observations in the inner-core region along with a data assimilation method that can effectively use the data to accurately estimate the initial vortex. Some of the challenges in the TC data assimilation are: (1) scarcity of systematic data assimilation in the inner-core region, and/or, (2) absence of enough information about this region, and/or (3) the model resolution is inadequate to capture the structures at these smaller scales. This study examines the impact of assimilating high-resolution inner-core Airborne Doppler Radar (ADR) winds on two major hurricanes, Ike (2008) and Earl (2010). The primary objective is to understand its impact in the initial vortex structure and how it translates to the resulting forecasts. With the development of advanced data assimilation techniques, ADR data can improve the specification of the vortex and potentially improve intensity and structure forecasts. Nevertheless, there are two important factors that can affect the effectiveness of the method: (1) resolution on the grid where DA is performed and (2) the background error covariance used. This work focuses on improving the 4-Dimensional Variational (4DVar) data assimilation technique by using a high-resolution DA domain of 4-km in order to better represent convective scales features and by generating a new static background error covariance more suitable for the current DA experiment. This static error covariance includes the vortex structure information. The impacts of these two aspects were revealed by comparing the analyses and forecasts generated by 4DVar with relatively coarse resolution of 12-km that used the standard background error covariance file (that do not contain any vortex information), a 4DVar at 4-km that used the same background error covariance, and with a 4DVar at 4-km that used the newly generated covariance. This method is first applied on Hurricane Ike. The second experiment performed on Hurricane Earl only included one 4DVar setup: 4-km DA domain with the new static covariance that contains the vortex information. The results for Hurricane Ike experiment showed that increasing the resolution from 12-km to 4-km in 4DVar largely improved the initial vortex structure, enhancing the small eye and the inner-wind maximum. The newly generated vortex specific background covariance used in 4DVar helped to remove some unrealistic features in the wind field showed by the 4-km 4DVar that used the non-vortex static covariance. The adjustment in the initial condition brought the intensity and structure forecast to be in better agreement wit the observations. The mean errors of the maximum wind speed and track forecasts by both 4-km 4DVar experiments were smaller than those by the 12-km 4DVar. In contrast, the mean errors of the sea-level pressure forecast showed that the 12-km 4DVar produced a lower pressure at earlier stages of the forecast. This was attributed to the fact that in the higher-resolution 4DVar analyses, the model was not able to maintain the very small eye, double eyewall and strong pressure gradient features for a longer time. Detailed diagnostics of the surface structure revealed that the asymmetry was well maintained by all the 4DVar cases. However the 4-km 4DVar that used the vortex-specific background covariance gave a better fit with the observations. The control experiment in which no data was assimilated did not develop the inner-core structure and continuously over-estimated the storm intensity. Results from the second experiment performed on Hurricane Earl further demonstrated the advantages of using 4DVar to correct the initial conditions of a hurricane forecast model. For this case, the ADR winds were continuously assimilated during a period of 5 days. Overall the analyses showed that having continuous DA events better estimated the long-term intensity of the storm. The errors of the 4DVar intensity forecasts were evidently smaller than the forecasts with no DA (non-DA) initialized with GFS. The initial conditions were clearly adjusted to match the observed structure. Detailed verification of vertical structures showed that the 4DVar analyses constantly improved the inner-core structure reproducing the inner-wind maximum and maintaining the small eye during the intervening forecasts. This work also demonstrated one of the advantages of assimilating 3D winds in 4DVar since it was able to simulate the deepening and strengthening of the vortex during the rapid intensification event clearly observed by the ADR data.

Download or read book Improving Hurricane Intensity Forecasts written by Patricia Sánchez - Rodríguez and published by LAP Lambert Academic Publishing. This book was released on 2018-06-27 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decades, researchers have focused on improving tropical cyclone forecasts. Accurate TC predictions are very important in order to protect life and property. Scientists examine two important pieces regarding TC prediction: where the storm is going and how strong it will be in the future. These are referred as track and intensity forecasts. TC track forecast has improved tremendously over the last several decades. However, hurricane intensity forecasts continue to be a great challenge in operational and research communities. Previous studies have found that the lack of progress in intensity forecasts is partly due to the lag in the ability to specify the initial vortex in the numerical weather prediction model, in addition to the lag in representing the observed inner-core storm intensity, structure and internal dynamics. Researches have introduced various data assimilation techniques to address the problem of determining the initial vortex. However, in order to better represent these features, there must be sufficient observations in the inner-core region along with a data assimilation method that can effectively use the data to accurately estimate the initial vortex.

Download or read book Hurricane written by Robert Simpson and published by American Geophysical Union. This book was released on 2003 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based upon presentations at an historical symposium on hurricanes convened by the American Geophysical Union at its Fall meeting in San Francisco, December 16, 2000".

Download or read book A Statistical Model to Forecast Short term Atlantic Hurricane Intensity written by Kevin T. Law and published by . This book was released on 2006 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The accuracy of hurricane intensity forecasts has lagged the accuracy of hurricane track forecasts thereby creating a need for improvement. Many models struggle capturing the rapid intensification period and identifying when it will occur which causes a large amount of error in the intensity forecasts. The method described in this paper uses a discriminant function analysis (DFA) to help identify how intense the tropical cyclone will become and also how close it is to the rapid intensification period. Identifying the proximity to the rapid intensification period is a key factor in improving the intensity forecasts. Based upon the intensity and its proximity to its rapid intensification period, as selected by the DFA, an appropriate regression model is applied to forecast the 24-hour and 6-hour pressure reduction and wind speed increase. Other statistical intensity models apply the same regression model throughout the entire lifecycle of the tropical cyclone. This model relies on the premise that factors which cause intensification affect the tropical cyclone differently throughout its life cycle. Therefore, by using the DFA, different stages in its life cycle are identified, which allows the regression model to use the most significant variables at the particular stage. They are shown to improve the intensity forecasts at the stages leading up to and during the rapid intensification, which happen to be the most difficult stages to predict. The forecasts were validated with 13 independent case studies and compared with the official National Hurricane Center (NHC) forecasts.

Download or read book Improving Hurricane Intensity Forecasting Through Data Assimilation Environmental Conditions Versus the Vortex Initialization written by Zhaoxia Pu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improved Short term Atlantic Hurricane Intensity Forecasts Using Reconnaissance based Core Measurements written by David Andrew Murray and published by . This book was released on 2009 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finally, stepwise multiple linear regression is performed to create a SHIPS-style intensity forecast model (Atlantic-based Statistical Prediction of Hurricane Intensity using Recon, or ASPIRE). Examination of the regression equations and the change in predictors selected with varying intensity and forecast length offers additional insight into the science of TC intensity forecasting. Cross-validation results show that the ASPIRE technique outperforms SHIPS at nearly every forecast time and initial intensity, indicating that a new benchmark for TC intensity forecasting may have been attained. Two dependent case studies of Hurricane Ivan and Hurricane Katrina are presented for further analysis of the ASPIRE technique. Further work involving the utilization of satellite data to create proxy VDMs may lead to an expanded climatological database of inner-core data for TCs in the Atlantic basin as well as the capability to create similar regression schemes in the East Pacific and West Pacific basins.

Download or read book Tropical Cyclone Intensity Analysis Using Satellite Data written by Vernon F. Dvorak and published by . This book was released on 1984 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Probabilistic Prediction of Hurricane Intensity with an Analog Ensemble written by Christopher Rozoff and published by . This book was released on 2014 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving Hurricane Fred Forecast with METEOSAT 10 All Sky Radiances written by Alisha Wellington and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hurricane Fred made landfall on Cape Verde August 31, 2015, as a category 1 hurricane. The hurricane originated from an African easterly wave that developed from a broad cyclonic rotation within the lower atmosphere off the coast of West Africa on August 29. The low-pressure system quickly intensified over the warm water of the Atlantic into a tropical storm and later a category 1 hurricane. Cape Verde and the eastern Atlantic Ocean are considered a data void region due to the lack of buoys and radars that are vital in providing meteorologists information on the state of the atmosphere. As a result, the track and intensification of Hurricane Fred were poorly forecasted. The main objective of this project was to improve the forecast of Hurricane Fred using the Weather Research and Forecasting (WRF) Model together with advanced data assimilation of all-sky infrared radiances from Meteosat-10. Without assimilation of satellite all-sky infrared radiances, biases in the WRF track, minimum surface pressure, and maximum surface wind forecasts existed when compared to the best track observations from the National Hurricane Center (NHC). When comparing the observed and WRF forecasted tracks, the WRF forecasted track was shifted to the north compared to the best track observations from 1800 UTC August 30 to 1200 UTC August 31. Regarding the WRF forecasted minimum surface pressure, the WRF forecast considerably underestimated the minimum surface pressure when compared to the best track observations. Similarly, the WRF forecasted maximum surface winds significantly underestimated the observations. Lastly, the WRF forecasted brightness temperatures were also quite different from those based on the Meteosat-10 radiances. Data assimilation (DA) served as a way for us to improve Hurricane Fred's track and intensity forecasts. DA is a statistical technique that combines information from model forecasts and observations to create the best estimate of the atmosphere. In this study, data assimilation was used to create more accurate forecasts of Hurricane Fred. To this end, the Penn State WRF Ensemble Kalman Filter (EnKF) system was used to assimilate conventional observations and all-sky infrared radiances from Meteosat-10 into the WRF model. With updated initial conditions via data assimilation, four deterministic forecasts were initialized: i)CONV 08/29 18Z, ii) CONV 08/30 00Z, iii) IR 08/29 18Z, and iv) IR 08/30 00Z. CONV represents experiments in which only conventional observations were assimilated, and IR represents experiments in which both conventional and all-sky infrared radiances were assimilated. Both the CONV and IR forecasts initiated at 1800 UTC August 29 were nearly spot on with the best track observations on August 31. When assessing the surface minimum pressure, the IR 08/30 00Z forecasts had much smaller absolute errors compared to the CONV forecasts. For the maximum wind speed forecasts, all four forecasts captured the highest maximum wind speed that occurred on August 31, with the IR forecasts having smaller absolute errors compared to the CONV forecasts. Satellite all-sky infrared radiance data assimilation improved the intensity forecast of Hurricane Fred, demonstrating potential value of this approach for hurricane forecasting in the eastern Atlantic Ocean.

Download or read book Next Generation Earth System Prediction written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-08-22 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the nation's economic activities, security concerns, and stewardship of natural resources become increasingly complex and globally interrelated, they become ever more sensitive to adverse impacts from weather, climate, and other natural phenomena. For several decades, forecasts with lead times of a few days for weather and other environmental phenomena have yielded valuable information to improve decision-making across all sectors of society. Developing the capability to forecast environmental conditions and disruptive events several weeks and months in advance could dramatically increase the value and benefit of environmental predictions, saving lives, protecting property, increasing economic vitality, protecting the environment, and informing policy choices. Over the past decade, the ability to forecast weather and climate conditions on subseasonal to seasonal (S2S) timescales, i.e., two to fifty-two weeks in advance, has improved substantially. Although significant progress has been made, much work remains to make S2S predictions skillful enough, as well as optimally tailored and communicated, to enable widespread use. Next Generation Earth System Predictions presents a ten-year U.S. research agenda that increases the nation's S2S research and modeling capability, advances S2S forecasting, and aids in decision making at medium and extended lead times.

Download or read book Earth Science and Applications from Space written by National Research Council and published by National Academies Press. This book was released on 2007-10-01 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural and human-induced changes in Earth's interior, land surface, biosphere, atmosphere, and oceans affect all aspects of life. Understanding these changes requires a range of observations acquired from land-, sea-, air-, and space-based platforms. To assist NASA, NOAA, and USGS in developing these tools, the NRC was asked to carry out a "decadal strategy" survey of Earth science and applications from space that would develop the key scientific questions on which to focus Earth and environmental observations in the period 2005-2015 and beyond, and present a prioritized list of space programs, missions, and supporting activities to address these questions. This report presents a vision for the Earth science program; an analysis of the existing Earth Observing System and recommendations to help restore its capabilities; an assessment of and recommendations for new observations and missions for the next decade; an examination of and recommendations for effective application of those observations; and an analysis of how best to sustain that observation and applications system.

Download or read book The Atmospheric Sciences written by Board on Atmospheric Sciences and Climate and published by National Academies Press. This book was released on 1998-11-05 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technology has propelled the atmospheric sciences from a fledgling discipline to a global enterprise. Findings in this field shape a broad spectrum of decisions--what to wear outdoors, whether aircraft should fly, how to deal with the issue of climate change, and more. This book presents a comprehensive assessment of the atmospheric sciences and offers a vision for the future and a range of recommendations for federal authorities, the scientific community, and education administrators. How does atmospheric science contribute to national well-being? In the context of this question, the panel identifies imperatives in scientific observation, recommends directions for modeling and forecasting research, and examines management issues, including the growing problem of weather data availability. Five subdisciplines--physics, chemistry, dynamics and weather forecasting, upper atmosphere and near-earth space physics, climate and climate change--and their status as the science enters the twenty-first century are examined in detail, including recommendations for research. This readable book will be of interest to public-sector policy framers and private-sector decisionmakers as well as researchers, educators, and students in the atmospheric sciences.

Download or read book A Safer Future written by National Research Council and published by National Academies Press. This book was released on 1991-02-01 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Initial priorities for U.S. participation in the International Decade for Natural Disaster Reduction, declared by the United Nations, are contained in this volume. It focuses on seven issues: hazard and risk assessment; awareness and education; mitigation; preparedness for emergency response; recovery and reconstruction; prediction and warning; learning from disasters; and U.S. participation internationally. The committee presents its philosophy of calls for broad public and private participation to reduce the toll of disasters.

Download or read book Weathering the Storm written by United States. Congress. Senate. Committee on Commerce, Science, and Transportation and published by . This book was released on 2010 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Numerical Modeling and Data Assimilation Techniques for Tropical Cyclone Predictions written by U.C. Mohanty and published by Springer. This book was released on 2016-11-21 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals primarily with monitoring, prediction and understanding of Tropical Cyclones (TCs). It was envisioned to serve as a teaching and reference resource at universities and academic institutions for researchers and post-graduate students. It has been designed to provide a broad outlook on recent advances in observations, assimilation and modeling of TCs with detailed and advanced information on genesis, intensification, movement and storm surge prediction. Specifically, it focuses on (i) state-of-the-art observations for advancing TC research, (ii) advances in numerical weather prediction for TCs, (iii) advanced assimilation and vortex initialization techniques, (iv) ocean coupling, (v) current capabilities to predict TCs, and (vi) advanced research in physical and dynamical processes in TCs. The chapters in the book are authored by leading international experts from academic, research and operational environments. The book is also expected to stimulate critical thinking for cyclone forecasters and researchers, managers, policy makers, and graduate and post-graduate students to carry out future research in the field of TCs.

Download or read book Sub seasonal to Seasonal Prediction written by Andrew Robertson and published by Elsevier. This book was released on 2018-10-19 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Gap Between Weather and Climate Forecasting: Sub-seasonal to Seasonal Prediction is an ideal reference for researchers and practitioners across the range of disciplines involved in the science, modeling, forecasting and application of this new frontier in sub-seasonal to seasonal (S2S) prediction. It provides an accessible, yet rigorous, introduction to the scientific principles and sources of predictability through the unique challenges of numerical simulation and forecasting with state-of-science modeling codes and supercomputers. Additional coverage includes the prospects for developing applications to trigger early action decisions to lessen weather catastrophes, minimize costly damage, and optimize operator decisions. The book consists of a set of contributed chapters solicited from experts and leaders in the fields of S2S predictability science, numerical modeling, operational forecasting, and developing application sectors. The introduction and conclusion, written by the co-editors, provides historical perspective, unique synthesis and prospects, and emerging opportunities in this exciting, complex and interdisciplinary field. - Contains contributed chapters from leaders and experts in sub-seasonal to seasonal science, forecasting and applications - Provides a one-stop shop for graduate students, academic and applied researchers, and practitioners in an emerging and interdisciplinary field - Offers a synthesis of the state of S2S science through the use of concrete examples, enabling potential users of S2S forecasts to quickly grasp the potential for application in their own decision-making - Includes a broad set of topics, illustrated with graphic examples, that highlight interdisciplinary linkages

Download or read book Advances in Geosciences written by Kenji Satake and published by World Scientific. This book was released on 2012 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: This invaluable volume set of Advances in Geosciences continues the excellent tradition of the Asia-Oceania scientific community in providing the most up-to-date research results on a wide range of geosciences and environmental science. The information is vital to the understanding of the effects of climate change and extreme weather on the most populated regions and fastest moving economies in the world. Besides, these volumes also highlight original papers from many prestigious research institutions which are conducting cutting-edge studies in atmospheric physics, hydrogical science and water resource, ocean science and coastal study, planetary exploration and solar system science, seismology, tsunamis, upper atmospheric physics and space science.