Radoslaw Goska

North Atlantic Tropical Cyclones and U.S. Flooding

Riverine flooding associated with North Atlantic tropical cyclones (TCs) is responsible for large societal and economic impacts. The effects of TC flooding are not limited to the coastal regions, but affect large areas away from the coast, and often away from the center of the storm. Despite these important repercussions, inland TC flooding has received relatively little attention in the scientific literature, although there has been growing media attention following Hurricanes Irene (2011) and Sandy (2012). Based on discharge data from 1981 to 2011, the authors provide a climatological view of inland flooding associated with TCs, leveraging the wealth of discharge measurements collected, archived, and disseminated by the U.S. Geological Survey (USGS). Florida and the eastern seaboard of the United States (from South Carolina to Maine and Vermont) are the areas that are the most susceptible to TC flooding, with typical TC flood peaks that are 2 to 6 times larger than the local 10-yr flood peak, causing ma...

A GIS-based methodology for the assessment of weather radar beam blockage in mountainous regions: two examples from the US NEXRAD network

The US National Weather Service (NWS) has installed a large network of weather Surveillance radars (WSR-88D) that provide precipitation maps for the United States. Many of these radars operate in mountainous regions and consequently suffer from beam blockage caused by terrain obstacles. The authors present a methodology for assessing the severity of the beam blockage and outline its implications for radar-derived precipitation estimates. The methodology involves the calculation of two-dimensional maps of power loss using a digital elevation model (DEM)-based algorithm of beam propagation for different radar antenna elevation angles. Using a large sample of actual radar data, the authors compare the simulated beam blockage results with the probability of detection of radar reflectivity above a certain threshold. The authors also compare their results with similar but coarser resolution blockage maps developed by the NWS and used in the NEXRAD system. For visualization, ArcGIS software is used to illustrate the results and offer a physical interpretation of the analyses. The study involves two NEXRAD sites: KRLX in Charleston, West Virginia and KEMX in Tucson, Arizona. The KRLX site does not suffer from significant blockage except for a single narrow sector. By contrast, the KEMX site contains several areas of blockage. The authors conclude that DEM-based prediction of radar beam occultation is a viable tool, as indicated by the good agreement of the calculated patterns of power loss with the actual long-term radar data.

Real-Time Flood Forecasting and Information System for the State of Iowa

AbstractThe Iowa Flood Center (IFC), established following the 2008 record floods, has developed a real-time flood forecasting and information dissemination system for use by all Iowans. The system complements the operational forecasting issued by the National Weather Service, is based on sound scientific principles of flood genesis and spatial organization, and includes many technological advances. At its core is a continuous rainfall–runoff model based on landscape decomposition into hillslopes and channel links. Rainfall conversion to runoff is modeled through soil moisture accounting at hillslopes. Channel routing is based on a nonlinear representation of water velocity that considers the discharge amount as well as the upstream drainage area. Mathematically, the model represents a large system of ordinary differential equations organized to follow river network topology. The IFC also developed an efficient numerical solver suitable for high-performance computing architecture. The solver allows the IF...

Data-Enabled Field Experiment Planning, Management, and Research Using Cyberinfrastructure

AbstractIn the spring of 2013, NASA conducted a field campaign known as Iowa Flood Studies (IFloodS) as part of the Ground Validation (GV) program for the Global Precipitation Measurement (GPM) mission. The purpose of IFloodS was to enhance the understanding of flood-related, space-based observations of precipitation processes in events that transpire worldwide. NASA used a number of scientific instruments such as ground-based weather radars, rain and soil moisture gauges, stream gauges, and disdrometers to monitor rainfall events in Iowa. This article presents the cyberinfrastructure tools and systems that supported the planning, reporting, and management of the field campaign and that allow these data and models to be accessed, evaluated, and shared for research. The authors describe the collaborative informatics tools, which are suitable for the network design, that were used to select the locations in which to place the instruments. How the authors used information technology tools for instrument moni...

Deployment and Performance Analyses of High-Resolution Iowa XPOL Radar System during the NASA IFloodS Campaign

AbstractThis article presents the data collected and analyzed using the University of Iowa’s X-band polarimetric (XPOL) radars that were part of the spring 2013 hydrology-oriented Iowa Flood Studies (IFloodS) field campaign, sponsored by NASA’s Global Precipitation Measurement (GPM) Ground Validation (GV) program. The four mobile radars have full scanning capabilities that provide quantitative estimation of the rainfall at high temporal and spatial resolutions over experimental watersheds. IFloodS was the first extensive test of the XPOL radars, and the XPOL radars demonstrated their field worthiness during this campaign with 46 days of nearly uninterrupted, remotely monitored, and controlled operations. This paper presents detailed postcampaign analyses of the high-resolution, research-quality data that the XPOL radars collected. The XPOL dual-polarimetric products and rainfall are compared with data from other instruments for selected diverse meteorological events at high spatiotemporal resolutions from...

Assessing Current and Future Freshwater Flood Risk from North Atlantic Tropical Cyclones via Insurance Claims

The most recent decades have witnessed record breaking losses associated with U.S. landfalling tropical cyclones (TCs). Flood-related damages represent a large portion of these losses, and although storm surge is typically the main focus in the media and of warnings, much of the TC flood losses are instead freshwater-driven, often extending far inland from the landfall locations. Despite this actuality, knowledge of TC freshwater flood risk is still limited. Here we provide for the first time a comprehensive assessment of the TC freshwater flood risk from the full set of all significant flood events associated with U.S. landfalling TCs from 2001 to 2014. We find that the areas impacted by freshwater flooding are nearly equally divided between coastal and inland areas. We determine the statistical relationship between physical hazard and residential economic impact at a community level for the entire country. These results allow us to assess the potential future changes in TC freshwater flood risk due to changing climate pattern and urbanization in a more heavily populated U.S. Findings have important implications for flood risk management, insurance and resilience.

Towards Better Utilization of NEXRAD Data in Hydrology: An Overview of Hydro-NEXRAD

Witold F. Krajewski (corresponding author) Anton Kruger Charles Gunyon Radoslaw Goska Bong-Chul Seo Piotr Domaszczynski A. Allen Bradley IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, IA 52242, USA E-mail: witold-krajewski@uiowa.edu James A. Smith Mary Lynn Baeck Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA Mohan K. Ramamurthy Jeffrey Weber Unidata Program Center, UCAR, Boulder, CO 80307, USA Stephen A. DelGreco National Climatic Data Center, Ashville, NC 28801, USA Ramon Lawrence Computer Science, University of British Columbia, Okanagan, BC V1V 1V7, Canada Matthias Steiner National Center for Atmospheric Research, Boulder, CO 80301, USA With a very modest investment in computer hardware and the open-source local data manager (LDM) software from University Corporation for Atmospheric Research (UCAR) Unidata Program Center, a researcher can receive a variety of NEXRAD Level III rainfall products and the unprocessed Level II data in real-time from most NEXRAD radars in the USA. Alternatively, one can receive such data from the National Climatic Data Center in Ashville, NC. Still, significant obstacles remain in order to unlock the full potential of the data. One set of obstacles is related to effective management of multi-terabyte datasets. A second set of obstacles, for hydrologists and hydrometeorologists in particular, is that the NEXRAD Level III products are not well suited for applications in hydrology. There is a strong need for the generation of high-quality products directly from the Level II data with well-documented steps that include quality control, removal of false echoes, rainfall estimation algorithms, coordinate conversion, georeferencing and integration with GIS. For hydrologists it is imperative that these procedures are basin-centered as opposed to radar-centered. The authors describe the Hydro-NEXRAD system that addresses the above challenges. With support from the National Science Foundation through its ITR program, the authors have developed a basin-centered framework for addressing all these issues in a comprehensive manner, tailored specifically for use of NEXRAD data in hydrology and hydrometeorology.

Bridge-Mounted River Stage Sensors (BMRSS)

We have developed a robust sensor for mounting on bridges over rivers and streams. These bridge-mounted river stage sensors (BMRSS) make periodic measurements of the distance from the sensor to the water level below. Properly interpreted, these measurements provide river-stage information, data of great importance to society and crucial to effective flood forecasting. The traditional approach to river stage measurement is the installation of pipes in rivers, digging stilling wells, and the construction of attendant brick-and-mortar infrastructure. The cost of this approach limits the deployment to larger rivers. In most instances, river-stage data from smaller tributaries are few, even though such data can greatly enhance the quality of flood-forecasting models’ outputs. In contrast, BMRSS units are an order of magnitude less expensive and allow for widespread deployment. BMRSS units incorporate an ultrasonic distance-measuring module, a solar panel/battery/charge controller, and a GPS receiver. In recent years, the Internet access through commercial cellular networks has become ubiquitous, even in most rural areas. BMRSS units incorporate cell modems and transmit data through the Internet to servers at the Iowa Flood Center. Here, the data are ingested into relational databases and made available to flood forecasting models and information systems. We have deployed and operated more than 220 BMRSS units across Iowa, many for several years continuously.