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Graduate Exam Abstract


Evan Ruzanski

Ph.D. Preliminary

April 7, 2010, 3-5 PM

Glover 201

This is a preliminary exam


Abstract: Short-term prediction (nowcasting) of high-impact weather events can lead to significant improvement in warnings and advisories and is of great practical importance. Nowcasting using weather radar reflectivity has been shown to be particularly useful. The Collaborative Adaptive Sensing of the Atmosphere (CASA) radar network provides high-resolution (0.5 km spatial, 1 min temporal) reflectivity images amenable to producing valuable nowcasts. The high-resolution nature of CASA data requires the use of an efficient nowcasting approach, which necessitated the development of the Dynamic Adaptive Radar Tracking of Storms (DARTS) and SINC-kernel-based advection nowcasting methodology. This presentation describes research that utilizes DARTS in two main contexts: 1) operational research and system development and 2) applied scientific research. In the operational research and system development context, DARTS was implemented operationally in the CASA Distributed Collaborative Adaptive Sensing (DCAS) system in a robust and efficient manner necessitated by the high-resolution nature of CASA data and distributed nature of the environment in which the nowcasting system operates. Nowcasts up to 15 min to support emergency manager decision-making and 1–5 min to steer the CASA radar nodes to better observe the advecting storm patterns for forecasters and researchers are currently provided by this system. Results of operational system performance during the 2009 CASA IP experiment are presented. Additionally, currently state-of-the-art scale-based filtering methods were adapted and evaluated for potential improvement of operational nowcasting performance in the CASA DCAS environment and preliminary results are presented. DARTS was also incorporated in the Weather Support to Deicing Decision Making system to provide more accurate and efficient snow water equivalent nowcasts for aircraft deicing decision support relative to the radar-based nowcasting method currently used in the operational system. Results of an evaluation using data collected from 2007–2008 by the WSR-88D outside Denver, Colorado, and the National Center for Atmospheric Research Marshall Test Site outside Boulder, Colorado, are presented. In the context of applied scientific research, details of two proposed studies will be presented. First, DARTS will be used as a tool to study the short-term predictability of precipitation patterns depicted by reflectivity images observed at microalpha scale (0.2–2 km) by the CASA radar network. Additionally, DARTS will be used to investigate the predictability and feasibility of nowcasting rainfall fields based on specific differential phase estimates, which have been shown to provide more accurate and robust rainfall estimates versus those made from reflectivity.

Adviser: Dr. V. Chandrasekar
Co-Adviser: N/A
Non-ECE Member: Dr. Paul Mielke (Statistics)
Member 3: Dr. V. N. Bringi
Addional Members: N/A

Publications:


Program of Study: