Tyler Barbero is awarded the William M. Gray Award!
(2024-12-03) -- written by Levi Silvers
Tyler Barbero, a PhD candidate in Professor Bell’s Tropical Weather and Climate Research group was awarded the William M. Gray award for the best technical manuscript submitted for publication during the previous 18-month period on research advancing understanding of the physics and dynamics of the tropical atmosphere and ocean.
Congratulations Tyler!
The William M. Gray award was established in 2023 to honor the substantial contributions the late Bill Gray made to tropical meteorolgoy and hurricane research. William ‘Bill’ Gray was a professor at CSU from 1961 until his retirement in 2005. The Gray award includes scholarship funding that has been provided through an endowment from Gray’s family.
His legacy goes far beyond the seminal research papers that he published and includes the many graduate students he mentored and the more than 30 years of seasonal hurricane forecasts that he
made for the Atlantic.
Tyler Barbero’s researchi, “A Potential Vorticity Diagnosis of Tropical Cyclone Track Forecast Errors”, has been published in the Journal of Advances in Modeling Earth Systems and can be found here:
Abstract: Tropical cyclone (TC) track forecasting provides essential guidance for coastal communities. However, track forecast errors still occur, highlighting the need for continued research into error sources. Piecewise potential vorticity (PV) inversion is used systematically to quantitatively diagnose errors in track forecasts in four models during the 2017 Atlantic hurricane season. The deep layer mean steering flow (DLMSF) provides a sufficient proxy for hurricane movement, and DLMSF errors are correlated with TC track errors. Analysis of track forecasts for Hurricanes Harvey, Irma, and Maria reveals that their track errors are attributed to steering errors caused by misrepresentations of specific pressure systems. Harvey’s westward track error in the GFS resulted from zonal wind errors from the Continental High, while Irma’s northward track error in the SHiELD gfsIC resulted from meridional wind errors in the Bermuda High and Continental High. Maria’s southward track error in the IFS resulted from meridional wind errors in the Bermuda High and a misrepresentation of Jose to Maria’s northwest. The mean absolute error of the DLMSF shows that the Bermuda High contributed the most to steering flow errors in the cases examined. Our results show that piecewise PV inversion can identify the sources of biases in TC track forecasts. The correction of these biases may lead to improved track forecasts. Quantitative diagnostics presented here provide useful information for future model development.
Hurricane Fiona’s (2022) historical heavy precipitation devastated de Caribbean Island of Puerto Rico after it made landfall as a category 1 hurricane. Rainfall accumulation totals in southern interior region areas surpassed 900 mm during 18 – 19 September 2022. To analyze the rainfall mechanisms, we use output from the Hurricane Analysis and Forecast System (HAFS) configuration “B” modeling system and observations from the Puerto Rico Next Generation Weather Radar (NEXRAD) Level 2 Doppler radar and rain gauges around the island. Quantitative precipitation estimates from radar and rainfall measurements suggest that HAFSB simulated reasonably well the precipitation amounts and location. HAFSB track differences from the real trajectory contributed to discrepancies between the simulated and observed rainfall. We investigate three stages of the Hurricane Fiona rain event, each focusing on different processes. The first stage is associated with the primary eyewall and rainfall produced through boundary layer convergence. The second stage focuses on the principal rainband affecting the island and is associated with rainfall enhancement from vertical wind shear interactions with Fiona’s potential vorticity. The third and final stage analyzes the enhancement of a “tail rainband” both over open water and the southern portion of the island as Hurricane Fiona kept strengthening west of Puerto Rico. Our findings support the hypothesis that evaporative cooling within inner core rainfall from stage one and two sets up a favorable environment for isentropic uplift to enhance rainfall production in stage three. Additional enhancements of the rainfall occurred over Puerto Rico’s high terrain by orographic effects.