[Eoas-seminar] Seminar by Jonathan Christophersen (NRL) "Oceanic Rossby Wave Predictability" Monday March 3 at 1 pm at COAPS

[eoas-seminar at lists.fsu.edu]

Hi everyone,

I am pleased to share that Dr. Jonathan Christophersen, a Meteorologist at the Naval Research Laboratory in Monterey and an FSU alumni, will be visiting FSU and giving a presentation on Monday, March 3rd, at 1:00 PM ET. He will share his work on oceanic Rossby waves (more details below). The presentation will take place at COAPS, with remote access available for those unable to attend in person. A Zoom link will be shared closer to the date.

Oceanic Rossby Wave Predictability in ECMWF’s Subseasonal-to-Seasonal Reforecasts

In recent years, studies have put forth various theories and findings on the role of oceanic equatorial Rossby waves (OERW) in the subseasonal-to-seasonal (S2S) predictability of the Indian Ocean (IO). While much of the scientific literature uses data from in-situ, satellite, and/or reanalysis datasets, this study focuses on reforecast fields from the European Centre for Medium-Range Weather Forecasting’s (ECMWF) S2S dataset. Evaluation of the model’s predictive skill in representing OERWs and the associated variations in sub-surface-to-surface interaction and air-sea coupling are discussed. This work provides a unique methodology to calculate and evaluate the predictability of OERWs from model forecast data, which, to the author’s knowledge, is the first of its kind to do so. Our results indicate that the model forecasts OERWs with relatively high skill (anomaly correlation > 0.5 out to 40 days), indicating they are a key source of oceanic subseasonal predictability at extended lead times. Analysis of the wavenumber-frequency spectra for the IO indicates a reduction in power throughout the model forecast time period in the oceanic equatorial Kelvin wave (OEKW) regime, indicating the potential misrepresentation of the zonal winds. This erroneous weakening of the OEKWs is attributed to the weakening of the reflected oceanic equatorial Rossby waves (OERWs). This results in weaker transport of the associated westward advection of warm ocean heat content (OHC) anomalies via the OERWs, which has numerous implications for air-sea and sub-surface-to-surface coupling, as will be discussed. In general, the atmospheric response to the waning westward transport of OHC anomalies in the western IO is associated with the weakening of precipitation anomalies related to the diminishing intraseasonal oscillation.

Best regards,

Luna Hiron
Assistant Research Scientist
Center for Ocean-Atmospheric Prediction Studies (COAPS)
Florida State University ​
https://lunahiron.github.io<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flunahiron.github.io%2F&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7Cbc1ed5c2146d4ff5b4c308dd4c74b9ae%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C638750786397240424%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2FjrtS6IYDaAv2veynFvFyr6AVG2bjjRfU4njJ%2FrWCC8%3D&reserved=0>
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