Simulation and Prediction of Category 4 and 5 Hurricanes in the High-Resolution GFDL HiFLOR Coupled Climate Model*

Abstract

A new high-resolution Geophysical Fluid Dynamics Laboratory (GFDL) coupled model [the High-Resolution Forecast-Oriented Low Ocean Resolution (FLOR) model (HiFLOR)] has been developed and used to investigate potential skill in simulation and prediction of tropical cyclone (TC) activity. HiFLOR comprises high-resolution (~25-km mesh) atmosphere and land components and a more moderate-resolution (~100-km mesh) sea ice and ocean component. HiFLOR was developed from FLOR by decreasing the horizontal grid spacing of the atmospheric component from 50 to 25 km, while leaving most of the subgrid-scale physical parameterizations unchanged. Compared with FLOR, HiFLOR yields a more realistic simulation of the structure, global distribution, and seasonal and interannual variations of TCs, as well as a comparable simulation of storm-induced cold wakes and TC-genesis modulation induced by the Madden–Julian oscillation (MJO). Moreover, HiFLOR is able to simulate and predict extremely intense TCs (Saffir–Simpson hurricane categories 4 and 5) and their interannual variations, which represents the first time a global coupled model has been able to simulate such extremely intense TCs in a multicentury simulation, sea surface temperature restoring simulations, and retrospective seasonal predictions.

Shifting patterns of mild weather in response to projected radiative forcing

“…HiFLOR is built from a high-resolution atmospheric/land model (0.25°× 0.25°) coupled to a low-resolution oceanic/sea ice model (1°× 1°, Murakami et al 2015). The high atmospheric resolution allows for the better resolvement of coastlines and finer-scale mountains (e.g., Californian Sierra, European Alps) that are absent at resolution lower than 30 km (Kapnick and Delworth 2013;Van der Wiel et al 2016).…”

“…The spatial and temporal distribution is discussed, and projections of change in response to projected radiative forcing in the near and far future are made. A high-resolution global climate model, HiFLOR (Murakami et al 2015), is used to allow for the investigation of local features and changes.…”

Explaining Extreme Events of 2014 from a Climate Perspective

“…The ETS index (ETSI) is formed by an average over each region. Following Murakami et al (2015), we used a probabilistic rather than a deterministic approach. We will examine the probability of the ETSI of the three regions during DJF as a function of ETSI using the following equation:…”

“…We explore a suite of simulations using the Geophysical Fluid Dynamics Laboratory (GFDL) Forecast-oriented Low Ocean Resolution model (FLOR; Vecchi et al 2014;see Supplementary Material). Simulated TCs were detected using an automated tracking algorithm as proposed by Murakami et al (2015; see online supplemental material). For the observational dataset, we used "best-track" data obtained from the International Best Track Archive for Climate Stewardship (IBTrACS; Knapp et al 2010) and the Unisys Corporation website (Unisys 2015) for the period 1949-2014.…”

“…23.1b). Previous studies suggest that the frequency of tropical cyclones (TCs) around Hawaii will increase under global warming (Li et al 2010;Murakami et al 2013). The projected increase is primarily associated with a northwestward shifting of TC tracks in the open ocean southeast of the islands, where climate models robustly predict greater warming than the other open oceans.…”