Investigating the sensitivity of hurricane intensity and trajectory to sea surface temperatures using the regional model WRF

Kilic, Cevahir; Raible, Christoph C.

doi:10.1127/0941-2948/2013/0472

Cited by 12 publications

(8 citation statements)

References 31 publications

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“…However, for other scientific questions, a free simulation set-up could be more appropriate, as atmospheric processes and their interactions with regional-scale features are able to develop desirable disturbances that add value to RCM simulations. Typical examples are climate change projections (van der Linden and Mitchell, 2009;Gómez-Navarro et al, 2010;Jacob et al, 2013), paleosimulations (Gómez-Navarro et al, 2013), but also classical sensitivity and process studies (Kilic and Raible, 2013;Cipagauta et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Gómez-Navarro

Raible

Dierer³

2015

Geosci. Model Dev.

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Abstract. Simulating surface wind over complex terrain is a challenge in regional climate modelling. Therefore, this study aims at identifying a set-up of the Weather Research and Forecasting Model (WRF) model that minimises systematic errors of surface winds in hindcast simulations. Major factors of the model configuration are tested to find a suitable set-up: the horizontal resolution, the planetary boundary layer (PBL) parameterisation scheme and the way the WRF is nested to the driving data set. Hence, a number of sensitivity simulations at a spatial resolution of 2 km are carried out and compared to observations. Given the importance of wind storms, the analysis is based on case studies of 24 historical wind storms that caused great economic damage in Switzerland. Each of these events is downscaled using eight different model set-ups, but sharing the same driving data set. The results show that the lack of representation of the unresolved topography leads to a general overestimation of wind speed in WRF. However, this bias can be substantially reduced by using a PBL scheme that explicitly considers the effects of non-resolved topography, which also improves the spatial structure of wind speed over Switzerland. The wind direction, although generally well reproduced, is not very sensitive to the PBL scheme. Further sensitivity tests include four types of nesting methods: nesting only at the boundaries of the outermost domain, analysis nudging, spectral nudging, and the so-called re-forecast method, where the simulation is frequently restarted. These simulations show that restricting the freedom of the model to develop large-scale disturbances slightly increases the temporal agreement with the observations, at the same time that it further reduces the overestimation of wind speed, especially for maximum wind peaks.The model performance is also evaluated in the outermost domains, where the resolution is coarser. The results demonstrate the important role of horizontal resolution, where the step from 6 to 2 km significantly improves model performance. In summary, the combination of a grid size of 2 km, the non-local PBL scheme modified to explicitly account for non-resolved orography, as well as analysis or spectral nudging, is a superior combination when dynamical downscaling is aimed at reproducing real wind fields.

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Section: Discussionmentioning

confidence: 99%

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Gómez-Navarro

Raible

Dierer³

2015

Geosci. Model Dev.

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“…ever, wind is still not as widely studied as temperature or precipitation (e.g. Schär et al, 2004;Kjellström et al, 2007;Rajczak et al, 2013). For example, in areas of complex terrain like Switzerland, the main focus of high-resolution simulations with respect to wind is on case studies (Goyette, 2008;Etienne et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of the WRF model to PBL parametrizations and nesting techniques: evaluation of surface wind over complex terrain

Gómez-Navarro¹,

Raible²,

Dierer³

2015

Preprint

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Abstract. Simulating surface wind over complex terrain is a challenge in regional climate modelling. Therefore, this study aims at identifying a setup of the WRF model that minimizes systematic errors of surface winds in hindcast simulations. Major factors of the model configuration are tested to find a suitable setup: the horizontal resolution, the PBL parameterization scheme and the way WRF is nested to the driving dataset. Hence, a number of sensitivity simulations at a spatial resolution of 2 km are carried out and compared to observations. Given the importance of wind storms, the analysis is based on case studies of 24 historical wind storms that caused great economic damage in Switzerland. Each of these events is downscaled using eight different model setups, but sharing the same driving dataset. The results show that the unresolved topography leads to a general overestimation of wind speed in WRF. However, this bias can be substantially reduced by using a PBL scheme that explicitly considers the effects of non-resolved topography, which also improves the spatial structure of wind speed over Switzerland. The wind direction, although generally well reproduced, is not very sensitive to the PBL scheme. Further sensitivity tests include four types of nesting methods: nesting only at the boundaries of the outermost domain, analysis and spectral nudging, and the so-called re-forecast method, where the simulation is frequently restarted. These simulations show that restricting the freedom of the model to develop large-scale disturbances slightly increases the temporal agreement with the observations, at the same time that it further reduces the overestimation of wind speed, especially for maximum wind peaks. The model skill is also evaluated in the outermost domains, where the resolution is coarser. The results demonstrate the important role of horizontal resolution, where the step from 6 to 2 km significantly improves model performance. In summary, the combination of a grid size of 2 km, the non-local PBL scheme modified to explicitly account for non-resolved orography, as well as analysis or spectral nudging, is a superior combination when dynamical downscaling is aimed at reproducing real wind fields.

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“…As with previous SST sensitivity experiments (e.g. Evans et al, 1994;Kilic and Raible, 2013), this is a highly idealised sensitivity study and there are a number of limitations. As Emanuel and Sobel (2013) point out, changing the SST without changing the surface variables that would cause this change will result in imbalances in the surface energy balance and the observed changes may not be realistic.…”

Section: Summary and Discussionmentioning

confidence: 99%

The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: a sensitivity study

Lavender

Hoeke

Abbs

2018

Nat. Hazards Earth Syst. Sci.

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Abstract. Tropical cyclones (TCs) result in widespread damage associated with strong winds, heavy rainfall and storm surge. TC Yasi was one of the most powerful TCs to impact the Queensland coast since records began. Prior to Yasi, the SSTs in the Coral Sea were higher than average by 1–2 ∘C, primarily due to the 2010/2011 La Niña event. In this study, a conceptually simple idealised sensitivity analysis is performed using a high-resolution regional model to gain insight into the influence of SST on the track, size, intensity and associated rainfall of TC Yasi. A set of nine simulations with uniform SST anomalies of between −4 and 4 ∘C applied to the observed SSTs are analysed. The resulting surface winds and pressure are used to force a barotropic storm surge model to examine the influence of SST on the associated storm surge of TC Yasi. An increase in SST results in an increase in intensity, precipitation and integrated kinetic energy of the storm; however, there is little influence on track prior to landfall. In addition to an increase in precipitation, there is a change in the spatial distribution of precipitation as the SST increases. Decreases in SSTs result in an increase in the radius of maximum winds due to an increase in the asymmetry of the storm, although the radius of gale-force winds decreases. These changes in the TC characteristics also lead to changes in the associated storm surge. Generally, cooler (warmer) SSTs lead to reduced (enhanced) maximum storm surges. However, the increase in surge reaches a maximum with an increase in SST of 2 ∘C. Any further increase in SST does not affect the maximum surge but the total area and duration of the simulated surge increases with increasing upper ocean temperatures. A large decrease in maximum storm surge height occurs when a negative SST anomaly is applied, suggesting if TC Yasi had occurred during non-La Niña conditions the associated storm surge may have been greatly diminished, with a decrease in storm surge height of over 3 m when the SST is reduced by 2 ∘C. In summary, increases in SST lead to an increase in the potential destructiveness of TCs with regard to intensity, precipitation and storm surge, although this relationship is not linear.

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Investigating the sensitivity of hurricane intensity and trajectory to sea surface temperatures using the regional model WRF

Cited by 12 publications

References 31 publications

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Sensitivity of the WRF model to PBL parametrizations and nesting techniques: evaluation of surface wind over complex terrain

The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: a sensitivity study

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