The first Met Office Unified Model/JULES Regional Atmosphere and Land configuration, RAL1

Bush, Mike; Allen, Tom; Bain, Caroline L.; Boutle, Ian; Edwards, John M.; Finnenkoetter, Anke; Franklin, Charmaine; Hanley, Kirsty; Lean, Humphrey; Lock, A. P.; Manners, James; Mittermaier, Marion; Morcrette, C. J.; North, R. V.; Petch, J. C.; Short, Chris; Walters, David; Webster, Stuart; Weeks, Mark E.; Wilkinson, Jonathan; Wood, Nigel; Zerroukat, M.

doi:10.5194/gmd-2019-130

Cited by 55 publications

(109 citation statements)

References 60 publications

Supporting

Mentioning

107

Contrasting

Order By: Relevance

“…It is a limited-area configuration of the Met Office Unified Model (UM; Cullen 2003), coupled to the Joint UK Land Environment Simulator (JULES) model Clark et al, 2011) for the land surface. Both the UM and JULES contain a comprehensive set of parametrization schemes for key physical processes; the particular science configuration of these used in this study is known collectively as Regional Atmosphere and Land -Version 1 (RAL1; Bush et al, 2019). RAL1 is an updated version of the operational forecast model used at the time and has improved representation of the diurnal cycle of temperatures.…”

Section: The Modelling Systemmentioning

confidence: 99%

Sensitivity of the 2018 UK summer heatwave to local sea temperatures and soil moisture

Petch

Short

Best

et al. 2020

Atmospheric Science Letters

Self Cite

View full text Add to dashboard Cite

The impact of local climate conditions on air temperatures during a hot summer period over the United Kingdom in 2018 is studied using simple sensitivity experiments with a state‐of‐the‐art regional numerical weather prediction system. The experiments are designed to investigate the influence of sea surface temperature (SST) and soil moisture on the air temperatures over land. They involved applying changes to the analysed SST and soil moisture patterns with magnitudes consistent with the differences between forecast analysis and climatology. The results from daily 5‐day forecasts over an 11‐day period show that a 3°C reduction in SSTs reduces the simulated air temperatures averaged over all land points by just over 1°C. Moistening the soil while using the control SSTs reduces the temperatures by a little less than 1°C on average although this can be larger than 3°C locally. While the reduction in SST impacts the daily maximum and minimum temperatures to a similar extent, the increase in soil moisture had little impact on the daily minimum temperatures.

show abstract

Section: The Modelling Systemmentioning

confidence: 99%

Sensitivity of the 2018 UK summer heatwave to local sea temperatures and soil moisture

Petch

Short

Best

et al. 2020

Atmospheric Science Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…uSINGV (or urban SINGV) is adapted from SINGV which is the 1.5 km (horizontal resolution) tropical configuration of UM (Bush et al, 2019) used for numerical weather prediction by MSS. uSINGV runs at a high horizontal resolution (300 m) to properly capture interactions between the urban canopy layer and the atmosphere above.…”

Section: Atmospheric Componentmentioning

confidence: 99%

“…The subgrid orography drag scheme has also been deactivated in uSINGV assuming that the resolution is sufficient to resolve it. The remaining atmospheric physical parametrization schemes are the same as in SINGV (Bush et al, 2019;Webster et al, 2019, in preparation).…”

Section: Atmospheric Componentmentioning

confidence: 99%

Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

Simón-Moral

Dipankar

Roth

et al. 2019

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

A tropical version of the high‐resolution (300 m) UK Met Office forecast model (UM) using the MORUSES urban canopy parametrization (UCP) is adapted for Singapore. High‐resolution urban surface parameters are determined using a methodology based on Voronoi polygons applied to a 3D building database. The model is evaluated for clear sky and calm conditions at the neighbourhood scale by comparing its predictions with two sources of observations: energy balance data from an eddy covariance flux tower located in a low‐rise residential area, and a network of sensors measuring screen‐level temperature across the city. The model is able to reproduce the diurnal cycle of the surface energy balance fluxes. Net radiation is overestimated which likely follows from an underestimation in cloud cover and effective surface albedo. This overestimation partly explains the overestimation of the sensible‐ and latent‐heat fluxes. The higher model sensible‐heat flux is further hypothesised to be related to the overestimation of modelled canyon sensible‐heat flux. Its peak exhibits a 1 h delay, similar to simulated roof and canyon surface temperature. The model captures the diurnal cycle of temperature at a height of 20.5 m above ground and at screen level. A night‐time cold bias of 0.1–1.1 K and an overestimation of the daytime peak value are observed at both heights. These deviations are smaller than those predicted by other UCPs reported in the literature. A simple method to estimate the capability of an urban model to qualitatively distinguish screen‐level temperature differences across different urban morphologies is developed which shows that MORUSES is clearly able to represent the impacts of different neighbourhoods on the thermal environment.

show abstract

“…The MetUM uses the Wilson and Ballard (1999) bulk microphysics scheme with prognostic liquid and ice cloud, as well as prognostic graupel and rain in the CPM simulations. Further details of the regional atmosphere configurations will be presented in Bush et al (2019).…”

Section: Model Simulationsmentioning

confidence: 99%

Convective initiation and storm life cycles in convection‐permitting simulations of the Met Office Unified Model over South Africa

Keat

Stein

Phaduli

et al. 2019

Quart J Royal Meteoro Soc

Self Cite

View full text Add to dashboard Cite

Convective initiation is a challenge for convection‐permitting models due to its sensitivity to sub‐km processes. We evaluate the representation of convective storms and their initiation over South Africa during four summer months in Met Office Unified Model simulations at a 1.5‐km horizontal grid length. Storm size distributions from the model compare well with radar observations, but rainfall in the model is predominantly produced by large storms (50 km in diameter or larger) in the evening, whereas radar observations show that most rainfall occurs throughout the afternoon, from storms 10–50 km in diameter. In all months, the modelled maximum number of storm initiations occurs at least 2 hr prior to the radar‐observed maximum. However, the diurnal cycle of rainfall between the model and observations compares well, suggesting that the numerous storm initiations in the simulations do not produce much rainfall. Modelled storms are generally less intense than those in radar observations, especially in early summer. In February, when tropical influences dominate, the simulated storms are of similar intensity to observed storms. Simulated storms tend to reach their peak intensity in the first 15 min after initiation, then gradually become less intense as they grow. In radar observations, storms reach their peak intensity 15 min into their life cycle, stay intense as they grow larger, then gradually weaken after they have reached their maximum diameter. Two November case studies of severe convection are analysed in detail. A higher resolution grid length initiates convection slightly earlier (300 m as opposed to 1.5 km) with the same scientific settings. Two 1.5 km simulations that apply more subgrid mixing have delayed convective initiation. Analysis of soundings indicates little difference in the convective indices, suggesting that differences in convection may be attributed to the choice of subgrid mixing parameters.

show abstract

The first Met Office Unified Model/JULES Regional Atmosphere and Land configuration, RAL1

Cited by 55 publications

References 60 publications

Sensitivity of the 2018 UK summer heatwave to local sea temperatures and soil moisture

Sensitivity of the 2018 UK summer heatwave to local sea temperatures and soil moisture

Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

Convective initiation and storm life cycles in convection‐permitting simulations of the Met Office Unified Model over South Africa

Contact Info

Product

Resources

About