Contrasting lightning projection using the lightning potential index adapted in a convection-permitting regional climate model

Brisson, Erwan; Blahak, Ulrich; Lucas‐Picher, Philippe; Purr, Christopher; Ahrens, Bodo

doi:10.21203/rs.3.rs-339754/v1

Cited by 7 publications

(16 citation statements)

References 34 publications

(48 reference statements)

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“…The BB simulation drove, that is, provided lateral boundary and initialization conditions for, a simulation on a smaller domain but otherwise the same set‐up as the BB set‐up. The small domain simulation is called the Little‐Brother (LB) simulation and is chosen to have a typical domain size as in studies with realistic simulations (e.g., in Brisson et al., 2021; Purr et al., 2021). So‐called Coarse‐Brother (CB) simulations were performed on the BB domain with a coarser resolution to represent input data from a coarser model.…”

Section: Method Model and Experimentsmentioning

confidence: 99%

Sensitivity of Convection Permitting Simulations to Lateral Boundary Conditions in Idealized Experiments

Ahrens

Leps

2021

J Adv Model Earth Syst

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Limited‐area convection‐permitting climate models (CPMs) with horizontal grid‐spacing less than 4 km and not relying on deep convection parameterisations (CPs) are being used more and more frequently. CPMs represent small‐scale features such as deep convection more realistically than coarser regional climate models (RCMs) with deep CPs. Because of computational costs, CPMs tend to use smaller horizontal domains than RCMs. As all limited‐area models (LAMs), CPMs suffer issues with lateral boundary conditions (LBCs) and nesting. We investigated these issues using idealized Big‐Brother (BB) experiments with the LAM COSMO‐CLM. Grid‐spacing of the reference BB simulation was 2.4 km. Deep convection was triggered by idealized hills with driving data from simulations with different spatial resolutions, with/without deep CP, and with different nesting frequencies and LBC formulations. All our nested idealized 2.4‐km Little‐Brother (LB) experiments performed worse than a coarser CPM simulation (4.9 km) which used a four times larger computational domain and yet spent only half the computational cost. A boundary zone of >100 $ > 100$ grid‐points of the LBs could not be interpreted meteorologically because of spin‐up of convection and boundary inconsistencies. Hosts with grid‐spacing in the so‐called gray zone of convection (ca. 4–20 km) were not advantageous to the LB performance. The LB's performance was insensitive to the applied LBC formulation and updating (if ≤3 $\le 3$‐hourly). Therefore, our idealized experiments suggested to opt for a larger domain instead of a higher resolution even if coarser than usual (∼5 $\sim 5$ km) as a compromise between the harmful boundary problems, computational cost and improved representation of processes by CPMs.

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Section: Method Model and Experimentsmentioning

confidence: 99%

Sensitivity of Convection Permitting Simulations to Lateral Boundary Conditions in Idealized Experiments

Ahrens

Leps

2021

J Adv Model Earth Syst

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“…By accurately modeling hazardous convective weather, Gensini and Mote (2014) already suggested that such processes are likely to be well reproduced in CPRCMs. Early studies definitely assess that advanced parameterizations, particularly adapted for CPRCMs (that rely on updraft speed or/and graupel estimations), provide improved representations of lightning compared to more common parameterizations (Cloud top height, CAPExPREC) used in GCMs and RCMs (Brisson et al, 2021; Finney, Marsham, Wilkinson, et al, 2020; Lagasio et al, 2017). Hail applications using CPRCMs are rather limited due to the difficulty in both modeling and retrieving robust observations.…”

Section: Evidence Of Added Value In Cprcm Hindcast Simulationsmentioning

confidence: 99%

“…In studies analyzing thunderstorm indices with a CPRCM over central Europe, Schefczyk and Heinemann (2017) projected a decrease of thunderstorm frequencies, except over the Alps where an increase of thunderstorm occurrences and intensity was found. Brisson et al (2021) computed the climate change signals in future flash rates, highlighting the contrasted lightning projections between different diagnostics and model resolutions over central Germany.…”

Section: Climate Change Projections Using Cprcmsmentioning

confidence: 99%

Convection‐permitting modeling with regional climate models: Latest developments and next steps

Lucas‐Picher

Argüeso

Brisson

et al. 2021

WIREs Climate Change

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125

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Approximately 10 years ago, convection-permitting regional climate models (CPRCMs) emerged as a promising computationally affordable tool to produce fine resolution (1-4 km) decadal-long climate simulations with explicitly resolved deep convection. This explicit representation is expected to reduce climate projection uncertainty related to deep convection parameterizations found in most climate models. A recent surge in CPRCM decadal simulations over larger domains, sometimes covering continents, has led to important insights into CPRCM advantages and limitations. Furthermore, new observational gridded datasets with fine spatial and temporal ($1 km; $1 h) resolutions have leveraged additional knowledge through evaluations of the added value of CPRCMs. With an improved coordination in the frame of ongoing international initiatives, the production of ensembles of CPRCM simulations is expected to provide more robust climate projections and a better identification of their associated uncertainties. This review paper presents an overview of the methodology to produce CPRCM simulations and the latest research on the related added value in current and future climates. Impact studies that are already taking advantage of these new CPRCM simulations are highlighted. This review paper ends by proposing next steps that could be accomplished to continue exploiting the full potential of CPRCMs.

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“…The shortcomings of in situ measurements can be remedied by remote‐sensing techniques to an ever increasing degree. Remote‐sensing data used for investigating convective storms include lightning data (Wapler, 2013; Brisson et al, 2021) and weather radars (e.g. Moseley et al, 2013; Lochbihler et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Convective rain cell properties and the resulting precipitation scaling in a warm‐temperate climate

Purr

Brisson

Schlünzen

et al. 2022

Quart J Royal Meteoro Soc

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Convective precipitation events have been shown to intensify at rates exceeding the Clausius-Clapeyron rate (CC rate) of ca. 7% K −1 under current climate conditions. In this study, we relate atmospheric variables (low-level dew point temperature, convective available potential energy, and vertical wind shear), which are regarded as ingredients for severe deep convection, to properties of convective rain cells (cell area, maximum precipitation intensity, lifetime, precipitation sum, and cell speed). The rain cell properties are obtained from a rain gauge-adjusted radar dataset in a mid-latitude region, which is characterized by a temperate climate with warm summers (Germany). Different Lagrangian cell properties scale with dew point temperature at varying rates. While the maximum precipitation intensity of cells scales consistently at the CC rate, the area and precipitation sum per cell scale at varying rates above the CC rate. We show that this super-CC scaling is caused by a covarying increase of convective available potential energy with dew point temperature. Wind shear increases the precipitation sum per cell mainly by increasing the spatial cell extent. From a Eulerian point of view, this increase is partly compensated by a higher cell velocity, which leads to Eulerian precipitation scaling rates close to and slightly above the CC rate. Thus, Eulerian scaling rates of convective precipitation are modulated by convective available potential energy and vertical wind shear, making it unlikely that present scaling rates can be applied to future climate conditions. Furthermore, we show that cells that cause heavy precipitation at fixed locations occur at low vertical wind shear and, thus, move relatively slowly compared to typical cells.

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Contrasting lightning projection using the lightning potential index adapted in a convection-permitting regional climate model

Cited by 7 publications

References 34 publications

Sensitivity of Convection Permitting Simulations to Lateral Boundary Conditions in Idealized Experiments

Sensitivity of Convection Permitting Simulations to Lateral Boundary Conditions in Idealized Experiments

Convection‐permitting modeling with regional climate models: Latest developments and next steps

Convective rain cell properties and the resulting precipitation scaling in a warm‐temperate climate

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