scholarly journals The role of spatial and temporal model resolution in a flood event storyline approach in western Norway

2020 ◽  
Vol 29 ◽  
pp. 100259 ◽  
Author(s):  
Nathalie Schaller ◽  
Jana Sillmann ◽  
Malte Müller ◽  
Reindert Haarsma ◽  
Wilco Hazeleger ◽  
...  
Keyword(s):  
Flood Event ◽  
Model Resolution ◽  
Western Norway ◽  
Temporal Model

scholarly journals The role of spatial and temporal model resolution in a flood event storyline approach in Western Norway

2020 ◽  
Author(s):  
Nathalie Schaller ◽  
Jana Sillmann ◽  
Malte Müller ◽  
Reindert Haarsma ◽  
Wilco Hazeleger ◽  
...  
Keyword(s):  
Atmospheric Model ◽  
Flood Event ◽  
Model Resolution ◽  
Atmospheric River ◽  
Regional Atmospheric Model ◽  
Hourly Data ◽  
Temporal Model ◽  
The One ◽  
Peak Streamflow

<p><span>A physical climate storyline approach is applied to an autumn flood event caused by an atmospheric river in the West Coast of Norway. The aim is to demonstrate the value and challenges of higher spatial and temporal resolution in simulating impacts. The modelling chain used is the same as the one used operationally, to issue flood warnings for example. Its output is therefore familiar to many users, which we expect will facilitate stakeholder engagement. Two different versions of a hydrological model are run to show that on the one hand, the higher spatial resolution between the global and regional model is necessary to realistically simulate the high spatial variability of precipitation in such a mountainous region. On the other hand we also show that the intensity of the peak streamflow is only captured realistically with hourly data. The higher resolution regional atmospheric model is able to simulate the fact that with the passage of an atmospheric river, some valleys receive high amounts of precipitation and others not. However, the coarser resolution global model shows uniform precipitation in the whole region. Translating the event into the future leads to similar results: while in some catchments, a future flood might be 50% larger than a present one, in others no event occurs because the atmospheric river does not hit that catchment.</span></p>

On the role of vertical and horizontal model resolution for the simulation of stratospheric transport

2021 ◽  
Author(s):  
Hella Garny ◽  
Simone Dietmüller ◽  
Roland Eichinger ◽  
Aman Gupta ◽  
Marianna Linz
Keyword(s):  
Climate Models ◽  
Horizontal Resolution ◽  
Climate Forcing ◽  
Numerical Dispersion ◽  
Mixing Efficiency ◽  
Vertical Resolution ◽  
Model Resolution ◽  
Residual Circulation ◽  
Year 2000

<p>The stratospheric transport circulation, or Brewer-Dobson Circulation (BDC), is often conceptually seperated into advection along the residual circulation and two-way mixing. In particular the latter part has recently been found to exert a strong influence on inter-model differences of mean age of Air (AoA), a common measure of the BDC. However, the precise reason for model differences in two-way mixing remains unknown, as many model<br>components in multi-model projects differ. One component that likely plays an important role is model resolution, both vertically and horizontally. To analyse this aspect, we carried out a set of simulations with identical and constant year 2000 climate forcing varying the spectral horizontal<br>resolution (T31,T42,T63,T85) and the number of vertical levels (L31,L47,L90). We find that increasing the vertical resolution leads to an increase in mean AoA. Most of this change can be attributed to aging by mixing. The mixing efficiency, defined as the ratio of isentropic mixing strength and the diabatic circulation, shows the same dependency on vertical resolution. While horizontal resolution changes do not systematically change mean AoA, we do<br>find a systematic decrease in the mixing efficiency with increasing horizontal resolution. Non-systematic changes in the residual circulation partly compensate the mixing efficiency changes, leading to the non-systematic mean AoA changes. The mixing efficiency changes with vertical and horizontal resolution are consistent with expectations on the effects of numerical dispersion on mean AoA. To further investigate the most relevant regions of mixing differences, we analyse height-resolved mixing efficiency differences. Overall, this work will help to shed light on the underlying reasons for the large biases of climate models in simulating stratospheric transport.</p>

The role of a floodplain in regulating aquifer recharge during a flood event of the River Adour in southwest France

Wetlands ◽  
2003 ◽  
Vol 23 (1) ◽  
pp. 190-199 ◽  
Author(s):  
René-Claude Brunet ◽  
K. Brian Astin ◽  
Sophie Dartiguelongue
Keyword(s):  
Flood Event ◽  
Aquifer Recharge

scholarly journals A mathematical analysis of an activator-inhibitor Rho GTPase model

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Victor Ogesa Juma ◽  
Leif Dehmelt ◽  
Stéphanie Portet ◽  
Anotida Madzvamuse
Keyword(s):  
Computational Models ◽  
Rho Gtpase ◽  
Methodological Approach ◽  
Model System ◽  
Temporal Models ◽  
Temporal Model ◽  
Numerical Bifurcation ◽  
Rho Gef ◽  
Activator Inhibitor

<p style='text-indent:20px;'>Recent experimental observations reveal that local cellular contraction pulses emerge via a combination of fast positive and slow negative feedbacks based on a signal network composed of Rho, GEF and Myosin interactions [<xref ref-type="bibr" rid="b22">22</xref>]. As an examplary, we propose to study a plausible, hypothetical temporal model that mirrors general principles of fast positive and slow negative feedback, a hallmark for activator-inhibitor models. The methodology involves (ⅰ) a qualitative analysis to unravel system switching between different states (stable, excitable, oscillatory and bistable) through model parameter variations; (ⅱ) a numerical bifurcation analysis using the positive feedback mediator concentration as a bifurcation parameter, (ⅲ) a sensitivity analysis to quantify the effect of parameter uncertainty on the model output for different dynamic regimes of the model system; and (ⅳ) numerical simulations of the model system for model predictions. Our methodological approach supports the role of mathematical and computational models in unravelling mechanisms for molecular and developmental processes and provides tools for analysis of temporal models of this nature.</p>

Modeling large dust deposition events to alpine snow and their impacts: the role of model resolution

2021 ◽  
Author(s):  
Foteini Baladima ◽  
Jennie Thomas ◽  
Marie Dumont ◽  
Didier Voisin ◽  
Clementine Junquas ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Horizontal Resolution ◽  
Added Value ◽  
Model Resolution ◽  
Dust Deposition ◽  
Mountain Regions ◽  
Mountain Meteorology ◽  
The Alps

&lt;div&gt;Mineral dust and black carbon (BC) constitute the most important aerosols present in the atmosphere and cryosphere and have well known potential effects on regional and global climate. Upon their deposition they can impact snow albedo, snowpack evolution and timing of snow-melt. However, capturing BC and dust deposition events in mountain regions is currently a challenge due to the complexity of aerosol-cloud interactions and the specifics of mountain meteorological systems, which are difficult to represent in large scale models. Here, we use a case study of dust deposition, between 30 March and 5 April 2018, when a significant dust deposition event was observed within the seasonal snowpack at the Col du Lautaret in the French Alps. This comes in addition to the background BC deposition that occurred during the same period. Specifically, we investigate the role of model resolution in capturing both mountain meteorology, precipitation, and the resulting model predicted dust and BC deposition. For this, the meteorological-chemical model WRF-Chem is used with three nested domains including the primary dust emissions region in Africa (low resolution domain), a second domain that includes Europe, and a third high resolution domain over the Alps. We compare WRF-Chem predicted aerosol and meteorological properties (at different model resolution) with in-situ, remote sensing, and reanalysis products to validate the model and quantify the added value of high resolution modelling within the Alps. We conclude that predicted mountain meteorology including precipitation is significantly better when using the high resolution configuration (3 x 3 km horizontal resolution domain). Additionally, this improved meteorology predicted by the model has significant impacts on predicted dust deposition and BC. The better representation of the mountain meteorology when the resolution becomes finer leads to improved model predicted dust and BC deposition to alpine snow. Implications for this, including improved resolution within models that consider the full aerosol lifecycle in the atmosphere and in snow covered mountain regions is discussed.&lt;/div&gt;

scholarly journals Impact of Stochastic Physics and Model Resolution on the Simulation of Tropical Cyclones in Climate GCMs

2021 ◽  
Vol 34 (11) ◽  
pp. 4315-4341
Author(s):  
Pier Luigi Vidale ◽  
Kevin Hodges ◽  
Benoit Vannière ◽  
Paolo Davini ◽  
Malcolm J. Roberts ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Seasonal Cycle ◽  
General Circulation ◽  
Dynamic Environment ◽  
General Circulation Models ◽  
Model Resolution ◽  
Grid Spacing ◽  
The Cost ◽  
Stochastic Physics

AbstractThe role of model resolution in simulating geophysical vortices with the characteristics of realistic tropical cyclones (TCs) is well established. The push for increasing resolution continues, with general circulation models (GCMs) starting to use sub-10-km grid spacing. In the same context it has been suggested that the use of stochastic physics (SP) may act as a surrogate for high resolution, providing some of the benefits at a fraction of the cost. Either technique can reduce model uncertainty, and enhance reliability, by providing a more dynamic environment for initial synoptic disturbances to be spawned and to grow into TCs. We present results from a systematic comparison of the role of model resolution and SP in the simulation of TCs, using EC-Earth simulations from project Climate-SPHINX, in large ensemble mode, spanning five different resolutions. All tropical cyclonic systems, including TCs, were tracked explicitly. As in previous studies, the number of simulated TCs increases with the use of higher resolution, but SP further enhances TC frequencies by ~30%, in a strikingly similar way. The use of SP is beneficial for removing systematic climate biases, albeit not consistently so for interannual variability; conversely, the use of SP improves the simulation of the seasonal cycle of TC frequency. An investigation of the mechanisms behind this response indicates that SP generates both higher TC (and TC seed) genesis rates, and more suitable environmental conditions, enabling a more efficient transition of TC seeds into TCs. These results were confirmed by the use of equivalent simulations with the HadGEM3-GC31 GCM.

scholarly journals The impact of initial conditions on convection-permitting simulations of a flood event over complex mountainous terrain

2020 ◽  
Vol 24 (2) ◽  
pp. 771-791 ◽  
Author(s):  
Lu Li ◽  
Marie Pontoppidan ◽  
Stefan Sobolowski ◽  
Alfonso Senatore
Keyword(s):  
Snow Depth ◽  
Peak Flow ◽  
Initial Conditions ◽  
Flood Event ◽  
Precipitation Pattern ◽  
Mountainous Terrain ◽  
Western Norway ◽  
Snow Conditions ◽  
The Impact ◽  
Hbv Model

Abstract. Western Norway suffered major flooding after 4 d of intense rainfall during the last week of October 2014. While events like this are expected to become more frequent and severe under a warming climate, convection-permitting scale models are showing their skill with respect to capturing their dynamics. Nevertheless, several sources of uncertainty need to be taken into account, including the impact of initial conditions on the precipitation pattern and discharge, especially over complex, mountainous terrain. In this paper, the Weather Research and Forecasting Model Hydrological modelling system (WRF-Hydro) is applied at a convection-permitting scale, and its performance is assessed in western Norway for the aforementioned flood event. The model is calibrated and evaluated using observations and benchmarks obtained from the Hydrologiska Byråns Vattenbalansavdelning (HBV) model. The calibrated WRF-Hydro model performs better than the simpler conceptual HBV model, especially in areas with complex terrain and poor observational coverage. The sensitivity of the precipitation pattern and discharge to poorly constrained elements such as spin-up time and snow conditions is then examined. The results show the following: (1) the convection-permitting WRF-Hydro simulation generally captures the precipitation pattern/amount, the peak flow volume and the timing of the flood event; (2) precipitation is not overly sensitive to spin-up time, whereas discharge is slightly more sensitive due to the influence of soil moisture, especially during the pre-peak phase; and (3) the idealized snow depth experiments show that a maximum of 0.5 m of snow is converted to runoff irrespective of the initial snow depth and that this snowmelt contributes to discharge mostly during the rainy and the peak flow periods. Although further targeted experiments are needed, this study suggests that snow cover intensifies the extreme discharge instead of acting as a sponge, which implies that future rain-on-snow events may contribute to a higher flood risk.

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