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

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

High-resolution fully coupled atmospheric-hydrological modeling: a cross-compartment regional water and energy cycle evaluation

Abstract. The land surface and the atmospheric boundary layer are closely intertwined with respect to the exchange of water, trace gases, and energy. Nonlinear feedback and scale-dependent mechanisms are obvious by observations and theories. Modeling instead is often narrowed to single compartments of the terrestrial system or bound to traditional viewpoints of definite scientific disciplines. Coupled terrestrial hydrometeorological modeling systems attempt to overcome these limitations to achieve a better integration of the processes relevant for regional climate studies and local-area weather prediction. This study examines the ability of the hydrologically enhanced version of the Weather Research and Forecasting model (WRF-Hydro) to reproduce the regional water cycle by means of a two-way coupled approach and assesses the impact of hydrological coupling with respect to a traditional regional atmospheric model setting. It includes the observation-based calibration of the hydrological model component (offline WRF-Hydro) and a comparison of the classic WRF and the fully coupled WRF-Hydro models both with identically calibrated parameter settings for the land surface model (Noah-Multiparametrization; Noah-MP). The simulations are evaluated based on extensive observations at the Terrestrial Environmental Observatories (TERENO) Pre-Alpine Observatory for the Ammer (600 km2) and Rott (55 km2) river catchments in southern Germany, covering a 5-month period (June–October 2016). The sensitivity of seven land surface parameters is tested using the Latin-Hypercube–One-factor-At-a-Time (LH-OAT) method, and six sensitive parameters are subsequently optimized for six different subcatchments, using the model-independent Parameter Estimation and Uncertainty Analysis software (PEST). The calibration of the offline WRF-Hydro gives Nash–Sutcliffe efficiencies between 0.56 and 0.64 and volumetric efficiencies between 0.46 and 0.81 for the six subcatchments. The comparison of the classic WRF and fully coupled WRF-Hydro models, both using the calibrated parameters from the offline model, shows only tiny alterations for radiation and precipitation but considerable changes for moisture and heat fluxes. By comparison with TERENO Pre-Alpine Observatory measurements, the fully coupled model slightly outperforms the classic WRF model with respect to evapotranspiration, sensible and ground heat flux, the near-surface mixing ratio, temperature, and boundary layer profiles of air temperature. The subcatchment-based water budgets show uniformly directed variations for evapotranspiration, infiltration excess and percolation, whereas soil moisture and precipitation change randomly

Correlation between Choriocapillaris Density and Retinal Sensitivity in Stargardt Disease

The aim of this work was to characterize the choriocapillaris (CC) in patients with Stargardt disease (STGD) using the swept source widefield optical coherence tomography angiography (SS WF OCTA) and to compare CC perfusion density to retinal sensitivity, analyzed using microperimetry (MP). This cross-sectional study included 9 patients (18 eyes) with STGD and central CC atrophy (stage 3 STGD). The CC was analyzed using SS WF OCTA and areas of different CC impairment were quantified and correlated with retinal sensitivity analyzed using MP. The main outcome measures were the percent perfused choriocapillaris area (PPCA), retinal sensitivity, and correlation between PPCA and retinal sensitivity. Seventeen eyes of 9 patients suffering from stage 3 STGD were analyzed. SS WF OCTA revealed a vascular rarefaction in central atrophic zones and a near atrophy halo of choriocapillaris impairment. In all eyes were noticed a central atrophy (CA) area with absolute absence of CC that corresponded to 0 dB points at MP, a near atrophy (NA) zone of PPCA impairment that included points with decreased sensitivity at MP and a distant from atrophy (DA) zone with higher PPCA and retinal sensitivity values. The mean difference of PPCA and retinal sensitivity between NA and CA and DA and CA was statistical significantly different (p < 0.01), the latter showing higher values. A direct relationship between PPCA and retinal sensitivity was found (p < 0.001). Choriocapillaris damage evaluated using SS WF OCTA correlates with MP, these data suggest that CC impairment may be a predictor of retinal function in patients with STGD

Reduced Rate of Hospital Admissions for ACS during Covid-19 Outbreak in Northern Italy

To address the coronavirus (Covid-19) pandemic,1 strict social containment measures have been adopted worldwide, and health care systems have been reorganized to cope with the enormous increase in the numbers of acutely ill patients.2,3 During this same period, some changes in the pattern of hospital admissions for other conditions have been noted. The aim of the present analysis is to investigate the rate of hospital admissions for acute coronary syndrome (ACS) during the early days of the Covid-19 outbreak

Hydrometeorological Ensemble Forecast of a Highly Localized Convective Event in the Mediterranean

The uncertainties that affect hydrometeorological modelling chains can be addressed through ensemble approaches. In this paper, a convection-permitting ensemble system was assessed based on the downscaling of all members of the ECMWF ensemble prediction system through the coupled atmospheric-hydrological WRF-Hydro modelling system. An exemplary highly localized convective event that occurred in a morphologically complex area of the southern Italian coast was selected as a case study, evaluating the performance of the system for two consecutive lead times up to the hydrological forecast on a very small (11.4 km2) catchment. The proposed approach accurately downscales the signal provided by the global model, improving up to almost 200% the quantitative forecast of the accumulated rainfall peak in the area affected by the event and supplying clear information about the forecast uncertainty. Some members of the ensemble simulations provide accurate results up to the hydrological scale over the catchment, with unit peak discharge forecasts up to 3 m3∙s−1∙km−2. Overall, the study highlights that for highly localized convective events in coastal Mediterranean catchments, ensemble approaches should be preferred to a classic single-based simulation approach, because they improve the forecast skills and provide spatially distributed information about the forecast uncertainty, which can be particularly useful for operational purposes

Rilievo e ricostruzione virtuale della Chiesa di S. Antonio a Poggioreale Vecchia – Trapani

Le attività relative alla Chiesa di S. Antonio a Poggioreale Vecchia, si inseriscono in un più ampio progetto che la Regione Sicilia ha da tempo avviato a cura del Centro Regionale per la Progettazione e il Restauro (C.R.P.R.) e che prevede la redazione di una Carta Regionale del Rischio. La rilevanza del sito di Poggioreale vecchia risiede da un lato nella particolare situazione in cui si è venuto a trovare l'abitato a seguito del sisma che nel 1968 ha devastato l'area del Belice e che nello specifico ha determinato l’abbandono dell'edificato storico e lo spostamento del nuovo insediamento urbano in un'area ritenuta più sicura; dall’altro nell'attuale condizione di abitato demanializzato e ormai archeologizzato. All’interno del progetto generale, la presente ricerca si pone come obiettivo la conoscenza dettagliata di un singolo elemento, la Chiesa di S. Antonio, come entità “prototipo” di una realtà urbana estremamente significativa, al fine di poter successivamente definire criteri e obiettivi di un recupero ambientale e di una riqualificazione urbana correlati alla mitigazione dei vari fattori di rischio. Sono stati eseguiti: rilievi mediante scansione Laser 3D (Leica HDS 3000) e stazione totale, con realizzazione di elaborati bidimensionali con rappresentazione della pianta a curve di livello e i relativi prospetti e sezioni; studio dell’ordine architettonico del pronao (base e capitello) con analisi delle sezioni e realizzazione delle superfici; realizzazione di modello completo 3D texturizzato della Chiesa, completo di database gestionale per il controllo ed ottimizzazione dello stesso, con particolare attenzione alle trasformazioni dalla nuvola di punti alle superfici Mesh e NURBS, per rappresentazione interattiva via internet grazie alla tecnica del 3D Browsing

Il rilievo critico: un sistema aperto di conoscenza

L’operazione di rilievo rappresenta lo strumento fondamentale rivolto alla conoscenza di una porzione di realtà. Qualsiasi operazione di studio e di ricerca non può che prendere le mosse da un’operazione di tipo sintetico rivolta all’individuazione di un numero selezionato di informazioni sulla base delle quali effettuare le differenti ricerche e analisi. In buona sostanza, qualsiasi approccio con la realtà dà come risultato l’immediata individuazione di una complessità che è impossibile, e concettualmente “inutile”, analizzare al fine di ottenere le informazioni che necessitano: solo un approccio critico e culturalmente aperto, rivolto alla sintesi estrema di quelli che sono gli elementi fondamentali per la ricerca, potrà costituire la giusta base dati da utilizzare per il successivo approfondimento. Le fasi Partendo da questi concetti si possono distinguere tre diverse fasi: 1. la progettazione del rilievo; 2. la lettura del dato; 3. la costruzione di modelliThe survey operation is the instrument fundamental to understanding a portion of reality. Any study or research can only be guided by a synthetic operation aimed at identifying a selected amount of information on the basis of which the various research and analysis should be made. Basically, any contact with the object results in the immediate identification of a complexity that is impossible and conceptually "useless" to analyze in order to obtain the necessary information. Only a critical and culturally open approach aimed at achieving a concise summary of the key elements of the research can form the correct database to be used for subsequent investigation. On the basis of these concepts we can distinguish three different phases: 1. planning the survey; 2. reading the data; 3. constructing model