scholarly journals High resolution forecast of heavy precipitation with Lokal Modell: analysis of two case studies in the Alpine area

2005 ◽  
Vol 5 (4) ◽  
pp. 593-602 ◽  
Author(s):  
M. Elementi ◽  
C. Marsigli ◽  
T. Paccagnella
Keyword(s):  
Complex Structure ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
Northern Italy ◽  
Convective Precipitation ◽  
Moist Convection ◽  
Intense Rainfall ◽  
Precipitation Field ◽  
Alpine Area ◽  
Very High

Abstract. Northern Italy is frequently affected by severe precipitation conditions often inducing flood events with associated loss of properties, damages and casualties. The capability of correctly forecast these events, strongly required for an efficient support to civil protection actions, is still nowadays a challenge. This difficulty is also related with the complex structure of the precipitation field in the Alpine area and, more generally, over the Italian territory. Recently a new generation of non-hydrostatic meteorological models, suitable to be used at very high spatial resolution, has been developed. In this paper the performance of the non-hydrostatic Lokal Modell developed by the COSMO Consortium, is analysed with regard to a couple of intense precipitation events occurred in the Piemonte region in Northern Italy. These events were selected among the reference cases of the Hydroptimet/INTERREG IIIB project. LM run at the operational resolution of 7km provides a good forecast of the general rain structure, with an unsatisfactory representation of the precipitation distribution across the mountain ranges. It is shown that the inclusion of the new prognostic equations for cloud ice, rain and snow produces a remarkable improvement, reducing the precipitation in the upwind side and extending the intense rainfall area to the downwind side. The unrealistic maxima are decreased towards observed values. The use of very high horizontal resolution (2.8 km) improves the general shape of the precipitation field in the flat area of the Piemonte region but, keeping active the moist convection scheme, sparse and more intense rainfall peaks are produced. When convective precipitation is not parametrised but explicitly represented by the model, this negative effect is removed.

scholarly journals A Unified Convection Scheme (UNICON). Part I: Formulation

2014 ◽  
Vol 71 (11) ◽  
pp. 3902-3930 ◽  
Author(s):  
Sungsu Park
Keyword(s):  
Deep Convection ◽  
Convective Available Potential Energy ◽  
Horizontal Resolution ◽  
Vertical Transport ◽  
Convective Precipitation ◽  
Cold Pool ◽  
Quasi Equilibrium ◽  
Convection Scheme ◽  
Time Step ◽  
Turbulent Eddies

Abstract The author develops a unified convection scheme (UNICON) that parameterizes relative (i.e., with respect to the grid-mean vertical flow) subgrid vertical transport by nonlocal asymmetric turbulent eddies. UNICON is a process-based model of subgrid convective plumes and mesoscale organized flow without relying on any quasi-equilibrium assumptions such as convective available potential energy (CAPE) or convective inhibition (CIN) closures. In combination with a relative subgrid vertical transport scheme by local symmetric turbulent eddies and a grid-scale advection scheme, UNICON simulates vertical transport of water species and conservative scalars without double counting at any horizontal resolution. UNICON simulates all dry–moist, forced–free, and shallow–deep convection within a single framework in a seamless, consistent, and unified way. It diagnoses the vertical profiles of the macrophysics (fractional area, plume radius, and number density) as well as the microphysics (production and evaporation rates of convective precipitation) and the dynamics (mass flux and vertical velocity) of multiple convective updraft and downdraft plumes. UNICON also prognoses subgrid cold pool and mesoscale organized flow within the planetary boundary layer (PBL) that is forced by evaporation of convective precipitation and accompanying convective downdrafts but damped by surface flux and entrainment at the PBL top. The combined subgrid parameterization of diagnostic convective updraft and downdraft plumes, prognostic subgrid mesoscale organized flow, and the feedback among them remedies the weakness of conventional quasi-steady diagnostic plume models—the lack of plume memory across the time step—allowing UNICON to successfully simulate various transitional phenomena associated with convection (e.g., the diurnal cycle of precipitation and the Madden–Julian oscillation).

scholarly journals A flood episode in northern Italy: multi-model and single-model mesoscale meteorological ensembles for hydrological predictions

2013 ◽  
Vol 17 (6) ◽  
pp. 2107-2120 ◽  
Author(s):  
S. Davolio ◽  
M. M. Miglietta ◽  
T. Diomede ◽  
C. Marsigli ◽  
A. Montani
Keyword(s):  
Horizontal Resolution ◽  
Northern Italy ◽  
Ensemble Prediction ◽  
Limited Area ◽  
Prediction System ◽  
Model Ensemble ◽  
Single Model ◽  
Ensemble Prediction System ◽  
Forecasting System ◽  
Meteorological Models

Abstract. Numerical weather prediction models can be coupled with hydrological models to generate streamflow forecasts. Several ensemble approaches have been recently developed in order to take into account the different sources of errors and provide probabilistic forecasts feeding a flood forecasting system. Within this framework, the present study aims at comparing two high-resolution limited-area meteorological ensembles, covering short and medium range, obtained via different methodologies, but implemented with similar number of members, horizontal resolution (about 7 km), and driving global ensemble prediction system. The former is a multi-model ensemble, based on three mesoscale models (BOLAM, COSMO, and WRF), while the latter, following a single-model approach, is the operational ensemble forecasting system developed within the COSMO consortium, COSMO-LEPS (limited-area ensemble prediction system). The meteorological models are coupled with a distributed rainfall-runoff model (TOPKAPI) to simulate the discharge of the Reno River (northern Italy), for a recent severe weather episode affecting northern Apennines. The evaluation of the ensemble systems is performed both from a meteorological perspective over northern Italy and in terms of discharge prediction over the Reno River basin during two periods of heavy precipitation between 29 November and 2 December 2008. For each period, ensemble performance has been compared at two different forecast ranges. It is found that, for the intercomparison undertaken in this specific study, both mesoscale model ensembles outperform the global ensemble for application at basin scale. Horizontal resolution is found to play a relevant role in modulating the precipitation distribution. Moreover, the multi-model ensemble provides a better indication concerning the occurrence, intensity and timing of the two observed discharge peaks, with respect to COSMO-LEPS. This seems to be ascribable to the different behaviour of the involved meteorological models. Finally, a different behaviour comes out at different forecast ranges. For short ranges, the impact of boundary conditions is weaker and the spread can be mainly attributed to the different characteristics of the models. At longer forecast ranges, the similar behaviour of the multi-model members forced by the same large-scale conditions indicates that the systems are governed mainly by the boundary conditions, although the different limited area models' characteristics may still have a non-negligible impact.

scholarly journals Analysis of intense rainfall events on Madeira Island during the 2009/2010 winter

2012 ◽  
Vol 12 (7) ◽  
pp. 2225-2240 ◽  
Author(s):  
F. T. Couto ◽  
R. Salgado ◽  
M. J. Costa
Keyword(s):  
Precipitable Water ◽  
Heavy Precipitation ◽  
Rain Gauge ◽  
Horizontal Resolution ◽  
Pressure System ◽  
Orographic Effects ◽  
Madeira Island ◽  
High Rainfall ◽  
High Precipitation Events ◽  
Precipitation Events

Abstract. This paper constitutes a step towards the understanding of some characteristics associated with high rainfall amounts and flooding on Madeira Island. The high precipitation events that occurred during the winter of 2009/2010 have been considered with three main goals: to analyze the main atmospheric characteristics associated with the events; to expand the understanding of the interaction between the island and the atmospheric circulations, mainly the effects of the island on the generation or intensification of orographic precipitation; and to evaluate the performance of high resolution numerical modeling in simulating and forecasting heavy precipitation events over the island. The MESO-NH model with a horizontal resolution of 1 km is used, as well as rain gauge data, synoptic charts and measurements of precipitable water obtained from the Atmospheric InfraRed Sounder (AIRS). The results confirm the influence of the orographic effects on precipitation over Madeira as well as the tropical–extratropical interaction, since atmospheric rivers were detected in six out of the seven cases analyzed, acting as a low level moisture supplier, which together with the orographic lifting induced the high rainfall amounts. Only in one of the cases the presence of a low pressure system was identified over the archipelago.

The method of selective assembly for the RV reducer based on genetic algorithm

2017 ◽  
Vol 232 (6) ◽  
pp. 921-929 ◽  
Author(s):  
Xuyang Chu ◽  
Huihuang Xu ◽  
Xiaomin Wu ◽  
Jiping Tao ◽  
Guifang Shao
Keyword(s):  
Genetic Algorithm ◽  
Complex Structure ◽  
Selective Assembly ◽  
Matching Algorithm ◽  
Assembly Method ◽  
Assembly Accuracy ◽  
Manufacturing Errors ◽  
Rv Reducer ◽  
Assembly Precision ◽  
Very High

As a precision gear reducer, the RV reducer has a low-transmission backlash (very high assembly accuracy). Therefore, the selective assembly method is the only assembly method which can guarantee the assembly precision of the RV reducer. However, the RV reducer has a complex structure; it consists of a high number of parts whose machining tolerance cannot be very low. Furthermore, there are numerous parts, the tolerances of which influence the RV reducer transmission backlash. Therefore, it is difficult to achieve high assembly accuracy by using the traditional selective assembly method. In this paper, a method of selective assembly is proposed to make the backlash of the RV reducer meet the requirements through the analysis of the characteristics of the RV reducer structure, the processing and assembly process of the parts, and the influence of manufacturing errors on the backlash. Then, a mathematical model was established for the RV reducer assembly issue. And a matching algorithm based on a genetic algorithm was developed. Finally, the algorithm was applied to the selective assembly of the RV reducer for verifying the feasibility and validity of the proposed matching method.

scholarly journals On the skill of high frequency precipitation analyses

2014 ◽  
Vol 11 (10) ◽  
pp. 11605-11636
Author(s):  
A. Kann ◽  
I. Meirold-Mautner ◽  
F. Schmid ◽  
G. Kirchengast ◽  
J. Fuchsberger
Keyword(s):  
High Frequency ◽  
Cross Validation ◽  
Rain Gauge ◽  
Convective Precipitation ◽  
Convective Condition ◽  
Station Network ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial ◽  
Merging Algorithms ◽  
Very High

Abstract. The ability of radar-rain gauge merging algorithms to precisely analyse convective precipitation patterns is of high interest for many applications, e.g. hydrological modelling. However, due to drawbacks of methods like cross-validation and due to the limited availability of reference datasets on high temporal and spatial scale, an adequate validation is usually hardly possible, especially on an operational basis. The present study evaluates the skill of very high resolution and frequently updated precipitation analyses (rapid-INCA) by means of a very dense station network (WegenerNet), operated in a limited domain of the south-eastern parts of Austria (Styria). Based on case studies and a longer term validation over the convective season 2011, a general underestimation of the rapid-INCA precipitation amounts is shown, although the temporal and spatial variability of the errors is – by convective nature – high. The contribution of the rain gauge measurements to the analysis skill is crucial. However, the capability of the analyses to precisely assess the convective precipitation distribution predominantly depends on the representativeness of the stations under the prevalent convective condition.

Lichens as Biomonitors of Sulphur Dioxide Pollution in La Spezia (Northern Italy)

1990 ◽  
Vol 22 (3) ◽  
pp. 333-344 ◽  
Author(s):  
P. L. Nimis ◽  
M. Castello ◽  
M. Perotti
Keyword(s):  
Data Analysis ◽  
Sulphur Dioxide ◽  
Sampling Strategy ◽  
Statistical Correlation ◽  
Northern Italy ◽  
Automatic Mapping ◽  
Olive Trees ◽  
Very High ◽  
Scale Data

AbstractLichens epiphytic on olive trees were used as biomonitors of sulphur dioxide pollution in La Spezia (Northern Italy). The method adopted was designed to avoid subjectivity at all stages, from the sampling strategy to data analysis. Thus, lichen data are expressed by an index that does not depend on any sensitivity scale; data analysis relies on multivariate methods of classification and ordination, and the pollution maps have been produced by automatic mapping programmes. The index, based on the frequency of species within a sampling grid, showed a very high statistical correlation with pollution data measured by recording gauges. The results of classification and ordination indicate that Parmelia caperata is the species with a distribution best related to the lichen index. The quality of air pollution data obtained from biomonitors is discussed.

scholarly journals Problems of mineral raw material losses of quality and quantity management in developing of large-scale complex-structure deposits.

2018 ◽  
Vol 56 ◽  
pp. 04003
Author(s):  
Sergei Tkach
Keyword(s):  
Large Scale ◽  
Raw Materials ◽  
Complex Structure ◽  
Raw Material ◽  
Qualitative And Quantitative ◽  
Mineral Raw Material ◽  
Regulatory Documents ◽  
Geological Conditions ◽  
High Degree ◽  
Very High

The article deals with the problems of mineral raw material losses of quality and quantity management in developing of large-scale complex-structure and composition deposits of solid minerals. It is shown that a very high degree of mining and geological conditions variability in time and space for the development of mining units is typical for such deposits. This significantly complicates the qualitative and quantitative operating losses setting and accounting of mineral raw materials during its extraction in the framework of existing general and industry regulatory documents. Conceptual principles for face-by-face operational setting of losses and impoverishment of minerals for the conditions of bulk mining of complex-structure deposits with the formation of gross mining flow with economically feasible and specified level of quality (the content of commercial and harmful components) are stated. These principles generally do not contradict effective instructions main provisions and are made to minimize the total operating losses during the processing of several mine sections (faces).

Toward very high horizontal resolution NWP over the alps: Influence of increasing model resolution on the flow pattern

2011 ◽  
Vol 59 (6) ◽  
pp. 1205-1235 ◽  
Author(s):  
Michał Z. Ziemiański ◽  
Marcin J. Kurowski ◽  
Zbigniew P. Piotrowski ◽  
Bogdan Rosa ◽  
Oliver Fuhrer
Keyword(s):  
Flow Pattern ◽  
Horizontal Resolution ◽  
Model Resolution ◽  
High Horizontal Resolution ◽  
The Alps ◽  
Very High

High-resolution numerical modelling of convective precipitation over Northern Italy

1992 ◽  
Vol 50 (1-3) ◽  
pp. 143-163 ◽  
Author(s):  
T. Paccagnella ◽  
S. Tibaldi ◽  
R. Buizza ◽  
S. Scoccianti
Keyword(s):  
High Resolution ◽  
Numerical Modelling ◽  
Northern Italy ◽  
Convective Precipitation

scholarly journals Parameter Modulation of Madden-Julian Oscillation Behaviors in BCC_CSM1.2: The Key Role of Moisture-Shallow Convection Feedback

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 241 ◽  
Author(s):  
Kai Huang ◽  
Hong-Li Ren ◽  
Xiangwen Liu ◽  
Pengfei Ren ◽  
Yuntao Wei ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Latin Hypercube Sampling ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Physical Parameters ◽  
Madden Julian Oscillation ◽  
Shallow Convection ◽  
Climate System Model ◽  
New Strategy

To reveal key parameter-related physical mechanisms in simulating Madden-Julian Oscillation (MJO), seven physical parameters in the convection and cloud parameterization schemes of Beijing Climate Center Climate System Model (BCC_CSM1.2) are perturbed with Latin hypercube sampling method. A new strategy is proposed to select runs with good and poor MJO simulations among 85 generated ones. Outputs and parameter values from good and poor simulations are composited separately for comparison. Among the seven chosen parameters, a decreased value of precipitation efficiency for shallow convection, higher values of relative humidity threshold for low stable clouds and evaporation efficiency for deep convective precipitation are crucial to simulate a better MJO. Changes of the three parameters act together to suppress heavy precipitation and increase the frequency of light rainfall over the Indo-Pacific region, supplying more moisture in low and middle troposphere. As a result of a wetter lower troposphere ahead of the MJO main convection, the low-level moisture preconditioning along with the leading shallow convection tends to be enhanced, favorable for MJO’s further development and eastward propagation. The MJO’s further propagation across the Maritime Continent (MC) in good simulations is accompanied with more land precipitation dominated by shallow convection. Therefore, the above-mentioned three parameters are found to be crucial parameters out of the seven ones for MJO simulation, providing an inspiration for better MJO simulation and prediction with this model. This work is valuable as it highlights the key role of moisture-shallow convection feedback in the MJO dynamics.

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