scholarly journals Dynamic downscaling of the ERA-40 data using a mesoscale meteorological model

2011 ◽  
Vol 12 (1) ◽  
pp. 183 ◽  
Author(s):  
A. PAPADOPOULOS ◽  
G. KORRES ◽  
P. KATSAFADOS ◽  
D. BALLAS ◽  
L. PERIVOLIOTIS ◽  
...  
Keyword(s):  
Dynamical Downscaling ◽  
Weather Forecasting ◽  
Quantitative Estimation ◽  
Three Dimensional ◽  
Atmospheric Model ◽  
Hydrological Models ◽  
Atmospheric Conditions ◽  
Meteorological Model ◽  
Medium Range ◽  
Forecasting System

A sophisticated downscaling procedure that was applied to reproduce high resolution historical records of the atmospheric conditions across the Mediterranean region is presented in this paper. This was accomplished by the dynamical downscaling of the European Center for Medium-Range Forecasts ERA-40 reanalyses with the aid of the atmospheric model of the POSEIDON weather forecasting system. The full three dimensional atmospheric fields with 6 hours of temporal resolution and the surface meteorological parameters at hourly intervals were produced for a 10-year period (1995-2004). The meteorological variables are readily available at 10 km resolution and may constitute the atmospheric forcing to drive wave, ocean hydrodynamic and hydrological models, as well as the baseline data for environmental impact assessment studies. A brief overview of the procedure and a quantitative estimation of the benefit of the new dynamical downscaling dataset are presented.

scholarly journals Improvements in medium range weather forecasting system of India

2014 ◽  
Vol 123 (2) ◽  
pp. 247-258 ◽  
Author(s):  
V S PRASAD ◽  
SAJI MOHANDAS ◽  
SURYA KANTI DUTTA ◽  
M DAS GUPTA ◽  
G R IYENGAR ◽  
...  
Keyword(s):  
Weather Forecasting ◽  
Medium Range ◽  
Forecasting System

scholarly journals A snowmelt runoff forecasting model coupling WRF and DHSVM

2009 ◽  
Vol 13 (10) ◽  
pp. 1897-1906 ◽  
Author(s):  
Q. Zhao ◽  
Z. Liu ◽  
B. Ye ◽  
Y. Qin ◽  
Z. Wei ◽  
...  
Keyword(s):  
Weather Forecasting ◽  
Atmospheric Model ◽  
Forecasting Model ◽  
Tianshan Mountain ◽  
Mountain Range ◽  
Snowmelt Runoff ◽  
Runoff Simulation ◽  
Limited Region ◽  
Runoff Forecasting ◽  
Forecasting System

Abstract. This study linked the Weather Research and Forecasting (WRF) modelling system and the Distributed Hydrology Soil Vegetation Model (DHSVM) to forecast snowmelt runoff. The study area was the 800 km2 Juntanghu watershed of the northern slopes of Tianshan Mountain Range. This paper investigated snowmelt runoff forecasting models suitable for meso-microscale application. In this study, a limited-region 24-h Numeric Weather Forecasting System was formulated using the new generation atmospheric model system WRF with the initial fields and lateral boundaries forced by Chinese T213L31 model. Using the WRF forecasts, the DHSVM hydrological model was used to predict 24 h snowmelt runoff at the outlet of the Juntanghu watershed. Forecasted results showed a good similarity to the observed data, and the average relative error of maximum runoff simulation was less than 15%. The results demonstrate the potential of using a meso-microscale snowmelt runoff forecasting model for forecasting floods. The model provides a longer forecast period compared with traditional models such as those based on rain gauges or statistical forecasting.

scholarly journals Three-dimensional visualization of ensemble weather forecasts – Part 1: The visualization tool Met.3D (version 1.0)

2015 ◽  
Vol 8 (7) ◽  
pp. 2329-2353 ◽  
Author(s):  
M. Rautenhaus ◽  
M. Kern ◽  
A. Schäfler ◽  
R. Westermann
Keyword(s):  
Visual Analysis ◽  
Weather Forecasting ◽  
Spatial Perception ◽  
Three Dimensional ◽  
Atmospheric Model ◽  
Weather Forecasts ◽  
Research And Teaching ◽  
Grid Topology ◽  
Ensemble Visualization ◽  
The Impact

Abstract. We present "Met.3D", a new open-source tool for the interactive three-dimensional (3-D) visualization of numerical ensemble weather predictions. The tool has been developed to support weather forecasting during aircraft-based atmospheric field campaigns; however, it is applicable to further forecasting, research and teaching activities. Our work approaches challenging topics related to the visual analysis of numerical atmospheric model output – 3-D visualization, ensemble visualization and how both can be used in a meaningful way suited to weather forecasting. Met.3D builds a bridge from proven 2-D visualization methods commonly used in meteorology to 3-D visualization by combining both visualization types in a 3-D context. We address the issue of spatial perception in the 3-D view and present approaches to using the ensemble to allow the user to assess forecast uncertainty. Interactivity is key to our approach. Met.3D uses modern graphics technology to achieve interactive visualization on standard consumer hardware. The tool supports forecast data from the European Centre for Medium Range Weather Forecasts (ECMWF) and can operate directly on ECMWF hybrid sigma-pressure level grids. We describe the employed visualization algorithms, and analyse the impact of the ECMWF grid topology on computing 3-D ensemble statistical quantities. Our techniques are demonstrated with examples from the T-NAWDEX-Falcon 2012 (THORPEX – North Atlantic Waveguide and Downstream Impact Experiment) campaign.

scholarly journals Exploring atmospheric boundary layer characteristics in a severe SO<sub>2</sub> episode in the north-eastern Adriatic

2009 ◽  
Vol 9 (13) ◽  
pp. 4467-4483 ◽  
Author(s):  
M. T. Prtenjak ◽  
A. Jeričević ◽  
L. Kraljević ◽  
I. H. Bulić ◽  
T. Nitis ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Static Stability ◽  
Pollution Sources ◽  
Small Scale ◽  
Dynamical Structure ◽  
Atmospheric Conditions ◽  
Meteorological Model ◽  
Industrial Areas

Abstract. Stable atmospheric conditions are often connected with the occurrence of high pollution episodes especially in urban or industrial areas. In this work we investigate a severe SO2 episode observed on 3–5 February 2002 in a coastal industrial town of Rijeka, Croatia, where very high daily mean concentrations (up to 353.5 μg m−3) were measured. The episode occurred under high air pressure conditions, which were accompanied with a fog and low wind speeds. Three air quality models (50-km EMEP model, 10-km EMEP4HR model and 1-km CAMx model) were used to simulate SO2 concentrations fields and to evaluate the relative contribution of distant and local pollution sources to observed concentrations. Results suggest that the episode was caused predominately by local sources. Furthermore, using three-dimensional, higher-order turbulence closure mesoscale meteorological model (WRF), the wind regimes and thermo-dynamical structure of the lower troposphere above the greater Rijeka area (GRA) were examined in detail. Modelled atmospheric fields suggest several factors whose simultaneous acting was responsible for elevated SO2 concentrations. Established small scale wind directions supported the transport of air from nearby industrial areas with major pollution sources towards Rijeka. This transport was associated with strong, ground-based temperature inversion and correspondingly, very low mixing layer (at most up to about 140 m). Additionally, the surface winds in Rijeka were light or almost calm thus, preventing ventilation of polluted air. Finally, a vertical circulation cell formed between the mainland and a nearby island, supported the air subsidence and the increase of static stability.

Impact of Coupling with an Ice–Ocean Model on Global Medium-Range NWP Forecast Skill

2018 ◽  
Vol 146 (4) ◽  
pp. 1157-1180 ◽  
Author(s):  
Gregory C. Smith ◽  
Jean-Marc Bélanger ◽  
François Roy ◽  
Pierre Pellerin ◽  
Hal Ritchie ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Large Scale ◽  
Weather Forecasting ◽  
Positive Impact ◽  
Weather Prediction ◽  
Ocean Model ◽  
Forecast Skill ◽  
Medium Range ◽  
Forecasting System ◽  
The Impact

The importance of coupling between the atmosphere and the ocean for forecasting on time scales of hours to weeks has been demonstrated for a range of physical processes. Here, the authors evaluate the impact of an interactive air–sea coupling between an operational global deterministic medium-range weather forecasting system and an ice–ocean forecasting system. This system was developed in the context of an experimental forecasting system that is now running operationally at the Canadian Centre for Meteorological and Environmental Prediction. The authors show that the most significant impact is found to be associated with a decreased cyclone intensification, with a reduction in the tropical cyclone false alarm ratio. This results in a 15% decrease in standard deviation errors in geopotential height fields for 120-h forecasts in areas of active cyclone development, with commensurate benefits for wind, temperature, and humidity fields. Whereas impacts on surface fields are found locally in the vicinity of cyclone activity, large-scale improvements in the mid-to-upper troposphere are found with positive global implications for forecast skill. Moreover, coupling is found to produce fairly constant reductions in standard deviation error growth for forecast days 1–7 of about 5% over the northern extratropics in July and August and 15% over the tropics in January and February. To the authors’ knowledge, this is the first time a statistically significant positive impact of coupling has been shown in an operational global medium-range deterministic numerical weather prediction framework.

scholarly journals Improving Operational Short- to Medium-Range (SR2MR) Streamflow Forecasts in the Upper Zambezi Basin and Its Sub-Basins Using Variational Ensemble Forecasting

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 188
Author(s):  
Rodrigo Valdés-Pineda ◽  
Juan B. Valdés ◽  
Sungwook Wi ◽  
Aleix Serrat-Capdevila ◽  
Tirthankar Roy
Keyword(s):  
Real Time ◽  
Optimal Parameter ◽  
Ensemble Forecasting ◽  
Hydrological Models ◽  
Streamflow Forecasting ◽  
Satellite Precipitation ◽  
Daily Streamflow ◽  
Medium Range ◽  
Streamflow Forecasts ◽  
Forecasting System

The combination of Hydrological Models and high-resolution Satellite Precipitation Products (SPPs) or regional Climatological Models (RCMs), has provided the means to establish baselines for the quantification, propagation, and reduction in hydrological uncertainty when generating streamflow forecasts. This study aimed to improve operational real-time streamflow forecasts for the Upper Zambezi River Basin (UZRB), in Africa, utilizing the novel Variational Ensemble Forecasting (VEF) approach. In this regard, we describe and discuss the main steps required to implement, calibrate, and validate an operational hydrologic forecasting system (HFS) using VEF and Hydrologic Processing Strategies (HPS). The operational HFS was constructed to monitor daily streamflow and forecast them up to eight days in the future. The forecasting process called short- to medium-range (SR2MR) streamflow forecasting was implemented using real-time rainfall data from three Satellite Precipitation Products or SPPs (The real-time TRMM Multisatellite Precipitation Analysis TMPA-RT, the NOAA CPC Morphing Technique CMORPH, and the Precipitation Estimation from Remotely Sensed data using Artificial Neural Networks, PERSIANN) and rainfall forecasts from the Global Forecasting System (GFS). The hydrologic preprocessing (HPR) strategy considered using all raw and bias corrected rainfall estimates to calibrate three distributed hydrological models (HYMOD_DS, HBV_DS, and VIC 4.2.b). The hydrologic processing (HP) strategy considered using all optimal parameter sets estimated during the calibration process to increase the number of ensembles available for operational forecasting. Finally, inference-based approaches were evaluated during the application of a hydrological postprocessing (HPP) strategy. The final evaluation and reduction in uncertainty from multiple sources, i.e., multiple precipitation products, hydrologic models, and optimal parameter sets, was significantly achieved through a fully operational implementation of VEF combined with several HPS. Finally, the main challenges and opportunities associated with operational SR2MR streamflow forecasting using VEF are evaluated and discussed.

scholarly journals Sensitivity, Structure, and Dynamics of Singular Vectors Associated with Hurricane Helene (2006)

2012 ◽  
Vol 69 (2) ◽  
pp. 675-694 ◽  
Author(s):  
Simon T. K. Lang ◽  
Sarah C. Jones ◽  
Martin Leutbecher ◽  
Melinda S. Peng ◽  
Carolyn A. Reynolds
Keyword(s):  
Three Dimensional ◽  
Growth Dynamics ◽  
Ensemble Forecasts ◽  
Weather Forecasts ◽  
Singular Vectors ◽  
Medium Range ◽  
Flow Features ◽  
Forecasting System ◽  
Diabatic Processes ◽  
The Impact

Abstract The sensitivity of singular vectors (SVs) associated with Hurricane Helene (2006) to resolution and diabatic processes is investigated. Furthermore, the dynamics of their growth are analyzed. The SVs are calculated using the tangent linear and adjoint model of the integrated forecasting system (IFS) of the European Centre for Medium-Range Weather Forecasts with a spatial resolution up to TL255 (~80 km) and 48-h optimization time. The TL255 moist (diabatic) SVs possess a three-dimensional spiral structure with significant horizontal and vertical upshear tilt within the tropical cyclone (TC). Also, their amplitude is larger than that of dry and lower-resolution SVs closer to the center of Helene. Both higher resolution and diabatic processes result in stronger growth being associated with the TC compared to other flow features. The growth of the SVs in the vicinity of Helene is associated with baroclinic and barotropic mechanisms. The combined effect of higher resolution and diabatic processes leads to significant differences of the SV structure and growth dynamics within the core and in the vicinity of the TC. If used to initialize ensemble forecasts with the IFS, the higher-resolution moist SVs cause larger spread of the wind speed, track, and intensity of Helene than their lower-resolution or dry counterparts. They affect the outflow of the TC more strongly, resulting in a larger downstream impact during recurvature. Increasing the resolution or including diabatic effects degrades the linearity of the SVs. While the impact of diabatic effects on the linearity is small at low resolution, it becomes large at high resolution.

THE ECMWF MULTI-TASKING WEATHER PREDICTION MODEL

1991 ◽  
Vol 02 (01) ◽  
pp. 158-186 ◽  
Author(s):  
A.J. SIMMONS ◽  
D. DENT
Keyword(s):  
Weather Prediction ◽  
Atmospheric Model ◽  
Horizontal Resolution ◽  
General Introduction ◽  
Weather Forecasts ◽  
Operational Forecasting ◽  
Medium Range ◽  
Computational Aspects ◽  
Forecasting System ◽  
And Performance

A general introduction to numerical weather prediction is given. The development of the operational forecasting system of the European Centre for Medium-Range Weather Forecasts is summarized, and some results are presented illustrating sensitivity to the horizontal resolution of the atmospheric model, the factor which is most significant in determining computational needs. The spectral method used for the horizontal discretization is described, and computational aspects of its implementation on CRAY-1 and CRAY X-MP machines are discussed. The organization of the multi-tasking employed in the model is presented, and performance figures are given. There is a brief concluding discussion of some likely future developments in medium-range weather prediction.

scholarly journals A comparison between ensemble and deterministic hydrological forecasts in an operational context

2011 ◽  
Vol 29 ◽  
pp. 85-94 ◽  
Author(s):  
M.-A. Boucher ◽  
F. Anctil ◽  
L. Perreault ◽  
D. Tremblay
Keyword(s):  
Weather Forecasting ◽  
Ensemble Forecasts ◽  
Meteorological Model ◽  
Resources Management ◽  
Weather Forecasts ◽  
Hydropower Production ◽  
Forecasting System ◽  
The Cost ◽  
Ensemble Weather Forecasts

Abstract. Ensemble forecasts can greatly benefit water resources management as they provide useful information regarding the uncertainty of the situation at hand. However, weather forecasting systems are evolving and the cost for reanalysis and reforecasts is prohibitive. Consequently, series of ensemble weather forecasts from a particular version of the forecasting system are often short. In this case study, we consider a hydrological event that took place in 2003 on the Gatineau watershed in Canada and caused management difficulties in a hydropower production context. The weather ensemble forecasting system in place at that time is now obsolete, but we show that with minimal post-processing of the forecasts, it is still beneficial to exploit ensemble rather than deterministic forecasts, even if the latter emerge from a more advanced meteorological model and possess superior spatial resolution.

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