Difference between revisions of "ECMWF-ENS(eng)"

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|Description
 
|Description
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|The Global Forecast System (GFS) is a weather forecast model produced by the National Centers for Environmental Prediction (NCEP). Dozens of atmospheric and land-soil variables are available through this dataset, from temperatures, winds, and precipitation to soil moisture and atmospheric ozone concentration. The entire globe is covered by the GFS at a base horizontal resolution of 18 miles (28 kilometers) between grid points, which is used by the operational forecasters who predict weather out to 16 days in the future. Horizontal resolution drops to 44 miles (70 kilometers) between grid point for forecasts between one week and two weeks.
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|For the medium-range forecasts an ensemble of 52 individual ensemble members are created twice a day. One member is at a higher spatial resolution than the other members (called the HRES at ECMWF), its initial state is the most accurate estimate of the current conditions and it uses the currently best description of the model physics.  
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The GFS model is a coupled model, composed of four separate models (an atmosphere model, an ocean model, a land/soil model, and a sea ice model), which work together to provide an accurate picture of weather conditions. Changes are regularly made to the GFS model to improve its performance and forecast accuracy. It is a constantly evolving and improving weather model. Gridded data are available for download through the NOAA National Operational Model Archive and Distribution System (NOMADS). Forecast products and more information on GFS are available at the GFS home page.
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Prior to January 2003, the GFS was known as the GFS Aviation (AVN) model and the GFS Medium Range Forecast (MRF) model. GFS-AVN and MRF products are a collection from NCEP's NOAAPort. Grids, domains, run frequencies, and output frequencies have changed over the years.
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The HRES provides a highly detailed description of future weather and averaged over many forecasts it is the most accurate forecast for a certain period, which is currently estimated as 10 days for large scale properties of the atmosphere. However for any particular forecast it may not be the most skilful member of the ensemble. Also when viewed in isolation it cannot provide an estimate of forecast uncertainty or confidence.
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Another member of the ensemble (CNTL: Control forecast) is at a lower spatial resolution than the HRES but at that lower resolution it utilises the most accurate estimate of the current conditions and the currently best description of the model physics. Its significance for the ensemble is that it provides the unperturbed member to which the perturbations for the remainder of the ensemble members are applied.
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The perturbed members (50 members) are similar to the CNTL but their initial states and model physics have been perturbed to explore the currently understood range of uncertainty in the observations and the model. They provide a range of possible future weather states. When averaged over many forecasts (although not necessarily for any particular forecast) these have lower skill than either the HRES or the CNTL.  However they do provide an estimate of the forecast uncertainty or confidence.
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The CNTL and perturbed members are continued beyond fifteen days at a reduced horizontal resolution.
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The sections below highlight the variety of ECMWF medium-range forecast products.
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Depending on who you are, you will be able to access different types of products. The linked charts are only displayed if you have correct access rights for that product.
  
 
More info at: [https://www.ecmwf.int/en/elibrary/19749-part-v-ensemble-prediction-system ECMWF-ENS documentation on line]
 
More info at: [https://www.ecmwf.int/en/elibrary/19749-part-v-ensemble-prediction-system ECMWF-ENS documentation on line]
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|[[File:all_leg_ecmwfens.JPG|800px|thumb|centre|Legend]]
 
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|Screenshot
 
|[[File:all_ecmwfens2.JPG|1000px|thumb|centre|]]
 
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|[[File:all_leg_ecmwfens2.JPG|800px|thumb|centre|Legend]]
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|[[File:all_leg_ecmwfens21.JPG|800px|thumb|centre|Legend]]
 
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|style="background-color: grey;"| Properties
 
|style="background-color: grey;"| Properties
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|Available accumulations
 
|Available accumulations
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|3, 6, 12, 24, 48 and 72 hours
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|Amount of accumulated rainfall over the forecast range of 10 days for the median of the ensemble ECMWF forecast; Probability [%] of exceeding 50-150-300 mm of accumulated rainfall over the forecast range of 10 days for the ensemble ECMWF forecast.
 
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|Available interpolation algorithms
 
|Available interpolation algorithms

Latest revision as of 15:56, 24 November 2020

[Home] - [Forecast Models]


Layer name ECMWF-ENS
Tag Meteorological Models
Folder
Source ECMWF
Description For the medium-range forecasts an ensemble of 52 individual ensemble members are created twice a day. One member is at a higher spatial resolution than the other members (called the HRES at ECMWF), its initial state is the most accurate estimate of the current conditions and it uses the currently best description of the model physics.

The HRES provides a highly detailed description of future weather and averaged over many forecasts it is the most accurate forecast for a certain period, which is currently estimated as 10 days for large scale properties of the atmosphere. However for any particular forecast it may not be the most skilful member of the ensemble. Also when viewed in isolation it cannot provide an estimate of forecast uncertainty or confidence.

Another member of the ensemble (CNTL: Control forecast) is at a lower spatial resolution than the HRES but at that lower resolution it utilises the most accurate estimate of the current conditions and the currently best description of the model physics. Its significance for the ensemble is that it provides the unperturbed member to which the perturbations for the remainder of the ensemble members are applied.

The perturbed members (50 members) are similar to the CNTL but their initial states and model physics have been perturbed to explore the currently understood range of uncertainty in the observations and the model. They provide a range of possible future weather states. When averaged over many forecasts (although not necessarily for any particular forecast) these have lower skill than either the HRES or the CNTL. However they do provide an estimate of the forecast uncertainty or confidence.

The CNTL and perturbed members are continued beyond fifteen days at a reduced horizontal resolution.

The sections below highlight the variety of ECMWF medium-range forecast products.

Depending on who you are, you will be able to access different types of products. The linked charts are only displayed if you have correct access rights for that product.

More info at: ECMWF-ENS documentation on line

Screenshot
All ecmwfens.JPG
Legend
Screenshot
All ecmwfens2.JPG
Legend
Properties
Available variables Rainfall, 2-metre Temperature, 10-metre wind, 2-metre relative humidity
Available accumulations Amount of accumulated rainfall over the forecast range of 10 days for the median of the ensemble ECMWF forecast; Probability [%] of exceeding 50-150-300 mm of accumulated rainfall over the forecast range of 10 days for the ensemble ECMWF forecast.
Available interpolation algorithms
Available filters
Spatial aggregations NUTS2


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