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Description of the new Wetterzentrale

04-10-2016 20:31
This article describes the new features of the new Wetterzentrale. All items in the main menu at the top are described. The language can be changed by clicking on the flag at the upper right corner.

Top Karten

The 'Top Karten' section is the first menu item in the navigation bar on top. The weathermaps are split in two sections: one for global models and one for regional models that use the output from global models to simulate the flow in a smaller domain. Several new models have been added, such as the global model from the French weather service, Arpege. When a certain model is selected in the 'Top Karten' page, there is five blocks that are available to navigate through the maps.

Global/Regional model pages

Variables
This block shows all the availabe variables from a model: wetterzentrale uses freely available weather data from weather institutes around the world. For some institutes, such as the European Centre (ECMWF) or the UK Met Office, the amount of data is very limited. For other institutes, such as the German, Dutch and French meteorological institute there are many variables available. The currently selected variable will show up in black.
Region
In this block one can select a region. For the regional models the region which can be plotted is obviously limited by the model domain.
Run
Here one can select the run that one is interested in: if nothing is specified automatically the latest run that is available is shown, but one can switch to all runs from early that day or yesterday. When a run is selected which has not been updated today, the corresponding times above the maps will show up in red. The run that was most recently updated is denoted with a red outline.
Members
From some institutes there is not only a deterministic or operational (OP) model but also an ensemble model available. An ensemble model is essentially running the same model many times with slightly different input conditions, so that it becomes possible to give a probabalistic forecast that takes into account the chaotic nature of the atmosphere. For the models that have ensemble output available, there are some additional buttons shown here: when for example 'Temperature 850hPa' is selected, 'AVG' denotes the average and 'SPR' the spread or standard deviation of the temperature at 850 hPa of all the ensemble members. There is also the so-called spaghetti ('SPAG') plots which contain lines for of a certain variable for each ensemble member. These type of plots can be utilized to see the predictability of the atmosphere. When the output from all individual ensemble members is made available, these are denoted with 'PXX', where is XX is a perturbation identifier of that particular member.
Options
The first button in this box is a switch to activate the 'hover' behaviour of images: when it is activated, moving the mouse over an available time at the top of the map results in the map being changed to that particular time. This is particularly nice when all maps are already loaded in memory. This can be achieved by pressing 'Load all maps', below the map. Next to the 'hover' button, there is the possibility to adjust the time interval at which the maps are shown. Obivously the interval cannot be set smaller than the available model output interval, and therefore the buttons will only appear when it is possible to change to a smaller interval. Some buttons to share a page on the social media are also given here, together with the URL of the shown map. Finally there is the arrows below the map: one arrow to the left means one time step back and two arrows means back to the first available time step. The same holds for switching with the right arrows, but going forward in time.

Multimodel

The next item in the menu is the multi-model section. It has essentially the same setup as the Top Karten section, with variables and regions to be selected in the left panels. However, above the maps there is now a real date and time denoted, instead of the lead time of a certain forecast. This is because on this page we show all available model output for a certain time, variable and region. Therefore, the time cannot be changed with the arrows here, because the server has to know exactly which models are available. However, one still change the interval shown in the time bar. The maximum time that can be selected is given by the model that has the longest forecast range, which currently is GFS with 384 hours forecasts. When one selects a more detailed map, it is possible to compare regional models with each other. This is nice when for example precipitation is selected for Central Europe, and the the positioning of forecasted fronts can be studied.

Model status

On this page, the status of all models that are processed at wetterzentrale is shown. For a certain model and member the last date that the model was updated is shown. In the status column, one can see which particular map has been updated at what time. This can also give you an idea when to expect certain model output. Wetterzentrale is configured such that the maps are generated almost immediately after the model output is made available by the national weather institutes.

Bodenkarten/Fax

Here you can select the analysis of the surface weather made available by some meteorological institutes. In the old days, fronts were drawn by hand, but nowadays these maps are generated automatically. The maps from the UK Met office (UKMO) are perhaps most widely known and have been archived in wetterzentrale since 1998 and can be browsed in the archives. Other surface analysis from the Dutch, US and German meteorological office have also been archived.

Observations

Maps with observed values based on METAR and SYNOP data are generated about every 20 minutes on WZ. The time that the maps were last updated is given in the top right of a map. Similarly to the model output maps, on the left there are panels with variables and regions to navigate through the maps. The colours on the background are obtained by using the oacres algorithm from OpenGrads.

Diagrams

The ensemble diagrams and meteograms are also frequently used and are therefore given a seperate heading in the main menu, whereas previously they were reached within the Top Karten menu.

Models

Diagrams for several models can be reached from the 'model' section in the diagrams menu. Dependent on the model there is usually a 'meteogram' available and also for example the 'free atmosphere', 'surface values' plots from the old wetterzentrale are available here. Again there is blocks on the side:
Models
The first block shows the different model, where 'OP' denotes a operational (determenistic) run whereas 'ENS' is a ensemble run.
Variable
Just like in 'Top Karten', here you can select the variable of interest. The amount of variables depends on the model output that is made available.
Run
Similar as in Top Karten.
Options
If a interactive ensemble diagram is selected, it is possible to switch to a black or white background.
Options
The location search box can be used to select a city. Currently cities with more than 30000 people in Europe are available. For Germany the output is available with a resolution of 0.1 degree. All cities and zip codes in Germany are available and the nearest grid point to the selected location is chosen.

General

In an interactive meteogram one can click on a certain time step which brings you to the map from that time step. In all the diagrams the time axis is always given in the local time. In the interactive ensemble diagrams one can click on the time series, to see a map of a certain ensemble member. In the interactive ensemble diagrams you can also zoom in by dragging the mouse over the graph: a shaded grey region shows the extent of the zoom. When hovering over the different lines one can see the predicted value of each model. When the model output is available at the meteorological source, it is being made real-time available at wetterzentrale. Therefore if you see a non-complete forecast, it probably means that model is updating and you will have to wait until it is completely available. If you want to see a full forecast you have to look at one of the previous available runs.

Multi Model

The 'MULTI OP' shows every model that is available at wetterzentrale. This can be convenient to compare for example which model predicts the lowest or highest temperature: 2m Temp. Similar to the other diagrams, clicking on the line brings you the chosen model and variable.

Archive

The archive contains all the data that is archived at wetterzentrale.

Reanalysis

Reanalysis data are based on atmospheric models that assimilate observations and run the atmospheric equations on a certain grid. These data are available from the CFS reanalysis from NCEP, the ERA-interim reanalysis from the ECMWF and the NOAA 20th century reanalysis. The first two go back to 1979, whereas the latter goes all the way back to 1871.

FAX

The surface analysis of NCEP, UKMO and the DWD have been archived and are suitable to interpret the synoptic situations in the past. The NCEP archive goes back to 1999, the UKMO archive to 1998 and the DWD has only started in 2016.

GFS

The normal daily GFS 00Z output is archived at wetterzentrale since 1999.

Satellite

And archive of satellite images from EUMETSAT is available since 2016.

Weather data

Daily observations of weather stations in Germany and the Netherlands are available here. On top one can select the country, then one can select a certain period and station. Navigation through the dates can be done with the +/- buttons or by select a certain period with the dropdown lists. A summary of the several meteorological parameters is given the table on this page. The red or blue boxes with abbreviated names point to a table with highest or lowest values that have been reported for that station for the selected period. Furthermore a reanalysis map and maps with all observations are included. For the maps with observations one sometimes has to go back a few days, because these are plotted with a small delay to be sure all stations have reported when the map is generated.

Extremes

This page reports on extreme values measured at the selected station. First one selects a period and variable of interest and if the highest or lowest values should be given. When pressing 'load', a sorted table is shown with all the values for the chosen period and variable. One can click on one of the rows of the table to go that specific month to have an overview of the weather. The same can be achieved by clicking on the graph that is shown.

Station map

This map shows a geographic overview of the stations that reported on a certain day. Zooming in on the map reveals more stations and clicking on a station redirects you to the weather data of the chosen station.

Forum

A discussion forum about weather related topics.

About

A short explanation about the site and a contact form to ask questions or give remarks about the website.
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