User Manual

Table of contents:

Search for data

The web site allows you to search in a local metadata catalogue that contains information on actual datasets that are archived in external archives. It is set up so that you can search for data by selecting the chemical/physical variable, the data location, the database that holds the data, the type of data, the data acquisition platform, and the data matrix. The meaning of each of these multiple selection boxes are explained through the respective "info" links. In addition to the boxes, it is possible to limit the search by date or time period, location and region.

Note how the number of "Datasets total" is changing when you change your selections and also the number entries in the selection boxes are counted.

You may select more than one option in the same box by holding down the "CTRL" button when selecting the options. Use the "Reset Search" button when you will perform a new search to ensure that the filter is empty.

Data retrieval modes

Two different data retrieval modes are available in the ACTRIS data portal:

The Google map

The map shows the location of the data matching your search criteria, and can be used to visualise the geographical distribution of variables and networks, and also identify collocation of variables. When up to 3 variables are selected, these will be displayed in different colour codes, depending on the number of variables available at the sites. For example: Limit the data search to "aerosol.absorption.coefficient", "aerosol.extinction.coefficient" & "black.carbon.concentration" and the resulting map will show these in different colours; one colour for each single variable, and each of the possible combinations.

The default background of the map is a simple colour scheme, but in the upper right corner this can be changed to satellite, hybrid and terrain to get an impression of the surrounding area of a site. Zooming is also possible.

By clicking the balloons, information about the site and all variables measured at this site will appear and it is possible to list the dataset matching the search criteria for this site.

Note that the symbol on the upper right of the map will display the map in a larger version for improved visualisations.

Limitations

It is not possible to display more than 700 locations at the same time. These locations are displayed using JavaScript technology and too many marker overlays (i.e. locations) will cause the script-engine in your browser to run very slow and hence cause bad performance.

Note that you can limit the search both in time and by user selected regions.

List datasets

Click the "List Datasets" button to see the list of datasets/data files matching your search criteria. For example: Limit the data search to latitudes between 45 and 50 and longitude between 10 and 15, and select ozone (O3.concentration) in the component box. Click "List Datasets" button and you will get an overview of the datasets matching the search criteria. It is possible to click on the column headers to sort the list of datasets, and also employ various filters to further limit the list, for example exclude certain database/project or only show the dataset not requiring password for download.

Download of data

If the contributing database/framework allows it, you may select one or several data sets/data files and it will be possible to download the datasets through the ACTRIS portal. The portal contains information on whether a dataset is available to unregistered users or not and a login-box appears for the different databases if login is required to download a certain dataset. No user-information is stored by the ACTRIS portal. You will receive a zip-file containing the requested datasets and a log-file describing the status for each file. If the database does not allow download of data through ACTRIS, you will instead be given a link (URL) to where the data may be found.

Plotting of data

You can plot data online by using the "Online analysis and plotting" mode. Only data archived in ACTRIS core data repositories can be selected (data archived in EBAS, EARLINET DB, and Cloudnet DB). After selecting the data of interest, you proceed via "List Datasets" as done for the data download. You will be directed to the "Datasets"-tab. Select the data and proceed with "Next". The data will now be downloaded from the respective database. After clicking on "Continue" the download page will open and report the state of the downloaded data. If all data was successfully downloaded, you can select the data you want to plot and click "Plot". An interactive window containing the requested plots will open.

The scaling is flexible to user needs, and you can change the scale of the x- and y-axis by entering new values into the respective fields and clicking "Replot". By clicking "Reset X/Y" the default axis values will be applied. The legend can be turned on and off for each plot by setting the checkbox "Legend". If multiple lines are plotted within one graph, you can select/deselect the lines by clicking "Data Series". Additional information (metadata) on the plotted data can be found under "View information". If you want to increase the size of one plot click "Zoom". The graph will now cover the entire size of the plot page. You can exit the zoom mode by clicking the "X" in the upper right corner.

Single plots can be saved by making a right click on the graph and select "Save Image As...".