Search ERA5 products

The following code shows how to search for ERA5 products in WASDI

Prerequisites

To run this code you need:

• A running Python 3.x Environment

• A valid WASDI Account

• A valid Config file

If this is not clear, you probably need to take a look to the Python Tutorial before.

Recipe

Note

Assume you have at least one workspace and you have configured it in the config.json file.

To search for ERA5 products, the following fields are mandatory:

• Collection: this is always going to be ‘ERA5’

• Start Date

• End Date

• Bounding Box

Two additional search parameters, specific for ERA5 products, are also mandatory:

• dataset

• aggregation: this is used to specify how you want your data to be stored into the downloaded products. “daily” will produce one file per day, while “monthly” will produce one file per each calendar month

The other search parameters that you need to specify will depend from the specific dataset you are interested in. For ERA5 pressure levels, ERA5 single leels and ERA5 Land, you will need to speficy:

• product type

• variables

• format

Additionally, for ERA5 pressure levels, you need to specify:

• pressure levels.

Note

The aforementioned search filters: dataset, aggregation, variables, format and pressure levels, should be added to a dictionary, that you can then pass to the method wasdi.searchEOImages through the optional parameter aoParams

Let’s see an example of code to search for ERA5 pressure levels products, which is the more comprehensive with respect to search parameters involved:

def get_pressure_levels_products():
    wasdi.wasdiLog("** get_pressure_levels_products **")

    # Create the Bounding Box Object: usually you will read it from the parameters
    oBBox = wasdi.getParameter("BBOX", None)

    # If it is null we show here how to initialize manually
    if oBBox is None:
        oBBox = {
            "northEast": {
                "lat": 44.2879447888337,
                "lng": 9.5
            },
            "southWest": {
                "lat": 43.5,
                "lng": 8.4
            }
        }

    # Set Start Date
    sStartDate = wasdi.getParameter("START_DATE", "2023-07-01")

    # Set End Date
    sEndDate = wasdi.getParameter("END_DATE", "2023-07-31")

    aoParams = {'dataset': "reanalysis-era5-pressure-levels",
                "pressureLevels": "1000",
                'variables': "RH",
                'format': "netcdf",
                'aggregation': "daily"}

    aoProductsFoundArray = wasdi.searchEOImages(
        sPlatform='ERA5',
        oBoundingBox=oBBox,
        sDateFrom=sStartDate,
        sDateTo=sEndDate,
        sProvider='AUTO',
        sProductType='reanalysis',
        aoParams=aoParams)


    if len(aoProductsFoundArray) > 0:
        # let's see the file name corresponding to the product we found:
        wasdi.wasdiLog(aoProductsFoundArray[0]["title"])

What it does:

• Initializes the input variables

• Searches for the corresponding results

• checks that at least one file is returned

• accesses a field in the results

Note

The developer can decide what is needed in the params.json file. If you decide to use the WASDI User Interface your parameters will be generated automatically by WASDI.

Note

With the WASDI User Interface you can use the renderAsStrings flag to ask WASDI to get all your parameters in String Format. In this case you will be responsible to convert your data in your code.

Note

The Bounding Box Format used here is the one used by the User Interface when renderAsStrings is missing or false. The Bounding Box format when renderAsStrings: true is “NORTH,WEST,SOUTH,EAST”.

Note

The Date is formatted by the User Interface as “YYYY-MM-DD”.