Web-API FAQ - NEW

20 queued requests per user

Follow the instructions here: https://pypi.org/project/ecmwf-api-client/

We have limited the time period selection for retrievals from the Web User Interface (UI), in order to  improve the service performance but also to help the users to learn how to submit efficient MARS request

This interface will help you to navigate through the public datasets in a dynamic and user-friendly way.

Problem

ERROR 17X (DATASET_PHASED_OUT)

Status of the request: rejected

Problem

ecmwf.API error 1: User has no access to services mars

Solution

Problem

ERROR 70 (DHS_MOVE_TO_BOLOGNA)

Status of the request: rejected

Problem

ERROR 700: The public datasets service will not be available during the DHS Move. For more information see https://confluence.ecmwf.int/x/jSKADQ

Status of the request: rejected

Problem

WARNING: httplib2.URLError received None <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed

Solution

Please use the ECMWF Support Portal if you have any issue with the system. Problem accessing our products support

When you fill the form, please add the following information:

1. Userid or mail address

Problem

ERROR 192 ERA 5 migrated to CDS

Status of the request: rejected

Problem

ERROR 193 CAMS datasets migrated to CDS

Status of the request: rejected

Problem

ERROR 79 MARS_EXPECTED_FIELDS

This message will come with something like

Problem

ERROR 9 DATA_NOT_YET_AVAILABLE

This message will come with something like

Problem

ERROR 6 MARS_CACHE_CORRUPTION

This message will come with something like

You can list data in the Access MARS service through ECMWF WebAPI using a Python script. This will allow any user with access to MARS to list data. The syntax is

Problem

WARNING: HTTP received 429
{
  "message": "API rate limit exceeded.",
  "type": "rate_limit_exceeded",
  "documentation_url": "https://confluence.ecmwf.int/display/WEBAPI"
}
Error contacting the WebAPI, retrying in 60 seconds ...

Solution

• Yes,You only have to add in your request "format" : "netcdf"

Yes,If you have already set the "grid" keyword in your request, you can add the "area" : "coordinates" keyword

Solution

Web API python client, request is checked for validity and is visible in API job list.

In my Job List the target file can not be downloaded, the result column shows "download expired" 

Reasons:

If you are using the Web API Python client (Web API Downloads), the client will send a DELETE command to the server once the transfer of the target file has finished successfully. The file should be in your filesystem with the name specified on the 'target' keyword.

Some users might be used to the full MARS client to access MARS. There are some limitations if you use the Access MARS service compared to the full MARS client

In MARS activity you can see only the requests that are currently "active" on the Web API level. A "queued" request is not visible in MARS activity

Problem

ERROR 103 (FIELDS_LIMIT_EXCEEDED)

Status of the request: rejected

Problem

ERROR 15X (DATASET_LIMIT_EXCEEDED)

Status of the request: rejected

Problem

ERROR 99

Solution

Problem

ecmwf.API error 1: Resource not found: datasets/NAME

Solution

Problem

WARN - connect : marsxyz 9000 (Connection refused)

The application is attempting to connect to one of the MARS  archive servers, which is down

Problem

ERROR 191 C3S Seasonal migrated to CDS

Status of the request: rejected

Problem

Messages starting with Failed HPSS call: n = ::hpss_Read(fd_,buffer,... are HPSS errors. The actual message text can vary but they usually mean that the data is unavailable from tapes for some time.

Solution

Problem

ecmwf.API error 1: Resource not found: datasets None

Solution

Problem

grib_to_netcdf: "Wrong number of fields... Try using the -T option"

The request fail when it is trying to convert the GRIB file to netCDF.

Problem

FATAL - Signal 15 received

Internal MARS problem.

Problem

Error messages starting with Assertion failed: followed by offset[i] > offset[i-1] or handle[n] != 0 hint at an attempt to retrieve the same field more than once, e.g. by specifying param=z/t/z or step=24/48/24. The actual message varies depending on how exactly the data is retrieved. 

Solution

Problem

Error contacting the WebAPI, retrying in 60 seconds ...

Solution

Problem

ERROR 101 (USER_QUEUED_LIMIT_EXCEEDED)

Status of the request: rejected

Problem

ERROR 102 (SYSTEM_QUEUED_LIMIT_EXCEEDED)

Status of the request: rejected

Problem

ERROR 3 (or 4 or 5)  MARS_RESTRICTED_ACCESS_TO_XXX

You are trying to access restricted data.

Problem

ecmwfapi.api.APIException: u'ecmwf.API error 1: Invalid or missing key or token'

Solution

Problem

WARNING: httplib2.URLError received None <urlopen error unknown url type: https>

Solution

Problem

mars - ERROR - 20190507.231202 - Request validation failed:
mars - ERROR - 20190507.231202 - restricted access to valid data.
mars - ERROR - 20190507.231202 - For more information, look at 
mars - ERROR - 20190507.231202 - https://confluence.ecmwf.int/display/UDOC/MARS+access+restrictions#valid.

Problem

Maximum retrieve size XX.XX GB reached. Please split your request.

Solution

Problem

My requests is queued for a long period of time.

Solution

Problem

My request has aborted.

Solution

Problem

UserError: Cannot retrieve more than 600,000 fields in one request via the WebAPI. Please, split your request

Solution

Some applications require the input files separated each on them containing one single parameter or step. This is not the most efficient way to retrieve it from MARS but the solution is very easy.

The transformation and interpolation is done by MARS using a library called MIR.

MARS interpolation with MIR

 If you wish to cancel a request please visit  your job list and click on the cancel button.

Your job list can be used for tracing back tour requests.

Metview versions from 4.4.3 onwards have support for the Web API service. More information: Using the MARS Web API from Metview. 

There are limitations on the total number of fields

You can find some examples here Retrieval efficiency.

Related articles

• Page:
  How to use Python requests to list data from the Access MARS service - Web API FAQ

You can use the Access MARS service through ECMWF WebAPI using a Python script. This will allow any user with access to MARS to retrieve data. The syntax is

Yes, you can only access datasets that you have been given access rights to.

See https://www.ecmwf.int/en/forecasts/datasets/access-archive-datasets/ecmwf-web-api

This is extremely useful if you wish to download large amounts of data. Follow the Guidelines to write efficient MARS requests

Our archive consists of several Public Datasets and each of them has its own availability.

Licensed and Member State users have access to MARS.

You may start with the examples available on TIGGE sample scripts or by creating your request using our Datasets Web Interface.

Presumably, before you start using Web-API you need to be able to write your own "request" which describes the data you wish to download

The  request may take some time ( from some minutes, to many hours ) to complete, depending on some factors and limitations.

MARS stands for Meteorological Archive System. MARS is the ECMWF archival system which handles the requests that are submitted externally through the Web-API