---
title: "Geophysical observation variables catalog from WMO OSCAR/Space"
method: GET
path: "/api/v1/environment/oscar-wmo/variables"
tags: ["Environment"]
---

# Geophysical observation variables catalog from WMO OSCAR/Space

`GET /api/v1/environment/oscar-wmo/variables`

Return a filtered page of the WMO OSCAR/Space observation variables catalog. The catalog covers 237 geophysical variables such as sea surface temperature, atmospheric temperature, aerosol optical depth, soil moisture, biomass, sea ice extent, cloud top height. A subset carry the GCOS Essential Climate Variable (ECV) flag. Each variable publishes the 5-step relative capability rating criteria and the list of instruments that measure it. Attribution: WMO OSCAR/Space (World Meteorological Organization).

## Query parameters

- `q` string, nullable — Case-insensitive substring search across variable name.
- `limit` integer — Maximum number of records to return (1 to 500).
- `offset` integer — Zero-indexed offset into the filtered result list.

## Response `200`

Paginated list of variable records matching the requested filters, with total and filtered counts.

- EnvelopeOscarVariableListPayload
  - `data` OscarVariableListPayload, required — Variable catalog listing with pagination metadata.
    - `variables` OscarVariable[], required — Variable records matching the requested filters, paginated.
      - `variable_id` integer, nullable — Upstream numeric variable identifier.
      - `slug` string, nullable — URL-safe slug (primary key for detail lookup).
      - `name` string, nullable — Display name of the observation variable (e.g. `Accumulated precipitation`).
      - `ecv_variable` boolean, nullable — True when this variable is a GCOS Essential Climate Variable.
      - `sorting_criteria` string, nullable — Plain-text 5-step capability rating criteria (HTML stripped).
      - `sorting_criteria_html` string, nullable — Raw HTML rating-criteria table as published upstream.
      - `instruments` OscarVariableInstrumentRef[], nullable — Instruments that measure this variable, with capability ratings where published.
        - `instrument_id` integer, nullable — Upstream numeric instrument identifier.
        - `instrument_slug` string, nullable — Instrument slug for `/instruments/{slug}` lookups.
        - `instrument_name` string, nullable — Short instrument name or acronym.
        - `instrument_fullname` string, nullable — Full descriptive instrument name.
        - `providing_agency` string, nullable — Agency providing this instrument.
        - `capability_rating` string, nullable — Relative 5-step capability rating for this instrument measuring this variable (e.g. `3 - high`). Published upstream as `relevancy`.
    - `total` integer, required — Total number of variables across the entire catalog (before filtering).
    - `filtered` integer, required — Number of variables after applying client-side filters.
    - `limit` integer, required — Page size requested by the client.
    - `offset` integer, required — Zero-indexed starting offset requested by the client.
    - `notes` string, nullable — Advisory notes about this response.
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

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