# HY-2C Calibration Microwave Radiometer
*sensor . products*

Passive microwave radiometer flown on HY-2C for wet-tropospheric correction of altimetry observations.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cast
- **sensor**: {"instrument_family":"radiometer","measurement_principle":"passive","frequency_bands_ghz":[18.7,23.8,37],"scan_type":"static","notes":"Frequencies are representative of HY-2 correction microwave radiometers; full HY-2C instrument research should confirm per-channel configuration."}
- **entity type**: sensor
- **last verified date**: 2026-06-16
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cast
- **attributes**: {"kind":"sensor","product_status":"operational","deployment_context":"orbital","manufacturer":"cast","description":"Passive microwave radiometer flown on HY-2C for wet-tropospheric correction of altimetry observations.","sensor":"{\"instrument_family\":\"radiometer\",\"measurement_principle\":\"passive\",\"frequency_bands_ghz\":[18.7,23.8,37],\"scan_type\":\"static\",\"notes\":\"Frequencies are representative of HY-2 correction microwave radiometers; full HY-2C instrument research should confirm per-channel configuration.\"}"}
- **relevance**: in-scope

## Editorial
HY-2C Calibration Microwave Radiometer is the correction microwave radiometer payload on the HY-2C ocean dynamic environment satellite [^wmo-oscar-hy2c]. It is a fixed-beam passive microwave radiometer used to correct radar-altimeter wet path delay and wet tropospheric path delay [^mdpi-hy2c-cmr][^mdpi-hy2-cmr-constellation]. The instrument uses 18.7, 23.8, and 37 GHz channels for atmospheric correction of the altimeter measurement path [^mdpi-hy2c-cmr]. It performs passive microwave radiometry demonstrated on HY-2C for altimetry correction and on-orbit calibration work [^mdpi-hy2-cmr-constellation]. The instrument has been active on HY-2C since December 2020, with estimated or assumed end of life at or beyond 2026 [^wmo-oscar-hy2c].

## Compositional position
- hy-2c (missions) --[mission_payloads]--> HY-2C Calibration Microwave Radiometer

## Sources
- [wmo-oscar-hy2c] | WMO OSCAR satellite record: HY-2C | https://space.oscar.wmo.int/satellites/view/hy_2c | tier=community | accessed=2026-06-16
- [mdpi-hy2c-cmr] | Brightness Temperature and Wet Tropospheric Correction of HY-2C CMR | https://www.mdpi.com/2072-4292/15/14/3633 | tier=peer-reviewed | accessed=2026-06-16 | published=2023-07-17
- [mdpi-hy2-cmr-constellation] | On-Orbit Calibration Method for Correction Microwave Radiometer of the HY-2 Satellite Constellation | https://www.mdpi.com/2072-4292/15/24/5643 | tier=peer-reviewed | accessed=2026-06-16 | published=2023-12-07

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Source: https://eo-atlas.org/products/sensor/hy-2c-cmr
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