# SAPHIR
*sensor . products*

SAPHIR is a passive microwave humidity sounder for tropical atmospheric profiling.

## Specifications
- **manufacturer**: cnes
- **deployment context**: orbital
- **sensor**: {"instrument_family":"radiometer","measurement_principle":"passive","frequency_bands_ghz":[183.31],"scan_type":"cross-track","channel_count":6,"swath_km":1700,"ifov_km_range":"10"}
- **entity type**: sensor
- **last verified date**: 2026-06-11
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cnes
- **mass kg**: 18
- **avg power w**: 30
- **data rate mbps**: 0.0015
- **attributes**: {"kind":"sensor","manufacturer":"cnes","description":"SAPHIR is a passive microwave humidity sounder for tropical atmospheric profiling.","deployment_context":"orbital","sensor":"{\"instrument_family\":\"radiometer\",\"measurement_principle\":\"passive\",\"frequency_bands_ghz\":[183.31],\"scan_type\":\"cross-track\",\"channel_count\":6,\"swath_km\":1700,\"ifov_km_range\":\"10\"}"}
- **technology**: microwave-radiometry

## Editorial
SAPHIR (Sondeur Atmospherique du Profil d'Humidite Intertropicale par Radiometrie) is a cross-track passive microwave humidity sounder developed by CNES for the Megha-Tropiques mission, a joint CNES-ISRO satellite dedicated to tropical atmospheric observation.[^wmo-oscar-saphir][^mosdac-megha-payloads] The instrument operates six channels clustered around the 183.311 GHz water-vapour absorption line at offsets of +/-0.20, +/-1.10, +/-2.80, +/-4.20, +/-6.80, and +/-11.0 GHz, enabling vertical humidity profiling in the tropical troposphere.[^wmo-oscar-saphir] IFOV is 10 km at nadir and swath width is 1700 km.[^wmo-oscar-saphir] Instrument mass is 18 kg and average power consumption is 30 W.[^wmo-oscar-saphir]

Megha-Tropiques operated in a low-inclination orbit of 19 degrees, providing more frequent revisits over the tropics than sun-synchronous polar-orbiting platforms.[^eoportal-megha-tropiques] The mission was declared nominal through December 2021.[^eoportal-megha-tropiques] Data availability from SAPHIR was reduced from late 2018 onward due to instrument degradation.[^aeris-saphir]

## Compositional position
- megha-tropiques (missions) --[mission_payloads]--> SAPHIR

## Sources
- [wmo-oscar-saphir] | WMO OSCAR - SAPHIR instrument record | https://space.oscar.wmo.int/instruments/view/saphir | tier=agency-doc | accessed=2026-06-11
- [aeris-saphir] | SAPHIR instrument overview, AERIS data center | https://www.aeris-data.fr/en/projects/saphir/ | tier=operator-engineering | accessed=2026-06-11
- [eoportal-megha-tropiques] | Megha-Tropiques Mission Overview, eoPortal | https://www.eoportal.org/satellite-missions/megha-tropiques | tier=community | accessed=2026-06-11
- [mosdac-megha-payloads] | Megha-Tropiques Payloads, ISRO MOSDAC | https://www.mosdac.gov.in/megha-tropiques-payloads | tier=agency-doc | accessed=2026-06-11

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Source: https://eo-atlas.org/products/sensor/saphir
Maintainer: SpectraWorks B.V. (CC-BY 4.0)