# HY Ultraviolet Imaging and Calibration Sensor
*sensor . products*

Ultraviolet imaging and calibration sensor flown on HY-1D.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cast
- **sensor**: {"instrument_family":"passive-optical","measurement_principle":"passive","spec_disclosure":"undisclosed"}
- **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":"Ultraviolet imaging and calibration sensor flown on HY-1D.","sensor":"{\"instrument_family\":\"passive-optical\",\"measurement_principle\":\"passive\",\"spec_disclosure\":\"undisclosed\"}"}
- **relevance**: in-scope

## Editorial
The HY Ultraviolet Imaging and Calibration Sensor (UVI) is a passive UV-A instrument flown on the HY-1D ocean colour satellite.[^eoportal-hy1cd] It carries two UV-A spectral bands centred at approximately 355 nm (345-365 nm range) and 385 nm (375-395 nm range), each with approximately 20 nm bandwidth.[^eoportal-hy1cd] Spatial resolution and swath parameters are not publicly disclosed by the operator.[^eoportal-hy1cd][^wmo-oscar-hy1d] The UVI serves two documented functions in the HY-1D payload complement: providing atmospheric correction inputs for turbid coastal water colour retrieval, and supporting vicarious calibration of the co-flown Chinese Ocean Colour and Temperature Scanner (COCTS).[^scidir-uvi-cal-2025][^eoportal-hy1cd] Vicarious calibration using the UVI has been validated against in-situ measurements for ocean colour retrieval on the HY-1C mission.[^scidir-uvi-cal-2025]

## Compositional position
- hy-1d (missions) --[mission_payloads]--> HY Ultraviolet Imaging and Calibration Sensor
- hy-1c (missions) --[mission_payloads]--> HY Ultraviolet Imaging and Calibration Sensor

## Sources
- [eoportal-hy1cd] | HY-1C/1D mission page, eoPortal | https://www.eoportal.org/satellite-missions/hy-1c-1d | tier=operator-engineering | accessed=2026-06-16
- [wmo-oscar-hy1d] | WMO OSCAR satellite record: HY-1D | https://space.oscar.wmo.int/satellites/view/hy_1d | tier=community | accessed=2026-06-16
- [wmo-oscar-hy1c] | WMO OSCAR satellite record: HY-1C | https://space.oscar.wmo.int/satellites/view/hy_1c | tier=community | accessed=2026-06-16
- [scidir-uvi-cal-2025] | System vicarious calibration and ocean color retrieval from the HY-1C UVI, ScienceDirect 2025 | https://www.sciencedirect.com/science/article/pii/S1569843225000640 | tier=peer-reviewed | accessed=2026-06-16
- [wp-hy-satellite] | Haiyang (satellite), Wikipedia | https://en.wikipedia.org/wiki/HY_(satellite) | tier=community | accessed=2026-06-16

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