HAWCSat

Quick facts

Overview

Summary

Mission Capabilities

HAWCSat will carry two instruments, the Aerosol Limb Imager (ALI) and the Spatial Heterodyne Observation of Water (SHOW) instrument. ALI will observe scattered sunlight on the atmospheric limb to resolve information on stratospheric aerosol distribution including spectral extinction coefficient and particle size. SHOW has been developed to measure the vertical distribution of water vapour in the upper troposphere and lower stratosphere.

Performance Specifications

ALI operates in 10 channels, in the 610 - 1560 nm spectral range, with a swath width of 200 km and a vertical resolution of 0.25 km. SHOW operates in a spectral range of 1363 nm - 1366 nm to observe the vibrational band of water, and aims to achieve a vertical resolution of 500 m with a 63 km swath width. HAWCSat will operate in polar orbits with an altitude of 450 km.

Overview

The High altitude Aerosols, Water Vapour and Clouds (HAWC) mission is an Earth observation program currently under development by the Canadian Space Agency (CSA). The HAWCSat satellite will carry two Canadian developed instruments, the Aerosol Limb Imager (ALI), and the Spatial Heterodyne Observation of Water (SHOW) instrument. The mission aims to provide data supporting extreme weather prediction, climate modelling and disaster monitoring by measuring the size and density of aerosol particles, as well as of water vapour in the upper layers of the troposphere. Measurement of atmospheric aerosols will further strengthen existing climate models, as aerosol and cloud interactions remain a source of uncertainty in the field. HAWCSat will form part of the Atmosphere Observing System (AOS), which is an international constellation of four satellites: AOS-Storm and AOS-Sky, led by the United States, HAWCSat, and the Japan-led Precipitation Measurement Mission (PMM). The constellation aims to examine the links between atmospheric aerosols, clouds, convection and precipitation, as well as measure the vertical movement of water and ice within clouds. Additionally, AOS will produce global measurements linking the physical properties of clouds to heat transfer and radiation in Earth’s atmosphere.

Launch

The HAWC mission satellite component, HAWCSat, is planned for launch in 2031, and will operate alongside AOS-Sky as the polar orbiting components of AOS, at an altitude of 450 km.

Mission Status

• October 21, 2022: The Canadian government announced its funding for Canada’s contribution, a $200 million investment in the HAWCSat program. 3)
• October 18, 2022: Canada’s involvement in the NASA-led Atmospheric Observing System (AOS) was announced, with three instruments and one satellite planned for deployment in 2031. 3)
• September 2014: The Aerosol Limb Imager was tested aboard a Canadian stratospheric balloon flight, with analysis of the hyperspectral imaging conducted indicating a high image quality. 2)

Sensor Complement

Aerosol Limb Imager (ALI)

ALI is a 10 channel radiometer operating in the 610 - 1560 nm spectral range. ALI is designed to have a swath width of 200 km and a vertical resolution of 0.25 km, achieved through a limb scanning imaging method. This means that the instrument will observe scattered sunlight on the atmospheric limb to resolve information on stratospheric aerosol distribution, including spectral extinction coefficient and particle size. ALI will use a large-aperture acousto-optic tunable fibre (AOTF) to image the sunlit atmospheric limb and will also incorporate a liquid crystal polarisation rotator that provides dual linear polarisation measurement at several wavelengths. The high-aspect ratio field-of-view provides cross track coverage for nearly global daily coverage from a polar, low earth orbit.

Spatial Heterodyne Observation of Water (SHOW)

SHOW, also known as the Water Vapour Limb Imager, is a spatial heterodyne spectrometer (SHS), which has been developed to measure the vertical distribution of water vapour in the upper troposphere and lower stratosphere. SHOW combines an imaging system with a monolithic field-widened SHS to observe limb-scattered sunlight in a vibrational band of water between 1363 nm and 1366 nm. SHOW aims to achieve a vertical resolution of 500 m with a 63 km swath width.

References  

1) “Addressing climate change with satellites: Canada will contribute to NASA's international Atmosphere Observing System.” Canada.ca, 18 October 2022, URL: https://www.canada.ca/en/space-agency/news/2022/10/addressing-climate-change-with-satellites-canada-will-contribute-to-nasas-international-atmosphere-observing-system.html

2) “AMT - The Aerosol Limb Imager: acousto-optic imaging of limb-scattered sunlight for stratospheric aerosol profiling.” AMT - Recent, URL: https://amt.copernicus.org/articles/9/1261/2016/

3) “HAWC mission: Clouds and aerosols to help predict climate change.” Agence spatiale canadienne, 28 March 2023, URL: https://www.asc-csa.gc.ca/eng/satellites/hawc/

4) “Mission Overview.” NASA AOS, URL: https://aos.gsfc.nasa.gov/mission.htm

5) “Mission Spaceborne Architecture.” NASA AOS, 20 November 2023, URL: https://aos.gsfc.nasa.gov/spaceborne.htm

6) “Satellite: AOS-HAWCSat.” WMO OSCAR, 30 October 2023, URL: https://space.oscar.wmo.int/satellites/view/aos_hawcsat

7) “The Aerosol Limb Imager: a hyperspectral, polarization imager for aerosol and cloud profiling in the UTLS.” NASA/ADS, URL: [web source no longer available]

8) “The Aerosol Limb Imager.” HARVEST (uSask), 26 October 2016, URL:https://harvest.usask.ca/items/8ac9e16b-9d62-4c14-90e0-9dc647b1ad14

9) “The birth of the HAWC - CMOS BULLETIN SCMO.” cmos bulletin scmo, 7 November 2022, URL: https://bulletin.cmos.ca/the-birth-of-hawc/

10) NASA AOS - Home, URL: https://aos.gsfc.nasa.gov/

11) Nyberg, Karen. “National climate science satellite mission co-led by U of T secures more than $200 million.” University of Toronto, 18 October 2022, URL: https://www.utoronto.ca/news/national-climate-science-satellite-mission-co-led-u-t-secures-more-200-million

12) Parsons, Jon. “Waterloo researcher helping pave the way for space-age climate science | Waterloo News.” University of Waterloo, 21 October 2022, URL: https://uwaterloo.ca/news/environment/waterloo-researcher-helping-pave-way-space-age-climate

13) “Spatial Heterodyne Observations of Water (SHOW) vapour in the upper troposphere and lower stratosphere from a high altitude aircraft: Modelling and sensitivity analysis.” Science Direct, 16 June 2023, URL: https://www.sciencedirect.com/science/article/abs/pii/S0022407317309196