Press Release

Board View

First Anniversary of GEMS Launch toward Solid Cooperation over Asia

▷ Establishment of a satellite-based 3D air quality monitoring network and GEMS data service to the public

▷ Pandora Asia Network to be the foundation for air quality improvement and environmental cooperation over Asia

Marking the first anniversary of the launch of the Geostationary Environmental Monitoring Spectrometer (GEMS) onboard the GEO-KOMPSAT-2B satellite, the Ministry of Environment (ME) and the National Institute of Environmental Research (NIER) have announced main achievements and the plan for 2021 of the Environmental Satellite Center (ESC), the ground station of GEMS.  

The development of GEMS has been a top priority of the ME in its effort to improve air quality. GEMS data products can serve as scientific evidence for not only monitoring air pollution and climate change in line with the 2050 carbon neutral pledge by the Korean government but also establishment and assessment of the national air quality policy.

Joint research with NASA and other international institutes show that nitrogen dioxide (NO2) and ozone data of GEMS have about 80-90% accuracy when compared with ground-based measurements.

Considering that the expected lifetime of GEMS is about ten years, the first year in orbit is very significant in laying a solid foundation for seamless operation of GEMS. Three main achievements over the past year can be summerized as below.

< Main achievements over the first year >

First, following the eight-month in-orbit testing of GEMS since its launch, air quality imagery over Asia from GEMS was officially released on 18 November 2020.

The images depicted fine dust and particulate matter (PM) flowing into the Korean peninsula, a sulfur dioxide gas plume spewing from the Nishinoshima volcano eruption, and nitrogen dioxide emitted from large cities and industrial areas.

This proved that GEMS performs its mission well as designed. 

Second, broad cooperation with domestic and international space agencies, research institutes, and universities has been established in order to improve the accuracy of GEMS data.

The International GEMS Validation Team composed of 20 institues from North America, Europe, and Asia was formed in August 2020, and a four-party agreement* was signed in October to build a cooperative platform among 13 Asian countries** to improve air quality.

* National Institute of Environmental Research (NIER), Korea International Cooperation Agency (KOICA), United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP), Korea Environment Corporation (KECO)

** Bangladesh, Bhutan, Cambodia, India, Indonesia, Laos, Mongolia, Myanmar, Nepal, the Philippines, Sri Lanka, Thailand, Vietnam

Expanding the KORUS-AQ Campaign conducted in 2016, the ESC launched  the Satellite Integrated Joint Monitoring of Air Quality (SIJAQ) Campaign and carried out a pre-campaign from November to December last year. The results show that GEMS data has about 80~90% accuracy compared with ground-based measurements.

※ The Final Report of the pre-campaign is expected to be published by June 2021.

Third, the ESC started providing GEMS-based analysis data that can be used to improve the accuracy of air quality forecasting and address urgent air quality issues.

The performance analysis of the Seasonal Fine Dust Management was conducted with the aid of GEMS data and part of the hourly-produced GEMS products have been provided to the Air Quality Forecasting Center since last December. 

Based on this progress, the ESC/NIER is pushing forward with three major activities this year, including establishment of a GEMS-based three-dimensional air quality monitoring network.

< ESC's major activities for 2021 >

1. Establishment of GEMS-based 3D monitoring network of air quality and climate change

A 3D network of satellite, aircraft, ground-based instruments will be set up to reinforce scientific analysis on the implications of PM10/PM2.5 measurements and national air quality policy.

GEMS enables such 3D air quality monitoring combined with ground-based observation. During intensive monitoring, aircraft and ships will be included in the network, which will help identify occurrences and causes of air pollution such as fine dust, ozone, etc.

In addition, for regions with no ground-based instruments such as remote or offshore areas, whose air pollution concentrations have soly relied on model simulations, GEMS makes it possible to constantly monitor air quality and analyze high PM10/PM2.5 episodes and scenarios. 

2. Establishment of the Pandora Asia Network (PAN) for GEMS data application

The ESC has been building the Pandora Asia Network (PAN) that covers 13 Asian countries within the GEMS domain to promote environmental cooperation on air quality improvement by installing ground-based remote-sensing Pandora instruments in these countries. 

A total of 20 Pandoras will be installed in 2021-2022.  PAN is expected to become a robust platform for Korea to lead in the global effort improve air quality.

3. Launch of official GEMS data service

GEMS data will start to be officially available to the public from March 2021. 

Eight GEMS products including aerosol optical depth (AOD*, associated with fine dust pollution), NO2 column density, total ozone will be uploaded on the ESC website ( and five more products, totally 13 products**, will be added in October this year.

* AOD: A quantitative value of aerosols in the atmosphere expressed from 0 to 1, proportionate to the amount of arosols

** Aerosol optical depth, single scattering albedo, UV-VIS aerosol index, ozone total density, effective cloud pressure, effective cloud fraction, cloud radiance fraction, nitrogen dioxide, sulfur dioxide, UV index, plant dose rate, DNA damage dose rate, vitamin dose rate

Moreover, mobile responsiveness will be added to the website by June so that users can have access to GEMS data on their smartphone wherever they are.

< Closing >

Chang Yoon-Seok, President of the NIER said "The year of 2021 is especially important in establishing the GEMS-based 3D air quality monitoring network and building cooperative groundwork to share the benefits of GEMS with Asian countries," adding "We will make the best use of GEMS data to support the Seasonal Fine Dust Management that ends in March, as well as to implement the modified air quality policy direction according to the 2050 carbon neutral pledge. We are also working on developing next satellite instruments based on our accumulated experience and knowledge."


        1. Main Achievements of GEMS Development Project

        2. Outline of GEMS

        3. Q & A

        4. Terms and Definitions