Radar and satellite imagery services enhanced

Radar and satellite imagery services enhanced

Lau Tsz-ki

In March this year, the Observatory further enhanced the radar and satellite imagery services on its website. The update frequency of radar images covering the 128 kilometres and 256 kilometres ranges was increased from 12 minutes to every 6 minutes. In addition to the rainfall rate imagery for the 64 kilometres range at 3 kilometres above sea level, new imagery at a height of 2 kilometres was added, allowing the public to obtain a better picture of the rainfall situation in the lower atmosphere. The update frequency of the Fengyun-4B satellite images covering western Asia was increased from hourly to every 15 minutes. “All-day Visible” satellite imagery, and aerosol optical depth imagery from the Republic of Korea’s GK-2B satellite, were also introduced, to enhance monitoring of weather and visibility over southern China and the northern part of the South China Sea.

Weather radar images on the evening of 11 February 2025. Image at 2 kilometres above sea level (left) displays more radar echoes compared to the 3 kilometres height image (right), providing a clearer representation of rain area development in the lower atmosphere.

The update frequency of Fengyun-4B satellite images covering Western Asia has increased from hourly to every 15 minutes.

“All-day Visible” satellite images generated using a deep learning method can be used to enhance weather monitoring during nighttime. The image in the figure shows an “All-day Visible” image at around 8 p.m. on 5 September 2024, which is useful for analysing the spiral cloud bands of Super Typhoon Yagi.

Aerosol optical depth image from the Republic of Korea’s GK-2B satellite helps with monitoring visibility over southern China and the northern part of the South China Sea.