Abstract
Stereoscopic cloud-top height (CTH) retrieval from two geostationary (GEO) satellites is usually realized through a visible (VIS) band with a high horizontal resolution. A stereoscopic-based CTH retrieval algorithm (prototype dual-GEO CTH algorithm) proposed in our previous study also adopts this approach. Although this approach can retrieve accurate stereoscopic CTHs, the heights of optically thin upper clouds overlying the lower clouds are challenging to retrieve because the parallax difference between two GEOs is determined by the lower clouds owing to the low reflectance from the upper clouds. To address this problem, this paper proposes an improved stereoscopic CTH retrieval algorithm, named the improved dual-GEO CTH algorithm, for Himawari-8 and FengYun (FY)-4A GEOs. The proposed algorithm employs an infrared (IR) band in addition to a VIS band. A seamless image cloning technique is adopted to blend the VIS and IR images, which are then used to retrieve the stereoscopic CTHs. The retrieved CTHs are compared with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR) CTHs for three occasions involving upper clouds overlying lower clouds. Results show that the proposed algorithm outperforms the prototype dual-GEO CTH algorithm in the case of upper clouds overlying lower clouds. Notably, although the proposed algorithm is intended for Himawari-8 and FY-4A GEOs, it can be easily extended to any combination of two GEOs.
Highlights
Clouds are key entities that affect the radiation budget of the Earth’s atmospheric system
The retrieved stereoscopic cloud-top height (CTH) were compared to the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR) CTHs based on different measurement techniques
The CALIOP retrieved the heights of these upper clouds, but the prototype dual-GEO CTH algorithm retrieved the heights of lower clouds
Summary
Clouds are key entities that affect the radiation budget of the Earth’s atmospheric system. The CO2 -slicing method [2,3] exploits the different atmospheric CO2 absorption levels in two adjacent CO2 absorption bands to simultaneously retrieve the CTHs and cloud effective emissivity. For low-level clouds, usually, the single window channel method is used This approach compares the observed 11 μm brightness temperature with the ambient atmospheric temperature profile and determines the corresponding height as the CTH. Lee et al [16] proposed a stereoscopic-based CTH retrieval algorithm (hereafter, the prototype dual-GEO CTH algorithm) based on simultaneous measurements of Himawari-8 and FengYun (FY)-2E GEO satellites. This algorithm uses a visible (VIS) band to retrieve stereoscopic CTHs (VIS-band-based approach), and the retrieval accuracy generally tends to lie within the theoretical accuracy range.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
