Return
Cloud base height retrieval from multi-angle satellite data
DOI:10.5194/amt-12-1841-2019.png)
Abstract
En 中文
Clouds are a key modulator of the Earth energy budget at the top of the atmosphere and at the surface. While the cloud top height is operationally retrieved with global coverage, only few methods have been proposed to determine cloud base height (z(base)) from satellite measurements. This study presents a new approach to retrieve cloud base heights using the Multi-angle Imaging SpectroRadiometer (MISR) on the Terra satellite. It can be applied if some cloud gaps occur within the chosen distance of typically 10 km. The MISR cloud base height (MIBase) algorithm then determines z(base) from the ensemble of all MISR cloud top heights retrieved at a 1.1 km horizontal resolution in this area. MIBase is first calibrated using 1 year of ceilometer data from more than 1500 sites within the continental United States of America. The 15th percentile of the cloud top height distribution within a circular area of 10 km radius provides the best agreement with the ground-based data. The thorough evaluation of the MIBase product z(base) with further ceilometer data yields a correlation coefficient of about 0.66, demonstrating the feasibility of this approach to retrieve z(base). The impacts of the cloud scene structure and macrophysical cloud properties are discussed. For a 3-year period, the median z(base) is generated globally on a 0.25 degrees x 0.25 degrees grid. Even though overcast cloud scenes and high clouds are excluded from the statistics, the median z(base) retrievals yield plausible results, in particular over ocean as well as for seasonal differences. The potential of the full 16 years of MISR data is demonstrated for the southeast Pacific, revealing interannual variability in z(base) in accordance with reanalysis data. The global cloud base data for the 3-year period (2007-2009) are available at https://doi.org/10.5880/CRC1211DB.19.
Keywords:
STRATOCUMULUS
PERFORMANCE
OXYGEN
AI Summary
Key information extracted from the uploaded paper, including a brief overview, abstract, background, key highlights, visual analysis, and future outlook.
Journal
IF:
3.3
Papers:
5.4K
Citations:
1.6W

