While the western side of the tropical Pacific (around the Indonesian islands) is a region with high sea surface temperature in the world, the eastern side (the continental side of South America) is influenced by rising cold water off the coast of Peru, so the sea surface temperature is lower relative to the west side. It is known that the difference in sea surface temperature between the west side and the east side brings about a difference in convection activity and atmospheric humidity in each area, and as a result it brings about a difference in cloud height and precipitation system. However, the difference in the clouds was not well known in prior research. The physical quantity of the cloud particle scale such as the size of the cloud in the cloud is called the cloud microscopic quantity, and the vertical distribution of the cloud microphysical quantity not only determines the radiation characteristics of the cloud but also understands the process of cloud formation, maintenance and extinction. So it is important. In this research, we focused on the difference between the western side and the east side of the vertical distribution of the cloud microphysics, and analyzed using satellite data equipped with cloud radar and rider.

Analysis of the data for 2007 (1 year) showed that the aerosol amount is lower near the melting layer (temperature 0 degrees) in the eastern part of the tropical Pacific Ocean where the convective activity is relatively weak and the clouds are larger ( Fig. 1).

Fig. 1: Two-dimensional frequency distribution diagram of cloud particle effective radius (horizontal axis) and temperature (vertical axis) of optically thick clouds. The result from the left side, the result in the western part, the result in the eastern part, the difference between the frequencies of the western part and the eastern part

 

Published papers

Naoya Takahashi, Tadahiro Hayasaka, and Hajime Okamoto, 2016: Differences in ice cloud microphysical properties between western and eastern tropical Pacific regions derived from CloudSat and CALIPSO measurements. SOLA, 12, 91−95. https://doi.org/10.2151/sola.2016-021