Spatiotemporal variability of aerosol-cloud interactions in Northwestern Pacific and impact on NPP

Abstract

The growth and development of marine plants are largely dependent on nutrient input and solar radiation. Aerosols, through atmospheric deposition, can directly or indirectly influence the growth and distribution of marine organisms, while changes in cloud cover and aerosol presence can alter solar radiation levels. Gaining insight into aerosol-cloud interactions in the Northwest Pacific and their effects on marine plants can support the sustainable development and utilization of ocean resources. This study utilized aerosol optical depth (AOD) data from MODIS to examine the spatiotemporal distribution and potential sources of aerosols over the Northwest Pacific. Additionally, the study integrated MODIS data on cloud optical thickness of ice and liquid (COTI/COTL), cloud water path of ice and liquid (CWPI/CWPL), effective particle radii of ice and liquid clouds (CERI/CERL) and ocean net primary productivity (NPP) data from Oregon State University to analyze aerosol-cloud interaction patterns and their effects on marine phytoplankton. The results show that in the fishing grounds of the northwest Pacific (38°-46°N, 150°-175°E), the sustained northward migration and intensification of the subtropical high during summer weaken the upper-level atmosphere from Asia. This results in aerosols in the local marine area predominantly originating from the clean marine (CM) aerosols of the Pacific region, which typically peak from June to August each year (0.9). Aerosols in both the fishing and spawning grounds (20°-30°N, 130°-170°E) significantly affect the CWPI and CWPL, with those in the fishing grounds exerting a stronger influence. Furthermore, as the net primary productivity (NPP) in the fishing grounds is primarily influenced by clouds, aerosols indirectly impact local phytoplankton photosynthesis by suppressing cloud formation. In contrast, in the spawning grounds, the proximity to the East Asian continent leads to greater influence from human activities, with aerosol deposition and river inputs playing a dominant role in the local marine environment.