Effects of biomass burning on chlorophyll-a concentration and particulate organic carbon in the subarctic North Pacific Ocean based on satellite observations and WRF-Chem model simulations: A case study

Abstract

Abstract In recent years, the impact of aerosols on marine ecology has received increasing attention. However, the research on this aspect mainly focuses on the aspect of dust aerosols. As an important source of dissolved iron (Fe) and carbon in the ocean, biomass burning aerosol deposition has an extremely important impact on Marine ecosystem. In this study, a forest fire episode was investigated using satellite observations and the WRF-Chem model from 23 to 26 April 2014. Particular attention was paid to the biomass burning effects on the particulate organic carbon (POC) and chlorophyll-a (Chl-a) concentration in the subarctic North Pacific Ocean (SNPO). The geopotential height and CALIPSO results indicated that smoke (biomass burning) aerosols were transported from Northeast Asia to the SNPO in 2\xa0days with the effect of a low-pressure system in Mongolia. The WRF-Chem model also confirmed that CO spread southeastward and reached the SNPO in two days. Wet deposition of smoke aerosols occurred over the research region (RR) (40°-50°N, 150°-160°E) in the SNPO from 25 to 26 April 2014, and both the Chl-a concentration and POC over the RR increased nearly five times one day after the deposition of smoke aerosols. These significant increases were one order of magnitude higher than those that occurred in response to the dust episode, and the time delay was also shorter. This result indicates that smoke aerosols emitted by biomass burning lead to an increase in phytoplankton and POC once deposited and dissolved in the surface ocean, biomass burning emissions may have a more important effect in marine productivity and even ocean carbon cycles for some high nutrient and low chlorophyll (HNLC) regions compared with dust aerosols.