講演情報
[AOS25-P10]Chlorophyll-a Responses to Multiple Rainfall Events in the Indo-Pacific
Based on Satellite Observations
*Jedi Jamari Manullang1、Sayaka Yasunaka1 (1.Tohoku University)
キーワード：
Precipitation、Chlorophyll-a、Indo-Pacific、Satellite
Ocean productivity, as indicated by chlorophyll-a concentration, is primarily controlled by nutrient availability and light conditions. Rainfall (precipitation) affects both factors through contrasting mechanisms. While rainfall might deliver nutrients to surface waters, it simultaneously reduces light availability through increased cloud cover and atmospheric water vapor, creating compensating influences on marine productivity. This study explores the relationship between daily rainfall and surface chlorophyll-a (chl) concentrations using GSMaP rainfall data and GlobColour chl data from 1998 to 2023 in Indo-Pacific region. Monthly anomaly correlation of rainfall and chl shows a spatially-dependant relationship, with positive correlations in the Subtropical Pacific and negative correlations across the Equatorial Pacific and Maritime Continent. To capture these relationships in daily timescale, daily rain events are determined using connected-components analysis. Rain events are defined using a threshold where daily values exceed the climatological mean + 2σ, with a minimum requirement of 50 three dimensionally connected grids (longitude, latitude, and time) and isolated from 5mm/day rainfall 10 days before-after the event. Then, chl anomaly means were calculated within the event grid cells. 48 rain events are detected across the study region in 2019. In average, lag correlations exhibit the highest chl response occurs two days following the rain event. Overall analysis will be presented along with discussion of potential mechanisms driving these relationships.