Publications

Manche, SS; Swapna, M; Mishra, SK; Rajesh, S; Nayak, RK; Ramana, MV; Bothale, RV; Chauhan, P (2024). An Anomalous Decline of the Spring Bloom Chlorophyll Concentration in the Central Pacific is an Early Indicator of El Ni?o. JOURNAL OF THE INDIAN SOCIETY OF REMOTE SENSING, 52(5), 973-983.

Abstract
El Nino Southern Oscillation, a global climate phenomenon, occurs in the tropical Pacific with an anomalous warming phase (El Nino) and a cooling phase (La Nina) spanning for 2-5 years. A substantial decline of Nino3.4 region's spring bloom chlorophyll-a concentration (Chl-a) is an intrinsic characteristic of the central Pacific during the El Nino onset period, which has been considered as a predictor of the El Nino by earlier studies. This study investigated the concept, a marked decline of spring bloom Chl-a as the predictor of the El Nino, using satellite-measured Chl-a from MODIS Aqua for the period 2003-2023 in relation to the Oceanic Nino Index (ONI) and subsurface properties. It revealed that Chl-a exhibits a significant inverse relationship with ONI during past El Nino events. An intense, continuous decreasing phase of Chl-a during the spring season (February-April) of 2023 may indicate the onset of El Nino. The decline of the spring bloom Chl-a concentration has been explained as the response to the weakening of the upwelling strength in the study domain and associated nutrient depletion in the euphotic zone.

DOI:
10.1007/s12524-024-01848-8

ISSN:
0974-3006