INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results

Accurate estimation of air-sea fluxes is essential for advancing ocean modeling, observational studies, and understanding air-sea interactions. To address this need, the Indian National Centre for Ocean Information Services (INCOIS) developed and deployed a Flux Reference System (INCOIS-FRS) onboard...

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Main Authors: B. Praveen Kumar, Abhijith Raj, Asish K. Sasidharan, N. Sureshkumar, A. A. Gnanaraj, Deepak Sankar, K. Ramasundaram, Venkata Jampana, E. Pattabhi Rama Rao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2025.1570854/full
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author B. Praveen Kumar
Abhijith Raj
Abhijith Raj
Asish K. Sasidharan
Asish K. Sasidharan
N. Sureshkumar
A. A. Gnanaraj
Deepak Sankar
K. Ramasundaram
Venkata Jampana
E. Pattabhi Rama Rao
author_facet B. Praveen Kumar
Abhijith Raj
Abhijith Raj
Asish K. Sasidharan
Asish K. Sasidharan
N. Sureshkumar
A. A. Gnanaraj
Deepak Sankar
K. Ramasundaram
Venkata Jampana
E. Pattabhi Rama Rao
author_sort B. Praveen Kumar
collection DOAJ
description Accurate estimation of air-sea fluxes is essential for advancing ocean modeling, observational studies, and understanding air-sea interactions. To address this need, the Indian National Centre for Ocean Information Services (INCOIS) developed and deployed a Flux Reference System (INCOIS-FRS) onboard ORV Sagar Nidhi. This article provides an overview of the system, its components, data acquisition methods, flux computation techniques, and preliminary results. The INCOIS-FRS integrates an Eddy Covariance Flux System (ECFS) and an Automated Weather Station (AWS). The ECFS collects high-frequency (20 Hz) data to directly estimate the latent heat flux (LHF), sensible heat flux (SHF), and momentum flux (τ) using the Eddy Covariance (EC) method. The AWS records meteorological and oceanic variables at 1 Hz, enabling flux estimates using the COARE 3.5 algorithm. A spectrally flat Class-A pyranometer and a pyrgeometer provide climate-grade measurements of downward shortwave and longwave radiation, which, combined with EC-derived SHF and LHF, yield the net heat flux. This article presents preliminary results inferred from data collected by INCOIS-FRS during a cruise in the Arabian Sea from 1–16 July 2023. Data from this system are useful for validating model outputs and satellite observations, refining flux parameterizations, marine boundary layer studies, and improving air-sea interaction models. INCOIS-FRS represents a first step toward equipping more oceanographic platforms, both crewed and uncrewed, with flux reference units. Future plans include expanding such deployments to enhance observational coverage and support research on air-sea fluxes across the Indian Ocean and other regions.
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publisher Frontiers Media S.A.
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spelling doaj-art-b614ff78efb640268d82f9228443cde92025-08-20T02:24:26ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-06-011210.3389/fmars.2025.15708541570854INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial resultsB. Praveen Kumar0Abhijith Raj1Abhijith Raj2Asish K. Sasidharan3Asish K. Sasidharan4N. Sureshkumar5A. A. Gnanaraj6Deepak Sankar7K. Ramasundaram8Venkata Jampana9E. Pattabhi Rama Rao10Indian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaIndian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaSchool of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Cochin, IndiaIndian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaSchool of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Cochin, IndiaIndian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaNational Institute of Ocean Technology (NIOT), Ministry of Earth Sciences (MoES), Govt. of India, Chennai, IndiaNational Institute of Ocean Technology (NIOT), Ministry of Earth Sciences (MoES), Govt. of India, Chennai, IndiaNational Institute of Ocean Technology (NIOT), Ministry of Earth Sciences (MoES), Govt. of India, Chennai, IndiaIndian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaIndian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Govt. of India, Hyderabad, IndiaAccurate estimation of air-sea fluxes is essential for advancing ocean modeling, observational studies, and understanding air-sea interactions. To address this need, the Indian National Centre for Ocean Information Services (INCOIS) developed and deployed a Flux Reference System (INCOIS-FRS) onboard ORV Sagar Nidhi. This article provides an overview of the system, its components, data acquisition methods, flux computation techniques, and preliminary results. The INCOIS-FRS integrates an Eddy Covariance Flux System (ECFS) and an Automated Weather Station (AWS). The ECFS collects high-frequency (20 Hz) data to directly estimate the latent heat flux (LHF), sensible heat flux (SHF), and momentum flux (τ) using the Eddy Covariance (EC) method. The AWS records meteorological and oceanic variables at 1 Hz, enabling flux estimates using the COARE 3.5 algorithm. A spectrally flat Class-A pyranometer and a pyrgeometer provide climate-grade measurements of downward shortwave and longwave radiation, which, combined with EC-derived SHF and LHF, yield the net heat flux. This article presents preliminary results inferred from data collected by INCOIS-FRS during a cruise in the Arabian Sea from 1–16 July 2023. Data from this system are useful for validating model outputs and satellite observations, refining flux parameterizations, marine boundary layer studies, and improving air-sea interaction models. INCOIS-FRS represents a first step toward equipping more oceanographic platforms, both crewed and uncrewed, with flux reference units. Future plans include expanding such deployments to enhance observational coverage and support research on air-sea fluxes across the Indian Ocean and other regions.https://www.frontiersin.org/articles/10.3389/fmars.2025.1570854/fullEddy CovarianceFlux Reference SystemAutomated Weather StationAir-sea fluxesINCOIS-FRS
spellingShingle B. Praveen Kumar
Abhijith Raj
Abhijith Raj
Asish K. Sasidharan
Asish K. Sasidharan
N. Sureshkumar
A. A. Gnanaraj
Deepak Sankar
K. Ramasundaram
Venkata Jampana
E. Pattabhi Rama Rao
INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
Frontiers in Marine Science
Eddy Covariance
Flux Reference System
Automated Weather Station
Air-sea fluxes
INCOIS-FRS
title INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
title_full INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
title_fullStr INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
title_full_unstemmed INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
title_short INCOIS air-sea Flux Reference System onboard ORV Sagar Nidhi: overview and initial results
title_sort incois air sea flux reference system onboard orv sagar nidhi overview and initial results
topic Eddy Covariance
Flux Reference System
Automated Weather Station
Air-sea fluxes
INCOIS-FRS
url https://www.frontiersin.org/articles/10.3389/fmars.2025.1570854/full
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