A simple empirical band-ratio algorithm to assess suspended particulate matter from remote sensing over coastal and inland waters of Vietnam: application to the VNREDSat-1/NAOMI sensor
| Type | Article | ||||||||||||
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| Date | 2020 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Dinh Ngoc Dat1, 2, 3, Loisel Hubert1, 2, 3, Vantrepotte Vincent1, 2, Chu Xuan Huy1, Nguyen Minh Ngoc1, Verpoorter Charles2, Meriaux Xavier2, Thi Minh Hanh Pham4, Le Thi Huong4, Le Vu Hong Hai6, Nguyen Van Thao5 | ||||||||||||
| Affiliation(s) | 1 : Space Technology Institute, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 2 : Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 59000 Lille, France 3 : LOTUS, University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 4 : Institute of Mechanics, Viet Nam Academy of Science and Technology, 264 Doi Can, Ba Dinh, Hanoi, Vietnam 5 : Institute of Marine Environment and Resources, Vietnam Academy of Science and Technology, 246 Da Nang, Ngo Quyen, Haiphong, Vietnam 6 : Institute of Techniques for Special Engineering, Le Quy Don University, 236 Hoang Quoc Viet, Bac Tu Liem, Hanoi, Vietnam |
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| Source | Water (2073-4441) (MDPI AG), 2020 , Vol. 12 , N. 9 , P. 2636 (16p.) | ||||||||||||
| DOI | 10.20944/preprints202009.0212.v1 | ||||||||||||
| Note | This article belongs to the Section Oceans and Coastal Zones | ||||||||||||
| Keyword(s) | VNREDSat-1/NAOMI, Landsat-8/OLI, Suspended particulate matter, algorithm | ||||||||||||
| Abstract | VNREDSat-1 is the first Vietnamese satellite enabling the survey of environmental parameters such as vegetation and water coverages, or surface water quality at medium spatial resolution (from 2.5 to 10 meters depending on the considered channel). The NAOMI sensor on board VNREDSat-1 has the required spectral bands to assess the suspended particulate matter concentration, SPM. Because recent studies have shown that the remote sensing reflectance, Rrs(ƒÜ), at the blue (450 ¡V 520 nm), green (530 ¡V 600 nm), and red (620 ¡V 690 nm) spectral bands can be assessed from NAOMI with a good accuracy, the present study is dedicated to the development and validation of an algorithm (hereafter referred to as V1SPM) to assess SPM from Rrs(ƒÜ) over inland and coastal waters of Vietnam. For that purpose, an in situ data set of hyper-spectral Rrs(ƒÜ) and SPM (from 0.47 to 240.14 g.m-3) measurements collected at 205 coastal and inland stations has been gathered. Among the different approaches, including 4 historical algorithms, the polynomial algorithms involving the red-to-green reflectance ratio presents the best performance on the validation data set (MAPD of 18.7%). Compared to the use of a single spectral band, the band ratio reduces the scatter around the polynomial fit as well as the impact of imperfect atmospheric corrections. Due to the lack of matchup data points with VNREDSat-1, the full VNREDSat-1 processing chain (RED-NIR and V1SPM) aiming at estimating SPM from the top-of-atmosphere signal was applied to the Landsat-8/OLI match-up data points with relatively low to moderate SPM concentration (3.33-15.25 g.m-3) yielding a MAPD of 15,8%. An illustration of the use of this VNREDSat-1 processing chain during a flooding event occurring in Vietnam is provided. |
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