Decadal Pattern of Spatial and Temporal Variability of Nitrate Along the Southwest Bay of Bengal Using Remote Sensing Techniques

• Published in: Journal of the Indian Society of Remote Sensing Vol. 47; no. 3; pp. 487 - 495
• Main Authors: Poornima, D., Shanthi, R., Senthilnathan, L., Thangaradjou, T., Saravanakumar, A., Sarangi, R. K.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 07.03.2019; Springer Nature B.V
• Subjects: Annual variations; Anthropogenic factors; Chlorophyll; Earth and Environmental Science; Earth Sciences; Nitrates; Pollution control; Remote sensing; Remote Sensing/Photogrammetry; Research Article; Seasons; Spatial distribution; Statistical significance; Variability; Variance analysis; Wind speed; Bay of Bengal; Chlorophyll; Nitrate; Seasons; SST; Paraboloid; MODIS
• DOI: 10.1007/s12524-018-0915-7
• ISSN: 0255-660X

The seasonal and interannual variability of sea surface nitrate was studied in the southwest Bay of Bengal. MODIS-Aqua-derived SST and chlorophyll data are used to develop seasonal nitrate maps for the period of 2002–2017. Seasonally developed nitrate images were validated for the year 2013 with corresponding in situ datasets, and the validation of this nitrate model provides the statistically significant relationship for postmonsoon ( R 2  = 0.612), summer ( R 2  = 0.535), premonsoon ( R 2  = 0.554) and monsoon ( R 2  = 0.533) seasons. The seasonal SST, chlorophyll a, nitrate and wind speed images depict the clear seasonal pattern between the seasons without any abrupt increase or decrease in trend observed during all these years. This was also confirmed by the Kruskal–Wallis one-way analysis of variance on ranks with a statistical significance ( P  = < 0.001) between the seasons. From the results, this is a clear indication that the nitrate concentration is under the natural control without any anthropogenic contaminations.