Abstract Chlorophyll-a (Chl-a) concentration is an important issue in ocean ecosystem management and research. This study investigates seasonal and annual variability in Chl-a and its relationship with sea surface temperature (SST) and river discharge in the shelf region of the Northern Bay of Bengal (BoB), as well as validates satellite data against in-situ data. Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite data on Chl-a concentration and SST from 2002–2018 were used in this study. River discharge data were obtained from the Bangladesh Water Development Board (BWDB). The annual Chl-a concentration ranged from 2.08 to 2.94 mg m−3, with an average of 2.43 ± 0.24 mg m−3. The Chl-a concentration was found higher (2.21 ± 0.56 mg m−3) during the northeast monsoon (October–February) and lower (1.81 ± 1.14 mg m−3) during the pre-monsoon season (March–May). The study revealed a declining trend in Chl-a concentration from 2002 to 2018, and the rate of change was −0.0183 mg m−3 year−1. Chl-a concentration showed a weak inverse relationship with SST, both annually and seasonally, especially in the pre-monsoon season. River discharge masked the effect of SST on Chl-a variability during the southwest and northeast monsoon. A reasonable correlation (r = 0.78) was found between the MODIS-Aqua data and in-situ Chl-a observations.

中文翻译：

---

使用 MODIS-Aqua 数据分析孟加拉湾北部陆架区叶绿素 a 的季节性和年度变化

摘要 叶绿素-a (Chl-a) 浓度是海洋生态系统管理和研究中的一个重要问题。本研究调查了孟加拉湾北部 (BoB) 陆架区 Chl-a 的季节性和年度变化及其与海面温度 (SST) 和河流流量的关系，并根据原位数据验证了卫星数据。本研究使用了 2002-2018 年有关 Chl-a 浓度和 SST 的中分辨率成像光谱仪 (MODIS) Aqua 卫星数据。河流流量数据来自孟加拉国水资源开发委员会 (BWDB)。Chl-a 年浓度范围为 2.08 至 2.94 mg m-3，平均为 2.43 ± 0.24 mg m-3。在东北季风（10 月至 2 月）期间发现 Chl-a 浓度较高（2.21 ± 0.56 mg m-3）和较低（1.81 ± 1）。14 mg m−3) 在季风前季节（3 月至 5 月）。研究表明，从 2002 年到 2018 年，Chl-a 浓度呈下降趋势，变化率为 -0.0183 mg m-3 year-1。Chl-a 浓度与 SST 呈弱负相关，无论是每年还是季节性，尤其是在季风前季节。在西南和东北季风期间，河流流量掩盖了 SST 对 Chl-a 变异性的影响。在 MODIS-Aqua 数据和原位 Chl-a 观测之间发现了合理的相关性 (r = 0.78)。在西南和东北季风期间，河流流量掩盖了 SST 对 Chl-a 变异性的影响。在 MODIS-Aqua 数据和原位 Chl-a 观测之间发现了合理的相关性 (r = 0.78)。在西南和东北季风期间，河流流量掩盖了 SST 对 Chl-a 变异性的影响。在 MODIS-Aqua 数据和原位 Chl-a 观测之间发现了合理的相关性 (r = 0.78)。