Two-decade dynamics of MODIS-derived Secchi depth in Peninsula Malaysia waters

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Marine Systems Pub Date : 2022-12-01 DOI:10.1016/j.jmarsys.2022.103799

Md Suffian Idris , Hing Lee Siang , Roswati Md Amin , Madihah Jafar Sidik

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引用次数: 2

Abstract

Secchi disk depth (Z_sd) is an essential environmental factor for studying ecosystem dynamics and biogeochemical processes in aquatic environments. Monitoring the long-term changes in water transparency is critical to predict the cascading impacts of climate change on marine ecosystems. We investigated the seasonal and interannual dynamics of Z_sd in the eastern coast of Peninsula Malaysia (ECPM) and the Straits of Malacca (SoM) using a 21-year time series of MODIS ocean color data. To enable the reliable assessment of Z_sd and its long-term variability, the performance of existing and regional algorithms was investigated using in-situ optical measurements collected during different monsoon seasons and in various environmental conditions. Our validation results showed that the existing Z_sd algorithms performed adequately, but exhibited large errors, especially at relatively high Z_sd values. On the other hand, the regional empirical algorithm based on a direct relationship between remote sensing reflectance and Z_sd showed significant improvements by reducing the overall bias observed in existing Z_sd schemes. The results indicated that the monthly climatological Z_sd over the period 2000–2020 showed distinct patterns in different seasons. The ECPM waters had deeper Z_sd than SoM waters. Maximum transparency usually occurred during the southwest and spring inter-monsoon and minimum transparency occurred during the northeast monsoon. Long-term seasonal evolution of Z_sd reveals that widespread and persistent anomalies dominated the ECPM and SoM regions. Interannual trends indicate notable and complex changes in Z_sd that were probably driven by variability in the ocean-atmosphere dynamics of Niño-Southern Oscillation (ENSO) and local environmental conditions. This study highlights the extensive analysis of Z_sd status and its spatio-temporal pattern from space, which can significantly benefit long-term ocean monitoring efforts in the ECPM and SoM regions.

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马来西亚半岛海域MODIS导出的Secchi深度20年动态

塞奇盘深度(Zsd)是研究水生生态系统动力学和生物地球化学过程的重要环境因子。监测水透明度的长期变化对于预测气候变化对海洋生态系统的级联影响至关重要。利用MODIS海洋颜色数据的21年时间序列，研究了马来西亚半岛东海岸(ECPM)和马六甲海峡(SoM) Zsd的季节和年际动态。为了能够可靠地评估Zsd及其长期变化，利用在不同季风季节和不同环境条件下收集的原位光学测量数据，研究了现有算法和区域算法的性能。我们的验证结果表明，现有的Zsd算法性能良好，但误差较大，特别是在相对较高的Zsd值下。另一方面，基于遥感反射率与Zsd直接关系的区域经验算法通过降低现有Zsd方案观测到的总体偏差，取得了显著的改进。结果表明:2000-2020年的月气候Zsd在不同季节表现出明显的变化规律。ECPM水体的Zsd值高于SoM水体。最高透明度通常出现在西南季风和春季季风间期，最低透明度出现在东北季风期间。Zsd的长期季节演变表明，广泛和持续的异常主导了ECPM和SoM区域。年际趋势表明，Zsd发生了显著而复杂的变化，这可能是由Niño-Southern涛动(ENSO)的海-气动力学变率和局地环境条件驱动的。本研究强调了从空间上对Zsd状态及其时空格局的广泛分析，这对ECPM和SoM区域的长期海洋监测工作具有重要意义。

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来源期刊

Journal of Marine Systems 地学-地球科学综合

CiteScore

6.20

自引率

3.60%

发文量

审稿时长

6 months

期刊介绍： The Journal of Marine Systems provides a medium for interdisciplinary exchange between physical, chemical and biological oceanographers and marine geologists. The journal welcomes original research papers and review articles. Preference will be given to interdisciplinary approaches to marine systems.