Modeling Kuwait Seawater Clarity: A Spatial-Temporal Study Using Remote Sensing And GIS

Kuwait water clarity is an important water quality indicator that influences the entire Kuwait coastal ecosystem. The spatial and temporal distributions of this important water characteristic should be well understood to obtain a better knowledge about this productive coastal environment. The aim of this project was therefore to study the spatial and temporal distributions of Kuwait Secchi Disk Depth (SDD), a water clarity measure, using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data collected from November 1998 to October 2004 and January 2003 to June 2007, respectively. Kuwait SDD was measured through two steps: first, computing the diffuse light attenuation coefficient at 490 nm, Kd(490), and 488 nm, Kd(488), derived from SeaWiFS and MODIS, respectively, using a semi-analytical algorithm; second, establishing two SDD models based on the empirical relationship of Kd(490) and Kd(488) with in situ SDD data that we collected from the study area during June 2007 and those collected by the Kuwait Environmental Public Authority (EPA) between November 1998 and June 2007. Kd(490) and Kd(488) showed a significant relationship with in situ SDD data (r 2 = 0.67 and r 2 = 0.68, respectively). Kuwait SDD derived from SeaWiFS and MODIS images showed that Kuwait water clarity increased from north to south and from inshore to offshore. This spatial pattern was mainly attributed to three factors: the Shatt Al-Arab discharge, water circulation, and coastal currents. The Kuwait SDD increased from January to May and, then, started to decrease until November with a minor decrease in April and a minor increase in December. The temporal variations in Kuwait water clarity were influenced by the Shatt Al-Arab discharge variation. The SeaWiFS and MODIS data compared to in situ measurements provided a comprehensive view of Kuwait SDD that improved the estimation of overall SSD mean within Kuwait waters. Thus, we recommend involving this method in monitoring Kuwait coastal environments.