River runoff effect on the suspended sediment property in the upper Chesapeake Bay using MODIS observations and ROMS simulations

Abstract

Ocean color data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the satellite Aqua from 2002 to 2012 and simulations from the Regional Ocean Modeling System (ROMS) are used to study the impact of the Susquehanna River discharge on the total suspended sediment (TSS) concentration in the upper Chesapeake Bay. Since the water in the upper Chesapeake Bay is highly turbid, the shortwave infrared (SWIR)-based atmospheric correction algorithm is used for deriving the normalized water-leaving radiance nL w (k) spectra from MODIS-Aqua measurements. nL w (k) spectra are further processed into the diffuse attenuation coefficient at the wavelength of 490 nm K d (490) and TSS. MODIS-Aquaderived monthly TSS concentration in the upper Chesapeake Bay and in situ Susquehanna River discharge data show similar patterns in seasonal variations. The TSS monthly temporal variation in the upper Chesapeake Bay is also found in phase with the monthly averaged river discharge data. Since the Susquehanna River discharge is mainly dominated by a few high discharge events due to winter-spring freshets or tropical storms in each year, the impact of these high discharge events on the upper Chesapeake Bay TSS is investigated. Both MODIS-measured daily TSS images and sediment data derived from ROMS simulations show that the Susquehanna River discharge is the dominant factor for the variations of TSS concentration in the upper Chesapeake Bay. Although the high river discharge event usually lasts for only a few days, its induced high TSS concentration in the upper Chesapeake Bay can sustain for 10-20 days. The elongated TSS rebounding stage is attributed to horizontal advection of slowly settling fine sediment from the Susquehanna River.

Modeling Impacts of Submersed Aquatic Vegetation on Sediment Dynamics Under Storm Conditions in Upper Chesapeake Bay

“…= ( @MC / B,J.BC ) * 0.8 (4) where, Qobs is the observed river discharge from the Conowingo station in m 3 s -1 , nrivers is the number of river grid cells over which the flow is distributed (Harris et al, 2008;Liu and Wang, 2014;Xue et al, 2012), and 0.8 represents a 20% reduction in flow. This was forced into ROMS as a horizontal momentum transport point source.…”

Quantitative Assessment on Multiple Timescale Features and Dynamics of Sea Surface Suspended Sediment Concentration Using Remote Sensing Data

“…On seasonal timescale, the SSC variation is mainly modulated by the monsoon wind and the stratification of sea water (Wang et al, ; Wang & Jiang, ). Moreover, the SSC also shows long‐term timescale variation due to long‐term climate change or anthropogenic activities such as the long‐term wind speed variation, sediment regulation, and sea reclamation which in turn cause long‐term variation of SSC (Cao & Yan, ; Liu & Wang, ; Pelling et al, ; Song et al, ).…”

High‐turbidity events in Western Lake Erie during ice‐free cycles: Contributions of river‐loaded vs. resuspended sediments

“…Given that suspended sediments from river loading and resuspension have distinct ecological functions and driving mechanisms, it is critical to understand their relative contributions to HTEs by tracking their origins explicitly. At present, however, this understanding cannot be fulfilled through field or satellite observations (e.g., Saldías et al 2012;Mendes et al 2017;Valipour et al 2017), nor has it been sufficiently investigated thoroughly in the modeling studies that have been conducted to date (e.g., Lou et al 2000;Liu and Wang 2014;Morales-Marin et al 2017;Yellen et al 2017).…”