IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution Lecture 8 Mesoscale variability and coastal pollution
This lecture includes the following topics: 1.Phytoplankton, the main contributor to ocean color: -Passive tracer -Active growing biomass 2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea 3. Spring bloom in Southern California Bight resulting from coastal upwelling IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes off southern California
Multi-discipline approach implies that the simultaneous measurements of distribution of phytoplankton and physical environment enable the studies of physical factors, which determine the distribution of phytoplankton. SeaWiFS surface chlorophyll AVHRR Sea Surface Temperature IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
1. Phytoplankton is both a passive tracer transported by water circulation and an active biomass growing under favorable conditions (light, nutrients, etc.). It is important to distinguish between these two processes. Horizontal circulation transports phytoplankton in horizontal direction, resulting in changes in its horizontal distribution. Vertical stratification of water column regulates the growth of phytoplankton biomass. So, the mesoscale variability of phytoplankton visible at satellite images results from both passive transport and active growth. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The illustrative example of mesoscale variability of phytoplankton is the Black Sea located in southeastern Europe. The abyssal plain of depth more than 2000 m is separated from the margins by steep continental slopes, excluding the shallow northwestern part. The wide northwestern continental shelf (mean depth about 50 m) occupies the region between the Crimean peninsula and the west coast. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea A basin scale cyclonic boundary Rim Current is the main feature of the Black Sea general circulation. The Rim Current is <75 km wide and has an average speed of 20 cm s -1. Along the coastal lines anticyclonic vorticity arises due to the Rim Current meandering, resulting in anticyclonic eddies in coastal zones. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea High-resolution AVHRR images enabled studies of the formation and evolution of the cyclonic and near-shore anticyclonic eddies along the coast and their influence on distribution of remote-sensed chlorophyll. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea These AVHRR images illustrate the dynamics of the cyclonic eddies (C- 1, C-2) and near-shore anticyclonic eddies (NAE-1, NAE-2, etc.) during the autumn IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea These AVHRR images illustrate the dynamics of the cyclonic eddies (C- 1, C-2) and near-shore anticyclonic eddies (NAE-1, NAE-2, etc.) during the autumn IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea These AVHRR images illustrate the dynamics of the cyclonic eddies (C- 1, C-2) and near- shore anticyclonic eddies (NAE-1, NAE-2, etc.) during the autumn IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea These AVHRR images illustrate the dynamics of the cyclonic eddies (C- 1, C-2) and near-shore anticyclonic eddies (NAE-1, NAE-2, etc.) during the autumn IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The propagation of the near- shore anticyclonic eddies resulted in change of the direction of currents over the continental slope. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea Hydrographical observations support upwelling in the cyclonic eddies and downwelling in the anticyclonic eddies. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea Torrential rains in the beginning of October 1997 resulted in increased freshwater discharge and accumulation of phytoplankton and pollutants in the near-shore anticyclonic eddies. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The concentration of chlorophyll increased in the cyclonic eddies and decreased in the anticyclonic eddies of the open sea. Near-shore anticyclonic eddies accumulated high concentrations of chlorophyll. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The process of transport of phytoplankton from productive shelf region to the open sea was observed during summer 1998 over the continental slope in the northwestern part of the Black Sea. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea Anticyclonic eddies slowly moved southwestward along the continental slope. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The largest anticyclone with diameter of 90 km displaced during three months southwestward with mean speed of about 3 cm/s. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
2. Horizontal transport of phytoplankton and pollutants offshore in the Black Sea The eddies transported chlorophyll- reach coastal waters to the deep basin. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
3. Spring bloom in Southern California Bight resulting from coastal upwelling Circulation in the Southern California Bight is cyclonic, resulting from the interaction between California Current and Southern California Countercurrent. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
3. Spring bloom in Southern California Bight resulting from coastal upwelling Strong alongshore wind results in upwelling and phytoplankton bloom. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
3. Spring bloom in Southern California Bight resulting from coastal upwelling Strong alongshore wind results in upwelling and phytoplankton bloom. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
3. Spring bloom in Southern California Bight resulting from coastal upwelling Strong alongshore wind results in upwelling and phytoplankton bloom. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
From Level 3 time-series of SeaWiFS chlorophyll concentration we study statistical correlations between phytoplankton dynamics and environmental factors.
Phytoplankton blooms regularly occur in SCB, typically in spring.
Seasonal variations of remote sensed SST and chlorophyll biomass averaged over SMB, air temperature at LAX, and wind (upwelling index at 33 o N, 119 o W). Seasonal minima: wind - December 19 (winter solstice); air T - February 7 (+50 days) SST - March 2 (+23 days). Seasonal maximum of Chl (February 27) coincides with SST minimum.
Chlorophyll biomass growth results from decrease of air temperature and increase of upwelling-favorable wind stress with time lag 5-6 days.
4. Stormwater plumes in southern California Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution
Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes in southern California
Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes in southern California
Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes in southern California
Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes in southern California
Mesoscale eddies transport offshore the rainstorm plumes with high suspended sediment and chlorophyll concentration. IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution 4. Stormwater plumes in southern California
On the basis of SeaWiFS observations collected over 7 years ( ) the basic statistical characteristics of plumes in the Southern California Bight were estimated. Normalized water-leaving radiation of 555 nm (nLw555) wavelength is highly correlated with the concentration of suspended sediments, resulting in brownish water color typical to stormwater plumes. Plume size was assessed from nLw555 exceeding a certain threshold, estimated as 1.3 mW cm -2 µm -1 sr -1. A primary factor regulating the plume size was rainstorm magnitude, i.e., the total volume of water precipitated over the coastal watershed.
Plume dynamics was studied in four southern California regions: Ventura, Santa Monica Bay, San Pedro, and Orange County/San Diego.
Maximum plume size ( km 2 ) was observed from the outlets of the Santa Clara and Ventura rivers, because of higher sediment concentration resulting from highly erosive river beds.
In Santa Monica Bay, the optical signature of stormwater plumes was much weaker (0.8 mW cm -2 µm -1 sr -1 ) than in other regions (1.3 mW cm -2 µm -1 sr -1 ).
In San Pedro region, typical plume size was km 2. The time lag between rainstorm and maximum plume size in this area was 1 day, in contrast to 2 days in three other regions.
In Orange County/San Diego region, typical plume size was small (10-40 km 2 ), resulting from bimodal watershed physiography, where river flow is often retained in the inland alluvial valleys.
In San Pedro region, the correlation between the precipitated rainwater and the plume size was almost linear, resulting from highly impervious surface in these developed watersheds.
In three other regions, power function better described the correlation between rainwater and plume size, resulting from more natural watersheds where water is partly infiltrated.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
The direction of plume propagation results from the near-shore circulation. In particular, during spring transition typical to California Current System, equatorward currents associated with wind-driven upwelling can transport stormwater plumes downcoast.
IoE The Basics of Satellite Oceanography. 8. Mesoscale variability and coastal pollution