SATELLITE MULTISPECTRAL COMPOSITIONAL MAPPING OF LAKE CYANOBACTERIAL BLOOMS AND LAND CHEMICAL COMPOUNDS
Presented at the Ohio Academy of Sciences, 2012.
Satellite Multispectral Compositional Mapping of Lake Blooms
1. Dr. Robert K. Vincent
Dept. of Geology
Bowling Green State University
rvincen@bgsu.edu
2. Besides the lone thermal infrared band, LANDSAT TM has
6 reflected sunlight spectral bands in the 0.4-2.5 µm
wavelength region with 30-m spatial resolution (each pixel
covers about 1/5th of an acre), yielding these advantages
over human observations from boats or docks:
◦ TM data can make observations as dense as 5 observations (or
measurements if a tested algorithm exists) per acre over an entire
body of water for most lakes (3 frames required for all of Lake
Erie).
◦ TM data can observe what humans cannot see, because 3 of its 6
spectral bands are outside the visible light wavelength range.
◦ TM looks ±3° from straight down (nadir), reducing surface (specular or glint)
reflection in calm water.
◦ TM data can be downloaded to the company’s computer within 24 hours of
overpass (every 16 days for one LANDSAT and every 8 days for 2 LANDSATs), and
the entire lake can be processed in a few hours.
Blue Water Satellite, Inc. has licensed 7 (one more being added)
algorithms for which BGSU has applied for patents thus far.
3. LBPC (Low Bloom Phycocyanin Content)
◦ Maps low blooms of cyanobacteria in water in the 2-17
µm/L (ppb) range, with rms error = 3.1 ppb
◦ Can map cyanobacteria blooms before they can be identified by a
human observer in a boat on the water (helps early mitigation)
HBPC (High Bloom Phycocyanin Content
◦ Maps high blooms of cyanobacteria in water in the 2-64
•m/L (ppb) range, with SE= 7.2 ppb
MC (Microcystin Content)
◦ Maps toxin Microcystin in high blooms of cyanobacteria in
water in 2-63 •m/L (ppb) range, and it has been correct on
45 of 47 water samples from 2 dates of collection, as to
whether MC was above or below the World Health
Organization sporting lake advisory limit of 20 •m/L (ppb)
4. Microcystin Toxin Measured in Water Samples Vs.
HBPC3RAT Algorithm (LANDSAT TM) Estimate of PC
on 25 Sept 2008
70
y = 0.514x - 17.133
60
R² = 0.8606
Microcystin Content ((•g/L)
50
40
30
Microcystin
20
Linear (Microcystin)
10
0
0 20 40 60 80 100 120 140 160
-10
-20
HBPC Algorithm Results for PC Content (•g/L)
5.
6. Red 90-150 µg/L
Orange 80- 89 •g/L
Yellow 60- 79 •g/L
Blue-Gr. 45- 59 •g/L
Blue 1 - 44 •g/L (in water)
D. Blue 0 (neg. numbers on land)
7.
8.
9. LRTP (Low-Range Total Phosphate in Water)
◦ Maps the amount of total phosphate in water in
range 9-100 µg/L (ppb); accuracy ±5 ppb from 9-33 ppb
HRTP (High-Range Total Phosphate in Water)
◦ Maps the amount of total phosphate in water in the range
100-700 •g/L (ppb); rms error = 69 ppb
TPL (Total Phosphate on Land)
◦ Maps the amount of total phosphorous on/in bare
soil in range 550-2500 mg/kg (ppm) with SE=531
ppm
10.
11. Fig. 5. Image showing the total P concentration (mg/kg) in surface soil samples of F34 (left side of the image) and
F11 (right side of the image) fields displayed as red (high P content) to Turquoise (low P content) obtained by
applying the P spectral ratio model to the LANDSAT 5 frame of May 20, 2005 which was used for developing the
model. Field near Oregon, OH; field on left had Class B sewage sludge injected hours earlier.
12. Tested algorithms pertaining to
cyanobacterial blooms currently exist that
employ LANDSAT TM data for mapping:
◦ Pigment content in surface waters (phycocyanin)
◦ Toxin content in surface waters (Microcystin)
◦ Nutrient content in surface waters (T. Phosphate)
◦ Nutrient content on bare soil (T. Phosphate)
◦ Others (Total Sulfate content in surface waters;
Copper and Sulfur contents in bare soils)
It is time to use satellite monitoring for
cyanobacterial blooms in lakes and streams.