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The primary page for the Reefquest project.

Project 2 - Overlaying temperature data onto maps and comparing inferred current data, as well as temperature data, to visual checks of the health of the reef site.

Resources on visually checking the health of the reef:
1. Coral Health color card: ReefQuest CORALWATCH Coral Health Card.pdf
2. Cards on expected and invasive species in Hawaiian reefs, as well as how to identify various reef illnesses: ReefQuest Eyes Of The Reef Identifiacation Cards.pdf
3. An overview of the Kahekili reef near Lahaina, Maui: ReefQuest Kahekili Coral Reef Overview C.R.A.jpg
4. ReefQuest Kahekili Reef Dead Zones Visualization:ReefQuest Kahekili Reef Dead Zones Visualization.pdf
5. ReefQuest Kahekili Reef Fisheries Management Area: ReefQuest Kahekili Reef Fisheries Management Area Info.pdf

Project 1 - Inferring current data from temperature data taken at Lahaina, Maui in August 2012.
Purpose: The purpose of this project is to find out where pollution is coming from, using turbidity and current patters.
Background research on tracing runoff in Lahaina.

Overview:
To find where pollution is coming from we first must find how many pollutant particles are in the water. We will do this by finding the turbidity of the water with light sensors. Once the turbidity is known we can use current as a function of time to figure out where the pollution is coming from. (The pollution is most likely waste products from resorts.)


Our current project with Reefquest involves the logging of data at five sensor sites at a reef site immediately off of the coast of Maui.

  1. Measured data (Note: All of the data can be stored as a vector, with the exception of surface light intensity and time, which are scalars. Temperature, depth, light intensity, current velocity, and absorption coefficients are all time dependent.).
Measure Value
Description
Units
Measurement frequency
Variable
Water temperature
Water temperature measured at depth
degrees Celsius
Every minute
T_i = {T_1, T_2, T_3, T_4, T_5}
Time
Absolute clock time
seconds
Every minute
t
Surface light intensity
Light intensity measured at one point for the surface of the reef
lux
Every minute
I_0
Initial depth
The depth of each sensor at the time of their placement. The time of placement needs to be recorded
meters
Once
D_i = {D_1, D_2, D_3, D_4, D_5}
Sensor positions
The gps coordinates of each sensor
degrees
Once
(X_i,Y_i) i=1,5

Calculated data
Calculated value
Variable
Units
Variable Formula
Inputs
Source Data
Distance between two sensor sites
r_ij
meters
r_ij = 2*R*arcsin(sqrt[sin^2(0.5*(X_i-X_j))+cos(X_i)*cos(X_j)*sin^2(0.5*(Y_i-Y_j))]
R = radius of the Earth = 6378100 meters
X_i
X_j
Y_i
Y_j

The angle from sensor site i to j
theta_ij
degrees
theta_ij = arctan^2([cos(X_i)*sin(X_j)-sin(X_i)*cos(X_j)*cos(X_j-X_i)]/[sin(Y_j-Y_i)*cos(X_j)])
X_i
X_j
Y_i
Y_j

The current speed from sensor site i to j
V_ij
meters per second
Step 1: Water temperature versus time is plotted to produce five graphs. Similar features between two graphs, say T_1 and T_2, are used to determine the difference in time, delta-T, between two similar peaks or troughs in temperature. This yields a delta-t between those two graphs at a particular interval, and is then used to determine the current speed during that same interval.
Step 2: V_ij = r_ij / delta-t
T_i
r_ij
t

The depth of the sensor as a function of time
D_i(t)
meters
D_i(t) = D_i + h(t), where h(t) is the change in tidal depth from the time of initial placement.
D_i
t
Tide charts
Tidal depth for Lahaina, Maui
The absorption coefficient
a_i(t)
Inverse meters
a_i(t) = (-1/D_i(t))*ln(I_i(t)/I_0)
D_i(t)
I_i(t)
I_0

Tilt angle for each sensor
theta
Radians
Tilt angle.png
T_brightest
T_noon
T_sunset
T_sunrise


Calculated value
Variable
Units
Variable Formula
Inputs
Source Data
Corrected lux
I_A
lux
Corrected lux.png
I_0
theta

Angle of the Sun
phi_A
Radians
Angle of the sun.png
T_current
T_sunrise
T_sunset

Albedo
alpha

Screen shot 2012-11-28 at 2.12.46 PM.png
theta
Astronomical correction data
Boundary Intensity
I_b
lux
Boundry Intencity.png
I_A
alpha

Absorption
a(t)
Inverse meters
absorption.png
D_i(t)
I_w
I_b
Astronomical correction data
Overall tilt angle
theta
Radians
Overall tilt angle.png
z
s
a
b
Astronomical correction data
Azimuth
a
Radians
Azimith.png
delta
phi_A
(represented by phi)
z
Astronomical correction data
Zenith
z
Radians
Zenith.png
phi_A (represented by phi)

delta
omega
Astronomical correction data
Angle of the sun relative to normal
Omega
Radians
Angle of the sun relitive to normal.png
phi_A
Astronomical correction data
Declination
delta
Radians
Declination.png
N
Astronomical correction data
Data from the August 2012 session in Lahaina, Maui: