application of remote sensing in the monitoring of plant...
TRANSCRIPT
Application of Remote Sensing in the
Monitoring of Marine pollution
By
Atif Shahzad
Institute of Environmental Studies
University of Karachi
Remote Sensing
"Remote sensing is the science
(and to some extent, art) of
acquiring information about the
Earth's surface without actually
being in contact with it. This is
done by sensing and recording
reflected or emitted energy and
processing, analyzing, and applying
that information.’’
The term, “remote sensing,” was
coined by Evelyn L. Pruitt (U.S.
Office of Naval Research) in 1960.
Evelyn Pruitt
Energy Source
The Sun
The first requirement for remote sensing is to have an energy source which
illuminates or provides electromagnetic energy to the target of interest.
From Lillesand & Kiefer, 2001
Electromagnetic Radiations
Long wave
Radio wave, Micro wave, IR
Visible
Red-VioletShort wave
UV, X-ray
The Electromagnetic Spectrum
Long wave
Visible
Short wave
Atmospheric interaction
As the energy travels from its
source to the target, it will
come in contact with the
atmosphere it passes through.
This interaction may take
place a second time as the
energy travels back from the
target to the sensor.
There are three types of
interactions.
Reflection
Absorption
Scattering
Atmospheric interaction
Platform
Platform is the place where sensors
are mounted on.
1. Balloon
2. Kite
3. Pigeon
4. Airplane
5. Satellite
Platforms
Balloon photography, 1858The first known aerial photograph is obtained by aeronaut Gaspard Felix
Tournachon, also known as Nadar, was a famous French photographer and
balloonist whose goal was to make land surveys from aerial photographs.
NADAR
Nadar’s 1868 photo of Paris
Platforms
Kite Photography, 1890Arthur Batut pioneered the development of kite aerial photography and took a
photograph of Labruguiere, France in 1890.
Labruguiere, France
Arthur Batut
One of Lawrence's 1906 photographs of San Francisco.
Platforms
In 1906, George R. Lawrence took oblique aerial pictures of San Francisco after the
earthquake and fires
Platforms
Pigeons Photography, 1903
In 1903, Julius Neubranner, photography enthusiast, designed and patented a breast-
mounted aerial camera for carrier pigeons
Platforms
Aerial Photography, 1909The first photographs from an aircraft were taken by L. P. Bonvillain, a passenger ofWilbur Wright, during a demonstration flight in France.
Aerial photographer during World War I, and a French air field
Satellite Imagery, 19721972 - Launch of ERTS-1, the first Earth
Resources Technology Satellite (later
renamed Landsat 1). Carried return beam
vidicon (RBV) and multispectral scanner
(MSS).
Platforms
Brazil Deforestation
Landsat mss June, 19 1975 vs
Landsat TM August 19, 1986Landsat 1
Sensor
After the energy has been reflected by, or emitted
from the target, we require a sensor (remote - not
in contact with the target) to collect and record
the electromagnetic radiation.
The sensor acquires several images (bands) at
once, each recording a specific color or range of
colors. When viewed, each individual band looks
like a black and white photograph
Types of Sensors
There are two types of sensors with respect to
illumination source.
Passive sensors measure natural radiation emitted by the
target material or/and radiation energy from other sources
reflected from the target.
Active sensors transmit their own signal and measure the
energy that is reflected (or scattered back) from the target
material.
Today, we will be focusing on passive remote sensing!
Passive Sensor (Landsat TM)
Karachi
A satellite view of Karachi from Landsat a passive remote sensing satellite
Active Sensor (Radarsat)
Karachi
Interaction with the feature
When electro-magnetic energy is incident on any given earth
surface feature, three fundamental energy interactions with the
feature are possible depending on the properties of both the
target and the radiation.
Transmission
Reflection
Absorption
Interaction with the feature
Basic interactions between electromagnetic energy and an earth
surface feature
The incident energy on an earth surface feature is a function of reflected, transmitted and
absorbed energy.
From Avery &
Berlin, 1977
Reflectance from a leafAn earth surface feature behaves differently against different spectral bands. As we
can see that a leaf absorbs incident energy in blue and red bands while it reflect
energy in green and near infra red bands.
Spectral Reflectance Curve
Spectral reflectance curve reveals that vegetation (leaves) has maximum reflectance in
NIR than green band.
Reflectance in different bands
Applications
On the basis of spectral reflectance
and field measurements we can
find parameters that are important
in the monitoring of plant diversity
1. Chlorophyll (a & b)
2. Vegetation density (NDVI)
3. Species Richness (No. of
Species)
Chlorophyll-a
This paper focused on developing and applying remote sensing
algorithms to determine the chlorophyll-a content of mesotrophic to
highly eutrophic lake waters, using Lake Taihu, China as a case study.
Statistical techniques have been the most commonly used approach to
derive a correlation between spectral data and chlorophyll
concentration values (Zhou yi et al., 2004). Such techniques were also
adopted in this study.
1. Weiqi Zhou, Shixin Wang, Yi Zhou. Determination of Chlorophyll a Content of the
Lake Taihu, China using Landsat-5 TM data. Institute of Remote Sensing Applications,
Chinese Academy of Sciences P O Box, 9718, Beijing 100101, P R. China.
2. Zhou yi, Zhou Weiqi, Wang shixin et al. Applications of Remote Sensing Techniques to
Inland Water Quality Monitoring. Advances in Water Science, 2004, 15(3), 312-317. (In
Chinese)
Field measurement
Water was sampled at 0.5m depths using a bottle and was laterfiltered and stored in liquid nitrogen to break the algae cells.Chlorophyll concentrations were retrieved from filtered waterusing the hot ethanol method, which use 90% hot ethanol as thechlorophyll-a extraction agent (Chen and Gao, 2000). 25 chl-aconcentration measurements were collected on October 27th and28th, 2003, which were used as the dependent variable in theregression analysis with corresponding satellite-derived watersurface reflectance. The values of chl-a concentration variedfrom 2.2 mgm-3 to 230.59 mgm-3.
Chen yuwei, Gao xiyun. Comparison of Two Methods for Phytoplankton Chlorophyll-a
Concentration Measurement. Journal of Lake Sciences, 2000, 12(2): 186-188. (In Chinese)
Numerical modelBased on the correlation analysis between chl-a and various
bands and bands combinations, the multiple regressions were
performed using the 22 chl-a concentration values and selected
bands combinations. Closeness of fit (r2 values) and mean Std.
Error of the Estimate (SEE) were used to assess the regression
models. A four-coefficient regression model using TM4/TM3
ratio and TM1, TM2 was a reliable predicator of chl-a (r2 =
0.837). The equation of this model is:
Where R1, R2 were the reflectance of TM1 and TM2; R43 was the reflectance ratio of
TM4 to TM3.
Remote Sensing Analysis
Map of chl-a concentrations (in mgm-3), by applying numerical
model to Landsat TM reflectance data from October 28th, 2003.