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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B1. Istanbul 2004
crop vigor and canopy chemistry. The spectral information that
can be related to canopy chemistry and/or temporal changes; and
carbon stock monitoring by combining remote sensing and
ancillary. information through models. This eventually should
lead to more comprehensive commodity yields and help us rid
famine in the future.
3.4 Public Health
The availability of remotely sensed information and its potential
capabilities allow it to be a unique addition to data applied to
public health applications. The use of such data for public health
has recently opened a new avenue in studying infectious diseases
and epidemics. Recent studies have shown that monitoring non-
infectious respiratory disease can also benefit from space based
observation in predicting near term Asthma illnesses in certain
geographic areas. These findings have ushered in a new era of
satellite remote sensing with greatly increased accuracy and new
observational capabilities. These data, when combined with data
collected by other satellite platforms, provide improved temporal
and spatial resolution adequate for local level investigations
critical for public health. Remote sensing and in situ
measurements (satellite and ground based) are critical in
determining a number of triggers related to heath such as aerosols,
source and spread of pollution, land cover and land use, other
environmental data, and spatial data. By combining these satellite
and ground based observations with environmental and climate
information, a value added product is obtained. This information
is further used in predictive models to forecast the outbreak of
certain disease patterns. For example one of the most common
vector borne diseases, malaria, infects 5 million people per year
and 1-3 million die from this controllable human catastrophe in
the African continent and in South East Asia. There are other
aspects which impact health issues such as air quality due to
transport of aerosol and black carbon from across continents and
changing the tropospheric chemical conditions. African and
Mongolian dust storms, which now can be detected and
monitored via the space-based sensors, may be carriers of various
diseases. This is a promising area of research that can have a
tremendous payback in terms of human safety and medical cost
benefits.
4. LEGACY SYSTEMS AND ‘WEBLIKE’ TOPOLOGY
There are many Earth observing satellites that have been placed
on-orbit by the US (NASA, NOAA). France (CNES) and JAXA
The A-Train
Nominal 15 minutes orbital separation
Figure 1. International constellation of atmospheric satellites.
(Japan) are already operating in the helio-synchronous orbit at a
nominal altitude of 795 km. They will be joined by other Earth
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remote sensing spacecraft planned to be launched within the next
two years. All of these satellites shown in Figure 1, are either
single instrument or multiple instrument satellites specifically
designed to study the Earth’s atmospheric chemistry, cloud
properties, water cycle, aerosol, and carbon cycle. These satellites
are designed as discrete science missions and they will provide
data and products to the models which are trying to synthesize
these science measurements to improve our understanding of the
planet Earth’s behavior as an integrated system. Most of these
satellites are capable of making measurements down to the top of
the boundary layer: Aura (to be launched in June 2004) and its
Troposphere Emission Spectrometer (TES) will penetrate the
tropospheric level to measure the ozone and other chemical
constituents. Researchers have created a constellation from this
configuration, as shown in Fig. [TBD] and provide
communication linkage via ground control between satellites.
Aura will be inserted into nearly the same orbital plane as Aqua:
it will be positioned such that it trails Aqua by approximately 15
minutes. Of significance, TES is a pointable IR-sensitive
instrument that will be used to measure Tropospheric ozone. As
such, it is desirable that TES make its measurements in cloud-free
regions. This form of formation flying provides an opportunity to
maximize useful TES science data return. For example, data
collected by the Moderate Resolution Infrared Spectrometer
(MODIS) on the Aqua satellite can be used to produce, in real
time, a cloud mask from which cloud free regions can be
identified to point Aura's TES instrument. This method of course
can be used by other instruments on the other satellites operating
in the same trajectory. These satellites were not originally
designed with space-based crosslinks. Yet one can still take
advantage of these assets and operate them as a small-scale event-
driven sensor web constellation via a bent-pipe ground processing
and communications approach. — Similar arrangements can be
made for the various land imaging satellites currently operating in
the same orbital plane. This includes MODIS, SPOT, LandSat
and Earth Orbiter-1(EO-1). However, EO-1 has both multispectral
and hyperspectral instruments on board and these instruments
have very narrow swath (about 9 km for the hyperspectral and 36
km for the multispectral). But, the idea is to detect some event
such as fire, flood or dust storms via the conventional system and
pass it on to the hyperspectral imager for a detailed look and
examination. To date this has been demonstrated via ground
operations.
S. MULTIPLE VANTAGE POINTS
One of the most complex and difficult areas to reach via remote
sensing techniques from space is the troposphere. However, this
region has a much to offer in terms of understanding its
photochemistry, anthropogenic impacts, carbon budget, air-sea
exchange, other polluting factors, the tropopause and the
stratosphere transition layer. Therefore, it is imperative to study
these processes in detail and make useful predictions regarding
the health of the planet system. Ultra long duration balloons
(ULDB) that can be deployed in troposphere at a high altitude (>
40,000 meters) offer a great promise for extended periods of time
(~ 6 months). Although keeping balloons stationary at one
observation point (i.e., station keeping) will be an intricate
problem, the advancements in GN&C technology may be able to
address this problem.
