|
The Geoscience and Remote Sensing Society
(GRS-S) Administrative Committee has established a Distinguished
Speaker's Program
to assist GRS-S Chapters in meeting travel and lodging expenses of qualified
speakers for a Chapter's technical meeting. Support of up to $600 per
Chapter meeting may be obtained by submitting a written request to the
GRS-S Chapters and Speakers Committee
Chairperson. This request should include the speaker's name, affiliation
and brief biographical summary, the talk title and abstract, and a budget
showing estimates of travel and lodging costs.
To encourage utilization of this program,
a list of suggested speakers has been compiled. If a Chapter requests
one of these speakers, the Chapter need only include the speaker's name
and the budget in their request. The current list contains the following
speakers and talk titles:
(Last Updated November 2005)
If you would like to have one of these speakers
present their talk at your local Chapter's technical meeting, contact
region chair or Contact Kamal Sarabandi
The West Antarctic ice sheet continues to be a climatic wild card in
scientists' attempts to predict the future of the planet. The mystery
rests as much on what we do know about ice sheets as what we don't
know.
The West Antarctic ice sheet rests on a bed below sea level where
ice-free periods have layered a bed of thick marine ooze. Ice can, and
does, slide rapidly on this slippery material. All other ice sheets of this type have slid back into the ocean, raising sea level over 100
meters. Will the West Antarctic ice sheet be the last to go? If it
happens as rapidly as its icy kin disappeared, a potential 5-meter
increase in sea level around the globe could occur fast enough to cause widespread economic and ecological damage.
Others have argued that the West Antarctic ice sheet is uniquely stable
pointing to its persistence in our warm climate.
The study of the peculiar case of West Antarctica has been full of
fascinating discoveries. These have come through a combination of
wearying field work in a hostile environment, intense scrutiny from a
vast stable of satellite sensors and complex numerical models. Remote
sensing data are used for everything from making better maps of field
areas, to quantifying surface elevations and velocities. Detailed
imagery also allows us to detect surface features that record past flow
directions. Twenty-five years of concentrated research have revealed a
multifaceted dynamic system that responds to what falls on it, what it
rests on and what it must push against. The ice sheet is changing
constantly and is a collage of different basins all behaving with a
high
degree of independence. But what of its future?
Wave Scattering Research Center, University
of Texas at Arlington
Contact Information:
Dr. Adrian K. Fung
Wave Scattering Research Center
Electrical Engineering Department
University of Texas at Arlington
UTA Box 19016
Arlington, TX 76019
USA
Tel.: 817-273-3422
Fax: 817-273-3443
E-mail: eefung@uta.edu
Major developments on active and passive
microwave remote sensing of soil moisture over the last twenty five years
are reviewed. The basic principles and experimental studies with ground
truth on active and passive sensing of soil moisture are discussed. This
is then followed with the indications of field experiments on the applicability
and practicality of anticipated emission and scattering behaviors. Reported
results include ground-based, airborne and spaceborne emission and backscattering
measurements as a function of soil moisture and other system, geometric
and soil surface parameters. Based upon the observed scattering and emission
characteristics and measured soil conditions, various approaches to soil
moisture retrieval have been developed. The requirements and practical
aspect of these retrieval methods are briefly summarized. Finally, the
complementary nature and the relative merits of active and passive sensing
are discussed and a possible approach to soil moisture retrieval is presented.
Useful surface and volume scattering models for bare soil, sea surface, vegetation, and snow and ice are reviewed. Applications of models to numerically simulated, laboratory contolled, and field meausrements are shown for surface scattering in vertical and horizontal polarizations over a wide range of angles and frequencies. It is noted that the sea surface is generally skewed by the wind and hence its scattering properties cannot be explained by the use only of the surface spectrum. In particular, upwind and downwind difference is due to the surface bispectrum which has been widely overlooked in applications.
Generally, scattering from vegetation can be explained by a combined surface and volume scattering model using the radiative transfer method. One needs only the phase functions for a leaf, a branch and a trunk to put into the radiative transfer model. However, some vegetations have specific leaf patterns. The leaf pattern effect can show up at certain frequencies. In this case, the phase function for leaves that form a pattern will be needed. An example, based on field measurements, is given to illustrate this point.
Snow and ice form a dense medium. It may be spatially dense meaning that the scatterers are close together so that the adjacent scatterers are not in the far field of each other. It may also be electrically dense meaning that the spacing between adjacent scatterers is smaller than the exploring wavelength. Hence, in modeling both of these effects should be included. Here again, both surface and volume scattering are generally present and one can use the radiative transfer method to integrate them. Applications to field and laboratory measurements of such a dense medium model are shown.
Contact Information:
Professor Albin J. Gasiewski
Department of Electrical and Computer Engineering
University of Colorado
Boulder, Colorado
USA
Tel.: 604-363-0776
Fax: 604-363-0775
E-mail: al.gasiewski@noaa.gov
Remote sensing of geophysical processes involving water in its various phases is increasingly important to weather and climate forecasting, agriculture, and transportation. Passive microwave sensing plays a key role in hydrological observation due to the wide range of interactions of microwaves with natural media. Using appropriate microwave frequencies, measurements of soil moisture, sea surface temperature, water vapor, ocean surface winds, cloud water content, and rain rate can be made. High-resolution microwave imaging using airborne radiometers allows unique views of the hydrological state at spatial scales comparable to the natural scale of convection, specifically, at scales that are approximately a factor of 10-100 times smaller than those available using satellite microwave sensors. The use of fully polarimetric imaging techniques further facilitates the observation of hydrological features by providing additional independent data. The talk will summarize past work in airborne passive microwave imaging at sub-mesoscale spatial resolutions, and focus on high-resolution conically-scanned polarimetric imagery of microwave thermal emission from snow fields, sea ice, soil moisture fields, and severe weather. The application of such data to the design of new passive microwave imaging sensors - both airborne and spaceborne - are discussed.
Advanced Forest Technologies Program, Natural
Resources Canada
Contact Information:
Dr. David G. Goodenough
Pacific Forestry Centre
Natural Resources Canada
506 West Burnside Road
Victoria, B.C. V8Z 1M5
CANADA
Tel.: 250-363-0776
Fax: 250-363-0775
E-mail: dgoodeno@nrcan.gc.ca
Website: http://rseng.cs.uvic.ca/faculty/d_goodenough.html
In order to monitor the resources and environment of the planet, it is necessary to use remote sensing from multiple sensors and integrate these data with historical information contained within geographical information systems (GIS). Multiple sensors are required to identify attributes of interest. In forestry, resource managers want to know the amount of the resource by species, area, timber volume, etc., the spatial distribution, the health (chemistry) of the forests, and the temporal changes of the resource, both past and predicted for the future. The technologies of the IEEE Geoscience and Remote Sensing Society are used to create information systems to support resource and environmental management. In this presentation we describe hyperspectral and radar methods and systems to obtain valuable forest information, such as chemistry, above-ground carbon, species, and biomass.
Models of forests are used to predict remote sensing results. The inversion of these results can lead to the estimation of forest parameters. National and global monitoring requires systems for distributed data management. We have created a system (www.saforah.org) using GRID architecture, optical light paths, and a petabyte data store at the University of Victoria. SAFORAH serves out to the public and research community remotely sensed data of Canada and forest information products for land cover, biomass, and change. Hyperspectral sensing is used to obtain species distribution and forest chemistry. Examples of this work for forest applications and the generation of Kyoto Protocol products are presented.
Laboratory of Space Technology, Helsinki
University of Technology
Contact Information:
Prof. Martti T. Hallikainen
Helsinki University of Technology
Laboratory of Space Technology
Otakaari 5A FIN-02150 Espoo
FINLAND
Tel.: 358-9-451-2371
Fax: 358-9-451-2898
E-mail: Hallikainen@hut.fi
Recent development of microwave remote sensing
in Europe has been rapid both in technology and in applications. Europe's
first remote sensing satellite ERS-1 has provided scientists with SAR
scenes, AMI wind mode and wave mode data, and altimeter data. The ERS-2
satellite was launched in 1995, and the next two satellites, ENVISAT-1
(launch in 1999) and METOP (launch in 2000), are under construction. For
the development of applications, numerous ERS-1/2 Announcement of Opportunity
and Pilot Projects are in progress, and data has been obtained from the
first tandem flight of two spaceborne SAR sensors. Recent ESA initiatives
include the Earth Explorer (application development) and Earth Watch (operational
remote sensing) programs.
Advanced spaceborne sensors are under development
by ESA, including the ASAR synthetic aperture radar (C-band, VV polarization,
swath width 500 km) and RA-2 radar altimeter Ku-band and S-band). Development
of the MIMR microwave radiometer (dual-polarized, 6 to 89 GHz) has been
temporarily halted, because the sensor could not be accommodated onboard
near-future satellites.
Airborne SAR sensors have been constructed
in several countries, including Germany (ESAR), Denmark (EMISAR), The
Netherlands (PHARE) and France. Airborne scatterometers have been built
in the Netherlands, France, Finland and Germany. Airborne MIMR simulators
for application development are available in Finland and France.
The role of the European Union in remote
sensing is increasing. The European Microwave Signature Laboratory (EMSL)
is used to study the basic scattering behavior of various targets and
to develop methods for interpretation of satellite data. The Centre for
Earth Observation (CEO) is a European Commission funded program for advancing
the use of Earth observation data. Numerous EU-funded research projects
are in progress; the project teams consist of remote sensing institutes
and companies in various EU member countries and other participating countries.
The main research topics in microwave remote
sensing in Europe include ocean, sea ice, forests, agriculture, snow,
atmosphere and environmental monitoring. Ocean-related studies are conducted
mainly in Atlantic and Mediterranean countries. Sea ice studies are in
progress concerning the Greenland Sea, Norwegian Sea and Baltic Sea. In
forestry, topics ranging from boreal to tropical forests are under study.
Application of ERS-1/2 SAR data to the inventory of forests is an important
topic. Radiometer and radar studies of snow are conducted both in Scandinavia
and in the Alpine region.
In some areas, remote sensing activities
in Eastern European countries have reached a high standard. For example,
determination of soil moisture from radiometer data has been investigated
extensively in Russia, Hungary and Bulgaria. International programs have
been established to foster cooperation between East and West.
Jet
Propulsion Laboratory
Talk Abstract: Mapping
Beneath the Vegetation – The GeoSAR Mapping Instrument
GeoSAR is a program to develop a dual frequency airborne radar interferometric
mapping instrument designed to meet the mapping needs of a variety of
users in government and private industry. Program participants are the
Jet Propulsion Laboratory (JPL), Earthdata International, Inc., and the
California Department of Conservation with funding provided initially
by DARPA and currently by the National Imagery and Mapping Agency. Begun
to address the critical mapping needs of the California Department of
Conservation to map seismic and landslide hazards throughout the state,
GeoSAR is currently undergoing tests of the X-band and P-band radars designed
to measure the terrain elevation at the top and bottom of the vegetation
canopy. Maps created with the GeoSAR data will be used to assess potential
geologic/seismic hazard (such as landslides), classify land cover, map
farmlands and urbanization, and manage forest harvests. This system is
expected to be fully operational in 2002. This talk present an overview
of the system and show some examples of X-band and P-band data and maps
generated using the GeoSAR systems and comparison with other sensor data
such as LIDAR and photogrammetric data.
Talk Abstract: Mapping
the World’s Topography from Space – The Shuttle Radar Topography Mission
A
highly accurate global topographic map of the Earth’s surface has been
an elusive goal for at least three decades that will soon be achieved
with the newly acquired Shuttle Radar Topographic Mission (SRTM) data.
The
National Aeronautics and Space Administration (NASA) in conjunction with
the National Imagery and Mapping Agency (NIMA) of the US developed SRTM
to meet this critical mapping requirement. SRTM
collected data for 99.97% of the Earth’s landmass between –57° and 60°
latitude during an 11 day mission in February 2000. A modified version
of the SIR-C radar that previously flew on the shuttle in 1994 augmented
with a radar mounted on a 62 m boom was used to collect radar interferometric
data at C (5.6 cm wavelength) and X
(3 cm wavelength) bands. The C-band radar was operated in the SCANSAR
mode in order to extend the swath width to 225 km, the minimal amount
required to achieve contiguous coverage at the equator. By
combining the data from both ascending and descending orbits a seamless
mosaic of the Earth’s topography will be created. This talk will present
a mission overview, how the data was collected and being processed, and
show some examples of SRTM data and how it may be used.
Department of Geological Sciences, The Ohio
State University
Contact Information:
Kenneth C. Jezek
Byrd Polar Research Center and Department of Geological Sciences
The Ohio State University
1090 Carmack Road
Columbus OH, 43210
Tel: 614-292-7973
E-mail: jezek.1@osu.edu
Talk Abstract: Antarctica:
Its ice, land and ocean as viewed by RADARSAT-1
Antarctica is Earth’s coldest, windiest, and on average highest of continent.
Because of its harsh climate and because it is often covered by
clouds or shrouded in darkness during the long polar night, much of Antarctica
remained poorly mapped till the end of the last decade.
Then in 1997, NASA and the Canadian Space Agency embarked on a
collaboration to obtain the first, high resolution synthetic aperture
radar image of the southern continent.
The first imaging campaign was successfully completed in October
1997 and achieved the primary goal of producing a stunning, new view of
Antarctica. It revealed in
unprecedented detail extensive networks of ice streams, the positions
of ice divides and the ice margin, and even hinted about processes occurring
at the base of the ice sheet. Following
up on results from the 1997 effort, a second acquisition campaign occurred
in the fall of 2000. Along
with providing a second benchmark for measuring changes in ice sheet extent,
the 2000 campaign collected interferometric data over much of the ice
sheet. These data are being
used to measure the surface velocity of the ice sheet, an important parameter
for estimating ice sheet mass balance and for understanding the response
of the ice sheet to changing climate.
This
presentation summarizes results from the 1997 and 2000 imaging campaigns.
In addition to describing glaciological processes captured in the
image mosaics, the RADARSAT 1997/00 data are compared to assess spatial
patterns in ice margin advance/retreat, which are themselves contrasted
with earlier estimates of ice sheet behavior.
Surface velocity data over newly discovered East Antarctic ice
streams. These are used to
estimate ice stream mass balance the role of these ice streams on the
stability of the East Antarctic Ice Sheet.
Additional
information on the RADARSAT-1 Antarctic Mapping Project is available at:
http://bprc.osu.edu/rsl/radarsat/
Contact Information:
IREA-CNR
Riccardo Lanari
IREA-CNR
via Diocleziano 328
80124 Napoli
Italy
Tel: +39 081 5707999
Fax: +39 081 5705734
E-mail: lanari.r@irea.cnr.it
IREA-CNR WEB-site: http://www.irea.cnr.it/
See also the IREA-CNR InSAR WEB-GIS site:
http://www.irea.cnr.it/webgis/terra.html
Talk Abstract: Differential
SAR Interferometry: techniques and applications
Differential
SAR Interferometry (DIFSAR or DInSAR) is a technique that allows estimation
of earth surface deformations occurring in an area of interest, by exploiting
the phase difference (phase interferogram) of SAR images relative to that
zone and obtained by processing data acquired at different times; the
DIFSAR technique has already shown its capability in detecting, with a
centimetric (in some cases millimetric) accuracy, surface deformations
caused by different natural and antropogenic phenomena.
The
aim of this talk is to introduce the basic concepts involved in the DIFSAR
technique and to summarize which are the key applications of this method.
In particular, a discussion on the rationale of the DIFSAR approach will
be given first; in the following, the main limitations and the attainable
resolutions will be analyzed. Moreover, the possibility of combining several
SAR acquisitions relative to the investigated zone will be explored to
follow the evolution of the detected deformation. Some examples will be
presented for underlining the capability of the technique to analyze deformations
caused by different phenomena such as volcano deformations, earthquakes,
and urban subsidence.
Talk Abstract: Differential SAR Interferometry: basic principles, key applications and new developments
Differential SAR Interferometry (DInSAR or DIFSAR) is a microwave imaging technique that allows to investigate earth surface deformations occurring in an area of interest with a centimetre (in some cases millimetre) accuracy. In particular, the DInSAR technique exploits the phase difference (interferogram) of temporally separated SAR images relative to the investigated zone and has already shown its capability in detecting surface deformations caused by different natural and anthropogenic phenomena.
The aim of this talk is to introduce the basic concepts involved in the DInSAR technique, summarize the key applications of this method and present it new developments. In particular, a discussion on the rationale of the DIFSAR approach will be given first, highlighting the key points and the main limitations. Several examples will be presented for underlining the capability of the technique to analyze deformations caused by different phenomena such as volcano deformations, earthquakes and urban subsidence. Moreover, the possibility of combining several SAR acquisitions relative to the investigated zone will be explored; in particular, it will be shown how the integration of the information relevant to different radar observation directions can be exploited to retrieve the different components of the detected deformations. The last part of the talk will be dedicated to present the Persistent Scatterers algorithms that represent a development of the basic DInSAR technique, allowing to analyze the temporal evolution of the detected deformations from a data set of subsequently acquired SAR images.
Microwave Sensors Branch, NASA/Goddard Space
Flight Center
Contact Information:
Dr. David M. Le Vine
Mail Code 614.6
NASA/Goddard Space Flight Center
Greenbelt, MD 20771
USA
Tel: 301-614-6540
Fax: 301-614-5558
E-mail: David.M.LeVine@nasa.gov
Aquarius is a microwave remote sensing system designed to obtain global maps of the surface salinity field of the oceans from space. It will be flown on the Aquarius/SAC-D mission, a partnership between the USA (NASA) and Argentina (CONAE) with launch scheduled for launch early 2009. The objective of Aquarius is to monitor the seasonal and interannual variation of the large scale features of the surface salinity field in the open ocean to address questions associated with ocean circulation and its impact on climate. For example, salinity is needed to understand the large scale thermohaline circulation, driven by buoyancy, which moves large masses of water and heat around the globe. Salinity also has an important role in energy exchange between the ocean and atmosphere, for example in the development of fresh water lenses (buoyant water that forms stable layers and insulates water below from the atmosphere) which alter the air-sea coupling. Aquarius is a combination radiometer and scatterometer (radar) operating at L-band (1.413 GHz for the radiometer and 1.26 GHz for the scatterometer). The primary instrument for measuring salinity is the radiometer which responds to salinity because of the modulation salinity produces on thermal emission from sea water. The scatterometer will provide a correction for surface roughness (waves) which is one of the greatest unknowns in the retrieval. This talk will provide an introduction to remote sensing of sea surface salinity and then describe the Aquarius instrument and the Aquarius/SAC-D mission.
CNES
(French Space Agency)
Contact Information:
Didier
Massonnet
Centre National d’Etudes Spatiales,
18 Ave. E. Belin, 31055
Toulouse, FRANCE
Fax (33) 61 27 31 67
Radar
instruments are used to observe the Earth with radio waves. The resulting
image reflects both the physical properties of the waves and the technological
choices that have to be made to obtain a usable image from the raw data
gathered by the instrument. The means by which a radar image is obtained
through a computer can be described as a twofold image. The first part,
the amplitude, conveys a similar, but different information than conventional
imagery, such as the geometry of pixel layout on the ground and the estimation
of the speed of mobile targets on land or sea. The second part, the phase,
cannot be visualized by itself and gains value only through the comparison
with the similar part of a companion image. An accurate description of
terrain elevation can be obtained from the slight difference of point
of view between the images. A much more accurate assessment of terrain
displacement, down to millimeters, between the acquisition dates of the
images can also be obtained. In addition, otherwise invisible meteorological
phenomena can be mapped. Several examples are used to illustrate the way
these various pieces of information are obtained jointly or separately,
as well as ways to combine the results into a single color image.
Radar
images can be compared very precisely through the technique of radar interferometry,
which takes advantage of tiny differences of point of view between two
radar images to compute the topography. As an extension, a difference
in time on the order of one second between the acquisitions of two images
also allows mapping the velocity of ocean currents. The principle of interferometric
cartwheel consists of using a set (three in the standard implementation)
of receive-only satellites with a small antenna. This modest requirement
allows the payload to be put on microsatellites, which in turn fly in
formation while following a conventional radar satellite at a distance.
The lead satellite illuminates the ground, while the receive-only
systems in turn point at the same area.
In
order to obtain stable differences in viewing geometry, as well as of
acquisition times all along the orbit, the three receivers are given a
slightly higher eccentricity than the conventional radar satellite they
follow, while keeping the same orbital period. They describe an ellipse
around the orbital position they would have without the additional eccentricity.
The uniform distribution of the perigees results in receivers also being
uniformally distributed along the ellipse, which features a horizontal
axis twice as long as the vertical axis. It can be shown that, with three
receivers, the horizontal
and vertical baselines vary only by 7.5% along the orbit, with respect
to their average value, provided we consider the two satellites best positioned
for the purpose. Another
advantage of the constellation is that the diversity in point of view
also allows creation of radar images with a better resolution than that
of the emitter and are difficult to jam because the constellation is distanced
from the emitter, fully passive, and therefore silent.
The
primary applications of this invention are very accurate global topographic
modeling, with vertical accuracy of one meter or better, and mapping the
velocity of ocean currents by taking advantage of the horizontal baseline.
After actual testing of the super-resolution principle, distributed radar
systems could be build, creating very high resolution results from many,
passive microsatellites and a dedicated or opportunistic radar illuminator.
Cost-effectiveness results from the fact that the necessary resources,
in particular telemetry and antenna surfaces, are distributed between
the receivers, which do not need to produce the radio illumination of
the ground.
SAR
interferometry has been applied to tens of earthquakes and to many volcanoes
and caldera using ERS-1 as well as J-ERS radar satellites.
The average results were good (RMS misfit
~1-2 cm) and led to accurate modelling of the phenomena using elastic
half space models. Even interferograms of poor quality contribute significantly
to the success of the modelling as we observed, for instance, in the study
on Mount Etna.
The
accuracy of the results is mainly limited by the contribution of atmospheric
propagation heterogeneities. The limitation is especially important in
the study of very small displacements such as the centimeter-sized rift
that was observed in Iceland over several years. This contribution can
be detected using a pair-wise logic which requires many observations.
In analyzing this large data set, we learn that data acquired by night
tend to be superior. However, daytime acquisition is required when an
observation along different angles of view is needed. An alternate solution
is to observe the site combining satellites with different geometries,
as in the example of the Northridge earthquake.
Professor
in the Institute of Geophysics and Planetary Physics (IGPP) at Scripps
Institution of Oceanography
Contact
Information:
Jean-Bernard H. Minster
Scripps Institution of Oceanography
Institute of Geophysics and Planetary Physics
University of California, San Diego
La Jolla, CA 92093-0225
Tel: 858-534-5650
Fax: (858) 534-2902
Email: jbminster@ucsd.edu
Homepage: http://pauk.ucsd.edu
Talk
Abstract: Airborne and Spaceborne InSAR
and Lidar: New tools for Solid Earth Science
Airborne
and Spaceborne InSAR and Lidar: New tools for Solid Earth Science
Airborne
and satellite-based Synthetic Aperture Radar (SAR) and Lidar are active
remote sensing techniques that have matured substantially over the past
decade. In the Earth Sciences, the use of repeat-pass interferometry (InSAR)
to study surface deformations associated with earthquakes and volcanoes
has received considerable attention. Because it offers continuous spatial
coverage, InSAR is a natural complement to permanent, continuously operating
GPS networks which are being deployed in tectonic areas worldwide. Yet,
these spectacular results have all been obtained using data from non-US
spacecraft, which were not optimized for this class of scientific applications.
For this reason, the Earth science research community has recently recommended
that a NASA-led multi-agency SAR mission should become an important component
of the NSF-led EarthScope initiative.
Airborne
imaging lidar, now commercially available, is a powerful tool to conduct
geomorphological studies, even in inaccessible vegetated areas with rather
dense canopies. Imaging lidars are capable of delivering extremely detailed
Digital Elevation Models never before available for environmental and
geological research, with applications as diverse as the mitigation of
natural hazards or land use and urban studies. With the launch of the
ICESat mission in 2002, satellite-based lidar will provide researchers
with global access, and deliver precisely geolocated data sets for studies
of such topics as ice sheet mass balance, land surface and land cover
change, or structure and dynamics of clouds and aerosols.
Professor Emeritus, EECS, University of Kansas
Contact Information:
Dr. Richard. K. Moore
1712 Carmel Dr.
Lawrence, KS 66047-1840
USA
Tel: 785-843-3697 (H)
Fax: 785-864-7789 (O) 785843-3697(H - must be preceded by phone call)
E-mail: rmoore@sunflower.com
After discussing the nature of a radar remote-sensing system, we trace the development of radar sensing of oceans, vegetation, geology, and sea ice. This is followed by a brief discussion of system-development history. This leads to an assessment of the current state of knowledge in each area, and of unsolved problems that we can see today.
We conclude with some ideas on the philosophy and ultimate goals of microwave remote sensing. Finally, some suggestions follow on the future of spaceborne remote sensing.
You need aerial or space photographs of an area, but it is cloudy or dark. What can you do? You can use an imaging radar. It can look through clouds and rain and make a picture similar to a photograph. Moreover, radar is more sensitive to soil and plant moisture than optical sensors. Radar also penetrates thin vegetation and a little soil, so the pictures are some different, but give extra information not in photos. Thus, when both can be used together, they are complementary just as having more colors gives more information.
Radar also has special uses not available with other sensors. Special radars measure winds at the ocean surface. Imaging radars show ocean features not easily seen on photos. They also allow better monitoring of ice on the sea and continental ice sheets, and permit some measurements of snow properties.
After discussion of these topics, we will describe briefly how radar works. Then examples will be shown of various radar images from space, and of some results of wind measurements over the oceans.
Radars in space can add much to our knowledge of the dynamics of the world's oceans. Wind-vector scatterometers provide inputs to global meteorological and wave-forecast models. Imaging radars in space initially were intended to find wave spectra, but now we know that they provide much information on current boundaries, storm effects, shallow-water bottom topography, and other features. Imagers also give us up-to-date information on details of the ice cover on the oceans. Altimeters, the most mature space radars, give information on tides and the geoid
Radar backscatter strength from the ocean is, surprisingly, governed largely by the small-scale features, capillary waves and short gravity waves. It is this that allows the wind-vector scatterometer to work. We will discuss briefly the mechanisms and their application to scatterometry.
Spaceborne imaging radars usually use synthetic apertures to achieve resolutions of the order of tens of meters, although mesoscale features can also be seen on images from real-aperture radars. Many complications arise in interpreting SAR images of the sea because SAR uses the Doppler effect to produce its fine resolution, and the motions on the sea affect this process. We will discuss SAR principles briefly and point to the complications.
Airborne radars have been used in Russia and Canada for sea-ice monitoring for about 25 years. The Canadian RADARSAT provides much information, especially on sea ice. Images now available from ESA's ERS-1/2 and Envisat SAR, and ship-based experiments show some differences between typical ice responses in Arctic and Antarctic.
Contact Information:
Dr. Jay Pearlman
Chief Engineer
NCO C&EM
The Boeing Company
Seattle, Washington
USA
Remote Sensing Scientist at TWR
The Global Earth Observation System of Systems (GEOSS) is a complex system of sensors, communication devices, storage systems, computational and other devices used to observe the Earth and gather data needed for a better understanding of the EarthÕs processes. In addition, GEOSS includes models and methods to create information from the observation data.
GEOSS is focused on using this Earth Observation information to address major issues of society on a regional and global scale. There are nine societal benefit areas that are the initial focus on GEOSS:
- Reducing loss of life and property from natural and human-induced disasters
- Understanding environmental factors affecting humans
- Improving management of energy resources
- Understanding climate variability and change
- Improving water resource management through understanding of the water cycle
- Improving weather information, forecasting, and warning
- Improving the management and protection of terrestrial, coastal, and marine ecosystems
- Supporting sustainable agriculture and combating desertification
- Understanding, monitoring, and conserving biodiversity
GEOSS is being built initially from existing systems and initiatives, with an emphasis on the creation of synergies among GEOSS components that provide increased benefits to society. Realizing such benefits will require the exchange of data and information between disparate data and information systems, an interoperability challenge of unprecedented magnitude. Dr. Pearlman is a co-chair of the GEO Architecture and Data Committee and chair of the IEEE Committee on Earth Observation. In this presentation he provides insights into the challenges and opportunities of establishing a global observation system of systems and an overview of the progress in fulfilling the ten year development plan.
Contact Information:
Prof. Yoshio Yamaguchi
Department of Information Engineering, Niigata University
Ikarashi 2-8050
Niigata 950-2181
JAPAN
Remote Sensing Scientist at TWR
Detection of buried objects by polarimetric radar has been attractive
attention both in technology and in applications. Buried objects, for
example, are archaeological historical remains, human body
encountered by snow avalanche, land mines, gas pipes, electric pipes,
etc. The best instrument (radar, sonar, electric current method)
depends on the depth and target size. Polarimetric FM-CW radar is
suited for shallow objects detection.
Since FM-CW radar is low power instrument, easy to handle for short
range sensing, and can be equipped with polarimetric data take
function, it is expected to play essential role in the detection
field.
The basic principle of radar, together with polarimetric SAR imaging
scheme are reviewed. This is then followed with the field experiments
using several targets including myself in deep snowpack and sandy
ground. Polarimetric signal processing based on scattering matrix
helps target identification and recognition, which includes
decomposition of scattering matrix, enhancement of target,
ellimination, anisotropy, entropy, etc. Some experimental results
with 2-D and 3-D polarimetric detection images can be presented.
Ocean Remote Sensing Group in the Space,
Department of the Johns Hopkins University Applied Physics Laboratory
Contact Information:
Dr. Keith Raney
The Johns Hopkins University
Dr. Keith Raney
The Johns Hopkins University
Applied Physics Laboratory
Johns Hopkins Road
Laurel, MD 20723-6099
USA
Phone: 240 228-5384
FAX: 240 228-5548
E-Mail: Keith.Raney@jhuapl.edu
To catch the moon from the bottom of the
sea" is a very high-scoring combination in the game of Mah-Jong. The National
Oceanic and Atmospheric Administration (NOAA) and the Johns Hopkins University
Applied Physics Laboratory (APL) are planning to catch the bottom of the
sea from the International Space Station (ISS), using an original instrument
named ABYSS. It turns out that ABYSS and the ISS are a very high-scoring
combination. Sea-bottom topography has been mapped by inverting sea surface
slope data from height measurements provided by the Geosat radar altimeter,
a 1980's mission designed, built, and operated by APL. ABYSS will measure
sea-surface slopes down to one micro-radian, to spatial scales down to
6-km, and with balanced NS and EW slope measurement accuracy. These data
will support an order-of-magnitude improvement in bathymetric maps, due
primarily to the favorable inclination of the ISS orbit, and to the unique
precision and attitude-tolerance of the altimeter. ABYSS relies on new
concepts invented and flight-proven at APL. These same concepts also pave
the way toward miniaturized dedicated radar altimeter satellites, radar
altimeters that can measure the heights of sloping continental ice
sheets, and improved ground-penetrating radar.
“To catch the moon from the bottom of the sea" is a very high-scoring combination in the game of Mah-Jong. The National Oceanic and Atmospheric Administration (NOAA) and the Johns Hopkins University Applied Physics Laboratory (APL) are planning to invert this combination, by catching the bottom of the sea from space, through a radar altimeter mission named ABYSS-Lite. Sea-bottom topography can be mapped by analyzing sea surface slope data from height measurements provided by a precision radar altimeter. Sea-surface slope data are a direct expression of local gravity anomalies. ABYSS-Lite will measure sea-surface slopes down to one micro-radian, to spatial scales down to 6-km, and with balanced NS and EW slope measurement accuracy. These data will support an order-of-magnitude improvement in oceanic gravimetry and bathymetric maps, compared to the current state-of-the-art. This improvement is due primarily to the unique precision of the delay-Doppler altimeter. This altimeter relies on new concepts invented and flight-proven at APL. These same concepts also pave the way toward miniaturized dedicated radar altimeter satellites, radar altimeters (such as CryoSat) that can measure the heights of sloping continental ice sheets, and improved space-based ground-penetrating radar.
Dept.
of Electrical and Computer Engineering, The University of Arizona
Contact Information:
Dr.
John A. Reagan
Dept. of Electrical and Computer Engineering
The University of Arizona
1230 E. Speedway, Bldg. 104
Tucson, AZ 85721
USA
Phone:
520- 621-6193
Fax: 520- 621-8076
E-Mail: reagan@ece.arizona.edu
Technological
advances in lasers, detectors and high-resolution spectral filters during
the 1990's have enabled the development of relatively low-cost, eye-safe
miniature lidars, generally referred to as MPL's (Micro-Pulse Lidars).
The basics of lidar and particular technological innovations critical
to the realization of MPL's are first presented.
Design considerations including impacts and trade-offs of laser
pulse energy/rep rate, detector quantum efficiency/noise effects, transmitter/receiver
beam widths and implicit overlap limitations, narrow-band receiver filter
requirements, and optical system thermal stability limitations are then
addressed.
Finally, examples of MPL applications are presented including results
from field experiments demonstrating MPL approaches for sensing atmospheric
aerosols and progress reports of development efforts to realize water
vapor and wind sensing MPL's.
Senior
Scientist, Earth
Sciences Directorate, NASA/Goddard
Space Flight Center
Contact Information:
Dr. Vincent V. Salomonson
Research Professor
Departments of Meteorology and Geography (joint appointment)
University of Utah
Salt Lake City, Utah 84112
Send Mail to:
10067 S. Homecoming Avenue
South Jordan, Utah 84095
Ph: 801-523-6195 (home)
Ph: 801-585-9492 (work--Department of Meteorology)
Ph: 301-526-7708 (cell)
E-mail: Vincent.V.Salomonson@nasa.gov
The Moderate Resolution Imaging Spectroradiometer (MODIS) operating on both the Earth Observing System (EOS) Terra and Aqua Missions began to produce data from the Terra MODIS in February 2000 and the Aqua MODIS in June 2002. Both instruments continue to produce excellent data that have made and are making very considerable contributions to better understanding of land, oceans, and atmospheres processes and trends as well as contributing to better natural resources management. All subsystems of the instruments are performing as expected. The signal-to-noise (S/N) performance meets or exceeds specifications, band-to-band registration meets specifications, geodetic registration of observations is nearing 50 meters (one sigma) and the spectral bands are located where they were intended to be pre-launch and attendant gains and offsets are stable to date. The data from both instruments have been reprocessed several times. "Collection 4" has been completed and MODIS data products are available from the three EOS Distributed Active Archive Centers (DAAC's) responsible for archiving and distributing MODIS data. A new reprocessing effort ("Collection 5") of land and atmosphere products is getting underway and will be completed in 2006 (atmospheres products) or early 2007 (land products). Collection 5 will offer some considerable improvements in all land and atmosphere products. Land products are available and distributed by the Land Processes DAAC at the EROS Data Center in Sioux Falls, South Dakota. The atmospheres products are archived and distributed by the NASA Goddard DAAC. Cryosphere Products are archived and distributed by the National Snow and Ice Data Center in Boulder, Colorado. Producing MODIS ocean color products that are well characterized and validated over time has been problematic, but considerable progress has been made in getting Aqua MODIS ocean color data products to merge successfully with SeaWiFS products. Aqua MODIS ocean products (both ocean color and sea surface temperature) are being produced and distributed by the Ocean Color Data Processing System (OCDPS) at the Goddard Space Flight Center. Reprocessing of Terra MODIS ocean products will be reprocessed by the OCDPS at some point in the future after review and concurrence by NASA Headquarters and the science community. A MODIS-like instrument called the Visible and Infrared Imaging Sensor Suite (VIIRS) is being developed to fly on the National Polar Orbiting Environmental Satellite Series (NPOESS) Preparatory Project (NPP). The planned NPP is a “bridge mission” spanning the operations of the EOS Terra and Aqua spacecraft with the NPOESS operations that are scheduled to begin the 2009-2010 time frame. These activities should ensure that MODIS-like observations will be operationally available well into the second decade of the 21st century.
Microwave Remote Sensing Laboratory, University
of Massachusetts at Amherst
Contact Information:
Dr. Calvin T. Swift
Department of Electrical and Computer Engineering
University of Massachusetts at Amherst
College of Engineering
Amherst, MA 01003
USA
Tel: 413-545-2136
Fax: 413-545-4652
E-mail: klemyk@ecs.umass.edu
As part of a subcontract with the manufacturer
of the Defense Meteorological Space Program (DMSP) special sensor microwave/imager
(SSM/I), an operational wind speed algorithm was developed by Environmental
Research and Technology, Inc. (ERT). The ERT algorithm is based on the
"D-Matrix" approach, which seeks a linear relationship between
measured SSM/I brightness temperatures and environmental parameters. D-matrix
performance was validated by comparing algorithm derived wind speeds with
near-simultaneous and colocated measurements made by offshore ocean buoys
maintained by the National Oceanic and Atmospheric Administration. The
DMSP accuracy requirement of +- 2m/s for wind speed predictions in the
range of 3 m/s to 25 m/s was not obtainable with the original version
of the D-matrix, which had severe bias and scaling problems. Revisions
to the algorithm made at the University of Massachusetts caused it to
perform within specifications. Other topics include error budget modeling,
alternate wind speed algorithms, and D-matrix performance with one of
more inoperative SSM/I channels. Additional research is being done from
aircraft to measure high wind speeds in hurricanes. The C-band instrument
used for this purpose has measured wind speed as high as 70 m/s.
Aperture synthesis represents a new technology
being developed for passive microwave remote sensing of the environment.
The concept employs an interferometric technique in which the product
from pairs of antennas is sampled as a function of pair spacing. Substantial
reductions in the antenna aperture needed for a given spatial resolution
can be achieved with this technique. As a result, aperture synthesis could
lead to practical passive microwave remote sensing instruments in space
to measure parameters such as soil moisture and ocean salinity which require
observations at long wavelengths and, therefore, large antennas.
ESTAR is an L-band, aircraft prototype built
as part of research to develop this technique. ESTAR is a hybrid real-and
synthetic aperture radiometer which employs stick antennas to achieve
resolution along track and uses aperture synthesis to achieve resolution
across track. Experiments to validate the instrument's ability to measure
soil moisture have recently been conducted at the USDA watersheds at Walnut
Gulch in Arizona and the Little Washita River in Oklahoma. The results
of both experiments indicate that a valid image reconstruction and calibration
have been obtained for this remote sensing technique. A more advanced
instrument operating at 33 GHz is presently under evaluation.
Clare
Cockrell Williams Centennial Chair in Engineering, Center of Space
Research, University of Texas at Austin
Contact Information:
B
D. Tapley
University of Texas at Austin
Center of Space Research
The
Gravity Recovery and Climate Experiment (GRACE) is a dedicated satellite
mission whose objective is to map the global gravity field with unprecedented
accuracy over a spectral range from 500 km to 40,000 km. The measurement
precision will support gravity field solutions in this frequency range
that are between 10 and 1000 times better than our current knowledge.
Highly accurate measurements,
with both high spatial and temporal resolution, will allow studies of
the gravitational signals associated with the mass exchange between the
solid Earth and the hydrological, ocean and atmospheric components. The
primary measurement provided by the High Accuracy Inter-satellite Ranging
System (HAIRS) is the range change between two satellites orbiting one
behind the
other
at an approximate distance of 200 km. The range change will be measured
with a precision better than 10 microns. A highly accurate three-axis
accelerometer, located at the satellite mass center, will be used to measure
the surface force and attitude control induced accelerations. Satellite
GPS receivers will position the satellites over the earth with centimeter
level accuracy. With this set of measurements, GRACE will provide highly
accurate measurements of the global gravity field once every thirty days.
The two satellites, scheduled were launched on March 17, 2002, and were
designed to operate for a period of five years. The satellites will fly
in coplanar nearly polar orbits, at an altitude between
500
and 300 km, separated by approximately 200 km along track. The mission,
which is one of the first NASA Earth System Pathfinder Missions, is implemented
through a collaborative arrangement
by
NASA and DLR. The presentation will summarize the mission structure, the
satellite and instrument performance, the data system and ancillary data
requirements and will describe some of the early data results.
Institute for High Frequency and Electronics,
University of Karlsruhe
Contact Information:
Dr. Werner Wiesbeck
Institute for High Frequency and Electronics
University of Karlsruhe
Kaiserstrasse 12
Karlsruhe D 75210
GERMANY
Tel: 49-721-608-2522
Fax: 49-721-691-865
E-mail: ihe@ihe.uka.de
Talk Abstract: Digital Beam-Forming in Remote Sensing
The invention of the Synthetic Aperture Radar (SAR) principle dates back to the early 1950s. The basic idea is to filter targets in a side looking radar according to their Doppler history in azimuth and by pulse or FM modulation compression in range. Since this time SAR systems have been, from a technical point of view, considerably refined to the state of the art where resolution and accuracy are close to the theoretical limits. The best innovations have been reached in polarimetry and interferometry. Nevertheless, the principles are still the same: The SAR is a side-looking radar where resolution is achieved in range by bandwidth and in azimuth by Doppler processing. The beam-forming concepts for coverage are still the same: dish antennas (scanned or fixed), antenna arrays (phased or fixed) or switchable antenna systems. All these have the drawback that the coverage defines the synthetic aperture length and by this the azimuth resolution or for scanned beams the loss of coverage has to be taken into account. These drawbacks can be overcome by Digital Beam-Forming. Significant advantages result by this. In its simplest form the transmit antenna illuminates a usually larger footprint, as do the multiple receive antennas. The beam-forming is accomplished in a digital process. Multiple beams may be processed simultaneously. The RF losses can significantly be reduced, allowing lower gain for the antennas, and thus larger footprints. This talk will present the principles and applications of Digital Beam-Forming in Remote Sensing.
Timeframe: 40 – 50 min
Required: Beamer
Dr. Howard A. Zebker
Associate Professor of Electrical Engineering and Geophysics at Stanford
University
Contact:
Stanford University
Depts. of Geophysics and Electrical Engineering
Stanford, CA 94305-2215
zebker@stanford.edu
Talk Abstract: Measuring Earth Crustal Deformation
with Interferometric Synthetic
Aperture Radar
The Earth's surface is composed of about a dozen major crustal plates, each
floating on the interior mantle and in constant motion. Consequences of
plate motion include the formation of mountain ranges and other geologic
features, plus the more localized processes of earthquakes and volcanism.
Here we examine the use of space technology to measure and map the accumulation
of strain within the crust. Both the Global Positioning System satellites
and synthetic aperture radar (SAR) interferometry now enable us to observe
surface deformation with such sensitivity that it may be possible to measure
strains accumulating before earthquakes strike or volcanoes erupt. For example,
consider the San Andreas transform fault, located at the boundary of the
North American and Pacific plates. The sensitive new measurement methodologies
may lead to our ability to localize buildup of strain in the crust and aid
in forecasting and hazard assessment. These new technologies have already
produced graphic images of surface displacements that occur during and immediately
after major earthquakes, and it is the goal of current research to measure
pre-seismic motions. Measurement of surface displacements of similar magnitude,
such as on active volcanoes and flowing glaciers, are becoming commonplace
and it is likely that comprehensive investigations of complex fault systems
like the San Andreas will lead to a more complete understanding of tectonic
hazard potentials in many areas around the world.
Talk Abstract: Time-Lapse Imaging of Subsurface Flow
Using SAR Interferometry
A sensitive technique for observing subtle surface deformation patterns
with time permits inference of many subsurface flow processes. Interferometric
synthetic aperture radar, or InSAR, uses data acquired by an orbiting
satellite that revisits the same ground area multiple times. The satellite
measures precise changes in distance to each 10 m size resolution element
on the ground, over a swath 100 km wide, and hence presents an image of
crustal deformation. Combined with inverse methods design to recover pressure
changes or dislocations at depth, the deformation map may be interpreted
to yield subsurface flow. Here we present several examples of InSAR analysis,
which retrieve i) water flow patterns in an aquifer, ii) magma flow in
active volcanic regions, and iii) viscous flow of salt diapirs through
cracks in the overlying cap rock. In each case we are able to describe
properties of flow patterns help us understand the geophysical description
of the subsurface environment. In the case of water aquifers, the experiments
reveal permeability distributions and capacities of the reservoirs. For
volcanoes, tracing the flow of magma defines the plumbing system of the
volcano and can aid in predicting eruptions. And for the salt domes, we
are able to determine the viscosity and grain size of naturally occuring
salt at depth.
|
