IEEE International Geoscience and Remote Sensing Symposium

This paper presents a new solution for detecting and following the temporal evolution of small scale deformation phenomena; in particular our approach extends the capability of the SBAS technique, presented in P. Berardino et al. (2001), which is mainly focused on investigating large scale deformations with spatial resolutions of about 100 m/spl times/100 m. The proposed technique relies on small baseline differential SAR (DIFSAR) interferograms only, but it is implemented by using two different sets of data generated at low (multi-look data) and high spatial resolution (single-look data), respectively. The former are used to identify and estimate, via the SBAS technique or O. Mora et al. (2001, 2002), possible atmospheric phase artifacts and large scale deformation patterns; the latter to detect, on the high resolution residual phase components, structures highly coherent in time (buildings, rocks, lava structures, etc.), identified jointly to their heights and displacements. In particular the estimation of the temporal evolution of these local deformations is easily implemented by applying the SVD technique. The presented algorithm has been tested with data acquired by the European Remote Sensing (ERS) satellites relative to the Campania area (Italy).

High resolution (<2 nm) optical spectra and biophysical measurements were acquired from corn leaves from field plots having four nitrogen fertilizer application rates: 20%, 50%, 100% and 150% of optimal levels. Reflectance (R), transmittance (T), and absorptance (A) spectra were obtained for both adaxial and abaxial leaf surfaces. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the "red edge inflection point" (REIP): 1) anormalized first derivative maximum (Dmax) occurring between 695 and 730 nm (Dmax/D744); and 2) the wavelength associated with Dmax (WL of REIP). A nonlinear increase in the Dmax/D744 ratio as a function of C/N content was observed for all optical properties (r/sup 2/ = 0.90-0.95). Similarly, a nonlinear decrease in the WL of REIP as a function of C/N content was observed for all optical properties (RT, RB, TT, and AT) (r/sup 2/ = 0.85-0.96). The Dmax/D744 ratio increased as the WL of REIP declined from /spl sim/730 to 700 nm, with curves per optical property expressing different degrees of nonlinearity.

One of the forms of natural disasters given much attention by researchers all over the world during the International Decade for Natural Disaster Reduction (1990-2000) is the occurrence of landslides. Landslides take place in various regions of India, notably in the Himalayas and the Western Ghats, especially during monsoon. This paper describes some of the on-going studies related to modelling and risk evaluation of landslides at IIT Bombay, India. The studies described are: (i) rainfall induced landslide evaluation using DEM and GIS, (ii) fractal modelling of mass movement including critical failure surface determination using shortest path concept of GIS and (iii) evaluation of risk due to landslide. The unconventional methods used here demonstrate the usefulness of a GIS based technique in identifying potential slide regions in a long stretch of a hill slope and the corresponding risk, which could serve as supports for landslide hazard management.

W-band backscatter experiments have been performed at the wind-wave tank of the University of Hamburg. The aim of the experiments is to study the backscatter mechanisms under shallow incidence angles and to compare the results with previous ones obtained with an X-band scatterometer. The measurements were performed at three grazing angles, 7.5/spl deg/, 10/spl deg/, and 20/spl deg/, and at VV-, HH-, and VH-polarization. The wind speed ranged from 2 to 10 ms/sup -1/ and was increased in steps of 1 ms/sup -1/. The analysis of the acquired radar Doppler spectra shows that Bragg scattering from both bound and freely propagating Bragg waves is the dominant backscattering mechanism at all deployed wind speeds. In particular, at low wind speeds (up to 4 ms/sup -1/), when the overall backscatter is small, bound waves axe the dominating scatterers, whereas at higher wind speeds (5 ms/sup -1/ and above) the acquired signal is mainly caused by freely propagating Bragg waves. This is in qualitative agreement with similar findings, which have been made earlier with an X-band scatterometer working at moderate incidence angles.

The equation for the estimation of the Doppler shift is derived for the spectral function method. The measurement accuracy is analyzed for the mean and actual wind profiles at different atmospheric stratification.

A key point is to separate mixed temperature into soil and crop surface temperatures for inverting transpiration and CO/sub 2/ fluxes. We here present a new way of using two-temporal phase information to separate mixed surface temperature in instead of tow-angle data. Soil and canopy surface radiometric temperatures are very close at the time when net radiation is equal to zero. We can summarize that the radiometric temperature difference between soil and mixed pixels are equal to the diurnal amplitude difference between the radiometric temperature of soil and canopy divided by the percent vegetation cover. In practice, the relationship between the diurnal amplitude of the radiometric temperature of the soil and mixed pixels can be found by experiments. Through simultaneous thermal infrared images with high spatial resolution we can also find out the radiometric temperature of the bare soil in mixed pixels as well as its diurnal amplitude for lower resolution images. The method was validated in the experiment of monitoring radiometric temperature of a wheat field in spring of 2000. We also found out this rule by thermal camera in the Shunyi and Yucheng experiments in 2001. Thus this method is feasible based on theory and experiments.

Remote sensing data have been successfully used for environmental and natural resource tasks in Ukraine, enabling ocean observations and global climate change investigations, etc. to increase. The study of user needs during planning of equipment for new Ukrainian satellites, organising the receiving, storage and use of new data are also very important tasks. Users have problems searching data in Ukrainian and foreign databases, studying successful applications, and gaining common use of data for their own task-solving. The Ukrainian Aerospace Observation Network (UASON) was initiated by the National Space Agency of Ukraine (NSAU) to help solve these and other problems.

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) will be one of the atmospheric sounders on board Envisat, to be launched in early 2002. The instrument is designed to detect solar light scattered from the atmosphere in either nadir, limb or occultation geometry. Following the successful launch of Envisat and an initial outgassing phase activities will focus on instrument functional and performance verification, consolidation as well as geophysical validation of the operational data products. Activities will be conducted in a period 1...9 months after launch and involve a huge number of research teams, organised within the Envisat Atmospheric Chemistry Validation Team (ACVT).

The algorithms currently employed by the Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheres team to retrieve cloud height and cloud thermodynamic phase depend solely on infrared (IR) bands and operate independently of each other. Cloud heights are derived using bands located in the 15-/spl mu/m CO/sub 2/ band, i.e. the CO/sub 2/ slicing method. Cloud thermodynamic phase is inferred using an IR bispectral technique using bands located at 8.5 and 11 /spl mu/m.

Using the Vector Microwave Network Analyzer in broad band (from 0.2 to 18 GHz), a controlled laboratory experiment was conducted on artificially prepared wet saline soil samples. The complex dielectric constants of soil samples in a wide range of moisture and salinity contents were measured and the relationship to the moisture and salinity of the soils were analyzed. The experiment results shows that the imaginary part of the dielectric constant of wet soil is more sensitive to the salinity of soils at low frequency range (f<5 GHz). It indicates that L band or P band SAR can be more effective in soil salinity detection. Secondly, 41 soil samples were collected along a profile from a dried salt lake in late April of 2001. Their moisture and salinity vary along the profile differently. The Vector Microwave Network Analyzer measured the complex dielectric constants of the collected soil samples in laboratory. C band, HH polarization RADARSAT data were simultaneously acquired on April 23, 2001. The backscatter intensity taken from RADARSAT image correlates with the complex dielectric constant. The correlation coefficient between the backscatter intensity and the real part of the complex dielectric constant is 0.23, and the imagine part of the complex dielectric constant is 0.66. This result shows that SAR will contribute to salinity monitoring program.