.c.Montespertoli, Italy


Titles of Investigations:

I.		Contribution of SAR for Estimating Soil Erosion

II.		Test of Roughness and Moisture Algorithms Using Multiparameter Spaceborne SAR and Application to Surface Hydrology

Principal Investigators:

I.		Dr. Paolo Canuti
		University of Florence

II.		Dr. Daniel Vidal-Madjar
		CNET/CRPE

Site Description:

	The test site at Montespertoli is representative of the Thyrrenian slope of Apennines.  Bedrock in the area is comprised of Pliocene marine and lacustrine sediments and is intensively affected by erosion and mass movements.  More than half the site area is hilly (average height of about 250 m), with agricultural fields and little urbanization.  In the past 20 years, the hillsides have been extensively altered to make vineyards accessible to mechanized farm equipment that requires slope uniformity.  The northern part of the area is characterized by the flat alluvial wetlands of the Arno River, agricultural fields (colza, corn, sunflower, sugarbeet, and reed), and urbanization.  The average field dimensions are about 4-5 ha.  Hillsides in the southern part of the area is occupied by croplands (mostly vineyards, oliveyards, wheat, and grass) and woodlands.   The average annual rainfall is 904 mm, and the average air temperature is 15ĄC.

Objectives:

I.		a)	Evaluate SAR potential in the study of soil erosion problems.

		b)	Investigate the contributions of SAR images in reconstructing different stages of transport and redeposition of material on watershed slopes, using models which take into consideration several parameters of soil surface (moisture content, roughness, vegetation cover, etc.) that can be extracted from radar backscattering.

II.		a)	Evaluate the usefulness of radar-derived parameters in surface hydrology.

		b)	Demonstrate the usefulness of the squint mode in the case of bare soil observations.

		c)	Compare various roughness/moisture algorithms in a real space imaging mode.

Field Measurements:

I. 		a)	During the SIR-C/X-SAR experiment, the ground truth parameters listed below will be measured in the two sub-areas of the test site chosen for detailed experiments (Pesa Virginio).


		Soil
		„	soil moisture content (gravimetric and volumetric) at different depths (5.0, 10.0, and 20.0 cm) using a hand augers and in different parts of each field;
		„	dielectric constant of soils using dielectric probes at different frequencies;
		„	surface soil roughness, expressed as standard deviation of the heights (hstd) and correlation length (lc); and
		„	soil temperature at » 5 cm by a thermometric probe.

		Vegetation
		„	crop classification (crop type, variety);
		„	sowing date, phenological stage of plants, crop conditions, % weed cover;
		„	height and density of plants;
		„	number and dimension (length and width) of leaves, diameter of stems;
		„	leaf area index (m2/m2); and
		„	plant water content (computed as the difference between fresh and dry weight; kg/m2) of different plant constituents (leaves, stems, ears, etc.).

		b)	Selected parameters (soil moisture, crop classification, phenological stage, plant height and width) will be measured over the whole area.  In addition, sediment transport will be measured at a station on the Virginio stream, along with stream and rainfall measurements.  Texture, as well as other soil characteristics have already been determined.  A DTM has been prepared for some areas of Pesa and Virginio basins (Cerbaia and Lucardo zones).  Some meterological data (air temperature and humidity, rainfall) are available from three meterological stations in the area (Figure 1).

II.		a)	The proposal is based on comparison between radar observation and well documented ground truth within a watershed.

		b)	The radar data will be compared to ground data using existing surface/wave interaction models.

		c)	An airborne dual frequency (C and X) multipolarization scatterometer will be used to calibrate radar data and to complete the data set (in view angle).


Crew Observations:

1)	Crew Journal: Describe weather conditions and vegetation at the site.

2)	Cameras: Hercules and Hasselblad will be used to photograph the vegetation at the site.


Coverage Requirements:

The minimum coverage requirements for the Montespertoli test site are one (1) early pass and one (1) late pass.

Anticipated Results:

I.		a)	Quantitative assessment of the relative contribution of soil and different types of vegetation to the backscattering coefficient.

		b)	Map geological and erosional features from radar images.

		c)	Estimate geophysical parameters which are involved in the hydrological cycle (i.e., soil moisture, soil surface roughness, vegetation biomass, etc.).

		d)	Test and validate models to describe soil erosion processes at basin scale which can use SAR data as inputs.

II.		a)	Calibration of the shuttle radars over distributed targets.

		b)	Test of multi-incidence angle algorithms using squint mode SAR.

		c)	Test of roughness/moisture algorithms.

		d)	Evaluation of radar images in surface hydrology.