tio 
pd pd fd 
Ludhiana, 
3-151. 
1 vineyard 
approach. 
Malaysia. 
317-343. 
works on 
ition, Soil 
nd water 
iserv., 51: 
USDA, 
., 1998. 
al gully 
; of the 
et Kaur, 
ing this 
IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
ROLE OF MICROWAVE REMOTE SENSING IN SOIL EROSION STUDIES USING 
INVERSION PROCESS MODELLING - A PRECURSOR ATTEMPT IN LESSER 
HIMALAYAS 
Sameer Saran®*, P. S. Roy" Suresh Kumar®, G. Sterk" and P.J. van Oevelen® 
“Indian Institute of Remote Sensing (NRSA), 4, kalidas Road, Dehradun, India - (sameer, psr, suresh)@iirs.gov.in 
b 
Department of Environmental Sciences, Wageningen University, The Netherlands - (Geert.Sterk 9 wur.nl, 
Peter.vanOevelen Q wur.nl) 
KEY WORDS: Inversion modeling, hydrological model, soil erosion, microwave remote sensing 
ABSTRACT : 
The need to measure land degradation processes worldwide is increasing given the recent development of an International 
Convention on Desertification. The contributing factors of land degradation processes include climate, vegetation cover or biomass, 
soil physical and chemical properties and topographical properties of the landscape. The interactions between these factors are 
complex and much detailed study is needed to unravel this complexity. The present attempt will highlight the conceptual framework 
to derive physically based model for erosion studies using both optical and microwave remote sensing. Since the estimation of soil 
properties using remote sensing are not real values it is only feasible to derive effective parametric values with some accuracy level. 
The variations at different spatial and temporal scales will also be taken into account. Microwave remote sensing is one of the 
approaches for the estimation of the hydrological state of the soil, mainly because of the all weather capability and the sensor's 
sensitivity to the dielectric properties of the surface that can be linked to the moisture content. In addition the microwaves are 
sensitive to vegetation canopy structure and moisture, which will allow the estimation of vegetation parameters. An attempt will be 
made to derive a hydrological model using microwave remote sensing for soil erosion studies. The study will be carried out in one of 
the catchment of Lesser Himalayas with diverse attributes at different elevations. The model will be process based instead of 
empirical based because the study is focussed on physical laws considering spatial variability from place to place. 
1. INTRODUCTION 
Land degradation, which is one of representative deteriorating 
factor of the environment, which is observed world-wide. Land 
is a base to reproduce vegetation and its degradation 
corresponds to the restriction of vegetative activity by the 
change of growth conditions. Vegetative activity correlate with 
both agricultural productivity and environmental conservation. 
Land degradation tends to be an irreversible process, therefore 
in order to establish sustainable land use system it is important 
to make attempts to discover the areas prone to land 
degradation as well as to monitor the progress of degradation. 
The need to measure land degradation processes worldwide is 
increasing given the recent development of an International 
Convention on Desertification (United Nation, 1994). Apart 
from the ecologically precarious character of the environment, 
which facilitates the disruption of the natural equilibrium, 
human impact is the most important cause for disturbance of 
the delicate balance of this ecosystem (Tomaselli, 1981; 1977). 
Human impact comprises population pressure, grazing, 
deforestation and changes in land use (Azecvedo, 1990). The 
consequences of the degradation of an ecosystem are rather 
diverse but comprise detrimental processes such as soil erosion 
in the upper parts of catchments with 
sedimentation downstream, impoverishment of the flora and 
fauna and a reduction of productivity (Barrow, 1991). 
The quantitative erosion model is process based and is 
dependent on physical laws which includes the process of 
detachment by raindrop impact, transport, sediment and 
deposition by flow (Suryana, 1996). The model selected for the 
study is KINEROS (Kinematics Runoff and Erosion), which is 
best, suited for small watershed. The model helps in detailed 
741 
investigation of runoff and soil erosion because it is distributed, 
event-oriented and physically based describing the processes of 
surface runoff and erosion. Attempts to study the degradation 
process have resulted in qualitative and later quantitative 
models e.g. EuroSEM (Morgan et al., 1991), WEPP (Nearing et 
al., 1989), ANSWERS (De Roo, 1993) and the Morgan, 
Morgan and Finney method (Morgan et al., 1984). However the 
main problem with modelling is to obtain necessary 
information at a regional scale. Data requirements of 
degradation models are large and include vegetative cover and 
soil properties that can only be measured directly in the field or 
can be derived from other kinds of data such as supplied by 
remote sensing systems. Field surveys are labour-intensive and 
expensive and yield only information for one geographical 
location. For extensive areas, field surveys are often not 
feasible and in these cases remote-sensing techniques may 
prove a useful alternative by providing additional source of 
information. 
Criteria for a suitable data collection system to monitor and to 
model land degradation processes at a landscape scale are (De 
Jong, 1994). 
It should cover large areas easily 
It should collect data at regular time intervals 
It should have sufficient spatial and temporal resolution 
It should provide data on the required attributes accurately 
It should provide data in a form suitable for further 
processing 
It should be affordable 
Field survey is probably the best tool to provide accurate 
information on the variables controlling the land degradation 
processes. However, field methods do not fulfil the other