1224
A study showed how PBMR data could be used to map soil moisture variations (Mahantango
watershed-Pennsylvama) for use in a spatially distributed hydrologic model. [A similar approach was depicted in
Moran's talk].
Finally, several presentations were devoted to field measurements campaigns aimed at refining our
understanding / modelling of surface characteristics. The extensive work performed on snow (1-90 GHz) at the
university of Bon was presented as well as work related to the PORTOS experiment in Avignon. The latter were
mainly focused on surface roughness / moisture profiles / vegetation influence on the microwave signal at
frequencies ranging mainl y from 1.4 to 10 GHz. Also presented was the work done by the Florence group on the
relative influence of plant constituents on the microwave emission.
Most of the studies presented showed that extensive and good quality data sets are being collected
main ly for modelling and validation purposes
3 - MODELLING
Even though modelling results ware presented in almost all the presentations it seemed that two could be singled
out since they were completely "modelling oriented".
A review paper was given on direct modelling approaches and model invasion in passive microwaves.
It gave an overview of the state of the art, the most pro mi zing avenues by aiming at a dual approach (discrete +
continuous approaches). Also of intaest, a presentation whae -for the first to our knowledge- a microwave
emission model has been coupled to a vegetation growth model. Such approaches are innovative and worth
furtha consideration
4 - CONCLUSION
A severe gap was noted during this session. The retrieval of atmospheric parameters (except for rain) ova land
was not covered, partially due to the withdrawal of one papa from the plenary session.
Apart from this all the fields are covaed with a stress on vegetation charactaisties. The modelling
activities are quite healthy with significant efforts devoted to the simplification of sophisticated models. We felt
also that the work on surface temperature retrieval and coupling passive microwaves with aop or hydrologic
models is very promizing and should be encouraged.
From the results gained in instrumentation, we believe that more should be allotted to materialize the
"ESTAR" concept as synagistic with classical concepts (SSM/I - MIMR) for soil moisture retrieval. The
PORTOS instrument should prove to be an ideal tool for developing algorithms for MIMR and should be widely
used.
Finally, we believe that passive miaowaves are probably best suited to get direct measurements of
surface parameters such as soil moisture. We should thus strive to validate robust algorithms to retrieve useful
geophysical parameters from remotely sensed passive microwave data.
