Internacionales

Anuncio de oportunidad ESA-SMOS (EN CURSO)

This proposal is aimed at exploiting SMOS Level2-SM and L1C data in a large South American Basin, named De La Plata. In particular, the plans are:

– To test he capability of SMOS Level2-SM data for improving the predictions made by atmospheric and hydrological models;
– To use radiometric data for monitoring vegetation variables in a large forest, characterized by a variety of climatic conditions;
– To improve prediction and monitoring of flooding events by L band radiometry.

 The De La Plata Basin covers about 3.6 million km2. In terms of geographical extent, it is the fifth largest basin in the world. The principal sub-basins are those of the Paraná, Paraguay and Uruguay Rivers. > The annual mean total precipitation in the De La Plata Basin is about 1,100mm, of which only about 20% reaches the sea as surface water. The other 80% is evaporated and infiltrated into the ground. Consequently, any small change in the evaporation and infiltration rate may lead to greater changes in the runoff.

The variability in soil moisture, soil cover and soil use can have important impacts on the water cycle. For all these reasons, any improvement in the estimate of soil moisture leads to important benefits. The lower part of the basin is mostly covered by agricultural fields, and low vegetation, while the upper part is covered by the deciduous ChacoForest.

The main objective of the proposal is to improve the prediction of hydrological and atmospheric variables using SMOS L2-land data collected in the lower area (approximately 55W-65W, 28S-35S). For this area, the work will be subdivided into two phases. In the first phase, lasting one year, two test plots will be selected. Level2-SM, Level1C and ALOS-PALSAR data will be used to test the Level2 Soil Moisture Algorithm in the climatic conditions of the site. In particular, Level2-SM data will be compared with a-priori SM estimates obtained by the hydrologic VIC model, which was already applied to De La Plata basin. Moreover, it will be checked that the multi-temporal series of optical depth shows a trend which does not contradict with the one expected by a knowledge of vegetation evolution. Level1C and ALOS-PALSAR data will be used to interpret the comparison results. One observation per month will be sufficient in this phase.

In the second phase, lasting two years, the Level2-SM data will be assimilated into the atmospheric ETA model, and the hydrological VIC model, which are used for weather forecasts and predictions of hydrological variables. The improvements achieved in the precision of the predictions will be estimated. The full 3-day SMOS time series will be used for this second phase.

In the Chaco forest (60W-65W, 22S-28S), three plots will be selected,
belonging to areas with different climatic properties: humid, semiarid, arid. For the first year, we shall test the general performance of SMOS L2-SM algorithm over specific plots. In the two following years, we shall try to estimate forest variables, such as woody biomass and understory herbaceous biomass. To this aim, we shall use SMC information made available by Level2-SM data, Level1C data, higher frequency emissivity (from AMSR-E instrument), ALOS-PALSAR signatures and the forest emission model developed at Tor Vergata University. One sample per month will be sufficient for the Chaco forest work.

The capability of L band passive signatures in estimating the increase in water level in wetlands will be tested using also the microwave vegetation model available to us.

For the Tor Vergata University team, the manpower will be supported by public research funding (Italian Ministry of Research). For Argentine institutions, manpower and field work will be supported by the state institutions involved and by local research projects that have specific funds allocated for microwave remote sensing research.