Veronica Barraza

Instituto de astronomía y física del espacio (IAFE, CONICET/UBA) · Grupo de teledetección cuantitativa

In this work we have developed a random forest regressor to predict daily evapotranspiration in three eddy-covariance sites in Northern Australia from in-situ meteorological data and fluxes, and satellite leaf area index and land surface temperature data. The variable analysis for the random forest regressor suggests that leaf area index is the mos...

Previous studies have shown the potential of remote-sensing tools to monitor coastal wetlands at a landscape scale. Several biophysical parameters are typically used to evaluate ecosystem conditions such as the chlorophyll content, an indicator of photosynthesis activity. In natural environments characterized by a large fraction of standing litter...

In the context of HYPERNETS project, which is developing a relatively low cost hyperspectral radiometer (and associated pointing system and embedded calibration device for automated measurement of water and land bidirectional reflectance), the tidal coastal marsh in the Mar Chiquita (Argentina) lagoon is being characterized as a test site for valid...

The Dry Chaco Forest has the highest absolute deforestation rates of all Argentinian forests (current deforestation rate of 150,000 ha yr⁻¹, 0.85% yr⁻¹). The deforestation process is seen as a breakpoint in the enhanced vegetation index (EVI) time series, associated with the change from a typical forest phenology pattern to something else (e.g., ba...

In this study, the performance of the combined-source variational data assimilation scheme (CS-VDA) is assessed in detail using in situ heat fluxes (i.e. sensible heat (H) and latent heat (LE)) collected at a Eucalypt forest savanna of Northern Australia (Howard Springs). The CS VDA scheme estimates surface turbulent heat fluxes via assimilation of...

In this study, we compared different remote-sensing (RS)-based land surface models (LSM) and reanalysis latent heat flux (LE) products over different forest ecosystems. We analysed the performance of three RS products, the MOD16A2, the Breathing Earth System Simulator (BESS) model, and a combined optical-microwave model (COM) in their ability to re...

Latent heat flux (LE) and corresponding water loss in non-moisture-limited ecosystems are well correlated to radiation and temperature. By contrast, in savannahs and arid and semi-arid lands LE is mostly driven by available water and the vegetation exerts a strong control over the rate of transpiration. Therefore, LE models that use optical vegetat...

The objective of this article was to compare the performance of two vegetation indices (MODIS EVI (optical) and AMSR-E/ and TMI/TRMM LPRM VOD (microwave)) using an offline Bayesian change-point algorithm to monitor vegetation dynamics (retrospective analysis). We tested this model by simulating 8-day EVI and VOD time series with varying amounts of...

In this study, we evaluated and compared optical and passive microwave index based retrievals of surface conductance (Gs) and evapotranspiration (ET) following the Penman–Monteith (PM) approach. The methodology was evaluated over the growing season at five FLUXNET sites in the USA and Australia encompassing three forest types, deciduous broadleaf f...

This study focused on the time series analysis of passive microwave and optical satellite data collected from six Southern Hemisphere ecosystems in Australia and Argentina. The selected ecosystems represent a wide range of land cover types, including deciduous open forest, temperate forest, tropical and semi-arid savannas, and grasslands. We used t...

The objective of this paper is to analyze the dynamics of flooded area and water level in a floodplain wetland. To this end we studied a flood that occurred in 2009-2010 related to an ENSO (El Niño/Southern Oscillation) event over the Paraná River delta. The method for obtaining flooded area fraction (ff) and floodplain water level (WL), which is a...

The aim of this work is to investigate the exploitation of radiometric acquisitions from satellite sensors at different microwave frequencies in view of the prediction of river water level. A case study has been identified in the Bermejo basin, in northern Argentina. This river is seasonally affected by severe flooding events in the lower part, mos...

This paper compares the performance of Aquarius, SMOS and AMSR2 data to estimate the fraction of flooded area and mean water level inside a wetland, in the framework of an active/passive flood monitoring algorithm. The method, which is an extension of previously developed algorithms based on passive data, exploits the synergy of passive and active...

In this paper, a sensitivity analysis to soil moisture variations as a rain effect has been performed at several microwave bands over the lower Bermejo basin, a subtropical area of Argentina mostly spread by moderately dense forests. Parameters such as emissivity and Polarization Index have been considered to carry out the study. In particular, the...

Information about daily variations of vegetation moisture is of widespread interest to monitor vegetation stress and as a proxy to evapotranspiration. In this context, we evaluated optical and passive microwave remote sensing indices for estimating vegetation moisture content in the Dry Chaco Forest, Argentina. The three optical indices analyzed we...

The purpose of this work was to monitor and model land surface phenology over the past ten years in South American Bermejo River Basin using MODIS NDVI product. In order to do this, we evaluated characteristics of the satellite data and available information of the study areas ecosystem to choose the best model to capture temporal dynamics of NDVI...

The sensitivity of the microwave brightness temperature (T B) and emissivity (e) to rainfall and flooding has been already investigated by several scientists. It has been demonstrated that passive microwave sensors are able to detect soil conditions to some centimeter depth, depending on the instrument wavelength and that the combination of differe...

In this paper, we show that MODIS NDVI and AMSR-E microwave vegetation indexes (MVI) data can be used to monitor land surface phenology in the Bermejo River Basin. For this purpose, the statistical nature of the study area's NDVI and MVI time series was analyzed. For NDVI, widely known time series models were tested and modified. NDVI temporal vari...

The purpose of this work is to investigate the capability of AMSR-E and SMOS in monitoring soil moisture and flood events in the South American Bermejo Basin using temporal trends of the polarization indexes (ratio) at L, C, X and Ka bands. The Bermejo River Basin extends over some 123,000 Km2, originating in the Andes Mountains of northwestern Arg...

In this letter, multitemporal signatures collected by Advanced Microwave Scanning Radiometer (AMSR-E) over the dry forest of Chaco, located in North Argentina, are analyzed. The forest has a biomass of about 100 t/ha and a woody volume of about 120 $\hbox{m}^{3}/\hbox{ha}$. A clear increase of polarization index at C-band is observed after intense...

This paper describes a procedure to estimate both the fraction of flooded area and the mean water level in vegetated river floodplains by using a synergy of passive and active microwave signatures. In particular, AMSR-E at X band, and C band ENVTSAT ASAR in Wide Swath mode and ALOS PALSAR in WB1 mode, are used. The method, which is an extension of...

This paper describes a procedure to estimate both the fraction of flooded area and the mean water level in vegetated river floodplains by using a synergy of active and passive microwave signatures. In particular, C Band Envisat ASAR in Wide Scan mode and AMSR-E at X, Ku and Ka Band, are used. The method, which is an extension of previously develope...

This paper describes a procedure to estimate both the fraction of flooded area and the mean water level in vegetated river floodplains by using a synergy of active and passive microwave signatures. In particular, C band Envisat ASAR in Wide Swath mode and AMSR-E at X, Ku and Ka band, are used. The method, which is an extension of previously develop...

Using Microwave Remote Sensing techniques represents an important contribution to forecasting skill of regional scale flooding events occurring over time scales of days to weeks. Furthermore, it could add skills to predictions of flood peak timing and magnitude, besides climatic change predictions. In this paper, the temporal trends of Polarization...