Search results for "Transpiration"

Modelling bulk surface resistance by MODIS data and assessment of MOD16A2 evapotranspiration product in an irrigation district of Southern Italy

2016

Abstract In this study, accurate estimates of daily actual evapotranspiration, ET a , were obtained based on the direct Penman–Monteith application, in which the bulk surface resistance term was computed by considering, as main input, daily remotely sensed Land Surface Temperature (LST). In particular, Eddy Covariance measurements of ET a , associated to LST obtained by MODIS time series (MOD11A2) characterized by 8-day resolution, allowed to calibrate a simple bulk surface resistance model, based on two-years of data observations collected in a quite homogeneous irrigation district of Sicily, where olive grove is the main crop. The model was then validated by an independent database collec…

Global review and synthesis of trends in observed terrestrial near-surface wind speeds: Implications for evaporation

2012

Summary In a globally warming climate, observed rates of atmospheric evaporative demand have declined over recent decades. Several recent studies have shown that declining rates of evaporative demand are primarily governed by trends in the aerodynamic component (primarily being the combination of the effects of wind speed (u) and atmospheric humidity) and secondarily by changes in the radiative component. A number of these studies also show that declining rates of observed near-surface u (termed ‘stilling’) is the primary factor contributing to declining rates of evaporative demand. One objective of this paper was to review and synthesise the literature to assess whether stilling is a globa…

Dataset for the manuscript "Are remote sensing evapotranspiration models reliable 2 across South American ecoregions?" published in WRR

2021

Metadata of ‘Are remote sensing evapotranspiration models reliable across South American ecoregions?’ This document describes the file formatting and data used to run and evaluate the evapotranspiration models in this study. Because forcing data varies among models, each input file contains a different set of meteorological data placed within a folder named after the corresponding model. File format and time stamps Data files are CSV formatted with timestamps in the first column of the file. The following timestamps are used: GLEAM: Year (YYYY); Day of Year (DDD) PT-JPL: Year (YYYY); Month (MM); Day (DD) PM-MOD: Year (YYYY); Month (MM); Day (DD) PM-VI: Date (MM/DD/YYYY) Missing data Missing…

Mapping evapotranspiration on vineyards: A comparison between Penman-Monteith and energy balance approaches for operational purposes

2012

Estimation of evapotranspiration (ET) in Sicilian vineyard is an emerging issue since these agricultural systems are more and more converted from rainfed to irrigated conditions, with significant impacts on the management of the scarce water resources of the region. The choice of the most appropriate methodology for assessing water use in these systems is still an issue of debating, due to the complexity of canopy and root systems and for their high spatial fragmentation. In vineyards, quality and quantity of the final product are dependent on the controlled stress conditions to be set trough irrigation. This paper reports an application of the well-known Penman-Monteith approach, applied i…

Adapting FAO-56 Spreadsheet Program to estimate olive orchard transpiration fluxes under soil water stress condition

2012

The FLUXCOM ensemble of global land-atmosphere energy fluxes

2019

Although a key driver of Earth’s climate system, global land-atmosphere energy fluxes are poorly constrained. Here we use machine learning to merge energy flux measurements from FLUXNET eddy covariance towers with remote sensing and meteorological data to estimate global gridded net radiation, latent and sensible heat and their uncertainties. The resulting FLUXCOM database comprises 147 products in two setups: (1) 0.0833° resolution using MODIS remote sensing data (RS) and (2) 0.5° resolution using remote sensing and meteorological data (RS + METEO). Within each setup we use a full factorial design across machine learning methods, forcing datasets and energy balance closure corrections. For…

Understanding the Effects of Fires on Surface Evapotranspiration Patterns Using Satellite Remote Sensing in Combination with an Energy Balance Model

2011

Forest fires are highly destructive for nature, affecting the landscape, the natural cicle of the vegetation, and the structure and functioning of ecosystems. Beyond that, they also provoke changes in the local and regional meteorology, and particularly in the surface energy flux patterns. In a fire-affected area, changes in the ecosystem structure and species composition modify the evapotranspiration (LE) and the rest of the terms involved in the energy balance equation. Besides, these changes in the local energy balance may persist for decades (Randerson et al., 2006). There is an increasing concern among the scientific community about the effect of forest fires on climate change at this …

Estimation of leaf area index using PROSAIL based LUT inversion, MLRA-GPR and empirical models: Case study of tropical deciduous forest plantation, N…

2020

Abstract Forests play a vital role in biological cycles and environmental regulation. To understand the key processes of forest canopies (e.g., photosynthesis, respiration and transpiration), reliable and accurate information on spatial variability of Leaf Area Index (LAI), and its seasonal dynamics is essential. In the present study, we assessed the performance of biophysical parameter (LAI) retrieval methods viz. Look-Up Table (LUT)-inversion, MLRA-GPR (Machine Learning Regression Algorithm- Gaussian Processes Regression) and empirical models, for estimating the LAI of tropical deciduous plantation using ARTMO (Automated Radiative Transfer Models Operator) tool and Sentinel-2 satellite im…

Intercomparison of remote-sensing based evapotranspiration algorithms over amazonian forests

2019

Abstract Evapotranspiration (ET) is considered a key variable in the understanding of the Amazonian tropical forests and their response to climate change. Remote-Sensing (RS) based evapotranspiration models are presented as a feasible means in order to provide accurate spatially-distributed ET estimates over this region. In this work, the performance of four commonly used ET RS models was evaluated over Amazonia using Moderate Resolution Imaging Spectroradiometer (MODIS) data. RS models included i) Priestley-Taylor Jet Propulsion Laboratory (PT-JPL), ii) Penman-Monteith MODIS operative parametrization (PM-Mu), iii) Surface Energy Balance System (SEBS), and iv) Satellite Application Facility…

A simple method to directly retrieve reference evapotranspiration from geostationary satellite images

2013

Abstract Application of FAO-56 methodology for the assessment of reference evapotranspiration, ET 0 , is challenging in areas of the world with sparse meteorological network stations. For this reason alternative procedures using remotely observed data have been proposed in the literature. In this work, a simplified version of the Makkink approach [J. Inst. Wat. Eng. 11: 277–288, 1957] was tested in a typical Mediterranean environment (Sicily, Italy). The implemented Makkink approach (MAK) uses remotely estimated solar radiation derived from Meteosat Second Generation (MSG) satellite data and in situ observations of air temperature to assess ET 0 at daily time scale. Alternatively, taking ad…