Search results for "DSA"

Fusión de las imágenes Landsat y micrometeorológicas para hacer un seguimiento de la evapotranspiración diaria a escala regional

2008

El objetivo de este trabajo es mostrar la aplicabilidad operacional de un modelo propuesto recientemente (Sánchez et al., 2008) junto con imágenes de satélite para hacer un seguimiento de los flujos de energía de la superficie a escala regional. En concreto, nos centraremos en la obtención de la evapotranspiración diaria por la especial significación que tiene este flujo en la generación de precipitación o en la gestión de las fuentes de agua para usos agrícolas. Presentamos una metodología detallada para aplicar el Método Simplificado de Balance Energético de Dos Fuentes a las imágenes Landsat. Los distintos rasgos de las tierras de cultivo de superficie vienen caracterizados por los mapas…

Mapping snow density through thermal inertia observations

2023

Snow, as a fundamental reservoir of freshwater, is a crucial natural resource. Specifically, knowledge of snow density spatial and temporal variability could improve modelling of snow water equivalent, which is relevant for managing freshwater resources in context of ongoing climate change. The possibility of estimating snow density from remote sensing has great potential, considering the availability of satellite data and their ability to generate efficient monitoring systems from space. In this study, we present an innovative method that combines meteorological parameters, satellite data and field snow measurements to estimate thermal inertia of snow and snow density at a catchment scale.…

Cross-Sensor Adversarial Domain Adaptation of Landsat-8 and Proba-V images for Cloud Detection

2021

The number of Earth observation satellites carrying optical sensors with similar characteristics is constantly growing. Despite their similarities and the potential synergies among them, derived satellite products are often developed for each sensor independently. Differences in retrieved radiances lead to significant drops in accuracy, which hampers knowledge and information sharing across sensors. This is particularly harmful for machine learning algorithms, since gathering new ground truth data to train models for each sensor is costly and requires experienced manpower. In this work, we propose a domain adaptation transformation to reduce the statistical differences between images of two…

Estimating crop primary productivity with Sentinel-2 and Landsat 8 using machine learning methods trained with radiative transfer simulations

2019

Abstract Satellite remote sensing has been widely used in the last decades for agricultural applications, both for assessing vegetation condition and for subsequent yield prediction. Existing remote sensing-based methods to estimate gross primary productivity (GPP), which is an important variable to indicate crop photosynthetic function and stress, typically rely on empirical or semi-empirical approaches, which tend to over-simplify photosynthetic mechanisms. In this work, we take advantage of all parallel developments in mechanistic photosynthesis modeling and satellite data availability for an advanced monitoring of crop productivity. In particular, we combine process-based modeling with …

Growing stock volume from multi-temporal landsat imagery through google earth engine

2019

Growing stock volume (GSV) is one of the most important variables for.forest management and is traditionally- estimated from ground measurements. These measurements are expensive and therefore sparse and hard to maintain in time on a regular basis. Remote sensing data combined with national forest inventories constitute a helpful tool to estimate and map forest attributes. However, most studies on GSV estimation from remote sensing data focus on small forest areas with a single or only a few species. The current study aims to map GSV in peninsular Spain, a rather large and very heterogeneous area. Around 50 000 wooded land plots from the Third Spanish National Forest Inventory (NFI3) were u…

Kvalitetsindikatorer for kreftbehandling : erfaringer til mellomledere i sykehus

2014

Masteroppgave i helse- og sosialinformatikk HSI 500 Universitetet i Agder 2014 Background: During the last couple of years, the government has increased their attention on quality indicators and measures that can contribute towards improving cancer- diagnosis and treatment. Quality indicators were in 2011 approved for initiation of treatment within 20 days for lung, breast, and colon cancer. Given this, it is conducted a qualitative study with assistant managers in a hospital. The purpose of the study is to increase knowledge and understanding of how assistant managers are affected by quality indicators. The aim of the study is to illustrate assistant managers’ experience with quality indic…

Incenerimento elettrochimico di acido ossalico in presenza di NaCl

2008

Helsingin Jugendsali tilakokemuksena

2010

Tutkielman tavoitteena oli tarkastella Helsingissä sijaitsevan Jugendsalin tilallisia kokemuksia sen käyttäjien näkökulmasta. Tutkimuksessa tarkasteltiin, millaiseksi ihmiset kokivat Jugendsalin tilana, mitä siitä havainnoitiin ja mikä teki siitä merkityksellisen. Edellisten lisäksi haluttiin selvittää, miten ihmiset havainnoivat ympäristöään ja mitä tilat ihmisille merkitsevät. Kokemuksellisuuden tutkiminen rajattiin Jugendsalin Helsinki-tiedotuksen aikaan (vuodet 1984–2008) ja Café Jugendin aikaan (2008-). Tutkimuksen painotus oli Helsinki-tiedotuksen ajassa. Kuitenkin tutkimuksessa haluttiin tarkastella sitä, kuinka käyttötarkoituksen muutos vaikutti tilakokemukseen. Sen vuoksi myös Café…

Multi-Season Phenology Mapping of Nile Delta Croplands Using Time Series of Sentinel-2 and Landsat 8 Green LAI

2022

Space-based cropland phenology monitoring substantially assists agricultural managing practices and plays an important role in crop yield predictions. Multitemporal satellite observations allow analyzing vegetation seasonal dynamics over large areas by using vegetation indices or by deriving biophysical variables. The Nile Delta represents about half of all agricultural lands of Egypt. In this region, intensifying farming systems are predominant and multi-cropping rotations schemes are increasing, requiring a high temporal and spatial resolution monitoring for capturing successive crop growth cycles. This study presents a workflow for cropland phenology characterization and mapping based on…

Monitoring Coastal Lagoon Water Quality Through Remote Sensing: The Mar Menor as a Case Study

2019

The Mar Menor is a hypersaline coastal lagoon located in the southeast of Spain. This fragile ecosystem is suffering several human pressures, such as nutrient and sediment inputs from agriculture and other activities and decreases in salinity. Therefore, the development of an operational system to monitor its evolution is crucial to know the cause-effect relationships and preserve the natural system. The evolution and variability of the turbidity and chlorophyll-a levels in the Mar Menor water body were studied here through the joint use of remote sensing techniques and in situ data. The research was undertaken using Operational Land Imager (OLI) images on Landsat 8 and two SPOT images, bec…