Search results for "Sentinel-1"
showing 9 items of 9 documents
Sentinel-1 sintezētās apertūras radara izmantošana cirsmu konstatēšanai
2020
Bakalaura darbā ir pētīta sintezētās apertūras radara (SAR) Sentinel-1 datu lietderība cirsmu konstatēšanā. Analogi pētījumi, kas pierāda SAR un arī tieši Sentinel-1 sensora lietderību un izmantošanu, mežsaimniecībā ir veikti gan pasaulē, gan Latvijā, taču trūkst pētījumu, kas skaidrotu SAR, mežsaimnieciskās darbības un laikapstākļu likumsakarības. Tāpēc darbā tika pētīta laikapstākļu ietekme uz SAR atpakaļ saņemtās intensitātes vērtībām, jo, mainoties laikapstākļiem, mainās arī veģetācijas un virsmas dielektriskās īpašības, kā rezultātā mainās arī SAR atpakaļ saņemtā signāla vērtības. Pētījums tika izstrādāts balstoties uz faktu, ka ir būtiski veikt mežsaimniecības monitoringu neatkarīgi n…
Exploitation of SAR and Optical Sentinel Data to Detect Rice Crop and Estimate Seasonal Dynamics of Leaf Area Index
2017
This paper presents and evaluates multitemporal LAI estimates derived from Sentinel-2A data on rice cultivated area identified using time series of Sentinel-1A images over the main European rice districts for the 2016 crop season. This study combines the information conveyed by Sentinel-1A and Sentinel-2A into a high-resolution LAI retrieval chain. Rice crop was detected using an operational multi-temporal rule-based algorithm, and LAI estimates were obtained by inverting the PROSAIL radiative transfer model with Gaussian process regression. Direct validation was performed with in situ LAI measurements acquired in coordinated field campaigns in three countries (Italy, Spain and Greece). Res…
Flooding in the Digital Twin Earth: The Case Study of the Enza River Levee Breach in December 2017
2023
The accurate delineation of flood hazard maps is a key element of flood risk management policy. Flood inundation models are fundamental for reproducing the boundaries of flood-prone areas, but their calibration is limited to the information available on the areas affected by inundation during observed flood events (typically fragmentary photo, video or partial surveys). In recent years, Earth Observation data have supported flood monitoring and emergency response (e.g., the Copernicus Emergency Service) thanks to the proliferation of available satellite sensors, also at high spatial resolution. Under this umbrella, the study investigates a levee breach that occurred in December 2017 along t…
Quantifying Irrigated Winter Wheat LAI in Argentina Using Multiple Sentinel-1 Incidence Angles
2022
Synthetic aperture radar (SAR) data provides an appealing opportunity for all-weather day or night Earth surface monitoring. The European constellation Sentinel-1 (S1) consisting of S1-A and S1-B satellites offers a suitable revisit time and spatial resolution for the observation of croplands from space. The C-band radar backscatter is sensitive to vegetation structure changes and phenology as well as soil moisture and roughness. It also varies depending on the local incidence angle (LIA) of the SAR acquisition’s geometry. The LIA backscatter dependency could therefore be exploited to improve the retrieval of the crop biophysical variables. The availability of S1 radar time-series data at d…
SENTINEL-1 for wheat mapping and soil moisture retrieval
2015
The main objective of this study is to assess the use of Sentinel-1 (S-1) data for surface soil moisture (SSM) retrieval and wheat mapping (WM) at high spatial resolution (e.g. 100–500m), which constitute valuable information for improving crop yield forecast at large scale. A knowledge based classification method and a SSM retrieval algorithm, developed in view of the European Space Agency Sentinel-1 mission, have been applied to a time series of S-1A data collected from October 2014 to April 2015 over a well-documented agricultural site in southern Italy. In particular, observations of SSM content recorded by a network of ground stations deployed in an experimental farm have been used to …
Toward a Comprehensive Dam Monitoring: On-Site and Remote-Retrieved Forcing Factors and Resulting Displacements (GNSS and PS–InSAR)
2021
Many factors can influence the displacements of a dam, including water level variability and environmental temperatures, in addition to the dam composition. In this work, optical-based classification, thermal diachronic analysis, and a quasi-PS (Persistent Scatter) Interferometric SAR technique have been applied to determine both forcing factors and resulting displacements of the crest of the Castello dam (South Italy) over a one-year time period. The dataset includes Sentinel-1A images acquired in Interferometric Wide swath mode using the Terrain Observation with Progressive Scans SAR (TOPSAR); Landsat 8 Thermal Infrared Sensor (TIRS) thermal images, and Global Navigation Satellite System …
Sentinel-1 & Sentinel-2 Data for Soil Tillage Change Detection
2018
In this paper, an algorithm using Sentinel-1 (S-1) and Sentinel-2 (S-2) data to identify changes of tillage over agricultural fields at approximately similar to 100m resolution is presented. The methodology implements a multiscale temporal change detection on S-1 VH backscatter in order to single out VH changes due to agricultural practices only. The algorithm can be applied over bare or scarcely vegetated agricultural fields, which are identified from S-2 NDVI measurements. An initial assessment at farm scale using in situ and S-1 and SPOT5-Take5 data, acquired over the Apulian Tavoliere in southern Italy in 2015, is illustrated. A full validation of the approach is in progress over three …
Sentinel-1izmantošanas iespējas mežsaimnieciskās darbības kontrolē
2018
Darbā pētītas Sentinel-1 datu izmantošanas iespējas koku ciršanas konstatēšanai. Neskatoties uz to, ka dati ir brīvpieejas un informācija par visu Latvijas teritoriju pieejama ar aptuveni 6 dienu laika izšķirtspēju, to lietojums mežsaimniecības vajadzībām Latvijā nav plaši pētīts. Datu pieejamība un kvalitāte nav atkarīga no laikapstākļiem vai diennakts stundas, kas uzskatāma par priekšrocību meža monitoringa attīstības veicināšanai. Pētījumā secināts, ka radara informācija atkarīga no objektu dielektriskajām īpašībām, tādēļ augstākas koku ciršanas kontroles ticamības sasniegšanai radara datus nepieciešams iegūt pēc iespējas līdzīgos apstākļos. Darbā analizētas Sentinel-1 atstarojuma vērtīb…
Evaluation of different InSAR multi-baseline construction methods over a dam in southern Italy
2018
Monitoring dam displacements using different techniques allows an evaluation of their structural behaviour over time. In this study, dam displacements (for the Castello dam, Agrigento, Italy) have been investigated using different Interferometric Synthetic Aperture Radar (InSAR) techniques exploiting a freely available dataset from the EU Copernicus Sentinel-1 SAR built by the European Space Agency (ESA). The dataset includes Sentinel 1A (S1A) images acquired in dual-polarization and Interferometric Wide (IW) swath using the Terrain Observation with Progressive Scans SAR (TOPSAR) mode. Three main Multi-Baseline Construction methods based on the identification of Persistent Scatterers (PS) h…