Search results for "satellite"

Using Satellite precipitation data to support local climatology and weather monitoring. Application to Sicilia.

2012

A method to estimate soil moisture from Airborne Hyperspectral Scanner (AHS) and ASTER data: Application to SEN2FLEX and SEN3EXP campaigns

2012

Abstract In this paper the soil moisture is estimated at airborne level and at satellite level by combining remotely sensed images with in situ measurements. At airborne level we process high-resolution images acquired with the Airborne Hyperspectral Scanner (AHS) sensor, and at satellite level we compute images acquired with the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The study has been accomplished in the framework of two field campaigns in the Barrax region (Spain): the SEN2FLEX (SENtinel-2 and FLuorescence EXperiment) campaign which was developed in July of 2005 and the SEN3EXP (Sentinel-3 Experiment) campaign which was carried out in June of 2009. The me…

<title>Surface temperature retrieval from MODIS data</title>

2001

12 MODIS (Moderate Resolution Imaging Spectroradiometer) was launched on board the NASA's Terra Earth Observing System (EOS AM-1) Satellite on December 18, 1999. We propose in this work operative split-window algorithms for retrieving sea surface temperature (SST) and land surface temperature (LST) using MODIS data. In order to attain our goal, the MODTRAN 3.5 radiative transfer code was used to predict radiances for MODIS channels 31 and 32. To analyze atmospheric effects, a set of radiosoundings was used to cover the variability of surface temperature and water vapor concentration on a worldwide scale. These simulated data were split into two sets which have very similar distributions in …

Determination of sea surface temperature using combined TOVS and AVHRR data. Application to the Canary Islands area, Spain

1996

Abstract The determination of sea surface temperature from satellite is performed by means of multi-channel algorithms with channels 4 and 5 of AVHRRNOAA or using radiative transfer models and radiosounding profiles of air temperature and humidity. In this work, an alternative to the current algorithms has been established. A new method combining the information supplied by sensors of TOVS and AVHRR systems onboard NOAA satellites is proposed. It is based on the split-window technique, the coefficients A and B being determined as a function of the water vapour content, which is calculated using the TOVS sensors. The T4 and T5 temperatures are supplied by the AVHRR system. Then, combining bo…

Prototyping algorithm for retrieving FAPAR using MSG data in the context of the LSA SAF project

2007

This paper describes the prototyping algorithm developed for retrieving the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) using MSG data in the framework of satellite application facility on land surface analysis (LSA SAF). The prototyping relies on the Roujean and Breon (1995) method, which is based on simulations of visible and near infrared reflectance values in an optimal geometry. A relationship is found between a vegetation index and daily FAPAR The algorithm has been applied to one year of MSG BRDF data since August 2005, using a temporal frequency of 5-days, and then validated against a set of operational satellite FAPAR products such as MODIS, MERIS, SeaWiFS and …

Cloud motion detection from infrared satellite images

2002

The estimation of cloud motion from a sequence of satellite images can be considered a challenging task due to the complexity of phenomena implied. Being a non-rigid motion and implying non-linear events, most motion models are not suitable and new algorithms have to be developed. We propose a novel technique, combining a Block Matching Algorithm (BMA) and a best candidate block search along with a vector median regularisation.

A comparative analysis of different spatial sampling schemes: Modelling of SSRB data

2008

Low spatial resolution satellite sensors provide information over relatively large targets with typical pixel resolutions of hundreds of km2. However, the spatial scales of ground measurements are usually much smaller. Such differences in spatial scales makes the interpretation of comparisons between quantities derived from low resolution sensors and ground measurements particularly difficult. It also highlights the importance of developing appropriate sampling strategies when designing ground campaigns for validation studies of low resolution sensors. We make use of statistical modelling of high resolution surface shortwave radiation budget (SSRB) data to look into this problem. A spatial …

Thermal–infrared emissivities of natural surfaces: improvements on the experimental set-up and new measurements

2003

Ground measurements of thermal infrared emissivities of terrestrial surfaces are required to derive accurate temperatures from radiometric measurements, and also to apply and validate emissivity models using satellite sensor observations. This paper focuses on the demanding aspects that are involved in the field measurement of emissivity using the box method and a hand-held radiometer. Measuring emissivities in field conditions can be hampered by external factors such as wind and solar irradiance. This can increase the time spent on the field campaign but, most importantly, it can cause no-sense fluctuations between consecutive observations. Here we propose original developments for the exp…

APPROACHES TO STUDY BIODIVERSITY AND SALINITY TOLERANCE MECHANISMS IN MEDITERRANEAN FRUIT TREE SPECIES

Changes in global climate are going to increase the problem of drought and soil salinity in the Mediterranean area, where increases in temperature, drought and soil and water salinity are expected. Identification of plant genotypes with positive agronomic traits, such as salt tolerance, may reduce the effects of salinity and drought on productivity. Therefore, there is considerable effort being directed toward the development of salt-tolerant genotypes through plant breeding, with the aim to the introgression of salt-tolerance traits into new cultivars. The results presented in this thesis contributed to the develop of new tools to improve knowledge on the biodiversity and salinity toleranc…

The Sicilian peach (Prunus persica L. Batsch) germplasm: Evaluation of genetic diversity using SSRs

2006

The decrease in worldwide consumption of peaches due to the poor flavour quality of the fruit has increased the demand for new tasty cultivars. The availability of plant genetic resources is an important prerequisite for improving fruit quality by breeding. In Sicily there is a large collection of local cultivated peaches, whose production fills a niche in the local markets, but which is at risk of disappearing. Their characteristics include highly aromatic fruit and late ripening. Because of their important agronomic characteristics, the Department of Colture Arboree of Palermo University has collected the most interesting accessions to safeguard them and to use the indigenous resources in…