Search results for "Computers in Earth Science"
showing 10 items of 323 documents
UVolc: A software platform for measuring volcanic SO2 fluxes
2012
We present here a novel stand-alone software platform, UVolc, for remotely sensed measurement of volcanic SO"2 emission rates. Such data are important diagnostics of activity conditions, with utility in forecasting measures. This code is made user friendly to enable volcanologists, who are not experts in the underlying physics of spectroscopy, to perform their own measurements. The program provides considerable reduction in errors and far greater operating flexibility than existing analogous code, which, unlike UVolc, can only interface with hardware no longer in manufacture. UVolc will be described here, including a presentation of data collected with this program in the field.
Design and development of a Java-based graphical user interface to monitor/control a meteorological real-time forecasting system
2010
A regional forecasting system based on the Regional Atmospheric Modeling System (RAMS) is being run at the CEAM Foundation. The operational model involves several processes running in the background at specified times and executing a set of systematic steps. This system is being used as a support for a heat-wave warning system, a wind forecasting system for fire warning and prevention, and for general forecasting tasks. However, it is relatively difficult to use by researchers and forecasters without sophisticated information technology (IT) skill. In this paper, we report an effort to develop a tool to facilitate the monitoring of the system. This tool is based on the client-server archite…
Suitability of OMI aerosol index to reflect mineral dust surface conditions: preliminary application for studying the link with meningitis epidemics …
2013
12 pages; International audience; The aimof this study is to analyze the suitability of remotely-sensed aerosol retrievals to progress in the understanding of the influence of desert dust on health, and particularly on meningitis epidemics. In the Sahel, meningitis epidemics are a serious public health issue. Social factors are of prime importance in the dynamics of the epidemics, however climate and environmental factors are also suspected to play an important role. This study focuses on three Sahelian countries (Burkina Faso,Mali and Niger) which are among the most concerned in the "meningitis belt" and affected by strong dust events every year. It investigates the capability of the aeros…
Atmospheric correction for land surface temperature using NOAA-11 AVHRR channels 4 and 5
1991
Abstract In this work, a theoretical model that permits relating the land surface temperature with the temperatures measured by thermal infrared sensors has been developed. The model has been derived by linearization of Planck's function and atmospheric trasmittance. In this way a split-window equation is obtained, which depends on atmospheric water vapor, viewing angle, and channel surface emissivities. Simulations of satellite measurements of land surface temperatures are made using the atmospheric transmittance-radiance model LOWTRAN-7 for NOAA-11 AVHRR Channels 4 and 5. From these simulations the accuracies of linearizations have been checked. The dependence of the split-window coeffici…
Application of a simple algorithm to estimate daily evapotranspiration from NOAA–AVHRR images for the Iberian Peninsula
2007
International audience; Evapotranspiration (ET) is a key process in land surface–atmosphere studies. It mainly depends on water availability and incoming solar radiation and then reflects the interactions between surface water processes and climate. In this paper, a methodology for retrieving ET from low spatial resolution remote sensing data is presented. It is based on the evaporative fraction concept, and it has been applied to Advanced Very High Resolution Radiometer (AHVRR) data acquired over the Iberian Peninsula. The methodology does not require other data than the data provided by the satellite and may be applied to areas with almost spatially constant atmospheric conditions and whi…
Retrieval of evapotranspiration over the Alpilles/ReSeDA experimental site using airborne POLDER sensor and a thermal camera
2005
Abstract Knowledge of land surface evapotranspiration is of prime interest for environmental applications, such as optimizing irrigation water use, especially in arid and semiarid rangelands where water shortage is a critical problem. Numerous methods aiming at estimating evapotranspiration have been proposed in the literature. In the current paper, we assess the potential of the evaporative fraction based on the S-SEBI (Simplified Surface Energy Balance Index) concept for estimating instantaneous evapotranspiration, and extend this potential to the retrieval of daily evapotranspiration (ETd). To this end, a feasible and operational method is developed, which allows mapping instantaneous an…
Performances of neural networks for deriving LAI estimates from existing CYCLOPES and MODIS products
2008
International audience; This paper evaluates the performances of a neural network approach to estimate LAI from CYCLOPES and MODIS nadir normalized reflectance and LAI products. A data base was generated from these products over the BELMANIP sites during the 2001-2003 period. Data were aggregated at 3 km x 3 km, resampled at 1/16 days temporal frequency and filtered to reject outliers. VEGETATION and MODIS reflectances show very consistent values in the red, near infrared and short wave infrared bands. Neural networks were trained over part of this data base for each of the 6 MODIS biome classes to retrieve both MODIS and CYCLOPES LAI products. Results show very good performances of neural …
A new calibration of the effective scattering albedo and soil roughness parameters in the SMOS SM retrieval algorithm
2017
Abstract This study focuses on the calibration of the effective vegetation scattering albedo (ω) and surface soil roughness parameters (H R , and N Rp , p = H,V) in the Soil Moisture (SM) retrieval from L-band passive microwave observations using the L-band Microwave Emission of the Biosphere (L-MEB) model. In the current Soil Moisture and Ocean Salinity (SMOS) Level 2 (L2), v620, and Level 3 (L3), v300, SM retrieval algorithms, low vegetated areas are parameterized by ω = 0 and H R = 0.1, whereas values of ω = 0.06 − 0.08 and H R = 0.3 are used for forests. Several parameterizations of the vegetation and soil roughness parameters (ω, H R and N Rp , p = H,V) were tested in this study, tre…
Spatial homogeneity from temporal stability: Exploiting the combined hyper-frequent revisit of Terra and Aqua to guide Earth System Science
2021
Abstract The terrestrial component of the Earth system has witnessed considerable changes in the past decades due to anthropogenic action. Throughout this period, the NASA Terra mission has been constantly monitoring the surface with the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. When combined with the MODIS instrument on-board of the Aqua platform, we obtain a hyper-frequent revisit capability providing sub-daily observations globally at a moderate resolution of ~250 m, but with a strong multi-angular variation of the observation footprint. Here we propose to exploit this particular configuration provided by the combined Terra + Aqua constellation to infer spatial ho…
A combined single range and single image device for low-cost measurement of building facade features
2008
The dimensions of building facades and window apertures are usually determined by making direct measurements using tapes and plummets. This approach, however, has a number of drawbacks including the physical risk to which the persons making the measurements are exposed. This paper proposes an indirect approach based on close range photogrammetry that is inexpensive, simple, fast and safe, and which does not require specialist staff or direct ground control measurements. The method is based on taking a picture using a digital camera and measuring the distance to the object using a handheld laser distance meter. Both items of equipment are mounted on a specially designed support that allows t…