Search results for "Atmospheric model"

Image simulation of geostationary sensor dedicated to ocean color

2010

A method of image simulation of geostationary sensor dedicated to ocean color for open water (case1) and coastal water (case2) is presented in this paper. This method uses HYDROLIGHT to model the radiative transfer in order to obtain the water surface radiance. MeRIS level 3 products have been used for input water components to provide a realistic spatial distribution. The atmospheric radiative transfer model and the sensor model finely lead to satellite remote sensing images. This system allows to evaluate the dynamic range of BOA and TOA radiances depending on solar and viewing angles in operational situation and latter their influence on water composition retrieval.

Comparison of Split-Window and Single-Channel Methods for Land Surface Temperature Retrieval from MODIS and AATSR Data

2008

In this study, two different methods for retrieving the Land Surface Temperature (LST) from Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) and Envisat/Advanced Along Track Scanning Radiometer (AATSR) data are compared against a database of ground measured LSTs. These are the split-window (SW) and the single-channel (SC) methods. The SW method expresses LST as a combination of the brightness temperatures in the 11 iquestm and 12 iquestm channels with coefficients that can have local or global validity, depending on the way they are obtained. SC methods are based on the atmospheric radiative transfer equation. To solve this equation, convenient atmospheric temperature and water v…

Revision of the Single-Channel Algorithm for Land Surface Temperature Retrieval From Landsat Thermal-Infrared Data

2009

This paper presents a revision, an update, and an extension of the generalized single-channel (SC) algorithm developed by Jimenez-Munoz and Sobrino (2003), which was particularized to the thermal-infrared (TIR) channel (band 6) located in the Landsat-5 Thematic Mapper (TM) sensor. The SC algorithm relies on the concept of atmospheric functions (AFs) which are dependent on atmospheric transmissivity and upwelling and downwelling atmospheric radiances. These AFs are fitted versus the atmospheric water vapor content for operational purposes. In this paper, we present updated fits using MODTRAN 4 radiative transfer code, and we also extend the application of the SC algorithm to the TIR channel …

Assessment of the Potential future high and medium resolution sensors on geosynchronous orbit for coastal zone monitoring

2009

Geosynchronous satellite can measure any area with high temporal repetitivity within its coverage region because of its relative static location compared to Earth. Considering the temporal repetitivity, it can satisfy requirements for coastal zone monitoring but also has to face the influence of the varying solar angle and sensor angle (zenith and azimuth). Up to now, there is no geosynchronous sensor dedicated to ocean color monitoring (a geosynchronous sensor "Korea Geostationary Ocean Color Imager" (KGOCI) is supposed to be launched in 2009 [1]). To obtain radiances from the ocean at 36000km of altitude, we have to use a simulation model. In this conference, we present generic model of s…

Improvement of Temperature Based ANN Models for ETo Prediction in Coastal Locations by Means of Preliminary Models and Exogenous Data

2008

This paper reports the application of artificial neural networks for estimating reference evapotranspiration (ETo) as a function of local maximum and minimum air temperatures and exogenous relative humidity and evapotranspiration in twelve coastal locations of the autonomous Valencia region, Spain. The Penman-Monteith model for ETo prediction, as been proposed by the Food and Agriculture Organization of the United Nations (FAO) as the standard method for ETo forecast, has been used to provide the ANN targets. The number of stations where reliable climatic data are available for the application of the Penman-Monteith equation is limited. Thus, the development of more precise predicting tools…

Prototype for Surface Albedo Retrieval Based on Sentinel-3 OLCI and SLSTR Data in the Framework of Copernicus Climate Change

2021

This work describes the different algorithmic steps used to retrieve the first Surface Albedo (SA) product based on Sentinel-3 (S-3) data in the framework of the Copernicus Climate Change Service (C3S). The atmospherically corrected Top-Of-Atmosphere (TOA) reflectances into Top-Of-Canopy (TOC) reflectances are brokered from the Copernicus Global Land Service (CGLS). The TOC reflectances are used to obtain a BRDF model. Next, the spectral and angular integration steps are implemented, which take the latter coefficients as input to produce spectral and broadband albedo quantities. The preliminary quality assessment of BSA broadband albedo for the total shortwave shows good overall spatiotempo…

2015

Abstract. A recent parcel model study (Reutter et al., 2009) showed three deterministic regimes of initial cloud droplet formation, characterized by different ratios of aerosol concentrations (NCN) to updraft velocities. This analysis, however, did not reveal how these regimes evolve during the subsequent cloud development. To address this issue, we employed the Active Tracer High Resolution Atmospheric Model (ATHAM) with full microphysics and extended the model simulation from the cloud base to the entire column of a single pyro-convective mixed-phase cloud. A series of 2-D simulations (over 1000) were performed over a wide range of NCN and dynamic conditions. The integrated concentration …

The 1-way on-line coupled atmospheric chemistry model system MECO(n) – Part 3: Meteorological evaluation of the on-line coupled system

2012

Abstract. Three detailed meteorological case studies are conducted with the global and regional atmospheric chemistry model system ECHAM5/MESSy(→COSMO/MESSy)n, shortly named MECO(n), in order to assess the general performance of the on-line coupling of the regional model COSMO to the global model ECHAM5. The cases are characterised by intense weather systems in Central Europe: an intense cold frontal passage in March 2010, a convective frontal event in July 2007, and the high impact winter storm "Kyrill" in January 2007. Simulations are performed with the new on-line-coupled model system and compared to classical, off-line COSMO hindcast simulations driven by ECMWF analyses. Precipitation o…

HICO L1 and L2 data processing: Radiometric recalibration, atmospheric correction and retrieval of water quality parameters

2015

The Hyperspectral Imager for the Coastal Ocean (HICO) is an imaging spectrometer designed with a very high signal-to-noise ratio to monitor coastal ocean and inland waters. The processing of Top-Of-Atmosphere radiance data down to surface reflectance is fundamental for the retrieval of water quality products. However, the current HICO processing chain does not provide atmospheric corrected data nor higher-level water quality products. This paper describes the algorithms implemented within an HICO data processing chain that includes image pre-processing, atmospheric correction and the retrieval of water quality parameters. The implemented algorithms have been validated over a set of HICO ima…

HICO level-2 data processing toolbox for the atmospheric correction and the retrieval of water quality parameters

2014

The Hyperspectral Imager for the Coastal Ocean (HICO) is an imaging spectrometer specifically designed to monitor the coastal ocean. The processing of Top-Of-Atmosphere (TOA) radiance data down to surface reflectance is fundamental for the retrieval of water quality products. However, the current HICO processing chain does not provide atmospheric corrected data nor higher-level water quality products. This work describes a toolbox for the atmospheric correction of HICO data and the retrieval of water quality products. The HICO toolbox, consisting on three main modules (image pre-processing, atmospheric correction and retrieval of water quality products), has been used over a set of HICO ima…