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ARD On-Demand Demonstrator User Manual

introduction

The objective is to generate an ARD on demand with the “on-demand” aspect indicating both the possibility to configure the ARD as desired (tailored or “made-to-measure”). The user could select his own configuration or select a default configuration and run it on a selected data set defined by sensor, area and time of interest.  So the data would be analysis ready for a given application/algorithm and would be interoperable between sensors provided that the same processing scheme is simultaneously applied to several sensors.

The Processors will make use of the G-POD (Grid-Processing ODemand) distributed computing platform to deliver timely the output data products.

Using the G-POD graphic interface, it is possible to easily select the geographical area of interest along with the time of interest in order to retrieve the input data and submit a processing task to the G-POD computing engines. After the task submission, it is possible to follow, in real time, the status of the processing task.


You find more information about how to use the generic G-POD graphic interface at the G-POD wiki page available here.


supported input data

The demonstartor has been built accordign to the requirements to support in input the following input data:

  • Sentinel-2 L1C
  • Landsat-8 L1TP

The list of input products can be retrieved by querying the catalogue according to the dataset series of interest and accordign to the AOI and time interval parameters defined via the map GUI.


IMPORTANT NOTE: in case MAJA algorithm is selected for the Atmospheric Correction only Sentinel-2 is supported by the current version of the ARD On-Demand demonstrator. Moreover for MAJA processign the input Sentinel-2 data should be selected on the same tile reference (e.g. 33TUG).


 

processing parameters

The following figure shows the processing parameters defined for the ARD On-Demand demonstrator.


Atmospheric Correction Algorithm

Among the supported atmospheric processor the user can choose on of the following options:

  • Sen2Cor
  • LaSRC
  • iCOR
  • MAJA

Sen2Cor

Provider:  ESA

Sen2Cor is a processor for Sentinel-2 Level 2A product generation and formatting; it performs the atmospheric-, terrain and cirrus correction of Top-Of- Atmosphere Level 1C input data. Sen2Cor creates Bottom-Of-Atmosphere, optionally terrain- and cirrus corrected reflectance images; additional, Aerosol Optical Thickness-, Water Vapor-, Scene Classification Maps and Quality Indicators for cloud and snow probabilities.

Full Sen2Cor documentation and software package can be found here.


LaSRC

Provider:  NASA/USGS

Landsat 8 Surface Reflectance data are generated from the Landsat Surface Reflectance Code (LaSRC), which makes use of the coastal aerosol band to perform aerosol inversion tests, uses auxiliary climate data from MODIS and uses a unique radiative transfer model. LaSRC hardcodes the view zenith angle to “0”, and the solar zenith and view zenith angles are used for calculations as part of the atmospheric correction.

Specific details about the LaSRC algorithm and Landsat 8 Surface Reflectance data products can be found in the Landsat 8 Surface Reflectance Product Guide.


iCOR

Provider: VITO

The atmospheric correction software, iCOR (previously known as OPERA), is available to the broad user community for the atmospheric correction of Sentinel-2 and Landsat-8  data. The strength of iCOR is that it is scene generic: it works just as well on land as on water targets (coastal, transitional and inland waters). The tool identifies whether a pixel is water or land and applies a dedicated correction.  iCOR runs without user interaction and all the input parameters can be retrieved from the image itself.

Full documentation and software package can be found here.


MAJA

Provider: CNES, DLR, CESBIO

The MAJA processor (MACCS ATCOR Joint Algorithm, say "maya") is a processor for cloud detection and atmospheric correction, specifically designed to process time series of optical images at high resolution, acquired under quasi constant viewing angles. It allows for instance to process time series of Sentinel-2 images.

Full documentation and software package can be found here.


IMPORTANT NOTE :  The ARD On-Demand demonstrator service output products are compliant with the output service specifications (except for format and projection) of the selected atmospheric correction processor. Therefore the specific processors (linked above) documentation can be used as reference for issues inherent to the product output structure.
 


Projection

According to the requirements, the ARD On-Demand demonstrator allows the user to select the output product projection.

The supported projections by the current version of the demonstrator are:

  • UTM
  • Geographic Lat/Lon (WGS84)

Format

According to the requirements, the ARD On-Demand demonstrator allows the user to select the output product format.

The supported formats by the current version of the demonstrator are:

  • GeoTiff
  • HDF
  • NetCDF
  • SAFE (only for Sen2Cor)

Advanced Configuration (Expert User Only)

If the checkbox is ticked a set of advanced parameters is displayed to the user. Such expert parameters are mostly referred to the selected Atmospheric Correction Processor and vary dynamically according to that selection as show in the following example figures (for Sen2Cor and LaSRC selections).

Sen2Cor advanced parameters:

LaSRC does not have any advanced parameters:


 


ARD On-Demand demonstrator video tutorial



Support Contacts

For any request or in case of issues in using the service please contact: rss_team@esa.int




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Page last modified on Thursday 20 of December 2018 12:51:26 CET by .