Please note that this web site is entirely under construction! We apologize for any inconvenience. We strongly advise to reload the pages frequently.

This web site is intended to be useful to all the people involved in the campaign activities carried out in Barrax, La Mancha, Spain, from 14 to 17 of July 2004. Initially, this activities were related with several projects not connected among them, but finally, they have become a joint activity under the umbrella of a formal ESA (European Space Agency) campaign as part of Phase-A Preparations for the SPECTRA mission.

News

Last Updates

Documentation Page Update

• PROBA quicklooks and view angles.
• Flight lines corresponding to days from July 15th to July 18th

Congratulations to all the participants since the SPARC2004 campaign was highly successful

We have moved the page to a temporary site, thanks to the GPDS group:
http://gpds.uv.es/sparc/

LEO group server had a crash on July 8th so the SPARC web page has been temporary moved to GPDS server. All the other web pages of LEO's projects are also down.

Sorry about the inconvenience, we are working hard to keep it updated
and running.

The SPARC2004 web site has been urgently opened.

Today,9th of July, the ESA SPectra bARrax Campaign (SPARC) web site has been opened to public access. The LEO Group has decided to publish this web page as an urgent response to the increasing interest in the field campaign. We are working hard to offer valuable content to all the people involved in the campaign.

Last update 22 July 2004 - 18:49h

Overview of the campaign

The activities planned over Barrax this summer 2004 originated from the combination of a number of initially not connected initiatives coming under different funding:

• Field activities in the framework of the EU projects DEMETER, EAGLE and SmartSPECTRA
• MERIS / ASAR synergy studies within an ENVISAT AO project,
• MERIS validation activities within the framework of another ESA project,
• CHRIS/PROBA acquisitions and data analysis under the framework of another initiative,
• MSG/SEVIRI validation activities under funding by EUMETSAT LSA SAF,
• Barrax as an additional site for VALERI activities,
• background activities for vegetation fluorescence modelling and validation studies,
• background activities for SPECTRA studies,
• other national projects

Moreover, parallel activities related to definition of core sites for satellite validations for CHRIS and ENVISAT data have motivated the interest in getting involved in this activity by other people, with activities also related to AATSR and ASTER thermal data validation.

Most of the activities to be performed in the campaign are highly relevant for SPECTRA, but in particular the issues related to retrieval of biophysical parameters from CHRIS and MERIS data will be of particular relevance, while scaling issues and complementary between SPECTRA (covering only local sites) and global sensors such as MERIS / SEVIRI are also key elements. Another aspect of the campaign is the use of CHRIS data to test geometric and atmospheric processing procedures to be developed for SPECTRA. CHRIS data also serves for SPECTRA simulation studies, as model-simulated Barrax scenes can be compared with actual data

The reason for the selection of the days 14th, 15th, 16th,17th of July to carry out the campaign is the coincidence with two consecutive days of CHRIS/PROBA overpasses. Since most of the other planned activities are somehow flexible in dates (more continuous satellite overpasses) the particular orbit of PROBA is the driver in choosing the preferable dates for the campaign.

For those not familiar with PROBA, the satellite was launched in a kind of orbit that has some special features. It makes possible to have coverage over a given site for 2 or 3 consecutive days, and then several days (around 6 at the latitude of Barrax) in between where access to the site is not possible due to the orbital coverage. The situation over Barrax on 15-16 July is particularly favourable, because PROBA will almost pass over (+18º across-track zenith angle) on 15th of July, and then on 16th of July (+8º across-track zenith angle) we have additional multi-angular coverage. Each orbit provides 5 images with different view angles (-55º, -36º, 0º, +36º, +55º along-track zenith angles). Then, it seems these are the optimum dates for the campaign for angular coverage. Overpass times are 11:12 and 11:24 (UT) for the two days, 15-16 July respectively:

Date Time Minimum Satellite

The plan is to get a multiangular reference dataset with 10 angles (5 angles along each of the 2 different orbits) and 62 spectral channels per angle during this concentrated campaign. This intensive dataset plus the multitemporal series of CHRIS data being collected over Barrax since 2003 will represent the SPECTRA reference dataset for SPECTRA-related studies. Specific atmospheric measurements are planned for each PROBA overpass on each day.

For MERIS it is possible to get Full Resolution data for two days during the campaign, 14th and 17th of July:

INTA will be in charge of the flights, with final confirmation of aircraft availability exactly for the days of CHRIS/PROBA overpass. The sensor to be used is INTA-AHS 80Airborne Hyperspectral Scanner.

Concerning atmospheric measurements, we plan to launch 2 radiosounding balloons every day of the campaign, one in the early morning (to get stable atmospheric condition) and the other just at the time of satellite/aircraft overpass. The combination of radiosoundings / LIDAR / sunphotometers / high spectral resolution sky radiance measurements will allow addressing a number of issues such as:

1. Aerosols optical thickness retrievals (more related aerosols parameters), by different methods and techniques.
2. Atmospheric correction of the satellite data, with several algorithms to be tested for CHRIS and MERIS.
3. High spectral resolution radiance measurements in the O2-A band for validation of MERIS pressure retrievals for Rayleigh corrections.

Vegetation measurements will focus on three main parameters: LAI, fCover, Chlorophyll. These three parameters are the official products being validated in the context of MERIS and SEVIRI activities. Obviously, for validation it is convenient to measure additional information about canopy architecture: canopy height, leaf size, etc. and other relevant information about phenology of each type of crop.

Radiometric measurements at the leaf and canopy levels will be performed by using the several available radiometers with different fields of view and different setups. At least 4 radiometers (two GER and two ASD) will participate in the campaign, two of them mounted in adapted hoist, with angular FOV ranging from 1 to 25 degrees. Different methods to measure LAI and chlorophyll will be used, as well as for fCover, including regular, hemispheric and stereoscopic digital photos. Some intercomparison of methods is planned before or after the main campaign, preferably before depending on the weather conditions and availability of the different teams.

Maps of the status of vegetation are already prepared as part of the background DEMETER activities already on going, and other satellite data (Landsat) are also available as part of the DEMETER project.

Although everybody would prefer that this is not the case, if extremely bad weather conditions develop during the planned campaign period 14-17 July, a backup solution is considered for 23 and 24 July, where CHRIS/PROBA overpasses are also possible.

This summer there will be new activities incorporated. One of them is the use of the SPARC2004 data as a "real world" test for the newly developed ESA Campaign Data Base (ESA-CDB) that will collect all the data from ESA supported field campaigns. In order to comply with the requirements of the data base, the data acquired by the scientific teams must be submitted in a very specific format. Because each data set usually is composed of several measurements, and each measurement involves several variables, the organization of the data is very relevant. It would be advised that each team reports the measurements that they have planned, also, it would help if you report data or meta-data that is missing from the templates that is essential for your data.

A document with tables of valid values of some of the fields is attached. In particular, it is very important the DATA_VARIABLES table. Data and associated metadata are packed in files and transferred from data originators to the data centre. This is required both for proper indexing, and to make the data useful to the end user that retrieves the file.

Metadata parameters are divided into Global Attributes (pertaining to an entire dataset contained in one single file), and Variable Attributes (pertaining to one single variable within a dataset). A variable is a chemical component or physical parameter that is reported in a file (the main content of the file). Several variables are normally included in a dataset. The term parameter is in our context normally used for a metadata element (a piece of information about a variable or an entire dataset). The term field is often used for a subdivision of the content of a parameter (for example, a person name parameter consists of both family name and first name).

SIMPLIFIED VIEW OF THE FILE DATA STRUCTURE