Ernesto Lopez Baeza Representing the ''Climatology from Satellites Group''
Servicio de la Universitat de València

[+]   [<=] [=>] Index of this webpage

**++Climatology from Satellites Group++**
**++Postgraduate++**
    ++Current Research Assistants (and Doctorate Students):++
    ++Doctorate on Remote Sensing Students:++
    ++Master Postgraduate:++
    ++Master Students:++
    ++Advanced Undergraduate:++
    ++Practicum - Practical Training:++
    ++Current External:++
    ++Past ..., but very close to us ...:++
**++Publications++**
**++Links to Significant Meetings++**
    ''**++2015++**''
    ''**++2014++**''
**++Active Collaborations++**
**++Acknowledgments**++
**++Book suggestions++**
**++Link of the Day++** (in reality, ... every now and then)
    2013
        December
**++Teaching Subjects++**
Postgraduate Course on ''New Observation and Watching Systems in Meteorology and Climatology''
    **Some Teaching Publications**
**++Research Lines++**
    **''I Validation of low spatial resolution remote sensing data and products (GERB, SMOS, EPS/MetOp, SMAP)''**
    **''II Radiative balance studies (GERB, CERES, SEVIRI, EarthCARE)''**
    **''III Soil moisture from passive microwaves (SMOS)''**
**++Valencia & Alacant Anchor Stations++**
    **What is an ''ANCHOR STATION''**? (from Professor H.-J. Bolle)/
    **Rationale**/
    **Desirable measurements at ''Anchor Stations''**/
     How Representative are the ''Alacant and the Valencia Anchor Stations'' Measurements of their Respective Surrounding Meteorology?
     Proposal for a ''Water Cycle Observatory'': The VALENCIA and the ALACANT ANCHOR STATIONS, Meteorological Reference Stations for Remote Sensing Data and Products
    **Publications**
            2008
            2007
            2006
            2005
            2003
            2002
**++Involvement in Satellite Earth Observation Missions++**
    **SMOS (''Soil Moisture and Ocean Salinity'')**/
        **SMOS Validation Rehearsal Campaign Activities at the Valencia Anchor Station**
            **Scientific Team**
            **Purpose**
            **Activities
                **SM Measurements**
                **Vegetation Measurements**
                **Soil texture**
            **Airborne Operations during the SMOS Validation Rehearsal Campaign (Tauriainen, 2008)**
            **Modelling**
        **Publications**
            2011
            2010
            2008
            2007
            2006
            2005
            2004
            2003
            2002
        **Projects**
    **EarthCARE (''Earth Clouds, Aerosols and Radiation Explorer'')**
        **Publications**
            2012
            2011
            2007
            2006
            2004
            2003
            2002
            2001
        **Projects**
    **GERB (''Geostationary Earth Radiation Budget'')**/
        **Publications**
            2011
            2008
            2007
            2006
            2005
            2004
            2000
        **Projects**
    **CERES (''Clouds and the Earth's Radiant Energy System'')**/
        **Publications**
            2012
            2008
            2007
            2006
            2005
            2004
            2000
        **Projects**
    **EPS/MetOp (''EUMETSAT Polar System / MetOp'')**/
        **Publications**
        **Projects**
**++Other Significant Research Projects and Contracts++**
        **Publications**
**++Field Campaigns++**
**++Supervision of Research Academic Work++**
**++Selected Significant Publications++**
**++Photographic Album: A Sample++**/
    2014
    2013
    2012
    2008
    2007
    2006
    2005
    2004
    2003
    2002
    2001
    2000
    1988

[<]   [<=] [=>]

**++Valencia & Alacant Anchor Stations++**





VAS_AAS02.gif

What is an ANCHOR STATION? (from Professor H.-J. Bolle)/

Anchor Stations are instrumented sites to measure in representative areas quantities which are needed to

run
calibrate
validate

models and algorithms e.g. such as those needed to quantitatively evaluate satellite data and convert them into geophysical information.

The stations must be instrumented with equipment for long time measurements of basic quantities (meteorological and hydrological background data) and, in addition, for quantities that are not readily assessed at operational meteorological and hydrological stations.

Anchor Stations, furthermore, must offer the infrastructure to undertake more refined measurements for shorter intensive observation periods in the surrounding of the station.

In addition to background quantities (temperature, moisture, pressure), they should also be measured:

fluxes (surface albedo, the four components of net radiation, soil heat flux, sensible and latent heat flux, carbon fluxes, water fluxes in the soil),
Bowen ratio
spectral atmospheric optical depth
atmospheric water vapour
aerosol parameters
ground water level
soil moisture
vegetation parameters (type, height or z0, resistances, biomass, NPP, LAI)

Not all Anchor Stations need to measure all parameters permanently

Rationale/

Mesoscale models
can in principle be operated with little instantaneous input from ground observations if topography and synoptic scale flow are known. Whether they produce the correct interactions with the surface (momentum, energy and mass fluxes) must be checked at least occasionally by direct measurements

Hydrological models
The same is true. In their case, it has to be validated whether they produce the correct soil moisture and run-off

Satellite data
are evaluated with complicated algorithms that tie the measured radiances to surface properties. These algorithms have to be tested against direct measurements and satellite instruments have to be re-calibrated

ISLSCP.gif
(From F. Becker, H.-J. Bolle and P.R. Rowntree, 1988, The International Satellite Land Surface Climatology Project)

Climate models
Not only need in addition to meteorological data carbon dioxide and other trace gas fluxes, they also need, according to the latest results, aerosol data. Anchor Stations should therefore also be equipped with instrumentation for spectral optical depth measurements or other kind of equipment that provides information about aerosol concentrations and types. The state of vegetation can, to some degree, be estimated from satellite observations. The conclusions from such kind of measurements may, however, be misleading if no ground truth is available

Desirable measurements at Anchor Stations/

Continuously:
Atmospheric transmittance (spectral)
Net radiation flux; preferable all four radiation fluxes plus in addition independently the net flux
Bowen ratio (including the measurements of air temperature and humidity at two levels)
Soil heat fluxes and temperatures at least at four levels
Precipitation
Soil moisture at three levels: near surface, intermediate, root layer
Effective radiation temperature of the surface
Ground water (piezometric) level

Occasionally (especially under extreme situations):
Sensible and latent heat fluxes separately by advanced methods (e.g. eddy correlation)
Vegetation parameters such as leaf area index (LAI), fractional coverage, biomass area density, stem flow, stomata resistance, vegetation height, vegetation structure, leaf orientation & size
Land use at and around the station

From time to time at longer intervals:
Soil quality
Radiometric characteristics (e.g. reflectance function)

At the central data bank the following derived quantities have to be computed from the measured values:

Wavelength dependent optical depth and vertical distribution of water vapour mass as needed for the correction of satellite data. The goal must be to derive a climatology of aerosol optical properties for the region. If reliable algorithms become available to compute atmospheric corrections from measurements made in space, this network serves the validation of these algorithms and the quality control of atmospheric corrections. This task can be supported by measurements made in the areas of the anchor stations by aircraft in order to obtain a better areal coverage.

Daily and monthly values of all flux components (radiation, sensible heat, latent heat, soil heat flux respectively heat storage in the soil).

Soil moisture as the difference between precipitation, latent heat flux, and storage.

Ratio of directional reflectance to albedo (according to models parametrized with respect to the measured quantities that are still to be developed).

Surface conductance.

VAS_AAS03.gif
Instruments on both Anchor Stations



How Representative are the Alacant and the Valencia Anchor Stations Measurements of their Respective Surrounding Meteorology?

The application of the Valencia and the Alacant Anchor Stations to validation activities of low spatial resolution Earth Observation remote sensing missions make it necessary to study the representativity and significance of the actual meteorological stations measurements with respect to the area they represent.

Meteorological simulations carried out with The Atmospheric Pollution Model (TAPM) (Hurley, 2005) carried out for the whole year of 2004 with the temporal resolution of one hour. The spatial resolution is 1 km, covering a total area of 75 x 75 km2. The grid is chosen such that the Anchor Station is placed in the central point, that is, the coordinate (38, 38).

The correlation between the simulated time series for every grid point and the corresponding Anchor Station simulated values is established by means of the Pearson�s correlation coefficient. The following figures show the correlation maps obtained for the parameters analysed, namely, temperature, relative humidity, u and v wind components, and precipitation.

RepresentativityAAS.gif
Correlation maps centered at the Alacant Anchor Station relative to the following meteorological parameters: a) temperature, b) relative humidity, c) u wind component, d) v wind component, e) precipitation


RepresentativityVAS.gif
Correlation maps centered at the Valencia Anchor Station relative to the following meteorological parameters: a) temperature, b) relative humidity, c) u wind component, d) v wind component, e) precipitation


A limit has been established in the correlation coefficients for each of the parameters and the zone of influence of the whole station has been taken as the intersection of the zones obtained for each of the parameters. Instead of using five correlation coefficients �one for each parameter- a specific percentile value, namely, 75, 85 95, has been chosen as limiting value for each of the correlation coefficients, thus defining different approximations degrees. The values of the limiting correlation coefficients relative to each meteorological parameter and for each proposed percentile are given in the following Table 1 for both Anchor Stations.

Limiting correlation coefficients for every parameter (temperature, relative humidity, u wind component, v wind component, precipitation) and percentile, respectively for the Valencia and the Alacant Anchor Stations TablePercentiles.gif

The graphical representation of the intersection of the areas obtained for each meteorological parameter is given in the followinf figure, where the red area represents the intersection of the zones obtained for each parameter taking as limiting R values those obtained for percentile 95; the yellow area for percentile 85 and the white area for percentile 75. The black area shows lower correlation values.

RepresentativeAreas.gif
Demarcation of the Valencia and the Alacant Anchor Stations, respective representative areas with three approximation degrees: the red area represents the intersection of the zones obtained for each parameter taking as limiting R values those obtained for percentile 95; the yellow area for percentile 85 and the white area for percentile 75. The black area shows lower correlation values

[Hurley P. (2005): The Air Pollution Model (TAPM) Version 3. Part 1: Technical Description, CSIRO Atmospheric Research Technical Paper No. 55]



Proposal for a Water Cycle Observatory: The VALENCIA and the ALACANT ANCHOR STATIONS, Meteorological Reference Stations for Remote Sensing Data and Products


The Valencia Anchor Station is showing its capabilities and conditions as a reference validation site in the framework of low spatial resolution remote sensing missions such as CERES, GERB and SMOS. The Alacant Anchor Station is a reference site in studies on the interactions between desertification and climate. Both stations separated a distance of about 150 km are actually twin stations, their representative areas have similar land use and soil types, but they are located in two different climatic zones: average annual precipitation is about 450 mm in the Valencia Anchor Station area and about 250 mm in the Alacant Anchor Station one. The parallelism between both Anchor Stations and the fact that one of them is under water-stressing conditions make it appropriate to define a Water Cycle Observatory where to study and compare meteorological parameters and surface fluxes of radiation, energy and water.

RadFluxes.gif
Surface radiation fluxes for the Alacant Anchor Station (left) and the Valencia Anchor Station (right) between 2 - 8 January 2005



Publications

2008

� F. Martinez, J. Mateu, F. Montes, A. Bodas-Salcedo and E. Lopez-Baeza (2008): A comparative analysis of different spatial sampling schemes: Modelling of SSRB data. International Journal of Remote Sensing, Vol. 29, No. 6, 20 March 2008, 1635�1647

� E. Lopez-Baeza, R. Acosta, A. Cano, C. Domenech, A.G. Ferreira, C. Millan, C. Narbon, J. Sanchis, A. Velazquez, S. Vidal (2008): Advanced Characterisation of the Valencia and the Alacant Anchor Stations. GIST 27, University of Valencia, 16th � 18th January 2008

2007

� E. Lopez-Baeza, Cano, A.; Domenech, C.; Estelles, V.; Ferreira, A.G.; Narbon, C.; Sanchis, J.; Velazquez, A.; Vidal, S.; Smith, G.L.; Szewczyk, Z.P.; Labajo, A.; Alonso, S.; Harries, J.E.; Russell, J.E.; Clerbaux, N.; Dewitte, S.; Rius, T.;Torrobella, J.; Pino, D.; Sanchez, J.J.; Tarruella, R. (2207): Validation of broadband radiation balance products at the Valencia and the Alacant Anchor Stations. GERB/CERES Ground Validation Campaigns. The EarthCARE Workshop. ESA-ESTEC, Noordwijk, The Netherlands, 7-9 May 2007

� S. Vidal, C. Narbon, A. Cano, E. Lopez-Baeza (2007): Methodology for the definition and delimitation of validation areas for remote sensing algorithms and low-resolution products. Application to the Valencia and Alacant Anchor Stations. International Geoscience and Remote Sensing Symposium (IGARSS) Symposium on -"Sensing and Understanding our Planet"-, Barcelona, 23-27 July 2007

� E. Lopez-Baeza & The Climatology from Satellites Group (2007): Making Sense of Satellite Data. Responding to Climate Change 2007. Research. Space & Earth Observation

� E. Lopez-Baeza S. Vidal, A. Cano, C. Domenech, A. Geraldo Ferreira, C. Millan-Scheiding, C. Narbon, J. Sanchis, A. Velazquez (2007): Representativity of the Valencia and the Alacant Anchor Stations in the Context of Validation of Remote Sensing Algorithms and Low-Resolution Products. Joint 2007 EUMETSAT Meteorological Satellite Conference and the 15th American Meteorological Society (AMS) Satellite Meteorology & Oceanography Conference. Amsterdam, The Netherlands, 24-28 September 2007

� Vel�zquez Bl�zquez, A., A. Cano, N. Clerbaux, S. Dewitte, C. Dom�nech, V. Estell�s, A.G. Ferreira, L. Gonzalez, J. Jorge Sanchez, N.G. Loeb, D. Pino, A. Rius, G. L. Smith, Z. P. Szewczyk, R. Tarruella, J. Torrobella, S. Vidal, E. Lopez-Baeza (2007): Simulation of CERES and GERB TOA Products over the Valencia Anchor Station for GERB Validation Purposes. Joint 2007 EUMETSAT Meteorological Satellite Conference and the 15th American Meteorological Society (AMS) Satellite Meteorology & Oceanography Conference. Amsterdam, The Netherlands, 24-28 September 2007

2006

� H.-J. Bolle, M. Eckardt, D. Koslowsky, F. Maselli, J. Melia Miralles, M. Menenti, F.-S. Olesen, L. Petkov, S.I. Rasool, A.A. Van de Griend (Eds.). Contributing Authors: H. Billing, A. Gitelson, F. G�ttsche, A. Jochum-Osann, E. Lopez-Baeza, F. Meneguzzo, J. Moreno, F. Nerry, P. Rossini, F. Veroustraete, R. Vogt, P.J. Van Oeleven (2006): Mediterranean Land-surface Processes Assessed from Space. Springer Berlin Heidelberg New York, 2006, XXVIII, 760 p., 442 iIIus., Hardcover, ISBN-10: 3-540-40151-2, ISBN-13: 978-3-540-40151-3

2005

� E. Lopez-Baeza, S. Alonso, A. Comer�n, R. Diaz-Pabon, C. Domenech, J.F. Gimeno-Ferrer, J. Jorge, A. Labajo, N. Pineda, D. Pino, A. Rius, F. Rocadenbosch, K Saleh, M. Sicard, R. Tarruella, J. Torrobella, and A. Velazquez (2005): A High-Quality Dataset of Land-Surface and Atmospheric Measurements for the Comparison/Crosscalibration of Data From Large Scale Optical Earth Observation Sensors in Space. The Valencia Anchor Station. Proceedings of the Workshop on Inter-Comparison of Large Scale Optical and Infrared Sensors. ESA/ESTEC 12-14 October 2004. ESA-WPP-244, Feb. 2005

� E. Lopez-Baeza C. Domenech, J.F. Gimeno Ferrer, A. Velazquez (2005): Proposal of a Water Cycle Observatory: The Reference Valencia and Alacant Anchor Stations for Remote Sensing Data and Products. XI Spanish Remote Sensing Congress, Puerto de la Cruz, Tenerife, 21-23 September 2005

2003

� Bodas Salcedo, E. Lopez-Baeza, F. Martinez, J. Mateu and F. Montes (2003): Spatio-Temporal Modelling and Prediction of Solar Radiation. Journal of Geophysical Research-Atmospheres, 108(D24), 8777, 2003

� E. L�pez-Baeza, A. Vel�zquez, C. Antol�n, A. Bodas, J. F. Gimeno, K. Saleh, F. Ferrer, C. Domenech, N. Castell, M. A. S�nchez (2003): The VALENCIA Anchor Station, a Cal/Val Reference Area for Large-scale Low Spatial Resolution Remote Sensing Missions. 3rd International Conference on Experiences with Automatic Weather Stations. Torremolinos (M�laga), 19-21 Feb. 2003

2002

� E. L�pez-Baeza, C. Antol�n Tom�s, A. Bodas Salcedo, J. F. Gimeno Ferrer, K. Saleh Contell, F. Ferrer, N. Castell Balaguer, C. Dom�nech Garc�a, M. A. Sanchez Aland�, and A. Vel�zquez Bl�zquez (2002): The Valencia Anchor Station: A Reference Cal/Val Area for Low-Resolution Remote Sensing Data and Products. Poster Recent Advances in Quantitative Remote Sensing, Torrente (Valencia), 16-20 September 2002






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