Photosynthetically Active radiation (PAR)
|Last update: May 2019|
Presentation of this activity
Evaluate the performance of 13 methods to assess PAR from satellite imagery at several ground stations. This axis of research and development was defined to fulfill the second most frequent demand from users to receive spectrally-resolved datasets.
The objective is to define the most adequate sets of services for SoDa based on the comparison of several methods developed by OIE and by other research laboratories.
The Illustration on the right hand side depicts the locations of the processed and to-be-processed ground measurements =>
List of processed stations in alphabetic order (to be processed in gray background, and in cloud-free conditions in orange background)
|Station||Code||Country||Latitude||Longitude||Altitude (m)||Period||Provider - Network||Type of climate|
|Bily Kriz Forest - CO2 enrichment experiment||BKF_control||Czech Rep.||49.502||18.539||2008-05-01 to 2011-11-02||GCAS||Continental|
|Bily Kriz Forest - Norway spruce forest before thinning||BKF_DF||Czech Rep.||49.502||18.537||2004-04-29 to 2007-11-01||GCAS||Continental|
|Bondville||BON||USA||40.05||-88.37||230||2010-01-01 to 2016-12-31||SURFRAD||Continental|
|Boulder||BOU||USA||40.12||-105.24||1689||2010-01-04 to 2016-12-31||SURFRAD||Continental|
|Desert Rock||DSR||USA||36.62||-116.02||1007||2010-01-12 to 2016-12-29||SURFRAD||Continental|
|Fort Peck||FPK||USA||48.31||-105.10||634||2010-02-10 to 2016-12-21||SURFRAD||Continental|
|Goodwin Creek||GWC||USA||34.25||-89.87||98||2010-01-01 to 2016-12-30||SURFRAD||Continental|
|Pennsylvania||PSV||USA||40.72||-77.93||376||2010-01-09 to 2016-11-23||SURFRAD||Continental|
|Peronne Saint-Quentin||PSQ||Netherlands||51.971||4.927||0||2005-2014||INRA - ICOS||Continental|
|Plataforma Solar de Alméria||PSA||UK||50.217||-5.317||88||2004-2007||CIEMAT||Continental - Mediterranean|
|Siouxfalls||SXF||USA||43.73||-96.62||473||2010-01-01 to 2016-12-31||SURFRAD||Continental|
|Třeboň Wetland||TRE||Czech Rep.||49.025||14.770||425||2006-04-29 to 2017-12-31||GCAS||Continental|
13 methods to assess PAR from satellite imagery
- Udo et Aro (1999) applied onto broadband GHI from HelioClim-3
- Szeicz (1974) on HC3
- Jacovides (2004) on HC3
- Wald on HC3 (Internal Report 2018)
- Weighted_Kato on HC3 (Wandji Nyamsi et al. 2014, 2015, and 2019)
- Discretized_Kato on HC3 (Wandji Nyamsi et al. 2014, 2015, and 2019)
- Udo et Aro applied onto GHI from CAMS Radiation Service
- Szeicz on CAMS-Rad
- Jacovides on CAMS-Rad
- Wald on CAMS-Rad
- Weighted_Kato on CAMS-Rad
- Discretized_Kato on CAMS-Rad
- DWD SARAH-3
Publications of this work - project applications
Peer-reviewed article ASR 2019
From the poster, an article has been proposed in January 2019. Status: under review.
EMS conference 2019: Copenhagen
An abstract has been submitted to this conference as an extension of the work proposed in the poster the year before. The 13 satellite methods will be confronted to at least 4 in-situ measurements, probably more by the date of the conference. (Work on going, no feedback yet from the Conference Organizers)
FPA 2019-2021: a service has been proposed in July 2018 for the application to Framework Partnership Agreement (FPA) of Copernicus. This action will support the dissemination of the activity toward the community via the organisation of training courses and workshops.
(Feedbacks from application planned on June 2019)
Call: H2020-SC5-2018-2019-2020 (Greening the economy in line with the Sustainable Development Goals (SDGs)
Type of action: IA
Proposal number: SEP-210573487
Proposal acronym: ExtendSolar
8 services have been proposed, 1 is about PAR.
(Feedbacks from application planned on June 2019)
(reverse chronological order)
29 Nov. 2017: rdv au CIEMAT. Discussion with the team about spectral developments
Oct. 2017: McClear v2 to McClear v3 => Stéphane is checking if ok. Correction of compute_gc_mcclear to correct the use of E0 (broadband instead of Kato)
Sept. 2017: McClear in real time
Aug. 2017: Self validation and first delivery of spectral radiation datasets to a user. Validation against in situ measurements is not yet carried out.
July: Bug in McClear v2 (change of atmospheric profile during the day generating sharp steps of radiation values). This has been corrected during the maintenance operation that occurred on 31st July 2017 (information not available in the release not as it impacted only the spectral data which is not an operational service).
Spring 2017: First developments of a precursor of service in Matlab following the work of William
2016 and before: research carried out by William Wandji, a PhD student from MINES ParisTech
Monthly and daily PAR from 2000-2016 : http://environment.snu.ac.kr/bess_rad/
Result from a radiation model transfer + neural networks with forcings from MODIS atmospheric products
Huete et al (2002) explique que l'indice EVI est plus adapté pour décrire l'activité photosynthétique des forêts tropicales (high-biomass forests) que le NDVI. (See Wikipedia for EVI - the values of coefficients for MODIS-EVI algorithm are; L=1, C1 = 6, C2 = 7.5, and G (gain factor) = 2.5)
PAR sensor, PSQ1 INRA Bornet June 2018: "A standardised PAR spectral response in the visible light range between 400nm and 700nm wavelength was defined by McCree (1972) such that each photon within this region is equally absorbed. ‘Blue' photons of shorter wavelength (higher frequency) have more energy than ‘Red' photons of longer wavelength. The amount of PAR is commonly expressed as Photosynthetic Photon Flux Density (PPFD) with a unit of µmol/m²·s."
Need for an online tool to convert µmol/m2/s into W/m2 or Wh/m2.
[le stress des plantes soumises à des grandes variabilités temporelles de l'éclairement solaire]
Proposition of division of the visible spectral by Dario: (not compliant with ISO 21348 Definitions of Solar Irradiance Spectral Categories)
- blu-violette, (400-490 nm),
- green (490-560 nm),
- yellow (560-590 nm);
- red-orange (590-700 nm)