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The HelioClim-3 Database |
A problem of units ? of terminology ? Consult the Education service. |
- Identity card of HC3
- HC3 services
- Successive versions
- Important facts since end of 2010
- More information on:
Identity card of HC3
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Additional Comments: Spatial coverage and resolution: click on this illustration to magnify.  Leadtimes: End of following day. If agreement with Eumetsat, very early morning of next day: Satellite data are received at MINES ParisTech by the means of a receiving station and are processed immediately. They are available 2-3 minutes after end of acquisition. For legal reasons, they are disseminated only 24 hours after. More information | ||||||||||||||||||||||
HC3 Services
Service names: HC stands for HelioClim + time step + plane orientation (default: horizontal)
The annual subscription to a HC3 service offers an unlimited access to this product during the twelve months following the opening of the account. The subscription to a product offers also access to products with a larger temporal step. For instance, the subscription to the HC15 service also allows to access to the products HCHour, HCDay, HCWeek and HCMonth. Moreover, the subscription of a product on an inclined (or normal) plane enables the access to the equivalent product on the horizontal plane. For instance, if you purchase HC15Incl, you will also be granted the possibility to assess to the services previously listed, as well as: HCmonthIncl, HCdayIncl and HChourIncl.
List of services:
HCmonth: HelioClim3 monthly irradiation values over a horizontal plane.
HCweek: HelioClim3 weekly irradiation values over a horizontal plane.
HCday: HelioClim3 daily irradiation values over a horizontal plane.
HChour: HelioClim3 hourly irradiation values over a horizontal plane.
HC15: HelioClim3 15 minute irradiation values over a horizontal plane.
HCmonthIncl: HelioClim3 monthly irradiation values over an inclined plane.
HCdayIncl: HelioClim3 daily irradiation values over an inclined plane.
HChourIncl: HelioClim3 hourly irradiation values over an inclined plane.
HC15Incl: HelioClim3 15 minute irradiation values over an inclined plane.
HCmonthDNI: HelioClim3 monthly irradiation values over a normal plane.
HCdayDNI: HelioClim3 daily irradiation values over a normal plane.
HChourDNI: HelioClim3 hourly irradiation values over a normal plane.
HC15DNI: HelioClim3 15 minute irradiation values over a normal plane.
Output column content: description of the content of the columns for each service.
HelioClim-3 successive versions
HC3v2 versus HC3v3: Warning message!
Be aware that we must advise you to use the former version HC3v2. The statistical results returned by this version turns out to be better than for HC3v2, unfortunately no document has been yet published on this version. After a discussion with the Center of Research of MINES ParisTech, feel free to use both version if you wish, but the Customer assumes all of the responsibilities for the use of the provided data. As it is written in our contracts "The provider TRANSVALOR and the author ARMINES/Mines ParisTech disclaim all warranties, expressed or implied, including, without limitation, the warranties or merchantability and of fitness for any purpose. "
| Version Number | Date | Comments |
|---|---|---|
| v3 | May. 2011 | Corrections: - A bug has been reported on March 21st 2011 on the slot acquired at 6 AM UT. An erroneously high value has been noted for the geographical location: (lat, lon) = (50.92°,3.395°) with a plane inclined 15° with an azimuth of 181°. Actually, there were two origins for this error:
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| May. 2011 | Corrections: - A bug has been reported on March 21st 2011 on the slot acquired at 6 AM UT. An erroneously high value has been noted for the geographical location: (lat, lon) = (50.92°,3.395°) with a plane inclined 15° with an azimuth of 181°. Actually, there were two origins for this error: - An error of 30 seconds on the solar angle in the routine which computes the reflected part of the irradiation over an inclined plane. - An error of 30 seconds on the solar angle in the routine which computes the angles alpha and beta of the inclined plane and in Normal Incidence. Besides the correction of these bugs, these changes affect all the DNI and Inclined computations. According to our tests, the difference is maximum 1 watt. |
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| Apr. 2011 | Corrections of: - the bug of the glitter. But please note that the bug is still present since Jan 2009 until Feb. 23rd 2011. learn more - the images with vertical zebra. Very weird images of HelioClim3 data were punctually stored in the database, under the form of vertical zebra of nul value, like in the image of Feb. 15th 2011 at 17:00 UT. It was due to wrong memory allocation in the routines. - Ap. 12th: an error of 1 minute has been reported due was made 4 times a year with the transformation of the time reference from TU to TST in the routines. |
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| Dec. 2010 | Innovations compared to HC3v2: - new method to split GHI into DHI et BHI - a better estimation of the values in the earliest/latest irradiation values of the day for all the plane orientations (Horizontal, Tilted and DNI values) On January 1st 2011, this version becomes available. |
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| v2 | Oct. 2010 | Corrections: Spikes or radiation (punctual spots of erroneously high radiation values) were observed during the earliest and latest instants of the day. These values have been corrected. |
| June 2009 | Innovations compared to HC3-beta: - Correction of the incohent low values on desertic areas, - It has ben demonstrated in (Wahab, Lel-Metwally, Hassan, Lefèvre, Oumbe and Wald, 2009) that a difference of 100 m of height has an important effect on solar radiation. The new version refines solar radiation values using sub-pixel databases of altitudes. - Because the orbit of the earth is an ellipse, the earth's angular speed varies slightly throughout the year. Combined with the earth rotation on itself which is very regular, it results that the sun does not reach its highest position in the sky at 12 h Mean Solar Time. This highest position, called solar noon, may differ from 12 h MST by up to 17 min.In order to take into account this variation, time sampling is reduced to one minute before time aggregation. The statistics which compared hc3-beta and hc3v2 are available here. |
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| beta | From Feb 2004 until Dec 2009 | Known defects: - The irradiance was underestimated during the afternoon in sites located east of 30 deg in desertic areas with local relief. - The irradiance may be at times slightly overestimated in Northern Europe for irradiance greater than 200 W/m2 and can be underestimated at times when the sun is low. |
| Innovations compared to HC2: - The cause of the major problem -underestimation in several desertic areas in Middle East- was identified as the juxtaposition of very bright areas (illuminated sand => large albedo) and very dark areas (shadowing due to local relief) within the same satellite pixel creates optical effects that are not well handled by the current version. A correction has been applied. |
Important facts since end of 2010
| Date | Comments |
|---|---|
| Nov. 24th 2011 | Improvements of the free webservice NASA-SSE-HC1: - through the website, the option output in csv is now available - the wget access is now available to any Customer who already has an annual subscription with the wget access. |
| Nov. 21th 2011 | Improvements of the free webservice NASA-SSE-HC1: |
| Oct. 25th 2011 | Improvements of the navigation within the formulaires in SoDa: From "POST" to "GET": no need to enter once more the inputs parameters in a request when using the "back" button. The formulaire keeps previous ones. |
| Sept. 29th 2011 | Major re-writting of the whole codes: This "re-writting" of all the code around HelioClim aimed at simplifying and increase the speed of all the routines. Many bugs have been reported after that, and solved: - disparition of the yearly averaged irradiation value from the service HCmonthIncl and HCmonthDNI de la moyenne annuelle pour les services HCmonthIncl et HCmonthDNI. Corrigé le 23 nov 2011, et rajout de cette moyenne sur HCmonth |
| Sept. 8th 2011 | Improvement of the clear sky model: In order to fit the litterature, a bug has been corrected on the computation of the rhog, the minimum of radiation computed for each pixel and supposed to represent the value of radiation in case of clear sky. The reference (?) gives: ρgday = min(ρg(15 last days),ρg(same day last year)) However, a bug was introduced that discard the value of the ρg of the last year. This bug has been corrected. |
| May 23rd 2011 | Improvement of the service HCweek: The service has been improved in order that the week begins not only on a Monday, but on any day of the week selected by the User. |
| March 3rd 2011 | Improvement of the map service: While a Customer was purchasing a map of irradiation for a country located by the sea, a new artefact appeared. The reason is that the albedo over the sea is fixed to the value 0.2. The condition which designates a sea or a ground pixel was based on the low spatial resolution database of elevation Terrain Base 5´. This resulted in large squarred artefacts all along the shore. For a better precision, SRTM instead TB5 has been used since this date. |
| Feb. 22th 2011 | Real time service: A new service in real time is now available. you can now ask for a quotation to retrieve irradiation values or maps as soon as the images are acquired and processed (about 5 min after the image reception). Please ask for a quotation |
| Feb. 9th 2011 | Duplication of the acquisition chain: In order to enhance the quality of the service, another chain of acquisition has been settled in Transvalor S.A., 694 av. du Docteur Maurice Donat, 06255 Mougins. Since then, our Customers can do their automatic wget requests to both sites: www.helioclim.com and pro.soda-is.com. |
| end 2010 | Improvement of the map service: The map service displayed large squarred artefacts of the images. This bug have been corrected. Learn more |
Last update: 4/5/12 6:50 PM