Hi there.
I have recently taken the template for the hours of sunshine from the example
under. Now I have noticed that my sunshine time in the xml is no longer
correct. I think it's because of the conversion?
The Result:
<solar>
<solar value="831"/>
<solar_max value="877"/>
<solar_max_time value="11:39"/>
<sun_unformatted value="135.0"/>
<sun value="135 h 0 m"/>
</solar>
The Code:
<solar value="$current.radiation.formatted"/>
<solar_max value="$day.radiation.max.formatted"/>
<solar_max_time value="$day.radiation.maxtime.format("%H:%M")"/>
<sun_unformatted value="day.sunshine_hours.sum.raw"/>
#set hours = int($day.sunshine_hours.sum.raw)
#set minutes = int(($day.sunshine_hours.sum.raw - $hours)*60 + 0.5)
<sun value="$hours h $minutes m"/>
It is also said to divide the 130 minutes into hours and minutes. That means
doing it with the existing code, but unfortunately it doesn't work anymore. Can
someone help me?
Am Donnerstag, 14. November 2019 13:34:16 UTC+1 schrieb Jacques Terrettaz:
>
> I agree with peter's comment.
> The Davis solar radiation sensor, or any comparable sensor, is measuring a
> global radiation ( direct + diffuse) and the surface of the sensor is
> parallel to the ground. A fixed threshold, such as 120 W/m2, can be used
> only with sensors measuring direct radiation and that have their surface
> always pointing to the sun (i.e surface of sensor is always perpendicular
> to the axis sun-sensor).
> With a Davis solar sensor, applying a fixed threshold to estimate sunshine
> duration give innacurate values. Why? A simple example, taken from the
> measurements of my Davis solar sensor, will make you understand:
> - On December 20, at 9:30, the sun was shining, and my solar sensor, in
> full sun, measured 105 W / m2.
> - On June 11, at 10 am, the sky was cloudy, and my solar probe measured
> 301 W / m2.
> How to choose a fixed threshold so that the sun of December with 105 W /
> m2 is considered as sunny and that a radiation of 301W / m2 under a cloudy
> sky of end of June is not considered as sunny?
> A measurement of the global solar radiation on a plane parallel to the
> ground is very dependent on the elevation of the sun. This elevation
> changes according to the time of day and according to the seasons.
> So with this type of solar sensors, a valid calculation of the sunshine
> duration can only be done with methods taking into account the elevation
> of the sun at the time of the measurement, calculated according to the
> latitude, longitude, date and the time of observation.
>
> Here is the weewx extension I am using, that I modified from
> https://github.com/brewster76/util-archer/blob/master/user/radiationhours.py
> by applying a formula developed by MeteoFrance to estimate sunshine
> duration from Davis sensors. (
> https://forums.infoclimat.fr/f/topic/17151-calcul-duree-ensoleillement/?do=findComment&comment=1216053).
>
> The idea is to determine at each measurements a threshold value that is
> calculated depending on the date, time and geographic location (latitude
> and longitude) of the sensor. If the measured solar radiation is higher
> than the calculated threshold, the sunshine duration for this measurement
> will be equal to the archive interval, otherwise it will be 0.
>
> """
> Adds a new observation field to weewx: [sunshine_time]
> Installation:
> 1. Save this file to your user customisations directory (which is often
> /usr/share/weewx/user)
> 2. Enable this service in weewx.conf by adding
> user.sunduration.SunshineDuration to the process_services list.
> [Engine]
> [[Services]]
> # This section specifies the services that should be run.
> They are
> # grouped by type, and the order of services within each group
> # determines the order in which the services will be run.
> prep_services = weewx.engine.StdTimeSynch
> process_services = user.sunduration.SunshineDuration,
> weewx.engine.StdConvert, weewx.engine.StdCalibrate, weewx.engine.StdQC,
> weewx.wxservices.StdWXCalculate
> 3. Add [sunshine_time] to the database schema so tables include this new
> observation field.
> In weewx.conf, change the wx_binding schema from schemas.wview.schema
> to user.sunduration.schema_with_sunshine_time
> [DataBindings]
> [[wx_binding]]
> # The database must match one of the sections in [Databases].
> # This is likely to be the only option you would want to
> change.
> database = archive_sqlite
> # The name of the table within the database
> table_name = archive
> # The manager handles aggregation of data for historical
> summaries
> manager = weewx.wxmanager.WXDaySummaryManager
> # The schema defines the structure of the database.
> # It is *only* used when the database is created.
> #schema = schemas.wview.schema
> schema = user.sunduration.schema_with_sunshine_time
> 4. Shutdown Weewx and update your database to bring in the new field.
> wee_database weewx.conf --reconfigure
> Make sure you know what you're doing at this point, you can
> potentially corrupt/lose your archive data.
> The weewx customization guide covers this in a lot more detail.
> 5. Tell Weewx about the units for this new type
> Add this to user/extensions.py:
> #
> # Units for sunshine_days calculated field
> #
> import weewx.units
> weewx.units.obs_group_dict['sunshine_time'] = 'group_interval'
>
> 6. Use [sunshine_time] in your graphs and html template tags.
> Lots more detail on this process can be found here:
>
> http://www.weewx.com/docs/customizing.htm#Adding_a_new_observation_type
> """
>
> import syslog
> from math import sin,cos,pi,asin
> from datetime import datetime
> import time
> import weewx
> from weewx.wxengine import StdService
> import schemas.wview
>
> class SunshineDuration(StdService):
> def __init__(self, engine, config_dict):
> # Pass the initialization information on to my superclass:
> super(SunshineDuration, self).__init__(engine, config_dict)
>
> # Start intercepting events:
> self.bind(weewx.NEW_ARCHIVE_RECORD, self.newArchiveRecord)
>
> def newArchiveRecord(self, event):
> """Gets called on a new archive record event."""
> seuil = 0
> tempe = float(event.record.get('outTemp'))
> radiation = event.record.get('radiation')
> event.record['sunshine_time'] = 0.0
> if radiation is not None:
> utcdate = datetime.utcfromtimestamp(event.record.get('dateTime'))
> dayofyear =
> int(time.strftime("%j",time.gmtime(event.record.get('dateTime'))))
> theta = 360 * dayofyear / 365
> equatemps = 0.0172 + 0.4281 * cos((pi / 180) * theta) - 7.3515 *
> sin(
> (pi / 180) * theta) - 3.3495 * cos(2 * (pi / 180) * theta) -
> 9.3619 * sin(
> 2 * (pi / 180) * theta)
>
> latitude= float(self.config_dict["Station"]["latitude"])
> longitude = float(self.config_dict["Station"]["longitude"])
> corrtemps = longitude * 4
> declinaison = asin(0.006918 - 0.399912 * cos((pi / 180) * theta)
> + 0.070257 * sin(
> (pi / 180) * theta) - 0.006758 * cos(2 * (pi / 180) * theta)
> + 0.000908 * sin(
> 2 * (pi / 180) * theta)) * (180 / pi)
>
> minutesjour = utcdate.hour*60 + utcdate.minute
> tempsolaire = (minutesjour + corrtemps + equatemps) / 60
> angle_horaire = (tempsolaire - 12) * 15
> hauteur_soleil = asin(sin((pi / 180) * latitude) * sin((pi / 180)
> * declinaison) + cos(
> (pi / 180) * latitude) * cos((pi / 180) * declinaison) *
> cos((pi / 180) * angle_horaire)) * (180 / pi)
> if hauteur_soleil > 3:
> seuil = (0.73 + 0.06 * cos((pi / 180) * 360 * dayofyear /
> 365)) *1080 * pow((sin(pi / 180) * hauteur_soleil), 1.25) * 0.90
> mesure = (((tempe * 1 - 25) * (-0.0012) * radiation) +
> radiation)
> if mesure > seuil:
> event.record['sunshine_time'] = event.record['interval']
>
> syslog.syslog(syslog.LOG_DEBUG, "Calculated sunshine_time = %f, based
> on radiation = %f, and threshold = %f" %
> (event.record['sunshine_time'], radiation, seuil))
>
>
> schema_with_sunshine_time = schemas.wview.schema + [('sunshine_time', 'REAL')]
>
>
>
>
>
>
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