On Saturday, December 5, 2020 at 7:26:00 PM UTC-8 gjr80 wrote: > When you are receiving wind speed values (only) every three seconds what > does windGust mean? The highest wind speed value seen in that three > second period? >
Let me explain the WF gear and UDP API that the weewx driver uses a bit... (https://weatherflow.github.io/Tempest/api/udp/v143/) Wf has two basic wind-related measurement elements in the UDP API... - obs_st is the station observation from the Tempest sensor suite. It has the usual wind things in it (speed, direction, gust, gust direction) for three different measurements they emit, called 'lull', 'avg', and 'gust'. Their wind lull and gust are the min/max 3-sec averages within that 60-sec obs_st period. The avg is of course the overall average through that 60-sec window - rapid_wind is a separate observation emitted every 3 seconds. It has speed+direction elements, which are averages within 'that' 3-sec rapid_wind window The obs_st and rapid_wind measurements aren't emitted at the same time, so there's some offset in periods there, but for discussion lets assume they were aligned perfectly. So theoretically if you had a magical one 3-sec 20 mph wind event at 'just' the right time... - the one 'wind gust' emitted by obs_st would have 20 mph (max 3-sec wind in that 60-sec period) - there would be one rapid_wind 'speed' that was 20 mph (wind average speed in that 3-sec period) - there would be 19 rapid_wind observations with wind zero for speed (no wind in 19 different 3-sec periods) - the obs_st min would be 0 mph (min for a 3-sec period over that 60-sec observation period) - the obs_st avg would be 0.15 mph (do the math...) That said, WF is kinda a strange beast, as it has all kinds of asynchronous observations for: - obs_st for most typical observations - rapid_wind for more often 'also' reporting some wind info - lightning events - rain start events - lightning strike events - device health status measurements - hub health status measurements The real question to me is what should weewx post to WU in terms if 'which elements are posted' and should it be different rapid-fire or non-rapid-fire ? An alternate question is whether the WF-UDP driver is doing the right thing re: partial packets and getting wind gust info into the LOOP packets to begin with. But personally I wonder if changing the sensor_map to use the obs_st wind value rather than the rapid_wind speed value will get the original poster more of what they're looking for if they turn rapidFire on. Unfortunately I don't have any WF gear anymore so I can't do that test... -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/4a5374fa-e504-4456-abfe-e59232042fdbn%40googlegroups.com.
