Unfortunately the results are not pretty: there has been a serious decline in availability of hourly weather data in recent years. The number of sites reporting consistently on an hourly basis has dropped by about 40% in the last decade, and only 19 reliable FAA/NWS sites remain in off-road-network locations. Check out the linked article for some striking graphics.
It's not difficult to observe the trend in the data. Here's a chart for Utqiaġvik showing the percentage of days each year with temperature and wind data from at least 18 of 24 hours (not necessarily at the top of the hour):
Last year the observation reliability fell of a cliff, with virtually the entire summer missing data in the overnight period. This year the same thing happened in March and April, but not in summer.
From a scientific standpoint it's a shame to see the lack of commitment to maintaining weather and climate monitoring with the FAA/NWS instrumentation, and from a public service standpoint it's bad news, as reliable real-time ground-level weather data is important for forecasting and decision making.
A significant counterpoint, however, is that NOAA's Climate Reference Network has expanded its coverage across Alaska in the last 20 years. There are now 25 sites installed, and while several aren't reporting currently, the overall volume of data has become substantial in recent years. The chart below shows the annual number of daily observations with maximum and minimum temperature across all the sites:
With the CRN sites being located preferentially in stable and often remote locations, and with high-quality instrumentation, the scientific value for long-term climate monitoring is potentially much higher than with airport instruments; but for real-time weather monitoring and forecasting, the CRN network can't replace the loss of FAA/NWS data in recent years.
Sad situation. The automated stations were advertised to increase reliability over manned stations as a trade off for the things they can't observe as well or at all, but it sure feels like that pact was broken.
ReplyDeleteMy reaction the the ACCAP article was they were being fairly forgiving on the criteria for categorizing stations as consistent or not. For aviation purposes 75% is a pretty low bar.
The point about unequal treatment of road vs off road (hinted also as bigger hubs (more important?) vs small towns (less important?) hits home. My local Haines airport (PAHN) has a fairly high rate of missing or bad data and the fix is often slow. In Juneau (PAHN) outages are few and get fixed a lot quicker. Of course they have real people on duty! So I was surprised that PAHN was shown as "stayed reliable" on the report. I think it was due to using only temperature. I used IEM plot #53 to compare missing obs of temperature vs visibility at PAHN and found that temperature was missing 0.33% of obs and visibility was missing 18.62% (I could not match the time period of the ACCAP report). PAJN was missing 0.12 and 0.04%.
Finally, you mention the rise of CRN stations, but I've noticed way more missing observations from them than it seems should be acceptable for stations designed to be ultra reliable and accurate. Your last graph hints at that drop off.
Thanks for the excellent comments, Jim. I agree with your sentiments, and I too find it disappointing that the CRN sites don't have better uptime. As of this morning, the NCEI/CRN "current observations" page shows that 6 of 25 sites don't have current data. Ivotuk and Deadhorse have been dead for a long time, which is puzzling as I would expect Arctic monitoring to have the highest priority.
DeleteMaybe ACCAP's next study can try to quantify the economic or other benefits of surface weather data.
The frustrating thing is that compared to other public weather-related investments (notably satellites and supercomputers), the cost of maintaining ground-level weather observations is tiny.
As if on cue, our "reliable" ASOS (PAHN) was out again, for just 6 hours this time after a 12 hour outage on the 2nd. This is during a prolonged period of poor flying weather. To my knowledge no flights have been in or out of Haines since at least the 2nd, probably longer. Sure, having an official report of IFR won't get the planes up but knowing asap when it improves enough to attempt the flight would be handy. Referring back to my earlier comment on small vs large towns, I could argue that Haines has a more pressing need of keeping the ASOS fixed since the minimums are higher here for most aircraft than at say, Juneau, and the importance of travel from Haines to Juneau is generally more than vice versa (medical, etc, etc).
DeleteThis is so disappointing. When I recently worked for a part 135 airline in Alaska, the decline in reliable AWOS/ASOS readings was dramatic and, at times, debilitating.
ReplyDeleteWhile the overall cost of maintenance isn't significant, the specifics of keeping ground-based obs up and running can be a logistical nightmare, particularly when the government is relying on a shrinking labor pool of qualified people to actually fly out to remote places to work on these systems. It's a bad situation.
Thanks for your perspective, Andy.
DeleteThe CRN program was predicated on decade-scale stable funding, which has gone out the window. Ivotuk is almost certainly never coming back online. The long term viability for CRN sites accessible only with helicopters is poor.
ReplyDeleteWhat a tremendous shame, the CRN program was a bright spot for me in the Alaska climate scene. I'm trying to hold out hope for a future revival of interest and funding.
DeletePresumably the CRN sites weren't included in the ACCAP study (not sure if they're considered NWS sites)?
The ACCAP analysis was specifically focused on FAA/NWS aviation AWOS/ASOS so did not include CRNs or any of the North Slope aviation obs that are operated by oil companies.
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