Thursday, January 2, 2014

Record Daily Temperatures in Alaska for 2013

** Updated on 1/6/13 *

1/6 Update Section: Due to my declining confidence in the NCDC records database, I decided to process all of the GHCN data for each station and sort the data from high to low and from low to high. The table is accurate and the 6 maps below the table represent the number of records in 2013 for 24 primary (mostly 1st order) stations across Alaska. In theory, it is a definitive list. The period of record mirrors the period of record that the NWS states in the daily climate summaries.

** Updated on 1/4/13 **

1/4 Update Section: I have come to the conclusion that the NCDC records database is of marginal utility – at least for Alaska. It is useful to display patterns but not to make comparisons from station to station.

Here is a table of the primary Alaska stations and the count of records in 2013 generated by downloading the complete station histories and ranking the temperatures and precipitation values by each day of the year. The rightmost columns give the number of partial and complete years in the database.



Original post:

Using the NCDC's daily record website, I extracted all of the daily records for Alaska in 2013. The list is pretty good but not perfect. A station needs to be in existence for 30 years with at least 50% completeness of data to have a record posted to the database. Even still, some are missed. All of the Yakutat records are missing (including the all-time record last June) and the Talkeetna records from June are missing too (but their January records are there). All but one of the Cold Bay record high temperatures are missing. Maybe someone can inquire with NOAA about the discrepancies.

In any event, here are two maps showing the number of days with a record high max temperature and the number of days with a record low min temperature. There is a strong clustering of observations around Fairbanks.











13 comments:

  1. The NOAA records database turns out to be only marginally useful. If anyone is interested in the six datafiles from NOAA (high max, low max, high min, low min, precip, snow) I have them as tab delimited files for the entire U.S.

    As a substitute, the analysis has been rerun using the go-to data sets – GHCN data from NCDC. A table has been added to the post. I'll convert the data in the table to a series of maps and post them to my FB page if anyone is interested.

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  2. Brian, That is rather mystifying... it is not rocket science to calculate these numbers. Makes me wonder if the NOAA records are any good for the lower 48.

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    1. NOAA listed 10,110 max temp records (for the whole U.S.) on their website and that is the number that I downloaded so there is no issue with not grabbing all of the data.

      Rick's comment on my FB page post the other day on the Low Temperature map was that "NCDC uses a database that does not have info about how much data there actually is for a station, only whether it was 'open.'"

      However, they have a few records for open stations. NOAA lists 2 hign max records for Cold Bay but there were actually 21 (it was the warmest year on record for Cold Bay).

      It is odd to say the least.

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  3. Here's an interesting contrast from two nearby WX reporting stations. Zoom in as required ~50 miles NE of Fairbanks and select maximum station density:

    http://www.wrh.noaa.gov/mesowest/gmap.php?zoom=4&extents=50.488302,-172.089844,72.893802,-130.960937&density=1

    The first is Angel Creek Lodge in a valley exposed to frequent wind mixing:

    http://www.wrh.noaa.gov/mesowest/getobext.php?sid=AGLA2

    The second is Chena Hot Springs to the NE of the above station. In a valley apparently not as exposed to most wind and subject to cold valley advection:

    http://www.wrh.noaa.gov/mesowest/getobext.php?sid=CNRA2

    Chena Hot Springs was the 2013 record holder above for cold, and close for warmth. I wonder how Angel Creek faired, and if anyone has recent calibration records for the respective sensors? The stations are about 5 miles apart (E-W) in the same river drainage .

    Tonight Angel Creek is reporting a temp of 17F, with winds gusting to 19. While at Chena Hot Springs its reported at 8F and no wind. Maybe the sensor is dead at the latter.

    Gary


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  4. While a tiny bit off topic, a somewhat formal study of the quality of the Lower 48 USHCN network is found at www.surfacestations.org. People were crowdsourced to find and report on the quality of weather stations. The majority were found to be rated 3/5.

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  5. I'm sorry. That's 4/5. And 5 is the worst and 1 is the best. (How do you edit a previous post?)

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  6. Interesting info Eric re station quality, which may reflect siting and accuracy issues. I'll read that interesting link you provided this morning. There's several in Alaska that are no doubt an enthusiast's fun project, but I didn't note any info for Alaska in their collection.

    The two above...Angel Creek and Chena Hot Springs reflect two often very different weather regimes as far as temp and winds. I spend time up in that area and it does blow more at Angel Creek (drainage from the West or North Fork Chena River or any NW>N>NE flow), while the other is in a relatively protected location.

    Angel Creek is listed as a BLM sourced RAWS station, while the Chena unit is listed as an APRS unit (APRSWXNET/CWOP).

    Perhaps someone can further explain the quality assurance of both sensors before the data is taken as a basis of fact for summaries.

    Gary

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  7. Here's some info I gen'd up via the Internet regarding Chena Hot Springs' CNRA2 WX observing instrument. I can't claim any +- details regarding the various author's comments, currency, or accuracy of the information.

    Note also that the Alaska Climate Research Center reports using a similar Davis instrument on their webpage (http://akclimate.org/weather-station). I wonder if they offer insight into its recent history of calibration?

    Anyhow, for CNRA2 it's listed as a Davis Vantage Pro 2:
    http://weather.gladstonefamily.net/site/search?site=CNRA2&Get+information=Get+information

    The alleged instrument:
    http://www.davisnet.com/weather/products/weather_product.asp?pnum=06152

    Some implied specifications:
    http://www.davis.com/Product/Davis_Instruments_Vantage_Pro2_Wireless_Integrated_Sensor_Suite/DO-86403-55

    Some Internet opinions. Note the discussion regarding range-end tolerance calibrations. Recall the old adage...opinions are like ******** and everybody has at least one:
    http://www.wxforum.net/index.php?topic=16856.0

    After all that I'd be suspicious of extreme cold readings without some QC measures. Brian did a good job of summarizing available data and should not be held to task for the accuracy of any reporting unit.

    Gary


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  8. The post has been completely redone to remove the ond (useless?) maps and to put much more useful ones in their place.

    As for the siting study that Eric mentioned, I have mixed feelings about it. Roger Pielke and Anthony Watts were the driving forces behind the study and both of them, and their followers, are highly determined to debunk any claims of anthopogenic warming. That leads me to believe that the crowd-sourced site photos they chose were especially unflattering. Nevertheless, their study was otherwise reasonable and it was published in a prestigious journal and is therefore an important contribution to the discipline.

    Finally, the Davis Vantage Pro is an excellent product. It does tend to break down when temperatures get below -30 or -40 since the voltage in the battery drops to an unreliable level.

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    1. Very good Brian. Anything electric, especially when using battery sourced bias current and variable sensor resistance, like Davis' P-N Junction silicon diodes, thermistors, or thermocouples as a measuring technique should be calibrated in the range of interest. Common knowledge and calibrators are available from Davis and others.

      Their sensor specs:
      http://www.davisnet.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf

      At -40F/C it's at their specified limit for whatever reason they deem necessary. Still, I'd keep a NWS approved therm handy to verify the data if I truly cared about accuracy.

      As far as politics versus reporting, that fact has and will continue to influence both sides of the warming fence. As noted, I took no position in my reply regarding the veracity of the information, as I have no interest in an endless debate that will certainly outlive all of us.

      Gary

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  9. I realized that the link I posted would be considered gray-ish in veracity. But considered on the merits of the study alone, it fills a need that should have been filled a long time ago. Due diligence is something that is lacking in almost all disciplines. I also knew that readers (or at least posters) would keep things to the science and not politics. I may occasionally go to Anthony Watts' page or climateaudit but the political back-and-forth gets old and, as Gary mentioned, seems to go on and on. There's enough of it at work and real life. That's why I like this site. As the tagline states: All science, no politics. What a refreshing concept.

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    1. Thanks for the Reply Eric. I should clarify that when I used the term 'followers' I was referring to a small set of people who those individuals them as their only source of climate information – not casual readers.

      Science thrives on scrutiny. I tell people that climate science is in a better place now due to the intense microscope that has been placed on the discipline over the last 10 years.

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  10. Not than anyone asked for it but since the data were already organized, I thought it would be interesting to see what years the records of Fairbanks were set. I added a chart at the end of the post showing the which years had the most temperature records in Fairbanks. Rick will probably cringe seeing the dates go back to 1904 but that is when NWS lists the record period for Fairbanks.

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