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Post by FrozenI69 on May 27, 2021 9:20:00 GMT -5
I would like to know what the average difference is between your nearest Airport, and the nearest PWS (if you have one).
Is the nearest airport Warmer, Colder, does it vary based on time of the day, or is it seasonally different from your PWS ? (specify seasonal differences).
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Post by Babu on May 27, 2021 10:08:56 GMT -5
So far it seems to vary with type of weather rather than any of your alternatives. During cloudy weather, the airport is consistently 0.1-0.5'C warmer than my PWS. This can mostly be explained by a 30m altitude difference. Also haven't calibrated my pws (yet) so it could be that it's reading a little too low. Calm clear nights are up to 5'C milder at my PWS though, and during sunny days my PWS can either be the same, or a few degrees warmer, depending on what kind of wind pattern there is.
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Post by tommyFL on May 27, 2021 10:12:46 GMT -5
It varies by time of day obviously, as the airport is much more moderated by the ocean. Cooler in the day and warmer at night.
As for a comparison to an official station, last month my PWS's mean temp was 0.05 F (0.03 C) cooler than the COOP station a mile from my house (Port Salerno 5W). It looks like this month will be similarly close.
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Post by Babu on May 28, 2021 7:23:10 GMT -5
Interesting. (the red circle indicates an error that probably has to do with lack of shade from that particular direction) The last few days have been sunny and windy (N winds), at after 10.00 today the winds shifted to SSE.  Compare that graph with how it looked on the 20th. That day it was sunny (with some infrequent small cumulus clouds in the afternoon), and pretty calm, with winds coming from the west and north, and the SE sea winds didn't kick in until 18.00.  Daytime temperature under under sunny conditions can be true temperature differences since my PWS obviously doesn't have sun shield issues during the day judging from the 20th. If anything, my PWS seems like it could be calibrated a degree too low, as well as being slightly slower at changing temperature (the airport has on certain days recorded highs more than 1'C warmer than the warmest hourly reading. On the 27th for example it recorded a daytime high of 10.1'C despite all the hourly readings sitting very stable around 9'C, showing that it can rise very rapidly in temperature if there's a gap in the clouds and winds, whereas my station is a little slower, as well as being in the shade meaning it isn't affected as much by a sudden gap in the clouds). As a side note, this is some pretty remarkable results from a PWS that costs only 35$ (+ a 15$ cheap radiation shield that mostly just helps against rain and indirect radiation). It even seems to measure dew point surprisingly accurately. |
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Post by Babu on Jun 14, 2021 12:43:23 GMT -5
Babu , those lows at your WS seem suspiciously high. Turku has a 11.2C avg low as well, with a 23.8C high. Kronoby's low so far is 8.4C. You're right. Comparing with the patio station at the university, that station has averaged 22.1/10.9. Some nights were milder at the Uni, and some nights were milder at my PWS, sometimes by as much as 1.2'C. The local topography around my PWS is very beneficial to mild lows, the response time isn't as quick as PRT sensors (I'm gonna do a comparison soon where I look at the airport station's highs' average deviation from the warmest hourly value, and do the same with my PWS to get an estimate for how much warmer the highs would be if the response time would be as quick as the AP station, and then do the same for the lows.) It's also surrounded by a few trees which will also help mitigate some of the cold. I guess you could say the station is representative of if you walked up to a small cluster of trees and sat yourself next to one of them in the shade. Uni patio vs PWS:   Apart from the Uni patio of course being a patio, it's in a less advantageous topographical location for mild lows than my PWS. Anyway, the PWS is still meant to offer another point of reference for the "range" of temperatures experienced around the city. A best vs worst case scenario, and it's always meant to be compared to the AP. Edit: When just looking at the hourly readings, the PWS averaged 21.2/11.3 and the AP 20.9/8.4. This can be considered a truer measurement for the actual different temperatures observed at the two sites as the response rate of the temperature sensor doesn't matter at 1h intervals. (I took every :00 reading from my PWS). So for the first two weeks of this June, my PWS can be assumed to have observed 0.3'C warmer highs and 2.9'C warmer lows on average. The AP recorded 21.6/8.1 which would indicate that my station would record 21.9/11.0 if it had the same response time to temperature change as the airport station. Here's a chart for each hour of the day, for the first 14 days of June. This includes the radiation shielding error from 18.30-20.30 that I fixed on the 10th of June. We can clearly see a trend where the temperature rises quicker in the early morning at the airport, and then the airport drops off around 10 where the PWS overtakes the airport, due to being a little less affected by the sea breeze.  Edit: There were a few hours of data missing at the airport, so I removed the same data for the PWS to make the comparison true. Interestingly, at 18:00 the AP is slightly warmer, likely just due to few-data noise. |
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Post by Babu on Apr 19, 2022 7:10:16 GMT -5
This has been my PWS compared ro the AP for the last week of warm and sunny weather. Surprising difference in terms of lows seeing as my PWS is pretty near the bottom of a long slope and somewhere I suspect to have several degrees colder lows on some clear nights compared to some other places not far away. Also interesting how my PWS is warmer on most days, but on one day the airport is significantly warmer, and on the warmest day the airport was slightly warmer as well. | April date | Airport | PWS | | 11th | 6.9/-6.0 | 7.3/-3.6 | | 12th | 7.8/-7.4 | 10.2/-4.3 | | 13th | 11.4/-6.9 | 8.5/-3.3 | | 14th | 9.1/-0.2 | 10.1/0.0 | | 15th | 7.6/-5.4 | 10.2/-2.6 | | 16th | 7.0/-4.0 | 9.0/-2.7 | | 17th | 14.4/-3.0 | 14.2/0.2 | | 18th | 8.5/-3.1 | 12.8/-2.1 | | Average: | 9.1/-4.5 | 10.3/-2.3 |
How reliable, representative and accurate do you guys reckon my station is? |
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Post by alex992 on Apr 19, 2022 12:17:37 GMT -5
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Post by Benfxmth on Feb 4, 2023 15:28:35 GMT -5
Not enough data for an estimated climate box for my PWS' location, but I found that, annually, the difference between my PWS vs. New Bern AP (KEWN) is approximately...
Average high: -1.5°F
Average low: +2.5°F
Actual April 2022-January 2023 difference so far:
Average high: -1.5°F
True mean (5-minute): +0.6°F
Average low: +2.6°F
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