The idea with measuring climate accurately, is to get as far away as possible from human/urban influences so that those things don’t bias the readings of the thermometer. For example, on my way from Las Vegas to Reno this week, I passed through the near-ghost town of Mina, Nevada, which has a USHCN station. Mina is about as in the “middle of nowhere” as you can be. In fact, the view to the east of the Mina USHCN station is stunning for it’s remote beauty:
According to Wikipedia, Mina has quite a varied range of temperature:
Average July high temperatures range from 61° to 96 °F, with January averaging between 22° and 47 °F. The highest temperature ever recorded in Mina was 110 °F in 1933, with a low in 1990 of –23 °F. Mina receives very little rainfall, and in an average year gets about six inches, with no month getting more than one inch in a normal year. The Mina Airport is at the southeastern end of town.
The USHCN station is at the private residence of the airport operator, who also runs a KOA type trailer/RV park. The airport is a simple dirt strip, so no runway to generate extra heat. I’ve been all over the USA looking at the USHCN network. In almost every station I visit, there’s some sort of surprise. Mina was no exception, and I discovered what Stevenson Screens are really used for:
– as mounts for other weather stations.
In this case, an Oregon Scientifc WMR-968 wireless weather station, which is quite possibly the worst electronic weather station on the market. I once sold these at my online store weathershop.com, and stopped doing so when failure rates started approaching 30% out of the box.
Fortunately, the WMR-968 is not the “primary” instrument of the USHCN station, though it appears to be used as backup for the primary MMTS/Nimbus instrument. In this photo, you can see the wire from the small solar panel running inside to the temperature sensor.
What is most interesting about this station, is that while it truly is in the “middle of nowhere” and has that great “rural” view to the east, the primary MMTS sensor is just a few feet from where all the RV’s park while they register at the office:
Click for a large image
Unlike the Stevenson Screen, The MMTS is just a few feet from the office due to the famous cabling issue. It also has some nice sized rocks to act as heat sinks for those cold desert nights:
View looking North – click for a larger image
Besides the mixture of shade, rock heat sinks, road and building proximity, there’s also the requisite BBQ or two:
View looking south – click for a larger image
The rain gauge also has issues, due to the wind ducting that is likely created by these two trailers:
Click for a larger image
You can see the complete set of photos at the Mina gallery at surfacestations.org
As for the temperature trend:
Data from GISS – see original plot here
The trend is up, curiously, even though the town appears to be dying, so urbanization shouldn’t be the cause. According to NCDC’s MMS database, the station switched from using the Stevenson Screen to the MMTS electronic sensor in 1986. MMTS is well known for building proximity, That may account for some of the trend. There was also a station move to the present location in August 2007.
US 95 is about 100 yards away from the Mina USHCN temperature sensor, so perhaps there is an urbanization component in the form of more traffic. I simply don’t know. Interestingly, the station at Bishop, to the west, shows very little long term trend, while the station to the south, Tonopah, does show a trend. But Tonopah is growing, unlike Mina, which is dying and is now listed on a Ghost Town forum. Tonopah also had it’s weather station converted to ASOS, which when combined with other airport improvements, tends to add a positive trend.
So it’s a puzzle, and I welcome comments with ideas.
The thing about the Mina station though, is that without knowing a site history and history of the surrounding changes, we simply don’t know how much of the signal is real or from land use changes around the sensor. In it’s new position at an active RV park, it is now in a dynamic environment within feet of daily vehicular traffic. We simply should not have to figure such things out for a climatic reference station, even if it is in the “middle of nowhere”.