What is the red dot?

A simple question; what is that red dot on the map? I was looking at the CONUS map browser depicting the 2008 temperature departure from normal provided by NOAA’s High Plains Regional Climate Center and noticed something odd:

Click for a larger image

Note the red dot in Arizona, which is the only one in the USA. Truly an anomaly. At first I thought it might be University of Arizona Tucson and its famous parking lot station, but that is further southeast.

The other map depiction HPRCC offers also shows it, and narrows it to a single data point:

Click for a larger image

HPRCC allows us to zoom in to the regional level to get a better handle on the location:

Unfortunately, I have not found any tools on the HPRCC website that will identify this station ID. I can narrow down the location to Pinal County Arizona, and using some crude graphical tools I can approximate the lat/lon of the red dot to be : 32.9, -111.4. This puts it near the town of Florence, AZ.

Doing a search in NCDC’s MMS database for all stations in Pinal county, I find that there is indeed a COOP station #23027  in Florence, and more importantly, it is part of the “A” sub-network, which makes it a climate reporting station.

According the NCDC MMS database the lat lon for Florence COOP station is 33.0363,-111.388 so it is not very far away from my crude lat/lon estimate as seen in this Google Earth view:

Further searching the NCDC MMS database tells me that the station is “current” and that the station has an MMTS temperature unit equipped with a newer NIMBUS LCD display, and a standard rain gauge.

Using the Location tab of the NCDC MMS database I find the station is located at:

Location Description: 1206 MAIN STREET WITHIN AND 0.1 MI NW OF PO AT FLORENCE, AZ

Prior to that it was located at: 1707 S WILLOW ST, WITHIN AND 0.4 MI SW OF PO AT FLORENCE, AZ

So, I put that address into Google Web Search and found this in the FCC database for a tower registration:

1206 Main St (Lat: 33.020056 Lon: -111.384000), Call Sign: WRA544

Assigned Frequencies : 155.475 MHz

Grant Date: 04/19/1999, Expiration Date: 07/05/2004, Cancelation Date: 09/26/2004

Registrant: Florence, Town Of, 130 Main St, Florence, AZ 85232, Phone: (602) 868-5873

So it appears the location is some city owned property, which makes sense, since COOP stations are often located at places that are staffed 24/7 (so somebody can take a reading once a day) and many city offices are. The lat/lon is fairly close to what the COOP coordinates are, but not quite close enough.  The street address is about a half mile south of the lat/lon listed in the NCDC database:

The new location is at about 500 Main Street, rather than the 1206 Main Street listed in the NCDC MMS database. Perhaps it has been moved to a new location and NCDC has not caught up with the street address change.  Perhaps the lat/lon is off. Anything is possible as I and the surfacestation volunteers constantly find discrepancies and errors in the database.

So I decided to use the new Google Street Level View feature to snoop around a bit at the two locations. I found nothing at 1206 S. Main Street except a lot of grass and buildings. It looks like perhaps a community college:

Click for an interactive view from Google Maps

But when I went looking around 500 Main Street – BINGO! I can spot both the MMTS sensor unit and the standard rain gauge to the west of the street:

Click for an interactive view from Google Maps

Looking at an aerial view using NCDC’s most current coordinates of 33.0363,-111.388 and Microsoft Live Search Maps, we can see what surrounds the sensor:

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Click for an MS Live Maps interactive view

You can just barely make out the MMTS in the aerial view. In the street level view, it looks as if some crushed rock has been laid down near the sensor and it is fairly fresh. But more importantly, look at what surrounds the sensor:

• Main Street with it’s traffic.

• Buildings North, South, and West within about 10-30 yards

• Parking lots West and East. The one East has quite an albedo. In the Arizona sun I’m sure it gets quite toasty in full sun.

It is possible this station was recently moved from the south Main Street location to the North Main Street location, which may be a warmer location, I don’t know for certain because I can’t locate any imagery of the sensor at 1206 South Main Street. Further research is needed to pin that down.

This is neither a USHCN station nor a GISS station. It is also not the only possibility for the station that produced the red dot in the HPRCC map

There is another nearby COOP “A” sub-network station at the Casa Grande National Monument run by the US Park Service, COOP station #21314:

Location Description: CASA GRANDE RUINS NATL MON OUTSIDE AND 1.7 MILES NW OF PO AT COOLIDGE AZ

Its lat/lon of 32.9947,-111.5367 is also close to my original crude estimate of 32.9, -111.4

You can see the red dot is question and it’s nearest neighbor here in this closeup of the HPRCC southwest US dot map:

When I plot both stations in Google Earth and compare to the HPRCC map above, it appears that the yellow dot lines up with Casa Grande, AZ and the red dot lines up with Florence, AZ. My original lat/lon estimate is the white marker:

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The Casa Grande COOP station also has some interesting issues that could be responsible for a temperature rise there. Comparing aerial images on the Google Earth and Microsoft Live Search maps, which are taken at different times by different vendors, show us that it appears the parking lot for the visitor center has recently been resurfaced:

Above: Casa Grande National Monument via Microsoft Live Search Maps – Click for a larger image

Above: Casa Grande National Monument via Google Earth – Click for a larger image

Since I have no time reference for the photos, it is also entirely possible that I have the sequence reversed and the parking lot has faded with time. But since I don’t see any significant vegetation changes nor other changes in the landscape between the two photos, and since fading usually takes a couple of years, I’m betting that we are seeing a resurface job, which can appear in a couple of days. I would expect more differences in vegetation or other changes if the pictures were taken years apart.

I think I can make out the Cotton region Shelter on the Google Earth image, just south of the visitor center. There is a street level view of the visitor center parking lot, which you can examine for yourself, but there are no weather instruments visible.

But there is another twist, according to the NCDC database, the station has recently been converted from a Cotton Region Shelter with max-min thermometers to the MMTS system, with the CRS maintained as backup instrument, So the MMTS may be closer to the building and/or the parking lot:

Click for a larger image

But on 10-18-2007 it appears the CRS was removed as a backup instrument. The picture above may be the only photographic record of it’s placement. As we have seen time and time again, the MMTS often gets closer to buildings due to trenching issues and cabling, so it may have introduced a bias in this station due to the placement change. It may not, I don’t know for certain since I can’t spot the MMTS at Casa Grande.

I also thought perhaps there may be a large amount of missing data in the observer B91 forms that could account for the anomaly. I checked both Florence and Casa Grande B91 observer forms at NCDC and they both appear current and well populated with data in the last year, you can search for B91 forms yourself here:

http://www7.ncdc.noaa.gov/IPS/coop/coop.html

I did note though that the Florence form changed in appearance from May of this year to November. It went from  hand written to typed, which suggests an observer/location change:

Casa Grande B91 11-2008 Florence B91 Form 05-2008 Florence B91 Form 11-2008 (PDF files)

So we have two possible candidates for the station that made the red dot. Both have potential placement issues. It makes you wonder how many more of the dots in the HPRCC map have issue like this. I only spotted this one because it was such a large singular anomaly. I’ll check with HPRCC on Monday to see if they can identify the dot’s data origin for me. In the meantime I need help from our readers and volunteers.

Can anyone living in Arizona get photographs of these stations for me?