LIS 518 – Verifiable Information Assignment
Due: April 18, 2017
Fact: Tucson Averages 12 Inches of Precipitation Yearly
According to one media source and three governmental sources, the Tucson area averages approximately 12 inches of rainfall per year. The averaged data of Tucson’s inches-per-year of rain is culled from four sources whose annual precipitation information on Tucson ranges from 120 years (1895-2015, from a 2016 KJZZ article and graph1), to just one year (2016, National Weather Service2), and from 29 years (1971-2000, from the Arizona Department of Water Resources3), to 67 years (1949-2016, via the NOAA/National Centers for Environmental Information4).
In the following paragraphs, I provide links to graphical and tabular data on Tucson’s annual precipitation, accessed and generated from the cited sources.
The graph1 accompanying the August 2016 KJZZ article shows data compiled from the National Weather Service, with the article1 stating that Tucson’s annual rainfall – averaged from 120 years of data, 1895-2015 – is about 11.3 inches.
The 2016 National Weather Service rainfall map2 (link opens a PDF), exhibits Tucson’s annual rainfall for 2016 by color, with the various green hues indicating that rainfall was between 10 inches, to 15 and 20 inches, depending on the area of town.
From the Arizona Department of Water Resources, this Tucson Climate data3 (link downloads an Excel spreadsheet – which includes this author’s utilization of Excel’s averaging tool; here is the same Tucson Climate data as a PDF) itemizes annual precipitation for the region (between 1971-2000, 29 years), with the last six data points listed in section A showing areas in the central Tucson region averaging 12.4 inches cumulatively (referring to the numbers from the Tucson 17 NW station the to Tucson U of Arizona station – the J:17-J:22 cells on the spreadsheet: 12.58 + 12.4 + 12.17 + 13.86 + 11.41 + 12=74.42/6=12.4.)
This NOAA graph4 (link opens a PDF), visually displays the data points on the NOAA rain table4 (link opens a PDF), and shows the mean rainfall amount as 11.7 inches over 67 years, 1949-2016. See the online version from the National Oceanic and Atmospheric Administration, but note that the graph only displays if your device has the most recent version of Adobe Flash player.
Since the data numbers are more specific from the KJZZ, Arizona Department of Water Resources and the NOAA National Centers for Environmental information sources, I chose to average the three numbers from those three organizations. The numbers are 11.3 inches (KJZZ) + 12.4 inches (Arizona Department of Water Resources) + 11.7 inches (NOAA National Centers for Environmental information) = 35.4. Divide that by 3, and the average between those three sources equals 11.8 inches, which is approximately 12 inches of rainfall in the Tucson area annually.
Why are these sources credible?
I chose these particular sources because they are information purveyors who send good signals that meet the generally accepted standards of information quality, which are: accuracy, authority, accessibility, objectivity, credibility, currency, completeness, and coverage. Through these attributes, information seekers can reasonably presume that they are receiving accurate information from these sources and determine that these organizations are credible. These agencies have also shown a commitment to providing accurate data through the numerous ways they share verifiable data – through graphs and charts, but also by posting statements on their websites addressing how they are committed to procuring and disseminating accurate information that is verifiable.
The links below open PDFs that detail the cited information sources and how they provide good signals, which make for accurate and verifiable information.
In addition to the above, here is the supporting documentation on this project’s intended audience and why it is relatively easy for readers to verify the information is accurate.
As I was working on this project, I was initially taking it for granted that people would trust information from governemental agencies – such as the National Weather Service or the National Oceanic and Atmospheric Administration (NOAA). The exercise of explaining the features that make the information verifiable made me realize how important it is for organizations/agencies to share – in detail – their standards, especially in this age of fake news and unreliable/bad information. I can now appreciate why the NOAA has an extremely detailed webpage (over 9,000 words) that outlines its information quality guidelines with numerous links to other operational guidelines. Also, considering the people who think that climate change is a hoax, at least we can point to detailed and verifiable facts based on solid science from agencies that explain their methodologies and how they strive to ensure that their data are accurate.
- Schaudt, S. (2016, August 16). How Much Rain Does Tucson Get Annually? KJZZ. Retrieved from http://science.kjzz.org/content/350855/how-much-rain-does-tucson-get-annually
- US Department of Commerce, National Weather Service. (2017). [Displaying 2016 Annual Observed Precipitation map, April 11, 2017]. QPE: Quantitative Precipitation Estimates. Retrieved from https://water.weather.gov/precip/index.php?analysis_date=1451606400&lat=32.2218778028&location_name=CONUS_%2B_Puerto_Rico&location_type=us&lon=-110.9264770000&
- Arizona Department of Water Resources, Tucson AMA Climate. (2005). [Displaying in Table 8.5-1A, an Excel spreadsheet, precipitation data between 1971-2000, sourced from the WRCC – Western Regional Climate Center]. Retrieved from http://www.azwater.gov/AzDWR/StatewidePlanning/WaterAtlas/ActiveManagementAreas/Climate/TucsonAMA.htm
- NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, Precipitation. (2017). [A graph and table showing the annual rain between 1949-2016]. Retrieved from http://www.ncdc.noaa.gov/cag/
Website last updated on April 18, 2017