A 27 year (1990-2017) meteorological database has been developed for the Southwest Watershed Research Center (SWRC) with 4 sites in southeastern Arizona at Walnut Gulch Experimental Watershed (WGEW) and Audubon Research Ranch (ARR). Meteorological elements measured at the weather stations include air temperature, relative humidity, wind speed, wind direction, barometric pressure, solar radiation, photosynthetically active radiation, and net radiation. Data are available at http://www.tucson.ars.ag.gov/dap. Modified from Keefer et al., 2008
Air Temperature [deg C]
Relative Humidity [%]
Wind Speed [m s-1]
Wind Direction [deg]
Barometric Pressure [mb]
Solar Radiation [W m-2]
Photosynthetically Active Radiation (PAR) [μmol s-1 m-2]
Net Radiation [W m-2]
Network Extent/Time line
Table 1: SWRC meteorological station locations and years of operation. Coordinates are not survey grade.
Kendall Met. Station (WGEW)
Lucky Hills Met. Station (WGEW)
Shop Met. Station (WGEW)
Audubon Research Ranch (ARR)
*The ARR met. station was moved in 2001 due to a fire.
Table 2: SWRC meteorological instrumentation specifications and periods of operation.
AKendall Met., BLucky Hills Met., CShop Met, DAudubon Met.
Table 3: SWRC meteorological instrumentation error specifications and sampling resolution.
AKendall Met., BLucky Hills Met., CShop Met., DAudubon Met.
*All output data is is averaged from 10-sec. samples over the measurement period, unless otherwise noted.
SDenotes an instantaneous sample taken at the end of the measurement period.
installation and Maintenance
All meteorological sensors were installed and are maintained according to manufacturer's specifications and use manufacturer supplied calibrations when appropriate.
Sensors are inspected and cleaned on an annual basis. Sensor repair or replacement is conducted as needed.
The SWRC meteorological stations record data using Campbell scientific dataloggers (CR1000 currently and CR10/CR10X historically) and multiplexers (AM16/32). Dataloggers are programmed using Campbell scientific's LoggerNet. CR10X dataloggers are programmed using EdLog and CR1000 dataloggers use CRBasic. While the programming languages differ in syntax, the logic and recording functions where shown to be interchangeable through thorough testing of the programs. All sensors, with the exception of barometric pressure, are sampled every 10 seconds and averaged over the recording period (e.g., 15, 20, 30 min). Barometric pressure is sampled once at the end of the recording period.
Shortly after midnight on a daily basis, data from the WGEW sites are downloaded automatically via radio and are transmitted to a computer at the SWRC Tombstone field office. VHF, spread spectrum, and cellular modems are used depending on the geographic location of the gauge. Raw data are archived in the Tombstone office and a series of batch processes are executed using LoggerNet to parse out relevant data to be processed in Tucson and to generate daily maintenance reports. The daily data are then transfered to a SWRC server residing in Tucson. Modified from Nichols and Anson., 2008
Data are processed quarterly using a combination of LoggerNet and Fortran processes.
The initial data stream from field sites may contain missing values for any property because the station was not in operation intentionally or accidentally, the sensor was not deployed at that time, or there was data collection, communication or computer failure. Data determined to be collected during periods when a sensor was known to be inoperable (e.g., vandalism, animal or natural interference) were coded with missing values.
Incoming data, after transformation from measured value to final units, if applicable, are screened by automated and visual graphic processes for outliers beyond acceptable limits. Outliers that are physically impossible (e.g., negative soil moisture, temperature above 100° C) are coded as missing.
Limits imposed on meteorological values are from various sources: 40 years of NWS Cooperative Observer station at WGEW field office for air temperature and relative humidity; sensor range from manufacturers manuals for wind speed, wind direction and barometric pressure; estimated limits for solar, photo- synthetically active and net radiation from the Arizona Meteorological Network (http://cals.arizona.edu/azmet/ azdata.htm). This process is completed quarterly. Modified from Keefer et al., 2008
The raw 15-min meteorological data is archived daily in an SQLServer database once received at the SWRC Tucson office. This provisional data is pushed to an SWRC FTP site, from which the data is ingested and served by the Long Term Agroecosystem Research Network (LTAR) daily. Once the meteorological data has been QA/QC'd (quarterly) it is archived locally and served from the SWRC FTP site, accessible from the SWRC Online Data Access Project Site (DAP) in csv format.
SWRC meteorological data can be accessed at the following websites:
SWRC Online Data Access (DAP) - QA/QC'd data updated approximately every 90 days
USDA Long-Term Agroecosystem Research Network - 15-min data updated daily (provisional data)
USDA National Agricultural Library Ag Data Commons - DAP mirror
Data Use Agreement
All data available through the SWRC data access website are in the public domain, and are not restricted by copyright.
The SWRC will review the research results to ensure sound scientific data interpretation in the context of our historical results and our in situ experience with these data. We expect that our support will be acknowledged through co-authorship and formal acknowledgment of field and/or data support in the manuscripts (see example below).
Datasets were provided by the USDA-ARS Southwest Watershed Research Center. Funding for these datasets was provided by the United States Department of Agriculture, Agricultural Research Service.
Please send 1 copy of the published manuscript to:
Southwest Watershed Research Center
2000 E. Allen Rd.
Tucson, AZ 85719
Known Data Issues
Examples of Data Use
References and KEY Literature
Goodrich, D.C., Marks, D., Seyfried, M.S., Keefer, T.O., Unkrich, C.L., Anson, E.A., Clark, P.E., Flerchinger, G.N., Hamerlynck, E.P., Hardegree, S.P., Heilman, P., Holifield Collins, C., Moran, M.S., Nearing, M.A., Nichols,M.H., Pierson,F.B., Scott, R.L., Stone, J.J., Van Vactor, S.S., Winstral, A.H., Wong, J.K. 2011. Utilizing long-term ARS data to compare and contrast hydroclimatic trends from snow and rainfall dominated watersheds. Proceedings of the 4th Interagency Conference of Research in the Watersheds, Fairbanks, AK., Sept. 26-30, 2011.
Keefer, T.O., Moran, M.S., Paige, G.B. 2008. Long-term meteorological and soil hydrology database, Walnut Gulch Experimental Watershed, Arizona, United States. Water Resources Research, Vol. 44, W05S07.