TITLE: Mesonet Automated Weather Observing System (AWOS) Iowa 1-min Data [JOSS] CONTACTS: Steve Williams UCAR/JOSS P.O. Box 3000 Boulder, CO 80307-3000 phone: 303-497-8164 email: sfw@ucar.edu 1.0 DATA SET OVERVIEW This data set contains 1-minute resolution surface meteorological data from the Automated Weather Observing System (AWOS) stations located across the state of Iowa. This data set covers the period from 13 May through 25 June 2002. The data are in ASCII format. 2.0 INSTRUMENT DESCRIPTION 2.1 Instrumentation information Some information on AWOS can be found at the Federal Aviation Administration Automated Weather Sensors page at: http://www.faa.gov/asos/ Information on the Iowa AWOS can be found at the Iowa Environmental Mesonet AWOS page at: http://mesonet.agron.iastate.edu/AWOS/ 2.2 Station Locations These station locations are taken from the AirNav database (http://www.airnav.com). Elevations are in meters. City ID State Latitude Longitude Elev ---------------------------------------------------------------- ALGONA AXA IA 43.0779106 / -94.2719928 371.6 ANKENY IKV IA 41.6912856 / -93.5663033 277.4 ATLANTIC AIO IA 41.4072672 / -95.0469064 360.3 AUDUBON ADU IA 41.7013756 / -94.9205417 392.3 BOONE BNW IA 42.0495694 / -93.8475722 353.6 Carroll CIN IA 42.0461944 / -94.7890000 367.0 CHARITON CNC IA 41.0196239 / -93.3596803 320.0 CHARLES CITY CCY IA 43.0726086 / -92.6107783 342.9 CLARINDA ICL IA 40.7217836 / -95.0264267 302 CLARION CAV IA 42.7419439 / -93.7589094 354.2 COUNCIL BLUFFS CBF IA 41.2594722 / -95.7599722 381.9 CRESTON CSQ IA 41.0214614 / -94.3633192 394.4 DECORAH DEH IA 43.2755014 / -91.7393739 352.7 DENISON DNS IA 41.9864325 / -95.3807208 388.9 FAIRFIELD FFL IA 41.0533242 / -91.9789233 243.5 FORT MADISON FSW IA 40.6592625 / -91.3268175 220.7 HARLAN HNR IA 41.5843889 / -95.3396389 375.2 KEOKUK EOK IA 40.4599078 / -91.4285011 204.5 KNOXVILLE OXV IA 41.2988856 / -93.1138156 282.9 LeMARS LRJ IA 42.7780178 / -96.1936894 364.5 MONTICELLO MXO IA 42.2240453 / -91.1658219 253.9 Mount Pleasant MPZ IA 40.9466139 / -91.5110750 223.7 MUSCATINE MUT IA 41.3678633 / -91.1482164 167.0 NEWTON TNU IA 41.6744297 / -93.0217292 290 OELWEIN OLZ IA 42.6808447 / -91.9744783 328.0 ORANGE CITY ORC IA 42.9902644 / -96.0627967 431 Pella PEA IA 41.4000667 / -92.9458833 269.7 RED OAK RDK IA 41.0105278 / -95.2598611 318.2 SHELDON SHL IA 43.2083936 / -95.8334331 432.5 SHENANDOAH SDA IA 40.7514817 / -95.4134722 296.0 STORM LAKE SLB IA 42.5971944 / -95.2406667 453.5 Vinton VTI IA 42.2186261 / -92.0259281 258 WASHINGTON AWG IA 41.2761008 / -91.6734439 229.8 WEBSTER CITY EBS IA 42.4366389 / -93.8688611 341.7 3.0 DATA COLLECTION AND PROCESSING UCAR/JOSS conducted no processing or quality control on these data. Further information is also available at the FAA Automated Weather Sensor Home Page: http://www.faa.gov/asos/index.htm 4.0 DATA FORMAT AND FILE NAMING 4.1 Data Format ADU 2002-06-02 00:02 92 54 11 130 0 10 0 29.78 9000 1 0 0 0 0 ADU - station identifier 2002-06-02 - yyyy-mm-dd 00:02 - hh:mm (UTC) 92 - temperature in Deg F 54 - dew point temperature in Deg F 11 - Wind Speed (knots) 130 - Wind Direction 0 - Wind Gust (knots) 10 - Visibility (statute miles) 0 - Hourly Precipitation Accumulator (inches; reset to 0.0 at 56 minutes after each hour) 29.78 - Altimeter (inches of mercury) 9000 - Cloud Deck 1 Height 1 - Cloud Deck 1 Coverage 0 - Cloud Deck 2 Height 0 - Cloud Deck 2 Coverage 0 - Cloud Deck 3 Height 0 - Cloud Deck 3 Coverage 4.2 File Naming Conventions ADU_20020602.txt ADU is the station identifier (see station list above) 20020602 is yyyymmdd 5.0 DATA REMARKSOn 10 April 2003, UCAR/JOSS was notified by Daryl Herzmann (akrherz@iastate.edu), program assistant at the Iowa Environmental Mesonet (http://mesonet.agron.iastate.edu), of a problem with precipitation observations from 1-minute Iowa AWOS stations. The 1-minute Iowa AWOS data are available in their "as is" format from UCAR/JOSS for the IHOP period at IHOP_2002 Mesonet: Automated Weather Observing System (AWOS) Iowa 1-min Data . Note that the following 20 1-minute Iowa AWOS stations had erroneous precipitation values as described in the email extract below: ADU, AIO, AWG, CBF, CNC, CSQ, DNS, EOK, FFL, FSW, HNR, ICL, IKV, MPZ, MUT, OXV, PEA, RDK, SDA, TNU.
Message from Daryl Herzmann (akrherz@iastate.edu)
* Program Assistant -- Iowa Environmental Mesonet
* http://mesonet.agron.iastate.edu
Sent 10 April 2003:
Anyway, most (not all) of these stations are outfitted with tipping buckets. All of you have been receiving the AWOS precipitation amounts from the raw METARs, but up until today, there has been a fundamental flaw with the observations. The site resets the hourly precipitation counter at :55 after the hour, but METARs were only relayed at :05, :25 and :45 after the hour. This would result in 10 minutes of missing potential rainfall data every hour.
The Iowa Department of Transportation sends us their 1 minute interval data archive from the network at the end of every month. While looking at this dataset, I noticed this timing problem last summer. The Des Moines WFO and the Iowa Mesonet have been working closely with the DOT to get this problem resolved. And today it has been. The Iowa AWOS sites are now reporting at :15, :35 and :55 after the hour, which eliminates the timing issue.
6.0 REFERNCES None.