Daily climate data quality control procedures of the Iowa State Climatologist

The State Climatologist Office of the Iowa Department of Agriculture and Land Stewardship has been performing data entry and data quality control of National Oceanic and Atmospheric Administration daily climate data in Iowa since July 1, 1987. This process uses comprehensive, automated quality control tests based on standard instrumentation and observing practices and on standard climatological consistency. Inconsistencies flagged by these tests are manually resolved using a standard procedure based on information available from other sources and surrounding stations. The process then uses a manual spatial test to flag additional suspect values, which are also manually resolved using a standard procedure based on information available from other sources and surrounding stations. For example, for suspect values spotted in snowfall and snow depth spatial plots, visible satellite imagery may be consulted along with snowfall at neighboring stations to produce reasonable snowfall and snow depth estimates. This manually intensive process has produced a unique resource for comparison of manual quality control with automated processes, as well as analysis of Iowa climate.