13th Conference on Applied Climatology and the 10th Conference on Aviation, Range, and Aerospace Meteorology

Monday, 13 May 2002: 10:45 AM
Quality Assurance of Monthly Temperature Observations at the National Climatic Data Center
Matthew J. Menne, NOAA/NESDIS/NCDC, Asheville, NC; and C. E. Duchon
Poster PDF (920.2 kB)
At the 12th Conference on Applied Climatology, we presented an outline describing an enhanced system of operational quality assurance (QA) for temperature observations archived at the National Climatic Data Center. The enhancements specifically target potential inhomogeneities in station records since, previously, routine homogeneity evaluation was not an integral part of the QA system. We outlined a three-level enhancement where inhomogeneity testing of station observations at each level is characterized by a specific data time resolution and record length. Levels 1, 2, and 3 are referred to as the short, medium and long-term perspectives, respectively, and evaluation at each level accordingly takes place using daily, monthly and annual temperature observations. We argue that each time perspective is required in order to maximize the capability of detecting inhomogeneities in an operational capacity. Testing at Level 1 has been described previously. Here, we describe the Level 2 (medium-term) perspective and summarize results of a Level 2 evaluation of mean monthly maximum and minimum temperature observations from approximately 240 First-Order stations over the period 1991-2000. This ten-year period encompasses the transition to the Automated Surface Observation System (ASOS) instrumentation at nearly all of the First Order locations. With ASOS station commissioning, a discontinuity may exist in First-Order temperature records. Examples of such discontinuities detected using Level 2 testing are presented and it is shown that the enhancements to the QA system can reduce the time otherwise required to identify data inhomogeneities.

Supplementary URL: