At present, IGRA does not contain adjustments for biases resulting from historical changes in instrumentation and observing practices. Users pursuing climate change studies sensitive to such inhomogeneities are referred to the Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC) which contains large-scale and selected station time series of temperature anomalies that are updated on a monthly basis using data from IGRA. (In the future, to support the general effort to assess uncertainties in trends of upper-air temperatures through intercomparisons of different products, a joint project between NCDC and the University of Alabama at Huntsville will explore the creation of temperature time series using methods not employed in any existing product.)References
Gaffen, D. J., 1996: A digitized metadata set of global upper-air station histories. NOAA Technical Memorandum ERL ARL-211, 37 pp.[NTIS# PB 96147491; available from Dian J. Seidel, NOAA Air Resources Laboratory (R/ARL) , 1315 East-West Highway, Silver Spring, MD 20190.]
Haimberger, L., 2005: Homogenization of radiosonde temperature time series using ERA-40 analysis feedback information. ERA-40 Project Report Series, 23, Eur. Cent. for Medium-Range Weather Forecasts, Reading, U.K., 73 pp. Available online (PDF)
Free M., D.J. Seidel, J.K. Angell, J. Lanzante, I. Durre and T.C. Peterson (2005) Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series, J. Geophys. Res., 10.1029/2005JD006169.