Graphics
Digital Data
J.K. Angell
1958-2005 (relative to a 1958-1977 average)
Surface temperatures and thickness-derived temperatures from a 63-station, globally distributed radiosonde network have been used to estimate global, hemispheric, and zonal annual and seasonal temperature deviations. Most of the temperature values used were column-mean temperatures, obtained from the differences in height (thickness) between constant-pressure surfaces at individual radiosonde stations. The pressure-height data before 1980 were obtained from published values in Monthly Climatic Data for the World. Between 1980 and 1990, Angell used data from both the Climatic Data for the World and the Global Telecommunications System (GTS) Network received at the National Meteorological Center. Between 1990 and 1995, the data were obtained only from GTS, and since 1995 the data have been obtained from National Center for Atmospheric Research files. The data are evaluated as deviations from the mean based on the interval 1958-1977. The station deviations have been averaged (with equal weighting) to obtain annual and seasonal temperature deviations for the globe, the Northern and Southern Hemispheres, and the following latitudinal zones: North (60° N-90° N) and South (60° S-90° S) Polar; North (30° N-60° N) and South (30° S-60° S) Temperate; North (10° N-30° N) and South (10° S-30° S) Subtropical; Tropical(30° S-30° N); and Equatorial (10° S-10° N). The seasonal calculations are for the standard meteorological seasons (i.e., winter is defined as December, January, and February; spring is March, April, and May, etc.) and the annual calculations are for December through the following November (i.e., for the four meteorological seasons). For greater details, see Angell and Korshover (1983) and Angell (1988, 1991).
It is interesting to compare temperature trends from the relatively sparse 63-station radiosonde network to those from some of the other well-known global temperature records, e.g., the Microwave Sounding Unit (MSU) data obtained from NOAA satellites (Christy et al. 2000). While comparisons between the exact same atmospheric layers cannot be made, the computed linear trend for the MSU from its beginning year (1979) through 2005 for the lower tropospheric layer from the surface up to 8 km (about 350 mb) shows an increase of about 0.09°C/decade; whereas the Angell record for the 850-300 mb tropospheric layer over the same period shows no trend. The University of East Anglia data of Jones et al. (2001), derived from thousands of stations over the globe, indicate a global surface warming of 0.12°C/decade over Angell's full period of record (1958-2005) compared to 0.17°C/decade for the Angell data. For the years overlapping with the "satellite" period of record (1979-2005), the surface data of Jones et al. show an increasing trend of 0.17°C/decade; quite close to the 0.21°C/decade trend obtained from the 63-station network of Angell.
Angell, J.K. 1988. Variations and trends in tropospheric and stratospheric global temperatures, 1958-87. Journal of Climate 1:1296-1313.
Angell, J.K. 1991. Changes in tropospheric and stratospheric global temperatures, 1958-88. pp. 231-47. In M.E. Schlesinger (ed.), Greenhouse-Gas-Induced Climatic Change: A Critical Appraisal of Simulations and Observations. Elsevier Science Publishers, Amsterdam, Netherlands.
Angell, J.K. 1999. Comparison of surface and tropospheric temperature trends estimated from a 63-station radiosonde network, 1958-1998. Geophys. Res. Lett. 26:2761-2764.
Angell, J.K. 2000. Tropospheric temperature variations adjusted for El Niño, 1958-1998. Journal of Geophysical Research 105:11841-11849.
Angell, J.K., and J. Korshover. 1983. Global temperature variations in the troposphere and stratosphere, 1958-82. Monthly Weather Review 111:901-21.
Christy, J.M., R.W. Spencer, and W.D. Braswell. 2000. MSU Tropospheric temperatures: Data set construction and radiosonde comparisons. J. Atmos. Oceanic Tech. 17:1153-1170.
Jones, P.D., T.J. Osborn, K.R. Briffa, C.K. Folland, B. Horton, L.V. Alexander, D.E. Parker, and N.A. Rayner, 2001. Adjusting for sample density in grid-box land and ocean surface temperature time series. J. Geophys. Res. 106:3371-3380.
6/2006