Trends of maximum and minimum temperatures in northern South America

This paper presents the results of testing the homogeneity of the basic data used in this study, that is, the mean monthly maximum and minimum temperature (as derived from daily observations) of several lung-term climatological stations of Venezuela and Columbia, and an evaluation of the fluctuations and deviations from long-term means of such parameters, as well as of the diurnal temperature ranges (DTR) during the 73-yr period, 1918-90. The 14 longest-term climatological stations in Venezuela and Colombia with available metadata and the most consistent temperature records were used. Homogeneity tests were dune by application of the Alexandersson's Test. Eleven stations (the ones with less inhomogeneities) were finally left for partial data adjustments of their records when needed (only a few of them), following the technique developed by Easterling and Peterson. Then, the temperature trends and deviations from long-term averages (1918-90) were determined. The most remarkable feature of the analysis is a relative and sustained increase of the minimum temperature series and a DTR decrease during the last 25 yr of the period at a significant rate in most of the station records.