Comparison of Mann-Kendall and Şen’s Innovative Trend Method for Climatic Parameters Over Nigeria’s Climatic Zones

Abstract

Abstract Creating innovative ways for the identification of trends is a very vital part of atmospheric studies. Different climatic locations present their unique variations, calling for the dynamism of trend analysis. In addition to the widely adopted Mann-Kendall (MK) trend test, the new Şen’s innovative trend analysis (ITA) method has been applied to analyze the trends of refractivity related (atmosphere pressure –AP, vapour pressure – VP, ambient temperature – T) and equivalent potential temperature – EPT related parameters (mixing ratio of air – R, absolute temperature at the lifting condensation level – TL, potential temperature – PT). This analysis was perfomed using 40 years’ data (1981 – 2020) from 4 stations from each climatic zone of Nigeria (Calabar – Tropical monsoon, Ibadan – Tropical Savannah, Kano – Warm semiarid climate, and Kukawa – Warm desert climate). The MK trend test identified monotonic (entirely increasing or decreasing) trends for specific parameters across the climatic locations; the Şen’s ITA method was important in the identification of trends even for parameters that showed non-monotonic variations. Other comparisons between both methods were outlined and explained; correlation heat maps were used to show the relationship between all parameters for each climatic location, describing the effect of climate on the variations of these parameters. The low, medium and high values revealed from the Şen’s ITA method can be informative for telecom and renewable energy applications, guiding engineers and system designers to understand the trends within range of values for a particular climatic parameter.