Evaluation of Meteorological Data Quality and Homogeneity in Nigerian Synoptic Stations

The quality and temporal homogeneity of meteorological station records are prerequisites for reliable climatological analysis, trend detection, and climate change assessment. This study evaluates the data quality and homogeneity of long-term temperature and rainfall records from 12 NiMet synoptic stations distributed across Nigeria's six geopolitical zones, covering the period 1980 to 2022. Quality control procedures including range checks, internal consistency tests, and spatial outlier detection were applied using the RClimDex software package. Homogeneity testing was performed using the Standard Normal Homogeneity Test and Pettitt test to detect artificial discontinuities attributable to station relocations, instrument changes, or observing practice modifications. Results identify statistically significant breakpoints in temperature records at five stations and in rainfall records at four stations, with the majority of detected breakpoints coinciding with documented station metadata events including relocation and instrument upgrades. Quality flagging reveals that missing data rates exceed 10 percent in six of the 12 stations, with Gusau and Yola showing the highest rates exceeding 18 percent in the 1990s. The study develops a practical station metadata documentation protocol and recommends mandatory homogeneity testing prior to use of Nigerian instrumental records in trend analysis and climate impact assessments. Keywords: data quality, homogeneity, synoptic station, NiMet, climate records.