Studies on the variability in ocean wave climate provide engineers and policy makers with information to plan, develop, and control coastal and offshore activities. Ocean waves bear climatic imprints through which the global climate system can be better understood. Using the recently updated ERA5 dataset, this study evaluated the spatiotemporal distribution and variability in significant wave height (SWH) in the Eastern Tropical Atlantic (ETA). The short-term trends and rates of change were obtained using the Mann–Kendall trend test and the Theil–Sen slope estimator, respectively, and decadal trends were assessed using wavelet transformation. Significant, positive monthly and yearly trends and a prevailing decadal trend were observed across the domain. Observed trends suggest that stronger waves are getting closer to the coast and are modulated by the Southern and Northern Atlantic mid-latitude storm fields. These observations have implications for the increasing coastal erosion rates on the eastern coast of the Tropical Atlantic.

This study presents the analysis of rainfall and temperature across the climatic zones in Nigeria. Data from ten Global Circulation Models (GCM) regridded to a 1° x 1° spatial resolution was used in this study. Model evaluation was carried out for the models using ground observed data from Nigerian Meteorological Agency (NIMET). Based on the comparison of the models with ground observed data, the ability of the models in simulating the seasonal pattern of precipitation and temperature over each climatic zone and the whole of Nigeria differ to different degrees. Of the four periods, June, July, August (JJA) showed the highest deviation. The seasonal variation of rainfall and temperature across the climatic zones revealed the influence of the Intertropical Discontinuity (ITD) in rainfall variation across each zone with dual rainfall peak over the Guinea. The rainfall distribution showed that Sahel recorded the lowest rainfall while guinea recorded the highest rainfall. Further analysis revealed that rainfall and temperature varied mostly in the sahel. The trend analysis of rainfall and temperature showed increasing trend in rainfall over the whole of Nigeria under RCP45 and RCP85. There was general increase in temperature for all RCPs across the zones and the whole of Nigeria. Further analysis revealed that sahel will experience more dry years in rainfall and more warm years across the zones for temperature. The changes in rainfall and temperature have implications in various sectors of the economy such as agriculture, water resources and health sector. It is well known that research and development complement each other. It is important that further research be carried out particularly in projecting the change in climate at regional scales. This will provide information about the expected change or variation in climate and hence help in the mitigation of the implications of the change in climate.

The Pacific Walker circulation (PWC) is one of the most important components of large-scale tropical atmospheric circulations. The PWC and its influences have been studied extensively by numerical models and reanalysis. The newly released ERA5 and NCEP2 are the most widely used reanalysis datasets and serve as benchmarks for evaluation of model simulations. If the results of these datasets differ significantly, this could lead to a bias in projected long-term climate knowledge. For better understanding of future climate change, it is necessary to evaluate PWC reanalysis productions. As a result, we compared the PWC structures between the ERA5 and NCEP2 datasets from month to seasonal time scales. We used the zonal mass streamfunction (ZMS) over the equatorial Pacific to indicate the strength of the PWC. The PWC’s average monthly or seasonal cycle peaks around July. From February to June, the NCEP2 shows a higher PWC intensity, whereas the ERA5 shows greater intensity from July to December. The circulation center in the NCEP2 is generally stronger and wider than in the ERA5. The ERA5, however, revealed that the PWC’s west edge (zero line of ZMS over the western Pacific) had moved 10 degrees westward in comparison to the NCEP2. In addition, we compared the PWC mean state in the reanalysis and CMIP6 models; the mean state vertical structures of the tropical PWC in the CMIP6 multi-model ensemble (MME) are similar to those of the reanalyses in structure but weaker and wider than in the two reanalysis datasets. The PWC is broader in CMIP6, and the western boundary is 7 and 17 degrees farther west than in the ERA5 and NCEP2, respectively. This study suggests that, when using reanalysis datasets to evaluate PWC structural changes in intensity and western edge, extreme caution should be exercised.

This research aims to determine the temperature extremes for Ikeja (Lagos), Osogbo (Osun) and Maiduguri (Borno), Nigeria, West Africa using Statistica analytical tool. Thirty (30) years daily maximum and minimum temperature data for Lagos, Osogbo and Maiduguri used for this study were collected from Nigeria Meteorological Agency (NIMET), Oshodi, Nigeria. Analysis of extreme temperature trend indicated that in Ikeja the percentage occurrence of warm days (TX90P) in which the maximum temperature is above 34°C (90^th percentile value) is increasing and the percentage occurrence of cold days (TX10P) in which the maximum temperature is below 28°C [10^thpercentile value] is decreasing, in Osogbo the percentage occurrence of warm days (TX90P) in which the maximum temperature is above 35°C [90^th percentile value) is increasing at a slower rate whereas the percentage occurrence of cold days (TX10P, number of days) in which the maximum temperature is below 27°C [10^th percentile value] is constant while in Maiduguri the percentage occurrence of warm days (TX90P, number of days) in which the maximum temperature is above 41°C [90^th percentile value] is constant whereas the percentage occurrence of cold days (TX10P, number of days) in which the maximum temperature is below 30°C [10^th percentile value] is slightly increasing. Percentage of warm days indicate constant value at around 13-15% during the three (3) decades under investigation across the study areas while day time cooling increases slightly by 2% in Ikeja, 1% in Osogbo and 3% in Maiduguri significant level and Cold night decrease at 1% in Ikeja and remain constant in Osogbo but decrease by 5% in Maiduguri significant level.