Hot days and tropical nights in Nigeria: trends and associated large-scale features
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The Department of Geological and Atmospheric Sciences offers majors in three areas: Geology (traditional, environmental, or hydrogeology, for work as a surveyor or in mineral exploration), Meteorology (studies in global atmosphere, weather technology, and modeling for work as a meteorologist), and Earth Sciences (interdisciplinary mixture of geology, meteorology, and other natural sciences, with option of teacher-licensure).
History
The Department of Geology and Mining was founded in 1898. In 1902 its name changed to the Department of Geology. In 1965 its name changed to the Department of Earth Science. In 1977 its name changed to the Department of Earth Sciences. In 1989 its name changed to the Department of Geological and Atmospheric Sciences.
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1898-present
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- Department of Geology and Mining (1898-1902)
- Department of Geology (1902-1965)
- Department of Earth Science (1965-1977)
- Department of Earth Sciences (1977-1989)
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- College of Liberal Arts and Sciences (parent college)
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Abstract
The impact on society of extreme temperature events is enormous. This study examines the temporal evolution and trends in mean temperatures (minimum temperature, TN and maximum temperature, TX) and warm extremes in Nigeria as well as in three regions in Nigeria (Guinea, Savanna, and Sahel) using homogenized daily TN and TX for the period 1971–2012. Warm extremes are defined as days with TX > 35 °C (HotD) and nights with TN > 20°C (TropN). The modified Mann-Kendall test is used to calculate and assess the statistical significance of trends in the indices. The results at annual and seasonal (JFM, AMJ, JAS, and OND) timescales indicate a significant positive increase in temperatures in Nigeria. The warming in annual and seasonal TN is greater than in TX. The temporal evolution in warm extremes is similar to those of the mean temperatures, with trends in TropN greater than those of the HotD. In all the regions, the temporal patterns of trends in mean temperatures and warm extremes are similar. The indices are characterized by positive trends, with the exception of HotD in Guinea with no data during JAS. Analysis of large-scale atmospheric fields during warm extreme days when both TX and TN exceed their respective 90th percentile thresholds shows that warm extreme days are associated with mid-tropospheric subsidence motion in vertical velocity anomaly that is connected with the core of the thermal low and the net convergent flow. These features are accompanied by positive surface shortwave radiation anomaly coupled with cloud cover reduction.
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This is a manuscript of an article published as Abatan, Abayomi A., Babatunde J. Abiodun, Elijah A. Adefisan, and William J. Gutowski. "Hot days and tropical nights in Nigeria: trends and associated large-scale features." Theoretical and Applied Climatology (2018). doi: 10.1007/s00704-018-2713-0. Posted with permission.