Characteristics of Urban Heat Island in Enugu During Rainy Season

The rainy season UHI characteristics at several sites in Enugu urban were evaluated using paired measurement programme. The aim was to determine the characteristic of urban heat island in the city during rainy season periods. The study was undertaken in Enugu municipality in the months of June – July of 2006 and 2007. The results indicate that UHI at day and night during rainy season were very different. A downtown –centered heat island was observed both day and night. The day time variations were strongly correlated to the amount of tree shading while in the night, city climate was highly correlated to sky-view factors and thermal properties in the city. Maximum UHI was about 32c during the day and hour-to-hour difference was observed at night around (1800hrs to 2300hrs). UHI over Enugu have been analyzed and results reveal some spatial and temporal characteristics. The UHI has been found to occur throughout the day and night during rainy season. Its structure was observed to be greatly influenced by weather, city, metabolism, anthropogenic activities and local geographic features, land-use, land-cover as well as vegetation and population.Keywords: Measurement, Temperature, Urban, Rural, Rainy, Vegetation

Using trees as urban heat island reduction tool in Enugu city Nigeria based on their air pollution tolerance index

The Study examined the air pollution tolerance indices (APTI) of five plant species around Enugu urban area. Four physiological and biological parameters including leaf relative water content (RWC), ascorbic acid (AA) content, total leaf chlorophyll (TCh), and leaf extract pH were used to develop an APTI. The vegetation monitoring in terms of its APTI acts as a ‘Bioindicator’ of air pollution and can be incorporated into assessment studies for selecting trees for urban heat island (UHI) mitigation strategy.The result of the APTI showed order of tolerance as Anacarduim occidentale (22.20), Pinus spp (22.35), Catalpa burgei (22.57), Mangifera indica (23.37), and Psiduim guajava (24.15). A comparative analysiswas also done between the shedding ability of these trees and their APTI. The result showed that the best tree that provides both shed and high air pollution tolerance appeared in that order: Psiduim guajava, Magifera indica, Catalpa burgei, Pinus spp and Anacarduim occidentale. The results of such studies are therefore handy for future planning, and as well provide tolerant species for landscape and urban heat island mitigation

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

A methodology has been applied to investigate the spatial variability and trends existent in a mid-twentieth century climatic time series (for the period 1943–1977) recorded by 58 climatic stations in the Albert–Victoria water management area in Uganda. Data were subjected to quality checks before further processing. In the present work, temporal trends were analyzed using Mann–Kendall and linear regression methods. Heterogeneity of monthly rainfall was investigated using the precipitation concentration index (PCI). Results revealed that 53 % of stations have positive trends where 25 % are statistically significant and 45 % of stations have negative trends with 23 % being statistically significant. Very strong trends at 99 % significance level were revealed at 12 stations. Positive trends in January, February, and November at 40 stations were observed. The highest rainfall was recorded in April, while January, June, and July had the lowest rainfall. Spatial analysis results showed that stations close to Lake Victoria recorded high amounts of rainfall. Average annual coefficient of variability was 19 %, signifying low variability. Rainfall distribution is bimodal with maximums experienced in March–April–May and September–October–November seasons of the year. Analysis also revealed that PCI values showed a moderate to seasonal rainfall distribution. Spectral analysis of the time components reveals the existence of a major period around 3, 6, and 10 years. The 6- and 10-year period is a characteristic of September–October–November, March–April– May, and annual time series.http://link.springer.com/journal/704hb201