Spatio-temporal Validation of Multi-Source Satellite Rainfall Products in the Upper Tekeze-Atbara Basin, Ethiopia (Published)

Precise and reliable rainfall data is crucial for regional water resource management. However, rainfall data in Ethiopia mainly characterized by sparse distribution and temporal inconsistency. Therefore, the spatial and temporal patterns of rainfall are poorly understood in the major basins. Recently, satellite rainfall products (SRPs) have been applied as an alternative source to obtain long-term rainfall data. This study evaluated the performance of three different SRPs, namely CHIRPS, PERSIANN_CDR, and TMPA3B42, with respect to observed data in the Upper Tekeze-Atbara River Basin using different statistical indices. The result showed that PERSIANN_CDR had very low PBIAS than other products. The PERSIANN_CDR had a slight overestimation tendency, while the CHIRPS and TMPA3B42 considerably overestimated observation rainfall. The PERSIANN_CDR performed well for kiremt, belg, and bega season, with the lowest RMSE value of 2.9, 1.4, and 0.8 mm/day, respectively. On the contrary, TMPA3B42 poorly performed for kiremt, belg, and bega seasons with the largest RMSE value of 3.1, 1.9, and 1.1 mm/day, respectively. The PERSIANN_CDR had the best skill to detect observation rainfall, while the CHIRPS had the worst detecting skill during all seasons. In kiremt seasons, the PERSIANN_CDR product showed a good estimation of the observed rainfall almost in all parts of the basin except for a slight overestimation in northwestern and underestimation in southwestern regions. Overall, the findings of this study demonstrated the PERSIANN_CDR product potentials and use for analyzing rainfall distribution and variability in Ethiopia’s Upper Tekeze-Atbara River Basin.

Citation:Achenafi Teklay (2022) Spatio-temporal Validation of Multi-Source Satellite Rainfall Products in the Upper Tekeze-Atbara Basin, Ethiopia, International Journal of Environment and Pollution Research, Vol.10, No.2 pp.50-76

Keywords: CHIRPS, PERSIANN_CDR, Spatio-temporal, TMPA3B42, Tekeze-Atbara, Validation, satellite rainfall products

THE IMPACT OF AUTOMOBILE EXHAUST FUMES ON CONCENTRATION LEVELS OF LEAD ON BREAD IN PORT HARCOURT CITY, NIGERIA (Published)

The study examined the spatio-temporal analysis of Lead (Pb) concentrations in bread in five selected bus terminals in Port Harcourt metropolis A total of one thousand and two hundred loaves of bread were exposed to air with two hundred in each bus terminals on Mondays and Fridays in the morning, afternoon, and evening for four weeks and used for laboratory analysis. Volume of vehicular counts was also determined in the morning, afternoon and evening across the selected bus terminals. Thirty samples of premium motor spirit (PMS) were randomly collected between July and September 2013 to determine the amount of Pb and octane rating present in the laboratory. The area of each bus terminal was determined by multiplying the length and the breadth of each bus terminals. Mean value of Pb concentration and octane ratings; the volume of vehicular counts, size of the bus was determined. ANOVA and regression analysis were used in the study. Result showed that the mean values of Pb concentrations in bread were highest in Flyover Mile 1 Park in the morning, afternoon and evening with a value of 0.464 g/g, 0.305g/g and 0.339g/g respectively. Generally, the Pb concentration in bread was highest in the morning (0.271g/g) and least in the evening (0.235g/g). A direct relationship existed between the concentration of Pb in bread in bus terminals and volume of vehicular counts (r2= 0.194). Similarly, the size of bus terminals accounted for 60.0% of the concentration of Pb in bread (r2 = 0.600). There was a significant variation in the Pb concentrations in bread recorded in the morning, afternoon and evening as F calculated was 10.451 at 0.5 significance level. Similarly, there was a significant variation in the Pb concentrations recorded in the selected locations as F calculated was 10.788 at 0.5significance level. Policy measured aimed at stopping the sale of bread at the bus terminals and the use of leaded petrol in the city is advocated.

Keywords: Bus terminals, Lead (Pb) concentration, Port Harcourt, Spatio-temporal, White bread