Trend analysis was performed for the long-term measured pan evaporation and estimated pan coefficient for 4 meteorological stations during 1976-2011 in Togo. Measured pan evaporation was recorded at four meteorologica...Trend analysis was performed for the long-term measured pan evaporation and estimated pan coefficient for 4 meteorological stations during 1976-2011 in Togo. Measured pan evaporation was recorded at four meteorological stations in Togo for the global period of 1976 to 2011 at Lome, Tabligbo, Atakpame, and Sokode. ETo was estimated using the Penman-Monteith model. The Mann-Kendall test was used for trend analysis. The results showed that annual Epan varied from 1803 to 2081 mm at Lome, from 1294 to 1496 mm at Tabligbo, from 1605 to 1974 mm at Atakpame and from 1839 to 1990 mm at Sokode. It had significant increasing trend at Lome, Tabligbo, and Sokode and a negative trend at Atakpame. Monthly Epan varied from 137 to 197 mm at Lome, 89 to 149 mm at Tabligbo, 137 to 214 mm at Atakpame and from 137 to 190 mm at Sokode. At Lome, Kpan varied from 0.61 to 1.17 and averaged 0.81. At Tabligbo, Kpan varied from 0.59 to 0.98 and averaged 0.75. At Atakpame, Kpan varied from 0.5 to 2.0 and averaged 1.12. At Sokode, Kpan varied from 0.43 to 1.92 and averaged 0.98. Monthly mean Kpan is recommended for use in hydrological studies, irrigation scheduling and water management in Togo.展开更多
The study focused on the detection of indicators of climate change in 24-hourly annual maximum series (AMS) rainfall data collected for 36 years (1982-2017) for Warri Township, using different statistical methods yiel...The study focused on the detection of indicators of climate change in 24-hourly annual maximum series (AMS) rainfall data collected for 36 years (1982-2017) for Warri Township, using different statistical methods yielded a statistically insignificant positive mild trend. The IMD and MCIMD downscaled model’s time series data respectively produced MK statistics varying from 1.403 to 1.4729, and 1.403 to 1.463 which were less than the critical Z-value of 1.96. Also, the slope magnitude obtained showed a mild increasing trend in variation from 0.0189 to 0.3713, and 0.0175 to 0.5426, with the rate of change in rainfall intensity at 24 hours duration as 0.4536 and 0.42 mm/hr.year (4.536 and 4.2 mm/decade) for the IMD and the MCIMD time series data, respectively. The trend change point date occurred in the year 2000 from the distribution-free CUSUM test with the trend maintaining a significant and steady increase from 2010 to 2015. Thus, this study established the existence of a trend, which is an indication of a changing climate, and satisfied the condition for rainfall Non-stationary intensity-duration-frequency (NS-IDF) modeling required for infrastructural design for combating flooding events.展开更多
文摘Trend analysis was performed for the long-term measured pan evaporation and estimated pan coefficient for 4 meteorological stations during 1976-2011 in Togo. Measured pan evaporation was recorded at four meteorological stations in Togo for the global period of 1976 to 2011 at Lome, Tabligbo, Atakpame, and Sokode. ETo was estimated using the Penman-Monteith model. The Mann-Kendall test was used for trend analysis. The results showed that annual Epan varied from 1803 to 2081 mm at Lome, from 1294 to 1496 mm at Tabligbo, from 1605 to 1974 mm at Atakpame and from 1839 to 1990 mm at Sokode. It had significant increasing trend at Lome, Tabligbo, and Sokode and a negative trend at Atakpame. Monthly Epan varied from 137 to 197 mm at Lome, 89 to 149 mm at Tabligbo, 137 to 214 mm at Atakpame and from 137 to 190 mm at Sokode. At Lome, Kpan varied from 0.61 to 1.17 and averaged 0.81. At Tabligbo, Kpan varied from 0.59 to 0.98 and averaged 0.75. At Atakpame, Kpan varied from 0.5 to 2.0 and averaged 1.12. At Sokode, Kpan varied from 0.43 to 1.92 and averaged 0.98. Monthly mean Kpan is recommended for use in hydrological studies, irrigation scheduling and water management in Togo.
文摘The study focused on the detection of indicators of climate change in 24-hourly annual maximum series (AMS) rainfall data collected for 36 years (1982-2017) for Warri Township, using different statistical methods yielded a statistically insignificant positive mild trend. The IMD and MCIMD downscaled model’s time series data respectively produced MK statistics varying from 1.403 to 1.4729, and 1.403 to 1.463 which were less than the critical Z-value of 1.96. Also, the slope magnitude obtained showed a mild increasing trend in variation from 0.0189 to 0.3713, and 0.0175 to 0.5426, with the rate of change in rainfall intensity at 24 hours duration as 0.4536 and 0.42 mm/hr.year (4.536 and 4.2 mm/decade) for the IMD and the MCIMD time series data, respectively. The trend change point date occurred in the year 2000 from the distribution-free CUSUM test with the trend maintaining a significant and steady increase from 2010 to 2015. Thus, this study established the existence of a trend, which is an indication of a changing climate, and satisfied the condition for rainfall Non-stationary intensity-duration-frequency (NS-IDF) modeling required for infrastructural design for combating flooding events.
