Time Series Analysis of Temperature and Rainfall in the Savannah Region in Togo, West Africa
Abstract
:1. Introduction
2. Materials and Methods
2.1. Description of the Study Area
2.2. Data Sources
2.3. Testing for Serial Correlation
2.4. Trend Tests
2.4.1. Mann–Kendall Trend Test
2.4.2. Sen’s Slope Estimator Test
2.4.3. Variance Correction Approaches
2.5. Variability Analysis
2.5.1. Coefficient of Variation (CoV %)
2.5.2. Rainfall Anomaly Index (RAI)
3. Results and Discussion
3.1. Annual and Seasonal Rainfall and Temperature Trend Analysis
3.1.1. Serial Correlation Analysis
3.1.2. Annual Rainfall Trend Analysis
3.1.3. Annual Temperature Trend Analysis
3.1.4. Coefficient of Variation
3.2. Rainfall Anomaly Index
4. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Stations | Latitude | Longitude | Elevation AMSL * (m) | Study Period | Number of Years |
---|---|---|---|---|---|
Mango | 10.22 | 0.28 | 146 | 1981–2019 | 39 |
Dapaong | 10.51 | 0.12 | 300 | 1981–2019 | 39 |
Emitter Type | Manufactures Coefficient | Interpretation |
---|---|---|
Point source | <0.05 | Excellent |
0.05–0.07 | Average | |
0.07–0.011 | Marginal | |
0.11–0.15 | Poor | |
>0.15 | Unacceptable | |
Line source | <0.10 | Good |
0.10–0.20 | Average | |
>0.20 | Marginal to |
RAI Range | Classification | |
---|---|---|
Rainfall Anomaly Index (RAI) | Above 4 | Extremely humid |
2 to 4 | Very humid | |
0 to 2 | Humid | |
−2 to 0 | Dry | |
−4 to −2 | Very dry | |
Below −4 | Extremely dry |
Period | Minimum (mm) | Maximum (mm) | Mean (mm) |
---|---|---|---|
January | 0 | 33.8 | 1.55 |
February | 0 | 42.4 | 3.56 |
March | 0 | 127.4 | 22.39 |
April | 4.4 | 209.3 | 67.98 |
May | 24.7 | 285.3 | 113.56 |
June | 57.9 | 265.7 | 143.20 |
July | 50.1 | 417.8 | 191.87 |
August | 94.2 | 440 | 232.144 |
September | 4.8 | 342.9 | 188.54 |
October | 0 | 197.5 | 72.19 |
November | 0 | 42.2 | 3.26 |
December | 0 | 47.1 | 1.21 |
Period | Minimum (mm) | Maximum (mm) | Mean (mm) |
---|---|---|---|
January | 0 | 98 | 2.54 |
February | 0 | 70.1 | 3.93 |
March | 0 | 220 | 20.53 |
April | 0 | 196.8 | 63.35 |
May | 22.5 | 306.9 | 104.8 |
June | 68.1 | 247.1 | 147 |
July | 54.7 | 984.4 | 211.3 |
August | 4 | 784.7 | 272.2 |
September | 3.5 | 348.8 | 189 |
October | 0 | 182.8 | 60.3 |
November | 0 | 51.1 | 4.44 |
December | 0 | 29.8 | 0.95 |
Time Series | p-Value | Sen’s Slope | MK | |||
---|---|---|---|---|---|---|
Dapaong | Mango | Dapaong | Mango | Dapaong | Mango | |
April | 0.122 * | 0.943 * | 0.526 | 0.040 | 0.174 | 0.009 |
May | 0.022 * | 0.010 * | 1.092 | 1.513 | 0.258 | 0.289 |
June | 0.371 * | 0.141 * | 0.726 | −0.830 | 0.101 | −0.166 |
July | 0.561 * | 0.471 * | −0.700 | 0.816 | −0.066 | 0.082 |
August | 0.699 * | 0.486 * | 0.406 | 0.7 | 0.045 | 0.080 |
September | 0.095 * | 0.014 * | 1.733 | −2.487 | 0.188 | −0.275 |
October | 0.432 * | 0.121 * | 0.540 | 0.173 | 0.089 | 0.173 |
ANNUAL | 0.050 * | 0.701 * | 5.500 | −0.937 | 0.220 | −0.045 |
Time Series | Corrected Zc | New p-Value | Sen’s Slope | MMKY | ||||
---|---|---|---|---|---|---|---|---|
Dapaong | Mango | Dapaong | Mango | Dapaong | Mango | Dapaong | Mango | |
April | 2.900 | 0.237 | 0.003 * | 0.812 * | 0.525 | 0.400 | 0.174 | 0.009 |
May | 5.917 | 7.170 | 0.000 * | 0.000 * | 1.091 | 1.513 | 0.021 | 0.288 |
June | 2.004 | −2.977 | 0.045 * | 0.002 * | 0.725 | −0.830 | 0.101 | −0.165 |
July | −1.091 | 1.576 | 0.275 * | 0.114 * | −0.700 | 0.815 | −0.066 | 0.082 |
August | 0.697 | 1.772 | 0.485 * | 0.076 * | 0.405 | 0.700 | 0.044 | 0.079 |
September | 4.788 | −7.100 | 0.000 * | 0.000 * | 1.733 | −2.486 | 0.187 | −0.276 |
October | 2.089 | 3.632 | 0.036 * | 0.000 * | 0.540 | 0.840 | 0.089 | 0.171 |
ANNUAL | 2.551 | −1.236 | 0.010 * | 0.216 * | 5.500 | −0.937 | 0.219 | −0.039 |
Time Series | p-Value (Two Tailed Test) | Sen’s Slope Estimate | Man Kendall Statistic (S) | |||
---|---|---|---|---|---|---|
Dapaong | Mango | Dapaong | Mango | Dapaong | Mango | |
January | 0.133 * | 0.095 * | 0.029 | 0.032 | 0.169 | 0.188 |
February | 0.240 * | 0.002 * | 0.027 | 0.053 | 0.132 | 0.340 |
March | 0.008 * | 0.001 * | 0.029 | 0.058 | 0.299 | 0.417 |
April | 0.529 * | 0.014 * | 0.006 | 0.030 | 0.071 | 0.275 |
May | 0.536 * | 0.012 * | 0.004 | 0.033 | 0.070 | 0.280 |
June | 0.203 * | 0.0001 * | 0.009 | 0.038 | 0.144 | 0.481 |
July | 0.053 | 0.0001 * | 0.015 | 0.032 | 0.220 | 0.562 |
August | 0.016 | 0.0001 * | 0.014 | 0.030 | 0.275 | 0.612 |
September | 0.395 | 0.0001 * | 0.006 | 0.035 | 0.097 | 0.535 |
October | 0.698 | 0.0001 * | 0.001 | 0.038 | 0.044 | 0.564 |
November | 0.020 | 0.001 * | 0.026 | 0.056 | 0.263 | 0.357 |
December | 0.255 | 0.040 * | 0.020 | 0.033 | 0.129 | 0.230 |
ANNUAL | 0.143 | 0.0001 * | 0.008 | 0.040 | 0.164 | 0.625 |
Time Series | p-Value (Two Tailed Test) | Sen’s Slope Estimate | Man Kendall Statistic (S) | |||
---|---|---|---|---|---|---|
Dapaong | Mango | Dapaong | Mango | Dapaong | Mango | |
January | 0.270 * | 0.022 * | 0.017 | 0.040 | 0.125 | 0.255 |
February | 0.164 * | 0.028 * | 0.023 | 0.040 | 0.157 | 0.246 |
March | 0.023 * | 0.001 * | 0.030 | 0.048 | 0.260 | 0.389 |
April | 0.309 * | 0.147 * | 0.014 | 0.027 | 0.114 | 0.162 |
May | 0.467 * | 0.425 * | 0.012 | 0.014 | 0.082 | 0.089 |
June | 0.255 * | 0.006 * | 0.040 | 0.034 | 0.129 | 0.304 |
July | 0.167 * | 0.001 * | 0.015 | 0.040 | 0.156 | 0.397 |
August | 0.244 * | 0.147 * | 0.010 | 0.014 | 0.133 | 0.162 |
September | 0.594 * | 0.137 * | 0.005 | 0.010 | 0.060 | 0.166 |
October | 0.771 * | 0.663 * | −0.005 | 0.004 | −0.033 | 0.049 |
November | 0.011 * | 0.001 * | 0.040 | 0.039 | 0.286 | 0.378 |
December | 0.018 * | 0.001 * | 0.043 | 0.056 | 0.267 | 0.386 |
ANNUAL | 0.008 * | 0.0001 * | 0.022 | 0.032 | 0.295 | 0.455 |
Mango Station | Dapaong Station | ||||
---|---|---|---|---|---|
Months | Stdev | CoV | Months | Stdev | CoV |
Annual | 152.506 | 0.146 | Annual | 217.922 | 0.2017 |
Jan | 6.798 | 4.375 | Jan | 15.688 | 6.161 |
Feb | 9.441 | 2.647 | Feb | 12.829 | 3.262 |
March | 29.342 | 1.310 | March | 39.254 | 1.912 |
April | 48.14 | 0.708 | April | 39.074 | 0.61 |
May | 50.845 | 0.448 | May | 50.047 | 0.478 |
June | 54.783 | 0.383 | June | 54.313 | 0.372 |
July | 75.284 | 0.392 | July | 143.15 | 0.677 |
August | 72.261 | 0.311 | August | 126.07 | 0.463 |
September | 73.853 | 0.392 | September | 73.224 | 0.388 |
October | 51.601 | 0.715 | October | 41.836 | 0.694 |
November | 7.884 | 2.417 | November | 10.454 | 2.353 |
December | 7.541 | 6.205 | December | 4.8934 | 5.103 |
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Yao, K.M.A.; Kola, E.; Morenikeji, W.; Filho, W.L. Time Series Analysis of Temperature and Rainfall in the Savannah Region in Togo, West Africa. Water 2023, 15, 1656. https://doi.org/10.3390/w15091656
Yao KMA, Kola E, Morenikeji W, Filho WL. Time Series Analysis of Temperature and Rainfall in the Savannah Region in Togo, West Africa. Water. 2023; 15(9):1656. https://doi.org/10.3390/w15091656
Chicago/Turabian StyleYao, Komlagan Mawuli Apelete, Edinam Kola, Wole Morenikeji, and Walter Leal Filho. 2023. "Time Series Analysis of Temperature and Rainfall in the Savannah Region in Togo, West Africa" Water 15, no. 9: 1656. https://doi.org/10.3390/w15091656