Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya
This study examined the extent of seasonal rainfall variability, drought occurrence, and the efficacy of interpolation techniques in eastern Kenya. Analyses of rainfall variability utilized rainfall anomaly index, coefficients of variance, and probability analyses. Spline, Kriging, and inverse dista...
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| Format: | Article |
| Language: | English |
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Wiley
2015-01-01
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| Series: | Advances in Meteorology |
| Online Access: | http://dx.doi.org/10.1155/2015/380404 |
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| author | M. Oscar Kisaka M. Mucheru-Muna F. K. Ngetich J. N. Mugwe D. Mugendi F. Mairura |
| author_facet | M. Oscar Kisaka M. Mucheru-Muna F. K. Ngetich J. N. Mugwe D. Mugendi F. Mairura |
| author_sort | M. Oscar Kisaka |
| collection | DOAJ |
| description | This study examined the extent of seasonal rainfall variability, drought occurrence, and the efficacy of interpolation techniques in eastern Kenya. Analyses of rainfall variability utilized rainfall anomaly index, coefficients of variance, and probability analyses. Spline, Kriging, and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model using ArcGIS. Validation of these interpolation methods was evaluated by comparing the modelled/generated rainfall values and the observed daily rainfall data using root mean square errors and mean absolute errors statistics. Results showed 90% chance of below cropping threshold rainfall (500 mm) exceeding 258.1 mm during short rains in Embu for one year return period. Rainfall variability was found to be high in seasonal amounts (CV = 0.56, 0.47, and 0.59) and in number of rainy days (CV = 0.88, 0.49, and 0.53) in Machang’a, Kiritiri, and Kindaruma, respectively. Monthly rainfall variability was found to be equally high during April and November (CV = 0.48, 0.49, and 0.76) with high probabilities (0.67) of droughts exceeding 15 days in Machang’a and Kindaruma. Dry-spell probabilities within growing months were high, (91%, 93%, 81%, and 60%) in Kiambere, Kindaruma, Machang’a, and Embu, respectively. Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region. |
| format | Article |
| id | doaj-art-17075c6e4de344d584dedf6bc2eae8b8 |
| institution | Kabale University |
| issn | 1687-9309 1687-9317 |
| language | English |
| publishDate | 2015-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Meteorology |
| spelling | doaj-art-17075c6e4de344d584dedf6bc2eae8b82025-02-03T01:12:35ZengWileyAdvances in Meteorology1687-93091687-93172015-01-01201510.1155/2015/380404380404Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern KenyaM. Oscar Kisaka0M. Mucheru-Muna1F. K. Ngetich2J. N. Mugwe3D. Mugendi4F. Mairura5Department of Environmental Science, Kenyatta University, P.O. Box 43844-00100, Nairobi, KenyaDepartment of Environmental Science, Kenyatta University, P.O. Box 43844-00100, Nairobi, KenyaDepartment of Agricultural Resource Management, Kenyatta University, P.O. Box 43844-00100, Nairobi, KenyaDepartment of Agricultural Resource Management, Kenyatta University, P.O. Box 43844-00100, Nairobi, KenyaEmbu University College, P.O. Box 6-60100, Embu, KenyaTSBF-CIAT, Tropical Soil Biology and Fertility Institute of CIAT, P.O. Box 30677-00100, Nairobi, KenyaThis study examined the extent of seasonal rainfall variability, drought occurrence, and the efficacy of interpolation techniques in eastern Kenya. Analyses of rainfall variability utilized rainfall anomaly index, coefficients of variance, and probability analyses. Spline, Kriging, and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model using ArcGIS. Validation of these interpolation methods was evaluated by comparing the modelled/generated rainfall values and the observed daily rainfall data using root mean square errors and mean absolute errors statistics. Results showed 90% chance of below cropping threshold rainfall (500 mm) exceeding 258.1 mm during short rains in Embu for one year return period. Rainfall variability was found to be high in seasonal amounts (CV = 0.56, 0.47, and 0.59) and in number of rainy days (CV = 0.88, 0.49, and 0.53) in Machang’a, Kiritiri, and Kindaruma, respectively. Monthly rainfall variability was found to be equally high during April and November (CV = 0.48, 0.49, and 0.76) with high probabilities (0.67) of droughts exceeding 15 days in Machang’a and Kindaruma. Dry-spell probabilities within growing months were high, (91%, 93%, 81%, and 60%) in Kiambere, Kindaruma, Machang’a, and Embu, respectively. Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region.http://dx.doi.org/10.1155/2015/380404 |
| spellingShingle | M. Oscar Kisaka M. Mucheru-Muna F. K. Ngetich J. N. Mugwe D. Mugendi F. Mairura Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya Advances in Meteorology |
| title | Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya |
| title_full | Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya |
| title_fullStr | Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya |
| title_full_unstemmed | Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya |
| title_short | Rainfall Variability, Drought Characterization, and Efficacy of Rainfall Data Reconstruction: Case of Eastern Kenya |
| title_sort | rainfall variability drought characterization and efficacy of rainfall data reconstruction case of eastern kenya |
| url | http://dx.doi.org/10.1155/2015/380404 |
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