Investigating Climate Variability In Spatio-Temporal Domains And Its Impact On Crop Production Using GIS And Statistical Techniques: The Case Of North And South Wello Zones, Northern Ethiopian Highlands

Abstract

Climate variability is the most complex and serious environmental problem facing the world today. Ethiopia has historically suffered from climate variability and extremes. Climate variability and change likely are significant contributing factors in food security challenges, Ethiopia currently experiences. The problem of climate change is broadly studied from various angles that emanates from seriousness of the problem. In this regard, the application of GIS and statistical techniques in analyzing climatic data and its impact on crop production is crucial. The study aimed at investigating climate variability and its impact on crop production in North and South Wello Zones, Northern Ethiopian Highlands. In this study, time series data of rainfall and temperature from NCEP’s CFSR and NMA, SST from NOAA and crop data from CSA were used. Mann-Kendall and Sen’s Slope methods have been used for the trend analysis and quantification. The result showed that total Kiremt RF decreased by 9.076mm per Kiremt season and the trend was statistically significant at 95% confidence interval. Similarly, total annual RF showed a decreasing trend by 9.632mm per year. On the contrary, Tmax, Tmin and SST showed an increasing trend both seasonally and annually during the last 33 years (1984-2016) in the study area. With regard to spatial and temporal distribution, the highest amount of mean total Kiremt and annual RF were 993.71mm and 1715.95mm, respectively. The highest values of mean annual Tmax and Tmin were 30.13°C and 11.1°C, correspondingly, while the lowest values of mean annual Tmax and Tmin were 19.94°C and 5.76°C, respectively. Furthermore, RF, Tmax and Tmin data of the study area were analyzed for the magnitude of temporal and spatial variations using percentage of coefficient of variations (CV). CV of Mean total Kiremt and annual RF were ranging from 24.8% to 62% and from 23.13% to 57.86%, respectively. The correlation between total Kiremt and Belg RF with mean SST were negative (r = -0.457) and positive (r = 0.385), respectively and statically significant at alpha 0.05 level.From the regression analysis, it was observed that the variation of crop production was explained by the variation of rainfall and temperature. For instance, the impact of mean Kiremt Tmax accounted for 21.8% (R2 = 0.218) of teff yield changes, whereas 47.5% (R2 = 0.475) of variations in Sorghum was explained by the variations in total Kiremt RF. From the study, it has been observed that current rainfall and temperature variability has a significant influence on crop production in the area and any unfavorable change in the local climate in the future will have serious implications for household level food security, unless efforts to adapt to the ongoing climate change should begin from tackling the current climate variability and take a climate risk management approach for adapting to the ongoing climate change.