Abstract:
In this study, the aim was to evaluate the contribution of rainfall and temperature variability and trend
on Lake Loggo (Hayk) size/volume change, in Ethiopia using rainfall, temperature, and a map of the
different years of the Lake data from 1986 to 2016. In addition, the 10-year interval Landsat map of
the Lake was used to see the variability and correlation with climate change. Coefficient of variation
(cv) and ArcGIS 10.5 was used to examine rainfall variability and Lake Loggo’s variability
respectively. Mann-Kendall (MK) test and Sen’s slope estimator was used to test the trend. The study
area has two rainfall seasons, Kiremt and Belg. Kiremt is the main rainy season which accounts for
91.66% of the annual rainfall, and Belg contributes 6.252%. The rate of change for annual mean, the
maximum and minimum temperature in the study area was 0.005 ◦C, 0.049 ◦C, and -0.039 ◦C,
respectively. Decadal mean rainfall amount was recorded as 1141.83 mm, 1159.43 mm, and 1124.05
mm, respectively. This clearly shows a decreasing rainfall trend from 1996 to 2016, which was about
35.83 mm per year. Decadal analysis of the mean maximum and mean minimum temperature of 25.45
◦C, 26.12 ◦C, and 26.55 ◦C for maximum temperature and 11.02 ◦C, 10.87 ◦C, and 10.17 ◦C for
minimum temperature over the last three decades, respectively. This analysis confirms increasing
trends for both mean maximum and mean minimum temperature in the study area. All seasons’ mean
temperature was below the long-term mean from 1986 to 2000, while it was above the long-term mean
since 2001. This result verifies the recent fast increment warming trend of the area. From the seasonal
analysis of rainfall, in all seasons below the mean long-term rainfall was observed since 2001. This
result may be related to the Lake Hayq variability. The study concludes that there was a significant
variation in rainfall and a significant increment in temperature throughout the observing period. The
high variability of rainfall and significant increase in temperature could have an interconnection with
the variation of Lake Hayq's size since 2001. Rainfall variation could cause flooding and outbreak of
human and livestock diseases and conservation agriculture practice is imperative for overcoming the
problem.
