Cross Assessment of Twenty-One Different Methods for Missing Precipitation Data Estimation

• The  results  of  metrological,  hydrological,  and  environmental  data  analyses  are  mainlydependent  on  the  reliable  estimation  of  missing  data.  In  this  study,  21  classical  methods  were evaluated to determine the best method for infilling the missing precipitation data in Ethiopia. The monthly data collected from 15 different stations over 34 years from 1980 to 2013 were considered. Homogeneity  and  trend  tests  were  performed  to  check  the  data.  The  results  of  the  different methods were  compared  using the mean absolute error (MAE),  root-mean-square  error (RMSE), coefficient  of  efficiency  (CE),  similarity  index  (S-index),  skill  score  (SS),  and  Pearson  correlation coefficient (rPearson). The results of this paper confirmed that the normal ratio (NR), multiple linear regression (MLR), inverse distance weighting (IDW), correlation coefficient weighting (CCW), and arithmetic average (AA) methods are the most reliable methods of those studied. The NR method provides  the  most  accurate  estimations  with  rPearson   of  0.945,  mean  absolute  error  of  22.90  mm, RMSE of  33.695  mm,  similarity  index  of 0.999,  CE  index of  0.998,  and  skill  score of  0.998.  When comparing the observed results and the estimated results from the NR, MLR, IDW, CCW, and AA methods, the MAE and RMSE were found to be low, and high values of CE, S-index, SS, and rPearson were achieved. On the other hand, using the closet station (CS), UK traditional, linear regression (LR),  expectation  maximization  (EM),  and  multiple  imputations  (MI)  methods  gave  the  lowest accuracy, with MAE and RMSE values varying from 30.424 to 47.641 mm and from 49.564 to 58.765 mm, respectively. The results of this study suggest that the recommended methods are applicable for different types of climatic data in Ethiopia and arid regions in other countries around the world.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Geoteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Geotechnical Engineering (hsv//eng)

Nyckelord

Nile Basin

missing data

estimation

precipitation

Ethiopia

classical methods

Soil Mechanics

Geoteknik

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