Author(s)

Usman Saleem¹, Mian Sohail Akram¹, Muhammad Fahad Ullah², Faisal Rehman^2*

¹Institute of Geology, University of the Punjab, Lahore, Pakistan.
²Departments of Earth Sciences, University of Sargodha, Sargodha, Pakistan.

The relative humidity in the atmosphere captured by AQUA satellite contains missing matrices. In order to fill such missing values four very popular imputation techniques: Bilinear, Inverse Distance Weighting, Natural Neighbor and Nearest Interpolations were tested. Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Coefficient of Determination (R²) and Correlation Coefficient (Corr), were used to check the accuracy of these interpolations. It was found that the Inverse Distance Weighting and Nearest Interpolation were proved not to be suited. Natural interpolation gave accurate results than the aforementioned two interpolations. Missing values of relative humidity were accurately refilled with Bilinear Interpolation. This interpolation produced RMSE of ±0.543 for relative humidity over 100, 150, 200, 250, 300, 400, 500 hPa while for 600, 700, 850 and 925 hPa RMSE remainnear to 1. A perfect fit to the surface and very strong correlation (value near to 0.99) was found between actual and imputed relative humidity data through Bilinear Interpolation. Therefore it was concluded that the Bilinear Interpolation is the most accurate and best imputation for missing values of relative humidity form 100 to 1000 hPa levels.

Imputation, Humidity, Aqua Satellite , Pakistan

Saleem, U. , Akram, M. , Ullah, M. and Rehman, F. (2018) Accurate Imputation for Relative Humidity over Pakistan Gathered from AQUA Satellite. Open Journal of Geology, 8, 987-1001. doi: 10.4236/ojg.2018.810059.