Geostatistical Approach in Spatial Estimates of Rainfall: Betwa River Catchment
| Main Author: | Ahlawat, Ritu |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 2014
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/4393541 |
Daftar Isi:
- As the point-based rainfall observation design has implications in correctly representing spatially continuous rainfall values, therefore methods ranging from simple arithmetic mean to isopleths and Thiessen’s polygon-based weighted means have been generally employed by hydrologists in order to obtain mean basin rainfall. The utility of these methods is important especially for analysing the spatial distribution of network and thereafter to suggest locations. Hence, advanced mathematical versions using network theory, geostatistical approach and optimum path analysis have been used to select the optimum design even in the preliminary stage of investigation. At a catchment level, an application of various interpolation methods using geostatistics is demonstrated here in case of Betwa river, one of the important southern tributary of Yamuna river after Chambal. The script for these methods was written in Geographical Information System (GIS) Software – ILWIS (Integrated Land and Water Information System) and it was run for normal rainfall parameters using data from Indian Meteorological Department. In the geostatistical analysis, it was found that trend surface, moving average and kriging based interpolated map provided good estimates of spatial accuracy of mean basin rainfall within 10-12 % of coefficient of variation when compared with normal rainfall at control stations. Among kriging methods, ordinary kriging was found to be best in terms of least root mean square deviation from validation results. Error map based on anisotropic kriging resulted into least amount of absolute error within 10% of estimation in rainfall from the measured normal values. The error can be further reduced if more rain-gauges are located in spatial dispersion zones by taking into account the effect of direction and elevation on rainfall.