Evaluating and merging model- and satellite-based precipitation products over varying climate and topography

Amjad, Muhamma
Before using the satellite- and model-based precipitation retrievals in hydrological studies, their uncertainty assessment is crucial. Improving their performance accuracy is another important issue worth consideration. This study first evaluates and intercompares a set of nine precipitation products (2 satellite estimation-based, 2 model reanalysis-based, and 5 model forecast-based products) over varying climate and topography by using the in-situ observed precipitation data as truth. The products were then merged, in the form of two groups, using two different merging techniques: 1. Taking ensemble mean (i.e., simple merging); 2. Taking ensemble mean after rescaling them by a linear regression method. The merged products obtained were statistically and hydrologically evaluated and inter-compared with the individual products using the same in-situ precipitation data and the observed surface runoff data, respectively. The results show that the errors in the products increase, while their correlation with the observed data decreases with the increasing terrain complexity. Comparatively, wetness and terrain slope have a more prominent role in the error variability of the products. Both the merging methods improve the errors and correlations of the products not only over the entire study area, but all its sub-regions classified based on the wetness, elevation, and terrain slope. Simple merging improves the precipitation detection ability of the individual products, while the merging after rescaling the products improves their random errors and correlation with the observed data. Overall, the merged products show better efficiency in regenerating the observed runoff data as compared to the individual products.


Investigation of the dependence of satellite-based precipitation estimate errors to distance from the coastline Uydu Kaynakli Yaǧmur Verilerinin Hata Oranlarinin Deniz Kiyilarina Olan Uzakliǧa Baǧli Analizi
YILMAZ, MERİÇ; Amjad, Muhammad; Bulut, Burak; Yılmaz, Mustafa Tuğrul (2017-01-01)
In this study, Tropical Rainfall Measuring Mission (TRMM) 3B42 v7 satellite based rainfall data are verified by using cumulative monthly rainfall data measured at 257 stations operated by the General Directorate of Meteorology between 1998 and 2014. Long-term mean values of station-based and satellite-based rainfall data, correlation between them, Standard deviation of monthly average and anomaly components, and standard deviation of satellite based data error are analyzed. Variation of satellite-based data...
Evaluating the hydro-estimator satellite rainfall algorithm over a mountainous region
Yücel, İsmail; Gochis, David J. (2011-01-01)
This study investigates the performance of the National Oceanic and Atmospheric Administration/National Environmental Satellite, Data, and Information Service (NOAA/NESDIS) operational rainfall estimation algorithm, called the hydro-estimator (HE), with and without its orographic correction method, in its depiction of the timing, intensity and duration of convective rainfall in general, and of the topography-rainfall relationship in particular. An event-based rainfall observation network in north-west Mexic...
Poyraz, Anıl; Yücel, İsmail (2018-06-02)
This study aims to assess the trends in drought by using the Standardized Precipitation Index(SPI) for 14 stations from Mediterranean climate region of Turkey. The SPI values for different timescales - from 1month to 1 year - are estimated for past and future by using the observed, uncorrected and bias corrected model data. The model data that correspond the grids which consist these 14 stations was obtained from 12 different climate models on CORDEX project. Bias correction method was applied using equival...
Assessment of flash flood events using remote sensing and atmospheric model-derived precipitation in a hydrological model
Yücel, İsmail (2011-07-07)
Remotely-sensed precipitation estimates and regional atmospheric model precipitation forecasts provide rainfall data at high spatial and temporal resolutions with a large-scale coverage, and can therefore be potentially used for hydrological applications for making flash flood forecasts and warnings. This study investigates the performance of the rainfall products obtained from the Hydro Estimator (HE) algorithm of NOAA/NESDIS and the Weather Research and Forecasting (WRF) model, and their use in a hydrolog...
Evaluation of a satellite-based global flood monitoring system
Yılmaz, Koray Kamil; Tian, Yudong; Hong, Yang; Pierce, Harold F. (2010-01-01)
This study provides an initial evaluation of a global flood monitoring system (GFMS) using satellite-based precipitation and readily available geospatial datasets. The GFMS developed by our group uses a relatively simple hydrologic model, based on the run-off curve number method, to transform precipitation into run-off. A grid-to-grid routing scheme moves run-off downstream. Precipitation estimates are from the TRMM Multi-satellite Precipitation Analysis (TMPA). We first evaluated the TMPA algorithm using a...
Citation Formats
M. Amjad, “Evaluating and merging model- and satellite-based precipitation products over varying climate and topography,” Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Civil Engineering., Middle East Technical University, 2020.