Accuracy analyses of numeric weather prediction-based stratiform and convective precipitation shortterm forecasts over Turkey

Aydın, Beril
This study was carried out to determine whether convective and stratiform (large-scale) precipitation datasets obtained from 5 model forecast-based products would be an adequate alternative for regions where station-based observation networks are sparse. Verification of precipitation types (convective or stratified) from numerical weather forecast (NWP) models (ALARO, CFS, ECMWF HRES, GFS, WRF) is done using station-based observations. Statistical assessments between these precipitation types in different topographies (complex and non-complex) are available between 2015 and 2018. Reference data are obtained from 836 Automatic Observation Stations (OMGI) operated by the Turkish State Meteorological Service (TSMS). Accuracy assessments are reviewed separately for each precipitation type (total, convective, stratiform) and topography (entire area, complex regions, non-complex regions). The results show that all model products have an average correlation of 0.6 in total and large-scale precipitation for all areas. In contrast, the convective component of precipitation has an average correlation of 0.16 and 0.19 for complex and non-complex regions, respectively. In complex areas where the risk of flash flooding is high and the slope is more than 5% under the influence of convective precipitation, the low prediction performance of model products reduces the ability to take precautions for dangerous situations. Overall, the ECMWF HRES product has the highest accuracy in total precipitation for all areas, while the WRF product has the highest correlation coefficient and closest spatial distributions in all regions for convective precipitation. The findings of this study will assist the global literature examining regions with complex topography not only over the entire study area but for future hydrological and hydrometeorological studies.


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...
Chemical composition of precipitation at different parts of Turkey
Ayaklı, Gül; Tuncel, Süleyman Gürdal; Department of Environmental Engineering (2014)
In this study major ion composition of rain water samples collected at General Directorate of Meteorology Antalya, Balıkesir and Trabzon rain sampling stations were analyzed. The major ions SO42-, NO3-, NH4+, Cl-, Ca2+, K+ and Na+ were analyzed by ion chromatography. Data generated in these stations are compared to evaluate how chemical composition of rainwater changes as air masses travel on the Anatolian plateau. Data also demonstrate how rainwater composition varies seasonally at different parts of Turke...
Impacts of climate nonstationarities on hydroclimatological variables in Turkey
Aziz, Rizwan; Yücel, İsmail; Yozgatlıgil, Ceylan; Department of Civil Engineering (2018)
Using multiple nonstationary frequency distributions, this study investigated the impacts of nonstationarities on yearly and seasonal extremes of hydroclimatological variables for observations and CORDEX projected data of period 2050-2100 in Turkey. Future streamflow is generated using the calibrated HBV-light hydrological model. Evaluation of CORDEX models suggests that for precipitation RCMs originated from GCMs EC-EARTH and HadGEM2-ES and for temperature GCM HadGEM2-ES coupled with RCM CCLM4-8-17 showed ...
Production of a high-resolution improved radar precipitation estimation map using gauge adjustment bias correction methods
Yousefi, Kaveh Patakchi; Yılmaz, Mustafa Tuğrul; Ozturk, Kurtulus; Yücel, İsmail; Yılmaz, Koray Kamil (null; 2020-05-08)
This study evaluates relative performances of different statistical algorithms to enhance radar-based quantitative precipitation estimation (QPE) accuracy using rain gauge network data. Initial investigations are implemented using observations obtained via 17 C-band radars located over different regions of Turkey. It was observed that there is an underestimation problem in radar estimations compared with the ground observations. According to the initial results, daily mean bias for radar estimations over di...
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...
Citation Formats
B. Aydın, “Accuracy analyses of numeric weather prediction-based stratiform and convective precipitation shortterm forecasts over Turkey,” M.S. - Master of Science, Middle East Technical University, 2023.