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Mr. Emir Toker
Eurasia Institute of Earth Sciences, Istanbul Technical University

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0 Extreme events
0 air-sea interaction
0 Earth Sciences
0 Meteorology Science
0 Atmosphere- Ocean Interaction

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Journal article
Published: 20 November 2020 in Atmospheric Research
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A heavy hailstorm developed over Istanbul on July 27, 2017 and inflicted substantial damage on hundreds of buildings and thousands of vehicles. Weather forecast models largely failed to predict this event. In this study, we investigate the performance of the Weather Research and Forecasting (WRF) model in simulating this particular hailstorm through a sensitivity experiment and the development of the supercell using one of the simulations that produce comparatively better performance in reproducing the hail event. A total of 24 sensitivity simulations involving different microphysics (Milbrandt, NSSL2, WDM6, and Goddard), cumulus (New SAS, New Tiedtke, and Kain Fritsch), and planetary boundary layer (PBL) (YSU, and MYNN2) schemes are conducted. The sensitivity simulations produce different rainfall patterns in the innermost domain, and the major differences in the spatial patterns arise because of the cumulus parameterizations, while microphysics schemes seem to influence the magnitude of the precipitation. All simulations reproduce thunderstorms resulting in substantial precipitation over Istanbul, however, only those with Kain Fritsch cumulus scheme are able to generate hail over the city. The simulation with YSU PBL, Kain Fritsch cumulus and Milbrandt microphysics schemes (YKM) produces hail paths that best match the observations. The YKM simulation reproduces a near typical structure of a storm cloud with an anvil shape, an overshooting top reaching about 12 km altitude, and a weak echo region in the front part. The model is able to simulate strong convection supported by the low-level convergence and low-to-mid-tropospheric wind shear that produces an updraft near the center of the storm where warm and moist air rises rapidly upward at velocities up to 28 m/s. The simulation yields 21.5 mm precipitation and 3.9 mm hail during the first 15 min when the storm starts to affect the city center. Our analysis suggests that the WRF model has high potential to realistically simulate the hailstorms if physics options are reasonably selected.

ACS Style

Emir Toker; Yasemin Ezber; Omer Lutfi Sen. Numerical simulation and sensitivity study of a severe hailstorm over Istanbul. Atmospheric Research 2020, 250, 105373 .

AMA Style

Emir Toker, Yasemin Ezber, Omer Lutfi Sen. Numerical simulation and sensitivity study of a severe hailstorm over Istanbul. Atmospheric Research. 2020; 250 ():105373.

Chicago/Turabian Style

Emir Toker; Yasemin Ezber; Omer Lutfi Sen. 2020. "Numerical simulation and sensitivity study of a severe hailstorm over Istanbul." Atmospheric Research 250, no. : 105373.

Article
Published: 06 October 2019 in Water
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Although the complexity of physically-based models continues to increase, they still need to be calibrated. In recent years, there has been an increasing interest in using new satellite technologies and products with high resolution in model evaluations and decision-making. The aim of this study is to investigate the value of different remote sensing products and groundwater level measurements in the temporal calibration of a well-known hydrologic model i.e., Hydrologiska Bryåns Vattenbalansavdelning (HBV). This has rarely been done for conceptual models, as satellite data are often used in the spatial calibration of the distributed models. Three different soil moisture products from the European Space Agency Climate Change Initiative Soil Measure (ESA CCI SM v04.4), The Advanced Microwave Scanning Radiometer on the Earth Observing System (EOS) Aqua satellite (AMSR-E), soil moisture active passive (SMAP), and total water storage anomalies from Gravity Recovery and Climate Experiment (GRACE) are collected and spatially averaged over the Moselle River Basin in Germany and France. Different combinations of objective functions and search algorithms, all targeting a good fit between observed and simulated streamflow, groundwater and soil moisture, are used to analyze the contribution of each individual source of information.

ACS Style

Mehmet Cüneyd Demirel; Alparslan Özen; Selen Orta; Emir Toker; Hatice Kübra Demir; Ömer Ekmekcioğlu; Hüsamettin Tayşi; Sinan Eruçar; Ahmet Bilal Sağ; Ömer Sarı; Ecem Tuncer; Hayrettin Hancı; Türkan Irem Özcan; Hilal Erdem; Mehmet Melih Koşucu; Eyyup Ensar Başakın; Kamal Ahmed; Awat Anwar; Muhammet Bahattin Avcuoğlu; Ömer Vanlı; Simon Stisen; Martijn J. Booij. Additional Value of Using Satellite-Based Soil Moisture and Two Sources of Groundwater Data for Hydrological Model Calibration. Water 2019, 11, 2083 .

AMA Style

Mehmet Cüneyd Demirel, Alparslan Özen, Selen Orta, Emir Toker, Hatice Kübra Demir, Ömer Ekmekcioğlu, Hüsamettin Tayşi, Sinan Eruçar, Ahmet Bilal Sağ, Ömer Sarı, Ecem Tuncer, Hayrettin Hancı, Türkan Irem Özcan, Hilal Erdem, Mehmet Melih Koşucu, Eyyup Ensar Başakın, Kamal Ahmed, Awat Anwar, Muhammet Bahattin Avcuoğlu, Ömer Vanlı, Simon Stisen, Martijn J. Booij. Additional Value of Using Satellite-Based Soil Moisture and Two Sources of Groundwater Data for Hydrological Model Calibration. Water. 2019; 11 (10):2083.

Chicago/Turabian Style

Mehmet Cüneyd Demirel; Alparslan Özen; Selen Orta; Emir Toker; Hatice Kübra Demir; Ömer Ekmekcioğlu; Hüsamettin Tayşi; Sinan Eruçar; Ahmet Bilal Sağ; Ömer Sarı; Ecem Tuncer; Hayrettin Hancı; Türkan Irem Özcan; Hilal Erdem; Mehmet Melih Koşucu; Eyyup Ensar Başakın; Kamal Ahmed; Awat Anwar; Muhammet Bahattin Avcuoğlu; Ömer Vanlı; Simon Stisen; Martijn J. Booij. 2019. "Additional Value of Using Satellite-Based Soil Moisture and Two Sources of Groundwater Data for Hydrological Model Calibration." Water 11, no. 10: 2083.