scholarly journals Modeling of Heavy Rainfall Triggering Landslide Using WRF Model

Agromet ◽  
2020 ◽  
Vol 34 (1) ◽  
pp. 55-65
Author(s):  
Danang Eko Nuryanto ◽  
Yuaning Fajariana ◽  
Radyan Putra Pradana ◽  
Rian Anggraeni ◽  
Imelda Ummiyatul Badri ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Temporal Pattern ◽  
Heavy Rainfall ◽  
Wrf Model ◽  
Cloud Formation ◽  
Rainfall Distribution ◽  
Model Simulations ◽  
Starting Time ◽  
Landslide Event ◽  
Event Based

This study revealed the behavior of heavy rainfall before landslide event based on the Weather Research Forecasting (WRF) model. Simulations were carried out to capture the heavy rainfall patterns on 27 November 2018 in Kulonprogo, Yogyakarta. The modeling was performed with three different planetary boundary layer schemes, namely: Yonsei University (YSU), Sin-Hong (SH) and Bougeault and Lacarrere (BL). Our results indicated that the variation of rainfall distribution were small among schemes. The finding revealed that the model was able to capture the radar’s rainfall pattern. Based on statistical metric, WRF-YSU scheme was the best outperforming to predict a temporal pattern. Further, the study showed a pattern of rainfall development coming from the southern coastal of Java before 13:00 LT (Local Time=WIB=UTC+7) and continued to inland after 13:00 LT. During these periods, the new clouds were developed. Based on our analysis, the cloud formation that generated rainfall started at 10:00 LT, and hit a peak at 13:00 LT. A starting time of cloud generating rainfall may be an early indicator of landslide.

scholarly journals Assessing Hurricane Rainfall Mechanisms Using a Physics-Based Model: Hurricanes Isabel (2003) and Irene (2011)

2018 ◽  
Vol 75 (7) ◽  
pp. 2337-2358 ◽  
Author(s):  
Ping Lu ◽  
Ning Lin ◽  
Kerry Emanuel ◽  
Daniel Chavas ◽  
James Smith
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Wrf Model ◽  
Hydrologic Model ◽  
Dominant Factor ◽  
Wind Model ◽  
Rainfall Distribution ◽  
Delaware River ◽  
Large Numbers ◽  
Frictional Convergence

Abstract We examine a recently developed physics-based tropical cyclone rainfall (TCR) model and apply it to assess the mechanisms that dominate the magnitude and spatial distribution of TC rainfall, with Hurricanes Isabel (2003) and Irene (2011) as study cases. We evaluate the TCR model using Weather and Research Forecasting (WRF) Model simulations. TCR-generated rainfall fields for the two storms compare well with WRF estimates in terms of both azimuthal mean and spatial distributions. When coupled with a hydrologic model, TCR generates flood peaks over the Delaware River basin for Irene as accurately as WRF. TCR accounts for four major rainfall mechanisms: surface frictional convergence, vortex stretching, interaction of the storm with topography, and interaction of the storm with large-scale baroclinity. We show that these rainfall mechanisms affected the rainfall pattern differently for Isabel and Irene. Frictional convergence is the dominant factor, while other mechanisms are also significant. The frictional convergence depends on the boundary layer formulation, which is relatively simple in TCR and may require calibration of boundary layer parameters. Furthermore, we find that the TC rainfall distribution is strongly dependent on the temporal and spatial variation of the TC wind field, mediated by the physical mechanisms represented by TCR. When coupled with various analytical wind models, TCR generally captures the rainfall distribution, with the Holland wind model performing the best. Given its high computational efficiency, TCR can be coupled with an analytical wind model, a hydrological model, and a TC climatology model to generate large numbers of synthetic events to assess the risk associated with TC rainfall and inland flooding.

scholarly journals Sensitivity of Simulations of Zambian Heavy Rainfall Events to the Atmospheric Boundary Layer Schemes

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 38
Author(s):  
Mary-Jane M. Bopape ◽  
David Waitolo ◽  
Robert S. Plant ◽  
Elelwani Phaduli ◽  
Edson Nkonde ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Weather Forecasting ◽  
Weather Prediction ◽  
Wrf Model ◽  
Extreme Rainfall ◽  
Maximum Temperature ◽  
Rainfall Events ◽  
Heavy Rainfall Events

Weather forecasting relies on the use of numerical weather prediction (NWP) models, whose resolution is informed by the available computational resources. The models resolve large scale processes, while subgrid processes are parametrized. One of the processes that is parametrized is turbulence which is represented in planetary boundary layer (PBL) schemes. In this study, we evaluate the sensitivity of heavy rainfall events over Zambia to four different PBL schemes in the Weather Research and Forecasting (WRF) model using a parent domain with a 9 km grid length and a 3 km grid spacing child domain. The four PBL schemes are the Yonsei University (YSU), nonlocal first-order medium-range forecasting (MRF), University of Washington (UW) and Mellor–Yamada–Nakanishi–Niino (MYNN) schemes. Simulations were done for three case studies of extreme rainfall on 17 December 2016, 21 January 2017 and 17 April 2019. The use of YSU produced the highest rainfall peaks across all three cases; however, it produced performance statistics similar to UW that are higher than those of the two other schemes. These statistics are not maintained when adjusted for random hits, indicating that the extra events are mainly random rather than being skillfully placed. UW simulated the lowest PBL height, while MRF produced the highest PBL height, but this was not matched by the temperature simulation. The YSU and MYNN PBL heights were intermediate at the time of the peak; however, MYNN is associated with a slower decay and higher PBL heights at night. WRF underestimated the maximum temperature during all cases and for all PBL schemes, with a larger bias in the MYNN scheme. We support further use of the YSU scheme, which is the scheme selected for the tropical suite in WRF. The different simulations were in some respects more similar to one another than to the available observations. Satellite rainfall estimates and the ERA5 reanalysis showed different rainfall distributions, which indicates a need for more ground observations to assist with studies like this one.

scholarly journals Presence of Longitudinal Roll Structures during Synoptic Forced Conditions in Complex Terrain

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 737
Author(s):  
Cory M. Payne ◽  
Jeffrey E. Passner ◽  
Robert E. Dumais ◽  
Abdessattar Abdelkefi ◽  
Christopher M. Hocut
Keyword(s):  
Boundary Layer ◽  
Agricultural Research ◽  
Wrf Model ◽  
Flow Characteristics ◽  
Critical Threshold ◽  
Department Of Agriculture ◽  
Synoptic Conditions ◽  
Lee Waves ◽  
Lee Wave ◽  
Usda Agricultural Research

To investigate synoptic interactions with the San Andres Mountains in southern New Mexico, the Weather Research and Forecasting (WRF) model was used to simulate several days in the period 2018–2020. The study domain was centered on the U.S. Department of Agriculture (USDA) Agricultural Research Service’s Jornada Experimental Range (JER) and the emphasis was on synoptic conditions that favor strong to moderate winds aloft from the southwest, boundary layer shear, a lack of moisture (cloud coverage), and modest warming of the surface. The WRF simulations on these synoptic days revealed two distinct regimes: lee waves aloft and SW-to-NE oriented Longitudinal Roll Structures (LRS) that have typical length scales of the width of the mountain basin in the horizontal and the height of the boundary layer (BL) in the vertical. Analysis of the transitional periods indicate that the shift from the lee wave to LRS regime occurs when the surface heating and upwind flow characteristics reach a critical threshold. The existence of LRS is confirmed by satellite observations and the longitudinal streak patterns in the soil of the JER that indicate this is a climatologically present BL phenomenon.

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