Yongjie Huang

University of Oklahoma | ou · Center for Analysis and Prediction of Storms (CAPS)

Record‐breaking rainfall of 524.1 mm in 24 hr occurred in the coastal metropolitan city of Guangzhou, China, during 6–7 May 2017 and caused devastating flooding. Observation analysis and a nested very large eddy simulation (VLES) with Weather Research and Forecasting (WRF) model were conducted to investigate various factors that contributed to the...

To investigate the mechanisms for the record‐breaking rainfall in the coastal metropolitan city of Guangzhou, China during 6–7 May 2017, budget analyses of advection and source/sink terms of the water vapor, potential temperature, and vertical momentum equations were conducted using the model output of a nested very large eddy simulation with the W...

Phased-array radar (PAR) technology offers the flexibility of sampling the storm and clear-air regions with different update times. As such, the radial velocity from clear-air regions, typically with lower signal-to-noise ratio, can be measured more accurately. In this work, observing system simulation experiments (OSSEs) are conducted to explore t...

Regions with high ice water content (HIWC), composed of mainly small ice crystals, frequently occur over convective clouds in the tropics. Such regions can have median mass diameters (MMDs) <300 µm and equivalent radar reflectivities <20 dBZ. To explore formation mechanisms for these HIWCs, high-resolution simulations of tropical convective clouds...

High ice water content (HIWC) regions in tropical deep convective clouds, composed of high concentrations of small ice crystals, were not reproduced by Weather Research and Forecasting (WRF) model simulations at 1 km horizontal grid spacing using four different bulk microphysics schemes (i.e., the WRF single‐moment 6‐class microphysics scheme (WSM6...

The Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) field project deployed two aircraft and ground-based assets in the vicinity of Houston, TX, between 27 May 2022 and 2 July 2022, examining how meteorological conditions, dynamics, and aerosols control the initiation, early growth stage, and evolution of coasta...

Using the Weather Research and Forecasting model with two planetary boundary layer schemes, ACM2 and MYNN, convection‐permitting model (CPM) regional climate simulations were conducted for a 6‐year period, including a one‐year spin‐up period, at a 15‐km grid spacing covering entire South America and a nested convection‐permitting 3‐km grid spacing...

To explore the potential impacts of climate change on precipitation and mesoscale convective systems (MCSs) in the Peruvian Central Andes, a region with complex terrain, two future convection‐permitting regional climate simulations and one historical one are conducted using the Weather Research and Forecasting (WRF) model. All simulations adopt con...

Convective clouds play an important role in the Earth’s climate system and are a known source of extreme weather. Gaps in our understanding of convective vertical motions, microphysics, and precipitation across a full range of aerosol and meteorological regimes continue to limit our ability to predict the occurrence and intensity of these cloud sys...

To explore the potential impacts of climate change on precipitation and mesoscale convective systems (MCSs) in the Peruvian Central Andes, a region with complex terrain, two future and one historical convection-permitting regional climate simulations are conducted using the Weather Research and Forecasting (WRF) model. All simulations adopt consist...

The South America Affinity Group (SAAG) was established in early 2019 by the National Center for Atmospheric Research (NCAR) Water Systems Program as a community effort focused on improving hydroclimate science over South America. SAAG supports large research efforts such as the ANDEX Regional Hydroclimate Program (Espinoza et al. 2020) as well as...

Using the Weather Research and Forecasting (WRF) model with two planetary boundary layer schemes, ACM2 and MYNN, convection-permitting model (CPM) regional climate simulations were conducted for a 6-year period at a 15-km grid spacing covering entire South America and a nested convection-permitting 3-km grid spacing covering the Peruvian central An...

Regional climate dynamical downscaling at convection-permitting resolutions is now practical and has potential to significantly improve over coarser-resolution simulations, but the former is not necessarily free of systematic biases. Evaluation and optimization of model configurations are therefore important. Twelve simulations at a grid spacing of...

Using the observations from the two‐dimensional video disdrometer and polarimetric radar, a detailed process‐based evaluation of five bulk microphysics schemes in the simulation of an extreme rainfall event over the mountainous coast of South China is performed. Most schemes reproduce one of the heavy rainfall areas, and the National Severe Storms...

Planetary boundary layer (PBL) schemes parameterize unresolved turbulent mixing within the PBL and free troposphere (FT). Previous studies reported that precipitation simulation over the Amazon in South America is quite sensitive to PBL schemes and the exact relationship between the turbulent mixing and precipitation processes is, however, not dise...

A Lagrangian model—the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT)—is used to quantify changes in moisture sources and paths for precipitation over North China’s Henan Province associated with tropical cyclone (TC) over the western North Pacific (WNP) during July–August of 1979–2021. During TC-active periods, an anomalou...

Predicted particle properties (P3) microphysics scheme was coupled with the weather research and forecasting (WRF)‐Chem model in this study. Cases of convective and stratiform mixed‐phase clouds were used to explore the differences and applicability of the simulation results of different types of clouds when different P3 configurations were coupled...

Planetary boundary layer (PBL) schemes parameterize unresolved turbulent mixing within the PBL and free troposphere (FT). Previous studies reported that precipitation simulation over the Amazon in South America is quite sensitive to PBL schemes and the exact relationship between the turbulent mixing and precipitation processes is, however, not dise...

Ensemble clustering analysis was performed to explore the role of the initial hurricane vortex‐scale wind structure in the prediction of the intensification of Hurricane Patricia (2015). Convection‐allowing ensemble forecasts were classified into spin‐down (SPD) and spin‐up (SPU) groups. Specifically, 10 members with an intensification rate >0 m/s...

Precipitation estimate is important for earth science studies and applications, and it is one of the most difficult meteorological quantities to estimate accurately. For regions such as Peru, reliable gridded precipitation products are lacking due to complex terrains and large portions of remote lands that limit the accuracy of satellite precipitat...

Secondary ice production (SIP) is an important physical phenomenon that results in an increase in the ice particle concentration and can therefore have a significant impact on the evolution of clouds. In this study, idealized simulations of a mesoscale convective system (MCS) were conducted using a high-resolution (250 m horizontal grid spacing) me...

We adapted the WRF‐Hydro modeling system to Hurricane Florence (2018) and performed a series of diagnostic experiments to assess the influence of initial soil moisture and precipitation magnitude on flood simulation over the Cape Fear River basin in the United States. Model results suggest that: 1) The modulation effect of initial soil moisture on...

A new method that automatically determines the modality of an observed particle size distribution ( PSD ) and the representation of each mode as a gamma function was used to characterize data obtained during the High Altitude Ice Crystals and High Ice Water Content (HAIC-HIWC) project based out of Cayenne, French Guiana in 2015. PSDs measured by a...

Secondary ice production (SIP) is an important physical phenomenon that results in an increase of ice particle concentration and can therefore have a significant impact on the evolution of clouds. In this study, idealized simulations of a mesoscale convective systems (MCS) was conducted using a high-resolution (250-m horizontal grid spacing) mesosc...

Phased-array radar (PAR) technology can potentially provide high quality clear-air radial velocity observations at a high spatiotemporal resolution, usually ∼1 min or less. These observations are hypothesized to partially fill the gaps in current operational observing systems with relatively coarse-resolution surface mesonet observations and the la...

Peru is considered as one of the most affected areas by Climate Change, as the increase in temperature and retreat of tropical glaciers over the Andean Mountain, its limited water resources is being challenged by the company of population growth, intensive mining, and water contamination. In this study, we used regional hyper resolution WRF coupled...

Resolutions of global climate models are too coarse to resolve local forcing and local weather, and some aspects of precipitation simulation are poor. Previous studies have indicated the added value of regional climate model (RCM) dynamic downscaling, especially at convection-permitting resolutions. In South America, the Andes have dynamic and ther...

An extreme rainfall event with maximum 12 hr accumulated rainfall of 464.8 mm associated with a quasi‐stationary mesoscale convective system occurred over the western coastal region of South China in June 2017. An observational analysis shows that early convective storms were initiated near the mountains and moved northeastwards. Moreover, a conver...

Hurricanes are the major flood generating mechanism dominating the upper tail of the peak discharge distribution over the Cape Fear River Basin (CFRB). In 2018, Hurricane Florence swamped CFRB as the ninth-most-destructive hurricane ever hit the United States and set new records of peak discharges over the main river channel and three out of five o...

High ice water content (HIWC) regions in tropical deep convective clouds, composed of high concentrations of small ice crystals, were not reproduced by Weather Research and Forecasting (WRF) model simulations at 1-km horizontal grid spacing using four different bulk microphysics schemes (i.e., the WRF single‐moment 6‐class microphysics scheme (WSM6...

High Ice Water Content (HIWC) regions above tropical mesoscale convective systems are investigated using data from the second collaboration of the High Altitude Ice Crystals and High Ice Water Content projects (HAIC-HIWC) based in Cayenne, French Guiana in 2015. Observations from in-situ cloud probes on the French Falcon 20 determine the microphysi...

In this study we adapted WRF-Hydro to the Cape Fear River basin (CFRB) to assess its performance during Hurricane Florence (2018). The model was first calibrated with a strategy of mixture of automatic and manual calibration during Florence and then evaluated with an independent hurricane event. With satisfactory NSE values (>0.4) achieved at all g...

Regions with high ice water content (HIWC), composed of mainly small ice crystals, frequently occur over convective clouds in the tropics. Such regions can have median mass diameters (MMDs)

Differences in rainfall budgets between convective and stratiform regions of a torrential rainfall event were investigated using high-resolution simulation data produced by the Weather Research and Forecasting (WRF) model. The convective and stratiform regions were reasonably separated by the radar-based convective--stratiform partitioning method,...

Idealized simulations are conducted using the Cloud Model Version 1 (CM1) to explore the mechanism of tropical cyclone (TC) genesis from a pre-existing midtropospheric vortex that forms in radiative-convective equilibrium. With lower-tropospheric air approaching near-saturation during TC genesis, convective cells become stronger, along with the int...

The rainfall processes during the formation of tropical cyclone (TC) Durian (2001) were investigated quantitatively using the three-dimensional (3D) WRF-based precipitation equation. The rain rate (PS) decreased slightly as the TC approached to formation, and then increased as Durian began to intensify. The rate of moisture-related processes (QWV)...

The impact of mid- and upper-level dry air, represented by low relative humidity (RH) values, on the genesis of tropical cyclone (TC) Durian (2001) in the South China Sea was investigated by a series of numerical experiments using the Weather Research and Forecasting model. The mid-level RH was lowered in different regions relative to TC Durian (20...

The formation of Typhoon Durian (2001) was simulated well by the Weather Research and Forecasting model. The vorticity field was separated into three scales: small scale (L < 30 km), intermediate scale (30 km < L < 120 km), and system scale (L > 120 km), where L is wavelength. During the formation, small-scale vorticity anomalies, associated with c...

A set of kinetic energy (KE) budget equations associated with four horizontal flow components was derived to study the KE characteristics during the genesis of Tropical Cyclone (TC) Durian (2001) in the South China Sea using numerical simulation data. The genesis process was divided into three stages: the monsoon trough stage (stage 1), the midleve...

High-resolution data of a torrential rainfall event in Sichuan, China, simulated by the WRF model, were used to analyze the cloud microphysical differences with precipitation intensity. Six-hourly accumulated rainfall was classified into five bins based on rainfall intensity, and the cloud microphysical characteristics and processes in different bi...

The interparcel mixing algorithm in the Lagrangian advection scheme with shape matrix (LASM) is updated to make the scheme more robust. The linear degeneration criterion is replaced by the maximum deviation of the skeleton points so that the new algorithm is more effective in controlling the shape of parcels, which is vital for long time simulation...

Water vapor sources and transport paths associated with torrential rains are very important to relative researches and forecasts. This study investigates main moisture sources and transport paths related to torrential rainfall events in the Sichuan Basin of China which is located east of the Tibetan Plateau，using a Lagrangian particle dispersion mo...

In July 2013, an extreme precipitation event occurred in Sichuan, China, causing severe flooding, debris flows, and substantial losses. Moisture sources and transport of this event and quantification of the contribution from moisture sources were studied using the Lagrangian method. The results show that the vast majority of particles influencing t...

High-resolution numerical simulation data of a rainstorm triggering debris flow in Sichuan Province of China simulated by the Weather Research and Forecasting (WRF) Model were used to study the dominant cloud microphysical processes of the torrential rainfall. The results showed that: (1) In the strong precipitation period, particle sizes of all hy...