Evaluation of WRF model simulations of tropical cyclones in the western North Pacific over the CORDEX East Asia domain

AbstractIn this study, the characteristics of simulated tropical cyclones (TCs) over the western North Pacific by a regional model (the WRF model) are verified. We utilize 12 km horizontal grid spacing, and simulations are integrated for 5 days from model initialization. One hundred and twenty-five forecasts are divided into five clusters through the k-means clustering method. The TCs in the cluster 1 and 2 (group 1), which includes many TCs moves northward in subtropical region, generally have larger track errors than for TCs in cluster 3 and 4 (group 2). The optimal steering vector is used to examine the difference in the track forecast skill between these two groups. The bias in the steering vector between the model and analysis data is found to be more substantial for group 1 TCs than group 2 TCs. The larger steering vector difference for group 1 TCs indicates that environmental fields tend to be poorly simulated in group 1 TC cases. Furthermore, the residual terms, including the storm-scale process, asymmetric convection distribution, or beta-related effect, are also larger for group 1 TCs than group 2 TCs. Therefore, it is probable that the large track forecast error for group 1 TCs is a result of unreasonable simulations of environmental wind fields and residual processes in the midlatitudes.

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Future Change in Tropical Cyclone Activity over the Western North Pacific in CORDEX-East Asia Multi-RCMs Forced by HadGEM2-AO

Journal of Climate ◽

10.1175/jcli-d-18-0575.1 ◽

2019 ◽

Vol 32 (16) ◽

pp. 5053-5067 ◽

Cited By ~ 4

Author(s):

Hyeonjae Lee ◽

Chun-Sil Jin ◽

Dong-Hyun Cha ◽

Minkyu Lee ◽

Dong-Kyou Lee ◽

...

Keyword(s):

Tropical Cyclone ◽

East Asia ◽

North Pacific ◽

Western North Pacific ◽

Climate Models ◽

Regional Climate ◽

Vertical Wind Shear ◽

Coastal Regions ◽

The Future ◽

Cordex East Asia

AbstractFuture changes in tropical cyclone (TC) activity over the western North Pacific (WNP) are analyzed using four regional climate models (RCMs) within the Coordinated Regional Climate Downscaling Experiment (CORDEX) for East Asia. All RCMs are forced by the HadGEM2-AO under the historical and representative concentration pathway (RCP) 8.5 scenarios, and are performed at about 50-km resolution over the CORDEX-East Asia domain. In the historical simulations (1980–2005), multi-RCM ensembles yield realistic climatology for TC tracks and genesis frequency during the TC season (June–November), although they show somewhat systematic biases in simulating TC activity. The future (2024–49) projections indicate an insignificant increase in the total number of TC genesis (+5%), but a significant increase in track density over East Asia coastal regions (+17%). The enhanced TC activity over the East Asia coastal regions is mainly related to vertical wind shear weakened by reduced meridional temperature gradient and increased sea surface temperature (SST) at midlatitudes. The future accumulated cyclone energy (ACE) of total TCs increases significantly (+19%) because individual TCs have a longer lifetime (+6.6%) and stronger maximum wind speed (+4.1%) compared to those in the historical run. In particular, the ACE of TCs passing through 25°N increases by 45.9% in the future climate, indicating that the destructiveness of TCs can be significantly enhanced in the midlatitudes despite the total number of TCs not changing greatly.

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Evaluation of climatological tropical cyclone activity over the western North Pacific in the CORDEX-East Asia multi-RCM simulations

Climate Dynamics ◽

10.1007/s00382-015-2869-6 ◽

2015 ◽

Vol 47 (3-4) ◽

pp. 765-778 ◽

Cited By ~ 25

Author(s):

Chun-Sil Jin ◽

Dong-Hyun Cha ◽

Dong-Kyou Lee ◽

Myoung-Seok Suh ◽

Song-You Hong ◽

...

Keyword(s):

Tropical Cyclone ◽

East Asia ◽

North Pacific ◽

Western North Pacific ◽

Tropical Cyclone Activity ◽

Cyclone Activity ◽

Cordex East Asia

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Comparison of Tropical Cyclone Activities over the Western North Pacific in CORDEX-East Asia Phase I and II Experiments

Journal of Climate ◽

10.1175/jcli-d-19-1014.1 ◽

2020 ◽

Vol 33 (24) ◽

pp. 10593-10607

Author(s):

Minkyu Lee ◽

Dong-Hyun Cha ◽

Myoung-Seok Suh ◽

Eun-Chul Chang ◽

Joong-Bae Ahn ◽

...

Keyword(s):

Tropical Cyclone ◽

East Asia ◽

North Pacific ◽

Western North Pacific ◽

Regional Climate ◽

Horizontal Resolution ◽

Added Value ◽

Convective Precipitation ◽

Coastal Regions ◽

Cordex East Asia

AbstractThis study evaluated tropical cyclone (TC) activity simulated by two regional climate models (RCMs) incorporated in the Coordinated Regional Climate Downscaling Experiment (CORDEX) framework with two different horizontal resolutions. Evaluation experiments with two RCMs (RegCM4 and MM5) forced by reanalysis data were conducted over the CORDEX-East Asia domain for phases I and II. The main difference between phases I and II is horizontal resolution (50 and 25 km). The 20-yr (1989–2008) mean performances of the experiments were investigated in terms of TC genesis, track, intensity, and TC-induced precipitation. In general, the simulated TC activities over the western North Pacific (WNP) varied depending on the model type and horizontal resolution. For both models, higher horizontal resolution improved the simulation of TC tracks near the coastal regions of East Asia, whereas the coarser horizontal resolution led to underestimated TC genesis compared with the best track data because of greater convective precipitation and enhanced atmospheric stabilization. In addition, the increased horizontal resolution prominently improved the simulation of TCs landfalling in East Asia and associated precipitation around coastal regions. This finding implies that high-resolution RCMs can improve the simulation of TC activities over the WNP (i.e., added value by increasing model resolution); thus, they have an advantage in climate change assessment studies.

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Riverine Flooding and Landfalling Tropical Cyclones over China

10.5194/egusphere-egu2020-3251 ◽

2020 ◽

Author(s):

Long Yang ◽

Maofeng Liu ◽

Lachun Wang ◽

Xiaomin Ji ◽

Xiang Li ◽

...

Keyword(s):

Tropical Cyclones ◽

North Pacific ◽

Flood Risk ◽

Western North Pacific ◽

Flood Control ◽

East Asian ◽

Wrf Model ◽

Asian Countries ◽

Spatial And Temporal Patterns ◽

Landfalling Tropical Cyclones

Riverine flooding associated with landfalling tropical cyclones (TCs) in the Western North Pacific basin is responsible for some of the most severe socioeconomic losses in East Asian countries. However, little is known about the spatial and temporal patterns of TC flooding and its synoptic controls, which constrain predictive understandings of flood risk in this highly populated region. In this study, we investigate hydrology, hydrometeorology, and hydroclimatology of riverine flooding over China induced by landfalling tropical cyclones, based on empirical analysis of dense networks of stream gauging and rainfall stations as well as downscaling simulations using the Weather Research and Forecasting (WRF) model driven by 20th Century Reanalysis fields. The most extreme floods in central and northeastern China are associated with TCs despite infrequent TC visits in these regions. Inter-annual variations in TC flooding demonstrate a mixture of climate controls tied to surface temperature anomalies in central tropical Pacific, western North Pacific and north Atlantic. We implement numerical modelling analysis of typhoon Nina (1975), typhoon Andy (1982) and typhoon Herb (1996) to further shed light on key hydro-meteorological features of landfalling TCs that are responsible for severe flooding over China. We highlight the important role of interactions of storm circulations with mid-latitude synoptic systems (e.g., upper-level trough) and complex terrains in producing extreme rain rates and flooding. Analytical framework developed in this study aims to explore utilization of hydro-meteorological approach in flood-control engineering designs by providing details on the key elements of flood-producing storms. We also highlight potential challenges of developing predictive tools of TC flood risk in east Asian countries.

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Impact of horizontal resolution on the tropical cyclone activity over the western North Pacific in CORDEX-East Asia phase I and II experiments

10.5194/egusphere-egu2020-4481 ◽

2020 ◽

Author(s):

Dong-Hyun Cha ◽

Minkyu Lee ◽

Myoung-Seok Suh ◽

Eun-Chul Chang ◽

Joong-Bae Ahn ◽

...

Keyword(s):

Tropical Cyclone ◽

East Asia ◽

North Pacific ◽

Western North Pacific ◽

Regional Climate ◽

Horizontal Resolution ◽

Added Value ◽

Convective Precipitation ◽

Coastal Regions ◽

Cordex East Asia

&#160;This study evaluated tropical cyclone (TC) activity simulated by two regional climate models (RCMs) incorporated in the Coordinated Regional Climate Downscaling Experiment (CORDEX) framework with two different horizontal resolutions. Evaluation experiments with two RCMs (RegCM4 and MM5) forced by reanalysis data were conducted over the CORDEX-East Asia domain with 25 km and 50 km horizontal resolutions. The 20-year (1989&#8211;2008) mean performances of the experiments were investigated in terms of TC genesis, track, intensity, and TC-induced precipitation. In general, the simulated TC activities over the western North Pacific (WNP) varied depending on the model type and horizontal resolution. The MM5 tended to simulate more reasonable TC activity compared with the RegCM4. For both models, higher horizontal resolution improved the simulation of TC tracks near the coastal regions of East Asia, whereas the coarse horizontal resolution led to underestimated TC genesis compared with the best track data because of greater convective precipitation and enhanced atmospheric stabilization. In addition, the increased horizontal resolution prominently improved the simulation of TCs landfalling in East Asia and associated precipitation around coastal regions. This finding implies that high-resolution RCMs can produce added value in improving the simulation of TCs over the WNP; thus, they have an advantage in climate change assessment studies.

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Statistical–Dynamical Seasonal Forecast of Western North Pacific and East Asia Landfalling Tropical Cyclones using the GFDL FLOR Coupled Climate Model

Journal of Climate ◽

10.1175/jcli-d-16-0487.1 ◽

2017 ◽

Vol 30 (6) ◽

pp. 2209-2232 ◽

Cited By ~ 27

Author(s):

Wei Zhang ◽

Gabriel A. Vecchi ◽

Gabriele Villarini ◽

Hiroyuki Murakami ◽

Richard Gudgel ◽

...

Keyword(s):

East Asia ◽

Correlation Coefficient ◽

Tropical Cyclones ◽

Hybrid Model ◽

North Pacific ◽

Western North Pacific ◽

Hybrid Models ◽

Predictive Skill ◽

Meridional Mode ◽

Landfalling Tropical Cyclones

Abstract This study attempts to improve the prediction of western North Pacific (WNP) and East Asia (EA) landfalling tropical cyclones (TCs) using modes of large-scale climate variability [e.g., the Pacific meridional mode (PMM), the Atlantic meridional mode (AMM), and North Atlantic sea surface temperature anomalies (NASST)] as predictors in a hybrid statistical–dynamical scheme, based on dynamical model forecasts with the GFDL Forecast-Oriented Low Ocean Resolution version of CM2.5 with flux adjustments (FLOR-FA). Overall, the predictive skill of the hybrid model for the WNP TC frequency increases from lead month 5 (initialized in January) to lead month 0 (initialized in June) in terms of correlation coefficient and root-mean-square error (RMSE). The hybrid model outperforms FLOR-FA in predicting WNP TC frequency for all lead months. The predictive skill of the hybrid model improves as the forecast lead time decreases, with values of the correlation coefficient increasing from 0.56 for forecasts initialized in January to 0.69 in June. The hybrid models for landfalling TCs over the entire East Asian (EEA) coast and its three subregions [i.e., southern EA (SEA), middle EA (MEA), and northern EA (NEA)] dramatically outperform FLOR-FA. The correlation coefficient between predicted and observed TC landfall over SEA increases from 0.52 for forecasts initialized in January to 0.64 in June. The hybrid models substantially reduce the RMSE of landfalling TCs over SEA and EEA compared with FLOR-FA. This study suggests that the PMM and NASST/AMM can be used to improve statistical/hybrid forecast models for the frequencies of WNP or East Asia landfalling TCs.

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