: Weather radar echo extrapolation plays a crucial role in weather forecasting. However, traditional weather radar echo extrapolation methods are not very accurate and do not make full use of historical data. Deep learning algorithms based on Recurrent Neural Networks also have the problem of accumulating errors. Moreover, it is difficult to obtain higher accuracy by relying on a single historical radar echo observation. Therefore, in this study, we constructed the Fusion GRU module, which leverages a cascade structure to effectively combine radar echo data and mean wind data. We also designed the Top Connection so that the model can capture the global spatial relationship to construct constraints on the predictions. Based on the Jiangsu Province dataset, we compared some models. The results show that our proposed model, Cascade Fusion Spatiotemporal Network (CFSN), improved the critical success index (CSI) by 10.7% over the baseline at the threshold of 30 dBZ. Ablation experiments further validated the effectiveness of our model. Similarly, the CSI of the complete CFSN was 0.004 higher than the suboptimal solution without the cross-attention module at the threshold of 30 dBZ.
{"title":"Improved Weather Radar Echo Extrapolation Through Wind Speed Data Fusion Using a New Spatiotemporal Neural Network Model","authors":"Huan-tong Geng, Bo-yang Xie, Xiao-yan Ge, Jin-zhong Min, Xiao-ran Zhuang","doi":"10.3724/j.1006-8775.2023.036","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.036","url":null,"abstract":": Weather radar echo extrapolation plays a crucial role in weather forecasting. However, traditional weather radar echo extrapolation methods are not very accurate and do not make full use of historical data. Deep learning algorithms based on Recurrent Neural Networks also have the problem of accumulating errors. Moreover, it is difficult to obtain higher accuracy by relying on a single historical radar echo observation. Therefore, in this study, we constructed the Fusion GRU module, which leverages a cascade structure to effectively combine radar echo data and mean wind data. We also designed the Top Connection so that the model can capture the global spatial relationship to construct constraints on the predictions. Based on the Jiangsu Province dataset, we compared some models. The results show that our proposed model, Cascade Fusion Spatiotemporal Network (CFSN), improved the critical success index (CSI) by 10.7% over the baseline at the threshold of 30 dBZ. Ablation experiments further validated the effectiveness of our model. Similarly, the CSI of the complete CFSN was 0.004 higher than the suboptimal solution without the cross-attention module at the threshold of 30 dBZ.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138988791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: This study assesses the predictive capabilities of the CMA-GD model for wind speed prediction in two wind farms located in Hubei Province, China. The observed wind speeds at the height of 70m in wind turbines of two wind farms in Suizhou serve as the actual observation data for comparison and testing. At the same time, the wind speed predicted by the EC model is also included for comparative analysis. The results indicate that the CMA-GD model performs better than the EC model in Wind Farm A. The CMA-GD model exhibits a monthly average correlation coefficient of 0.56, root mean square error of 2.72 m s –1 , and average absolute error of 2.11 m s –1 . In contrast, the EC model shows a monthly average correlation coefficient of 0.51, root mean square error of 2.83 m s –1 , and average absolute error of 2.21 m s –1 . Conversely, in Wind Farm B, the EC model outperforms the CMA-GD model. The CMA-GD model achieves a monthly average correlation coefficient of 0.55, root mean square error of 2.61 m s –1 , and average absolute error of 2.13 m s –1 . By contrast, the EC model displays a monthly average correlation coefficient of 0.63, root mean square error of 2.04 m s –1 , and average absolute error of 1.67 m s –1 .
:本研究评估了 CMA-GD 模型在中国湖北省两个风电场的风速预测能力。随州两个风电场的风机在 70 米高空的风速观测数据作为实际观测数据进行比较和测试。同时，EC 模型预测的风速也被纳入对比分析。结果表明，在 A 风场，CMA-GD 模型的性能优于 EC 模型。CMA-GD 模型的月平均相关系数为 0.56，均方根误差为 2.72 m s -1 ，平均绝对误差为 2.11 m s -1 。相比之下，EC 模式的月平均相关系数为 0.51，均方根误差为 2.83 m s -1 ，平均绝对误差为 2.21 m s -1 。相反，在风电场 B 中，EC 模型优于 CMA-GD 模型。CMA-GD 模型的月平均相关系数为 0.55，均方根误差为 2.61 m s -1 ，平均绝对误差为 2.13 m s -1 。相比之下，EC 模式的月平均相关系数为 0.63，均方根误差为 2.04 m s -1 ，平均绝对误差为 1.67 m s -1 。
{"title":"Performance of the CMA-GD Model in Predicting Wind Speed at Wind Farms in Hubei, China","authors":"Pei-hua Xu, Chi Cheng, Wen Wang, Zheng-hong Chen, Shui-xin Zhong, Yan-xia Zhang","doi":"10.3724/j.1006-8775.2023.035","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.035","url":null,"abstract":": This study assesses the predictive capabilities of the CMA-GD model for wind speed prediction in two wind farms located in Hubei Province, China. The observed wind speeds at the height of 70m in wind turbines of two wind farms in Suizhou serve as the actual observation data for comparison and testing. At the same time, the wind speed predicted by the EC model is also included for comparative analysis. The results indicate that the CMA-GD model performs better than the EC model in Wind Farm A. The CMA-GD model exhibits a monthly average correlation coefficient of 0.56, root mean square error of 2.72 m s –1 , and average absolute error of 2.11 m s –1 . In contrast, the EC model shows a monthly average correlation coefficient of 0.51, root mean square error of 2.83 m s –1 , and average absolute error of 2.21 m s –1 . Conversely, in Wind Farm B, the EC model outperforms the CMA-GD model. The CMA-GD model achieves a monthly average correlation coefficient of 0.55, root mean square error of 2.61 m s –1 , and average absolute error of 2.13 m s –1 . By contrast, the EC model displays a monthly average correlation coefficient of 0.63, root mean square error of 2.04 m s –1 , and average absolute error of 1.67 m s –1 .","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139020851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.030
Wei-lun Zhao, Chun-sheng Zhao
: Black carbon (BC) is the strongest visible-light-absorbing aerosol component in the atmosphere, with a significant impact on Earth’s radiative budget. Accurate measurement of BC light absorption is crucial for estimating its radiative effect. The micro-aethalometer model 200 (MA200) by AethLabs, USA, offers high-time-resolution measurement of the multi-wavelength absorption coefficient ( σ ab ) within 1 s, making it widely used in aerial measurement due to its compact size and light weight. However, the reliability of the measured σ ab has not been extensively studied in previous research. In this study, we evaluate the performance of MA200 by comparing σ ab measurements obtained from MA200 with those from the aethalometer model 33 (AE33) by Magee, USA. Our results revealed a significant variation in the determinant coefficient ( R 2 ) between σ ab measurements from MA200 and AE33, depending on the time resolution. The R 2 increases from 0.1 to 0.5 and further to 0.97 as the time resolution of σ ab increases from 1 s to 30 s and 60 s, respectively. We recommend a minimum time resolution of 30 s for stable σ ab measurements using MA200. Moreover, we determine σ ab from attenuation coefficient ( σ ATN ) measured by MA200 as σ ab = ( σ ATN – σ 0 )/ C MA , where σ 0 ranges from – 15.3 Mm –1 to – 6.4 Mm –1 and C MA ranges from 2.65 to 3.21. Correcting the measured σ ab based on the findings of this study can provide reliable results for estimating the radiative effects of BC.
:黑碳（BC）是大气中吸收可见光最强的气溶胶成分，对地球的辐射预算有重大影响。准确测量黑碳的光吸收对估计其辐射效应至关重要。美国 AethLabs 公司的微型大气吸收仪 200 型（MA200）可在 1 秒内对多波长吸收系数（σ ab）进行高时间分辨率测量，因其体积小、重量轻而广泛应用于航空测量。然而，以往的研究并未对测量到的σ ab 的可靠性进行广泛研究。在本研究中，我们通过比较 MA200 与美国 Magee 公司的 33 型（AE33）气压计的 σ ab 测量值来评估 MA200 的性能。结果表明，根据时间分辨率的不同，MA200 和 AE33 σ ab 测量值之间的行列式系数 ( R 2 ) 有很大差异。当 σ ab 的时间分辨率分别从 1 秒增加到 30 秒和 60 秒时，R 2 分别从 0.1 增加到 0.5，并进一步增加到 0.97。我们建议使用 MA200 进行稳定的 σ ab 测量时，最小时间分辨率为 30 秒。此外，我们根据 MA200 测得的衰减系数 ( σ ATN ) 确定 σ ab，即 σ ab = ( σ ATN - σ 0 )/ C MA，其中 σ 0 的范围为 - 15.3 Mm -1 至 - 6.4 Mm -1，C MA 的范围为 2.65 至 3.21。根据这项研究的结果对测量的 σ ab 进行校正，可以为估计 BC 的辐射效应提供可靠的结果。
{"title":"Correcting Black Carbon Absorption Measurements with Micro-aethalometer Model 200: Insights from Comparative Analysis","authors":"Wei-lun Zhao, Chun-sheng Zhao","doi":"10.3724/j.1006-8775.2023.030","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.030","url":null,"abstract":": Black carbon (BC) is the strongest visible-light-absorbing aerosol component in the atmosphere, with a significant impact on Earth’s radiative budget. Accurate measurement of BC light absorption is crucial for estimating its radiative effect. The micro-aethalometer model 200 (MA200) by AethLabs, USA, offers high-time-resolution measurement of the multi-wavelength absorption coefficient ( σ ab ) within 1 s, making it widely used in aerial measurement due to its compact size and light weight. However, the reliability of the measured σ ab has not been extensively studied in previous research. In this study, we evaluate the performance of MA200 by comparing σ ab measurements obtained from MA200 with those from the aethalometer model 33 (AE33) by Magee, USA. Our results revealed a significant variation in the determinant coefficient ( R 2 ) between σ ab measurements from MA200 and AE33, depending on the time resolution. The R 2 increases from 0.1 to 0.5 and further to 0.97 as the time resolution of σ ab increases from 1 s to 30 s and 60 s, respectively. We recommend a minimum time resolution of 30 s for stable σ ab measurements using MA200. Moreover, we determine σ ab from attenuation coefficient ( σ ATN ) measured by MA200 as σ ab = ( σ ATN – σ 0 )/ C MA , where σ 0 ranges from – 15.3 Mm –1 to – 6.4 Mm –1 and C MA ranges from 2.65 to 3.21. Correcting the measured σ ab based on the findings of this study can provide reliable results for estimating the radiative effects of BC.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.032
Xin Xue, Yan-xing Wu, Zhen Chen, Run Liu, Zhi-jun Zhao
: The frequent occurrence of dry and hot (DH) days in South China in summer has a negative impact on social development and human health. This study explored the variation characteristics of DH days and the possible reasons for this knotty problem. The findings revealed a notable increase in the number of DH days across most stations, indicating a significant upward trend. Additionally, DH events were observed to occur frequently. The number of DH days increased during 1970–1990, decreased from 1991 to 1997, and stayed stable after 1997. The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming (IOBW) in spring and the East Asian Summer Monsoon (EASM). Compared with the negative phase of IOBW, in the positive phase of IOBW, 500 hPa and 850 hPa geopotential height enhanced, the West Pacific subtropical high strengthened and extended abnormally to the west, more solar radiation reached the surface, surface outgoing longwave radiation increased, and there was an anomalous anticyclone in eastern South China. The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW, and the abnormal circulation of the positive (negative) phases of ESAM was unfavorable (favorable) for the increase in the number of DH days. A long-term prediction model for the number of summer DH days was established using multiple linear regression, incorporating the key climate factors. The correlation coefficient between the observed and predicted number of DH days was 0.65, and the root-mean-square error was 2.8. In addition, independent forecasts for 2019 showed a deviation of just 1 day. The results of the independent recovery test confirmed the stability of the model, providing evidence that climatic factors did have an impact on DH days in South China.
{"title":"Interannual Variation and Statistical Prediction of Summer Dry and Hot Days in South China from 1970 to 2018","authors":"Xin Xue, Yan-xing Wu, Zhen Chen, Run Liu, Zhi-jun Zhao","doi":"10.3724/j.1006-8775.2023.032","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.032","url":null,"abstract":": The frequent occurrence of dry and hot (DH) days in South China in summer has a negative impact on social development and human health. This study explored the variation characteristics of DH days and the possible reasons for this knotty problem. The findings revealed a notable increase in the number of DH days across most stations, indicating a significant upward trend. Additionally, DH events were observed to occur frequently. The number of DH days increased during 1970–1990, decreased from 1991 to 1997, and stayed stable after 1997. The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming (IOBW) in spring and the East Asian Summer Monsoon (EASM). Compared with the negative phase of IOBW, in the positive phase of IOBW, 500 hPa and 850 hPa geopotential height enhanced, the West Pacific subtropical high strengthened and extended abnormally to the west, more solar radiation reached the surface, surface outgoing longwave radiation increased, and there was an anomalous anticyclone in eastern South China. The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW, and the abnormal circulation of the positive (negative) phases of ESAM was unfavorable (favorable) for the increase in the number of DH days. A long-term prediction model for the number of summer DH days was established using multiple linear regression, incorporating the key climate factors. The correlation coefficient between the observed and predicted number of DH days was 0.65, and the root-mean-square error was 2.8. In addition, independent forecasts for 2019 showed a deviation of just 1 day. The results of the independent recovery test confirmed the stability of the model, providing evidence that climatic factors did have an impact on DH days in South China.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138989807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.031
Jian-jun Xue, Zi-niu Xiao
: Considering the complex topographic forcing and large cryosphere concentration, the present study utilized the polar-optimized WRF model (Polar WRF) to conduct downscaling simulations over the Qinghai-Tibet Plateau (TP) and its surrounding regions. Multi-group experiments with the 10 km horizontal resolution are used to evaluate the modeling of precipitation. Firstly, on the basis of the model ground surface properties upgrade and the optimized Noah-MP, the “better-performing” configuration suite for modeling precipitation is comprehensively examined. Various model parameters such as nudging options, five cumulus parameterization schemes, two planetary boundary layer schemes, and six microphysics schemes are investigated to further refine the Polar WRF configuration. Moreover, the precipitation simulation for a full calendar year is compared with multiple reanalyses and observations. The simulations demonstrate that the Polar WRF model successfully captures the general features of precipitation over this region and is sensitive to model parameters. Based on the results, it is recommended to use grid nudging with q intensity coefficient of 0.0002, the multi-scale kain-fritsch cumulus parameterization, the Yonsei University boundary layer scheme, and the Morrison 2-mom microphysics with reduced default droplet concentration value of 100 cm –3 . Overall, the model performance is better than the ERA-interim and TRMM 3b42. It is comparable to, and in some cases slightly better than, the CRA-Land, especially in the prediction for the western part of the plateau where in situ observations are limited, and the cryosphere-atmosphere interaction is more pronounced.
{"title":"Evaluation of Performance of Polar WRF Model in Simulating Precipitation over Qinghai-Tibet Plateau","authors":"Jian-jun Xue, Zi-niu Xiao","doi":"10.3724/j.1006-8775.2023.031","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.031","url":null,"abstract":": Considering the complex topographic forcing and large cryosphere concentration, the present study utilized the polar-optimized WRF model (Polar WRF) to conduct downscaling simulations over the Qinghai-Tibet Plateau (TP) and its surrounding regions. Multi-group experiments with the 10 km horizontal resolution are used to evaluate the modeling of precipitation. Firstly, on the basis of the model ground surface properties upgrade and the optimized Noah-MP, the “better-performing” configuration suite for modeling precipitation is comprehensively examined. Various model parameters such as nudging options, five cumulus parameterization schemes, two planetary boundary layer schemes, and six microphysics schemes are investigated to further refine the Polar WRF configuration. Moreover, the precipitation simulation for a full calendar year is compared with multiple reanalyses and observations. The simulations demonstrate that the Polar WRF model successfully captures the general features of precipitation over this region and is sensitive to model parameters. Based on the results, it is recommended to use grid nudging with q intensity coefficient of 0.0002, the multi-scale kain-fritsch cumulus parameterization, the Yonsei University boundary layer scheme, and the Morrison 2-mom microphysics with reduced default droplet concentration value of 100 cm –3 . Overall, the model performance is better than the ERA-interim and TRMM 3b42. It is comparable to, and in some cases slightly better than, the CRA-Land, especially in the prediction for the western part of the plateau where in situ observations are limited, and the cryosphere-atmosphere interaction is more pronounced.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139016060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.034
Xiao Feng, Yu Wu, Wei Yang, Xun Li
: This study assesses the performance of three high-resolution regional numerical models in predicting hourly rainfall over Hainan Island from April to October for the years from 2020 to 2022. The rainfall amount, frequency, intensity, duration, and diurnal cycle are examined through zoning evaluation. The results show that the China Meteorological Administration Guangdong Rapid Update Assimilation Numerical Forecast System (CMA-GD) tends to forecast a higher occurrence of light precipitation. It underestimates the late afternoon precipitation and the occurrence of short-duration events. The China Meteorological Administration Shanghai Numerical Forecast Model System (CMA-SH9) reproduces excessive precipitation at a higher frequency and intensity throughout the island. It overestimates rainfall during the late afternoon and midnight periods. The simulated most frequent peak times of rainfall in CMA-SH9 are 0–1 hour deviations from the observed data. The China Meteorological Administration Mesoscale Weather Numerical Forecasting System (CMA-MESO) displays a similar pattern to rainfall observations but fails to replicate reasonable structure and diurnal variation of frequency-intensity. It underestimates the occurrence of long-duration events and overestimates related rainfall amounts from midnight to early morning. Notably, significant discrepancies are observed in the predictions of the three models for areas with complex terrain, such as the central, southeastern, and southwestern regions of Hainan Island.
{"title":"Zoning Evaluation of Hourly Precipitation in High-resolution Regional Numerical Models over Hainan Island","authors":"Xiao Feng, Yu Wu, Wei Yang, Xun Li","doi":"10.3724/j.1006-8775.2023.034","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.034","url":null,"abstract":": This study assesses the performance of three high-resolution regional numerical models in predicting hourly rainfall over Hainan Island from April to October for the years from 2020 to 2022. The rainfall amount, frequency, intensity, duration, and diurnal cycle are examined through zoning evaluation. The results show that the China Meteorological Administration Guangdong Rapid Update Assimilation Numerical Forecast System (CMA-GD) tends to forecast a higher occurrence of light precipitation. It underestimates the late afternoon precipitation and the occurrence of short-duration events. The China Meteorological Administration Shanghai Numerical Forecast Model System (CMA-SH9) reproduces excessive precipitation at a higher frequency and intensity throughout the island. It overestimates rainfall during the late afternoon and midnight periods. The simulated most frequent peak times of rainfall in CMA-SH9 are 0–1 hour deviations from the observed data. The China Meteorological Administration Mesoscale Weather Numerical Forecasting System (CMA-MESO) displays a similar pattern to rainfall observations but fails to replicate reasonable structure and diurnal variation of frequency-intensity. It underestimates the occurrence of long-duration events and overestimates related rainfall amounts from midnight to early morning. Notably, significant discrepancies are observed in the predictions of the three models for areas with complex terrain, such as the central, southeastern, and southwestern regions of Hainan Island.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139025299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.029
Ling Huang, Chun-xia Liu, Qian Liu
: Wind gusts are common environmental hazards that can damage buildings, bridges, aircraft, and cruise ships and interrupt electric power distribution, air traffic, waterway transport and port operations. Accurately predicting peak wind gusts in numerical models is essential for saving lives and preventing economic losses. This study investigates the climatology of peak wind gusts and their associated gust factors (GFs) using observations in the coastal and open ocean of the northern South China Sea (NSCS), where severe gust-producing weather occurs throughout the year. The stratified climatology demonstrates that the peak wind gust and GF vary with seasons and particularly with weather types. Based on the inversely proportional relationship between the GF and mean wind speed (MWS), a variety of GF models are constructed through least squares regression analysis. Peak gust speed (PGS) forecasts are obtained through the GF models by multiplying the GFs by observed wind speeds rather than forecasted wind speeds. The errors are thus entirely due to the representation of the GF models. The GF models are improved with weather-adaptive GFs, as evaluated by the stratified MWS. Nevertheless, these weather-adaptive GF models show negative bias for predicting stronger PGSs due to insufficient data representation of the extreme wind gusts. The evaluation of the above models provides insight into maximizing the performance of GF models. This study further proposes a stratified process for forecasting peak wind gusts for routine operations.
{"title":"Adaptive Wind Gust and Associated Gust-factor Model for the Gust-producing Weather over the Northern South China Sea","authors":"Ling Huang, Chun-xia Liu, Qian Liu","doi":"10.3724/j.1006-8775.2023.029","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.029","url":null,"abstract":": Wind gusts are common environmental hazards that can damage buildings, bridges, aircraft, and cruise ships and interrupt electric power distribution, air traffic, waterway transport and port operations. Accurately predicting peak wind gusts in numerical models is essential for saving lives and preventing economic losses. This study investigates the climatology of peak wind gusts and their associated gust factors (GFs) using observations in the coastal and open ocean of the northern South China Sea (NSCS), where severe gust-producing weather occurs throughout the year. The stratified climatology demonstrates that the peak wind gust and GF vary with seasons and particularly with weather types. Based on the inversely proportional relationship between the GF and mean wind speed (MWS), a variety of GF models are constructed through least squares regression analysis. Peak gust speed (PGS) forecasts are obtained through the GF models by multiplying the GFs by observed wind speeds rather than forecasted wind speeds. The errors are thus entirely due to the representation of the GF models. The GF models are improved with weather-adaptive GFs, as evaluated by the stratified MWS. Nevertheless, these weather-adaptive GF models show negative bias for predicting stronger PGSs due to insufficient data representation of the extreme wind gusts. The evaluation of the above models provides insight into maximizing the performance of GF models. This study further proposes a stratified process for forecasting peak wind gusts for routine operations.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139014294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.3724/j.1006-8775.2023.033
Long-bin Ye, Jing Zhu, Yun Chen, Fei Li, Lin-ye Zheng
: In August 2021, a warm-sector heavy rainfall event under the control of the western Pacific subtropical high occurred over the southeastern coast of China. Induced by a linearly shaped mesoscale convective system (MCS), this heavy rainfall event was characterized by localized heavy rainfall, high cumulative rainfall, and extreme rainfall intensity. Using various observational data, this study first analyzed the precipitation features and radar reflectivity evolution. It then examined the role of environmental conditions and the relationship between the ambient wind field and convective initiation (CI). Furthermore, the dynamic lifting mechanism within the organization of the MCS was revealed by employing multi-Doppler radar retrieval methods. Results demonstrated that the linearly shaped MCS, developed under the influence of the subtropical high, was the primary cause of the extreme rainfall event. High temperatures and humidity, coupled with the convergence of low-level southerly winds, established the environmental conditions for MCS development. The superposition of the convergence zone generated by the southerly winds in the boundary layer (925–1000 hPa) and the divergence zone in the lower layer (700–925 hPa) supplied dynamic lifting conditions for CI. Additionally, a long-term shear line (southerly southwesterly) offered favorable conditions for the organization of the linearly shaped MCS. The combined effects of strengthening low-level southerly winds and secondary circulation in mid-upper levels were influential factors in the development and maintenance of the linearly shaped MCS.
:2021 年 8 月，在西太平洋副热带高压控制下，中国东南沿海发生了一次暖扇区强降雨事件。在线状中尺度对流系统（MCS）的诱导下，此次强降雨事件呈现出局地大暴雨、累积雨量大、降雨强度大的特点。本研究利用各种观测数据，首先分析了降水特征和雷达反射率的演变。然后，研究了环境条件的作用以及环境风场与对流启动（CI）之间的关系。此外，还采用多普勒雷达检索方法揭示了MCS组织内的动态抬升机制。研究结果表明，在副热带高气压影响下形成的线性对流状态是此次极端降雨事件的主要原因。高温和高湿，加上低层偏南风的辐合，为 MCS 的发展创造了环境条件。南风在边界层（925-1000 hPa）产生的辐合带与低层（700-925 hPa）的辐合带叠加，为 CI 提供了动态抬升条件。此外，一条长期切变线（偏南西南风）为线形多云天气的形成提供了有利条件。低层偏南风增强和中高层次级环流的共同作用，是线形多云天气发展和维持的影响因素。
{"title":"Observational and Mechanistic Analysis of a Nighttime Warm-Sector Heavy Rainfall Event Within the Subtropical High over the Southeastern Coast of China","authors":"Long-bin Ye, Jing Zhu, Yun Chen, Fei Li, Lin-ye Zheng","doi":"10.3724/j.1006-8775.2023.033","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.033","url":null,"abstract":": In August 2021, a warm-sector heavy rainfall event under the control of the western Pacific subtropical high occurred over the southeastern coast of China. Induced by a linearly shaped mesoscale convective system (MCS), this heavy rainfall event was characterized by localized heavy rainfall, high cumulative rainfall, and extreme rainfall intensity. Using various observational data, this study first analyzed the precipitation features and radar reflectivity evolution. It then examined the role of environmental conditions and the relationship between the ambient wind field and convective initiation (CI). Furthermore, the dynamic lifting mechanism within the organization of the MCS was revealed by employing multi-Doppler radar retrieval methods. Results demonstrated that the linearly shaped MCS, developed under the influence of the subtropical high, was the primary cause of the extreme rainfall event. High temperatures and humidity, coupled with the convergence of low-level southerly winds, established the environmental conditions for MCS development. The superposition of the convergence zone generated by the southerly winds in the boundary layer (925–1000 hPa) and the divergence zone in the lower layer (700–925 hPa) supplied dynamic lifting conditions for CI. Additionally, a long-term shear line (southerly southwesterly) offered favorable conditions for the organization of the linearly shaped MCS. The combined effects of strengthening low-level southerly winds and secondary circulation in mid-upper levels were influential factors in the development and maintenance of the linearly shaped MCS.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01DOI: 10.3724/j.1006-8775.2023.027
Yan CHEN, Hong-ming YAN, Yun TAO, Kun-lin YANG, Meng-qiu WANG
: Tropical cyclone (TC) activities in the North Indian Ocean (NIO) peak in May during the pre-monsoon period, but the TC frequency shows obvious inter-annual variations. By conducting statistical analysis and dynamic diagnosis of long-term data from 1948 to 2016, the relationship between the inter-annual variations of Indian Ocean SST and NIO TC genesis frequency in May is analyzed in this paper. Furthermore, the potential mechanism concerning the effect of SST anomaly on TC frequency is also investigated. The findings are as follows: 1) there is a broadly consistent negative correlation between NIO TC frequency in May and SST in the Indian Ocean from March to May, with the key influencing area located in the southwestern Indian Ocean (SWIO); 2) the anomalies of SST in SWIO (SWIO-SST) are closely related to a teleconnection pattern surrounding the Indian Ocean, which can significantly modulate the high-level divergence, mid-level vertical motion and other related environmental factors and ultimately influence the formation of TCs over the NIO; 3) the increasing trend of SWIO-SST may play an essential role in the downward trend of NIO TC frequency over the past 69 years.
{"title":"The Relationship Between Indian Ocean SST and Tropical Cyclone Genesis Frequency over North Indian Ocean in May","authors":"Yan CHEN, Hong-ming YAN, Yun TAO, Kun-lin YANG, Meng-qiu WANG","doi":"10.3724/j.1006-8775.2023.027","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.027","url":null,"abstract":": Tropical cyclone (TC) activities in the North Indian Ocean (NIO) peak in May during the pre-monsoon period, but the TC frequency shows obvious inter-annual variations. By conducting statistical analysis and dynamic diagnosis of long-term data from 1948 to 2016, the relationship between the inter-annual variations of Indian Ocean SST and NIO TC genesis frequency in May is analyzed in this paper. Furthermore, the potential mechanism concerning the effect of SST anomaly on TC frequency is also investigated. The findings are as follows: 1) there is a broadly consistent negative correlation between NIO TC frequency in May and SST in the Indian Ocean from March to May, with the key influencing area located in the southwestern Indian Ocean (SWIO); 2) the anomalies of SST in SWIO (SWIO-SST) are closely related to a teleconnection pattern surrounding the Indian Ocean, which can significantly modulate the high-level divergence, mid-level vertical motion and other related environmental factors and ultimately influence the formation of TCs over the NIO; 3) the increasing trend of SWIO-SST may play an essential role in the downward trend of NIO TC frequency over the past 69 years.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135735435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01DOI: 10.3724/j.1006-8775.2023.025
Ru-yue GUO, Wei-juan PAN, Min-ling KE, Wei WEI, Zi-qian WANG
: There is a continuous and relatively stable rainy period every spring in southern China (SC). This spring precipitation process is a unique weather and climate phenomenon in East Asia. Previously, the variation characteristics and associated mechanisms of this precipitation process have been mostly discussed from the perspective of seasonal mean. Based on the observed and reanalysis datasets from 1982 to 2021, this study investigates the diversity of the interannual variations of monthly precipitation in spring in SC, and focuses on the potential influence of the tropical sea surface temperature (SST) anomalies. The results show that the interannual variations of monthly precipitation in spring in SC have significant differences, and the correlations between each two months are very weak. All the interannual variations of precipitation in three months are related to a similar western North Pacific anomalous anticyclone (WNPAC), and the southwesterlies at the western flank of WNPAC bring abundant water vapor for the precipitation in SC. However, the WNPAC is influenced by tropical SST anomalies in different regions each month. The interannual variation of precipitation in March in SC is mainly influenced by the signal of El Niño-Southern Oscillation, and the associated SST anomalies in the equatorial central-eastern Pacific regulate the WNPAC through the Pacific-East Asia (PEA) tele-connection. In contrast, the WNPAC associated with the interannual variation of precipitation in April can be affected by the SST anomalies in the northwestern equatorial Pacific through a thermally induced Rossby wave response. The interannual variation of precipitation in May is regulated by the SST anomalies around the western Maritime Continent, which stimulates the development of low-level anomalous anticyclones over the South China Sea and east of the Philippine Sea by driving anomalous meridional vertical circulation.
{"title":"Diversity on the Interannual Variations of Spring Monthly Precipitation in Southern China and the Associated Tropical Sea Surface Temperature Anomalies","authors":"Ru-yue GUO, Wei-juan PAN, Min-ling KE, Wei WEI, Zi-qian WANG","doi":"10.3724/j.1006-8775.2023.025","DOIUrl":"https://doi.org/10.3724/j.1006-8775.2023.025","url":null,"abstract":": There is a continuous and relatively stable rainy period every spring in southern China (SC). This spring precipitation process is a unique weather and climate phenomenon in East Asia. Previously, the variation characteristics and associated mechanisms of this precipitation process have been mostly discussed from the perspective of seasonal mean. Based on the observed and reanalysis datasets from 1982 to 2021, this study investigates the diversity of the interannual variations of monthly precipitation in spring in SC, and focuses on the potential influence of the tropical sea surface temperature (SST) anomalies. The results show that the interannual variations of monthly precipitation in spring in SC have significant differences, and the correlations between each two months are very weak. All the interannual variations of precipitation in three months are related to a similar western North Pacific anomalous anticyclone (WNPAC), and the southwesterlies at the western flank of WNPAC bring abundant water vapor for the precipitation in SC. However, the WNPAC is influenced by tropical SST anomalies in different regions each month. The interannual variation of precipitation in March in SC is mainly influenced by the signal of El Niño-Southern Oscillation, and the associated SST anomalies in the equatorial central-eastern Pacific regulate the WNPAC through the Pacific-East Asia (PEA) tele-connection. In contrast, the WNPAC associated with the interannual variation of precipitation in April can be affected by the SST anomalies in the northwestern equatorial Pacific through a thermally induced Rossby wave response. The interannual variation of precipitation in May is regulated by the SST anomalies around the western Maritime Continent, which stimulates the development of low-level anomalous anticyclones over the South China Sea and east of the Philippine Sea by driving anomalous meridional vertical circulation.","PeriodicalId":17432,"journal":{"name":"热带气象学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135735420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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