Article
Environmental Sciences
Keiichiro Hara, Hisahiro Takashima, Ayako Yoshino, Akinori Takami, Chiharu Nishita-Hara, Yasushi Fujiyoshi, Masahiko Hayashi
Summary: This study conducted simultaneous measurements of wind profiles and atmospheric substances to investigate the relationship between local circulation and variations in aerosols and gases. The results showed that the diurnal cycles of wind profiles were associated with sea breezes and land breezes over the Fukuoka Plain. The diurnal variations of aerosols and gases were attributed to local anthropogenic emissions and the sea and land breeze cycles. The strengths of morning and evening peaks exhibited clear seasonal changes, with stronger peaks during colder seasons.
ATMOSPHERIC ENVIRONMENT
(2022)
Article
Meteorology & Atmospheric Sciences
Zheng Li, Johnny C. L. Chan, Kun Zhao, Xingchao Chen
Summary: This study investigates the relationship between changes in monsoonal rainfall diurnal variations over the south China coast and urban surface processes using data analysis and numerical simulations. The results show that urban sensible heat, evapotranspiration, and friction play significant roles in influencing the rainfall patterns in the region.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Meteorology & Atmospheric Sciences
Lidia Huaman, Courtney Schumacher, Andreas H. Fink, Erin Buttitta
Summary: This study analyzed the diurnal variations in meridional overturning and convection over West Africa during the premonsoon and monsoon seasons using ECMWF Reanalysis 5th Generation (ERA5) and satellite radar data from 1998 to 2019. The results showed that the diurnal cycle of convection and meridional circulations over West Africa is influenced by a daytime sea breeze and two nocturnal low-level jets, with varying impacts depending on the season. The study also found biases in the precipitation patterns over the Gulf of Guinea and West Africa in each season in the reanalysis data.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2023)
Article
Geosciences, Multidisciplinary
Lei Zhu, Lanqiang Bai, Guixing Chen, Y. Qiang Sun, Zhiyong Meng
Summary: Convection on tropical islands, such as Hainan Island, is influenced by local circulations responding to lower-troposphere ambient flow and diurnal thermal heating. In high-wind conditions, convection initiates predominantly over lee-side plains, while in low-wind conditions it initiates over mountains.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
Yihao Zhou, Shuguang Wang, Juan Fang
Summary: The study finds that the Madden-Julian Oscillation (MJO) has a significant impact on the precipitation anomaly over Borneo. Linear theory analysis reveals that the prevailing wind and topography are the key factors controlling the asymmetry and dipolar pattern of the precipitation anomaly. Nonlinear simulations further demonstrate the effects of island topography and solar radiative heating in different MJO phases. These findings highlight the distinct roles of MJO wind anomaly, island topography, and solar insolation in the formation of the dipolar pattern of Borneo precipitation.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Yuping Chen, Chen Yang, Lingling Xu, Xiaolong Fan, Jiayan Shi, Ronghua Zheng, Youwei Hong, Mengren Li, Taotao Liu, Gaojie Chen, Liqian Yin, Jinsheng Chen
Summary: Sea land breeze (SLB) affects local weather conditions and air pollutants. This study examined the variation of meteorological conditions, air pollutants concentrations, and aerosol chemical composition during SLB circulation in a coastal city in Southeast China. The results showed amplified day-night differences in meteorological parameters, with higher temperatures and UV levels during the day and lower boundary layer heights at night. The concentrations of non-refractory submicron particles (NR-PM1), as well as gaseous pollutants like NO2, peaked in the late evening on SLB days. The NR-PM1 in SLB conditions were characterized by a high fraction of organic aerosol (OA) and an increase in more-oxidized OOA during the sea breeze period.
ATMOSPHERIC RESEARCH
(2023)
Article
Engineering, Civil
Junzhi Liu, Lei Yang, Jingchao Jiang, Weihua Yuan, Zheng Duan
Summary: This study utilized a gauge-satellite merged precipitation dataset to map the diurnal cycles of summer precipitation over China using the K-means clustering algorithm. The results identified regions with similar patterns of diurnal cycles, reflecting the importance of macroterrain in precipitation variability. By analyzing different types and durations of precipitation events, the study provided detailed spatial insights into the regional characteristics and patterns of diurnal precipitation cycles in China.
JOURNAL OF HYDROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Y. Du
Summary: This study investigates the diurnal migration of the low-level jet (LLJ) over the Bay of Bengal in the summer monsoon. The LLJ exhibits maximum strength during the night and morning and migrates approximately 600 km from the eastern offshore of India to the center of the Bay of Bengal by afternoon. The migration is driven by inertia-gravity waves arising from the diurnal land-sea thermal contrast and is influenced by the westerly upstream wind from the Indian subcontinent.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Fu Dong, Xiefei Zhi, Ling Zhang, Chengzhi Ye
Summary: The study found two distinct coastal boundary layer jets (CBLJs) with different diurnal cycles over the northern South China Sea, located at the Beibu Gulf and coastal area of Guangdong, which are closely related to factors such as Hainan Island, mountains over Vietnam, and large-scale sea breezes. These jets are essential for the formation of nocturnal and morning rainfall over Guangxi and Guangdong Province, while afternoon rainfall is influenced by the thermal effects of Hainan Island and eastward-propagating rainfall belts from Guangxi Province.
MONTHLY WEATHER REVIEW
(2021)
Article
Meteorology & Atmospheric Sciences
Zhongxi Lin, Guixing Chen
Summary: Anthropogenically-induced changes in radiation balance affect the diurnal variation of regional circulations, leading to cooler days and warmer nights over the North China plains in July and August. This is mainly determined by the dominant cooling effect of anthropogenic aerosols during the daytime and the warming effect at night. These changes in regional circulations result in anomalous wind patterns and increased moisture convergence, leading to an increasing trend in nighttime precipitation over the North China plains.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Die Wang, Michael P. Jensen, Domenic Taylor, Grace Kowalski, Marcie Hogan, Brian M. Wittemann, Amanda Rakotoarivony, Scott E. Giangrande, J. Minnie Park
Summary: This study classifies meteorological regimes in southeastern Texas and identifies the conditions that favor sea-breeze induced convection. Three dominant synoptic regimes were distinguished using a Self-Organizing Map approach. The study found that when southeastern Texas is positioned to the southwest of a maritime high pressure system, increased cloud frequency and sea-breeze circulation occur, while a high pressure system over southeastern Texas leads to weak synoptic forcing and favorable conditions for sea-breeze circulation.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Environmental Sciences
Qiang Zhang, Wei Hu, Hong Ren, Jianbo Yang, Junjun Deng, Dawei Wang, Yele Sun, Zifa Wang, Kimitaka Kawamura, Pingqing Fu
Summary: The study investigates the impact of land-sea breezes on the atmospheric transport of organic aerosols in a coastal city in East China. Organic marker compounds showed diurnal/seasonal patterns, with different trends during land-sea breeze periods in early autumn and early spring. The study also found that the aging and reaction pathway of biogenic secondary organic aerosols (SOA) were related to land-sea breezes. Changes in the ratio of monoterpene SOA markers indicated different levels of aging during sea breeze and land breeze periods. The results provide new insights into the chemical composition shift of organic aerosols over coastal areas influenced by land-sea breezes.
ENVIRONMENTAL POLLUTION
(2023)
Article
Environmental Sciences
Shuhong Liu, Danling Tang, Hong Yan, Guicai Ning, Chengcheng Liu, Yuanjian Yang
Summary: Low-level jet (LLJ) significantly affects the synoptic-scale hydrometeorological conditions in the South China Sea, with impacts on the marine biophysical environment over the Beibuwan Gulf (BBG). LLJs lead to enhanced Ekman pumping, stronger photosynthetically active radiation, and lower precipitation, resulting in changes in sea surface temperature and chlorophyll-a concentrations in nearshore and offshore regions. The incidence and intensity of LLJs potentially cause intraseasonal and diurnal changes in the biophysical ocean environment, with a greater impact on the northern BBG compared to the southern region.
Article
Meteorology & Atmospheric Sciences
Qiang Li, Yongguang Zheng, Guobing Zhou, Yan Zhu, Chao Liu, Yan Liu
Summary: Based on the hourly rainfall data of meteorological stations in Chongqing from 2009 to 2016, this study investigates the diurnal characteristics of precipitation influenced by complex topography. The results show that the complex mountainous terrain significantly affects the diurnal variations and regional features of rainfall, with higher areas experiencing greater rainfall amounts, frequency, and intensity. Moreover, the elevation plays a significant role in the proportions of early-morning rainfall, with higher elevations exhibiting lower proportions of rainfall in the early morning period.
THEORETICAL AND APPLIED CLIMATOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Lixing Shen, Chuanfeng Zhao, Xingchuan Yang
Summary: This study quantifies the significance of sea-land breezes under different climates globally for the first time, and finds that climate type plays a leading role in the importance and trends of sea-land breezes. Adequate in-situ solar radiation and mild meteorological conditions are essential factors in ensuring the significant existence of sea-land breezes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
Man-Yau Chan, Xingchao Chen
Summary: Research has shown that assimilating all-sky upper tropospheric infrared radiance observations can improve the prediction of tropical squall lines. High-frequency assimilation of these radiance observations can enhance the analysis of the squall line's outflow position, leading to improved cloud field predictions.
ADVANCES IN ATMOSPHERIC SCIENCES
(2022)
Article
Meteorology & Atmospheric Sciences
James H. Ruppert, Steven E. Koch, Xingchao Chen, Yu Du, Anton Seimon, Y. Qiang Sun, Junhong Wei, Lance F. Bosart
Summary: In this review, the groundbreaking contributions of Fuqing Zhang in the field of atmospheric science, particularly in the dynamics of mesoscale gravity waves (MGWs), are highlighted. Zhang's research shed light on the generation and interaction of MGWs, as well as their importance in midlatitude weather and predictability. The review also emphasizes the need for further understanding of the amplification of MGWs through feedback with moist convection, which remains a critical open science issue.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2022)
Article
Geosciences, Multidisciplinary
Xingchao Chen, L. Ruby Leung, Zhe Feng, Fengfei Song, Qiu Yang
Summary: The study found that MCSs play an important role in the rapid onset phase of the South Asian summer monsoon in terms of rainfall, MSE sources, and MSE export. While deep convection always leads to energy export, mesoscale organization of deep convection accelerates the energy cycle of the monsoon onset.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
Qiu Yang, L. Ruby Leung, Zhe Feng, Fengfei Song, Xingchao Chen
Summary: Mesoscale convective systems (MCSs) play a significant role in summer precipitation over the central United States. A lack of understanding of MCS initiation has been identified as a key factor contributing to warm and dry bias in coarse-resolution climate models. Development of single-column and multicolumn models has helped simulate convective initiation and mesoscale cluster formation, providing insights for improving MCS simulations in global climate models.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2021)
Article
Meteorology & Atmospheric Sciences
Atsushi Okazaki, Takemasa Miyoshi, Kei Yoshimura, Steven J. Greybush, Fuqing Zhang
Summary: Online data assimilation performs better than offline data assimilation when the predictability of the system exceeds the averaging time of observations. The ocean plays a crucial role in extending predictability, aiding online data assimilation to outperform offline data assimilation. Moreover, the observations of near-surface air temperature over land are highly valuable in updating ocean variables, highlighting the importance of utilizing cross-domain covariance information between the atmosphere and the ocean in paleoclimate reconstruction.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Meteorology & Atmospheric Sciences
Fengfei Song, Zhe Feng, L. Ruby Leung, Binod Pokharel, S-Y Simon Wang, Xingchao Chen, Koichi Sakaguchi, Chi-chia Wang
Summary: This study aims to understand the environments supporting summer mesoscale convective system (MCS) initiation in the U.S. Great Plains by conducting a self-organizing map analysis to identify four types of summer MCS initiation environments during 2004-2017. Despite unfavorable large-scale environments, there are favorable sub-synoptic scale environments for MCS initiation in Type-3 and Type-4. The study also highlights the importance of coupled dynamical and moisture anomalies associated with eastward propagating waves in supporting MCS initiation in the Great Plains, leading to more rainfall production compared to those initiated at the foothill of the Rocky Mountains.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Geosciences, Multidisciplinary
Xingchao Chen, L. Ruby Leung, Zhe Feng, Qiu Yang
Summary: Based on satellite observations, this study reveals that precipitation over tropical oceans rapidly increases when the environmental column saturation fraction exceeds the critical value of 0.7. Non-deep convection, deep convection, and mesoscale convective systems (MCS) play sequential roles in the precipitation-moisture interactions, with MCS becoming the major contributor to total rain above the critical CSF value.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Fengfei Song, L. Ruby Leung, Zhe Feng, Xingchao Chen, Qiu Yang
Summary: This study investigates the historical and future changes of large-scale environments favorable for MCS initiation over the US Great Plains. The results show that the frequency of MCS environments related to the Great Plains low-level jet (GPLLJ) has increased in the past decades, mainly driven by decadal sea-surface temperature variations. Under a high emission scenario, the frequency of GPLLJ-related environments is projected to further increase, indicating more frequent MCSs in the warming world.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Xiaona Rao, Kun Zhao, Xingchao Chen, Anning Huang, Sheng Hu, Dongming Hu, Xiantong Liu
Summary: This study investigates the triggering mechanisms of a representative nocturnal convection event in the northern mountainous area of the Pearl River Delta. Enhanced low-level southerly winds, deflected easterly winds, and downslope winds associated with orographic cooling were found to be crucial for the formation of low-level convergence and strong updrafts. The intensification of low-level convergence and moisture transport was dominated by a zonal component related to the deflected easterly winds.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
Man-Yau Chan, Xingchao Chen, L. Ruby Leung
Summary: Modern global reanalysis products have greatly accelerated meteorological research in synoptic-to-planetary-scale phenomena. However, their use in studying tropical mesoscale convective systems (MCSs) and their regional-to-global impact has mostly been limited to supplying initial and boundary conditions for MCS-resolving simulations and providing information about the large-scale environments of MCSs. In this work, a Tropical MCS-resolving Reanalysis product (TMeCSR) was created over a region with frequent tropical MCSs. TMeCSR is produced by assimilating all-sky infrared radiances from geostationary satellites and other conventional observations into an MCS-resolving regional model using the Ensemble Kalman Filter. The resulting observation-constrained high-resolution (9-km grid spacing) data set is available hourly during the boreal summer (June-August) of 2017, during which widespread severe flooding occurred. Comparisons of TMeCSR and European Center for Medium Range Weather Forecast Reanalysis version 5 (ERA5) against independent satellite retrievals indicate that TMeCSR's cloud and multiscale rain fields are better than those of ERA5. Furthermore, TMeCSR better captured the diurnal variability of rainfall and the statistical characteristics of MCSs. Forecasts initialized from TMeCSR also have more accurate rain and clouds than those initialized from ERA5. The TMeCSR and ERA5 forecasts have similar performances with respect to sounding and surface observations. These results indicate that TMeCSR is a promising MCS-resolving data set for tropical MCS studies.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Meteorology & Atmospheric Sciences
Christopher M. Hartman, Xingchao Chen, Man-Yau Chan
Summary: Previous studies have shown that assimilating satellite all-sky infrared brightness temperatures (BTs) can improve intensity forecasts of tropical cyclones. In this study, it is found that assimilating upper-tropospheric water vapor channel BTs observed by the Meteosat-10 SEVIRI instrument can improve the genesis forecast of Hurricane Irma (2017) by up to 24 hours and capture its later rapid intensification. Without assimilating all-sky IR BTs, the assimilation of conventional observations leads to the premature genesis of the hurricane due to an overestimation of deep convection.
MONTHLY WEATHER REVIEW
(2023)
Article
Meteorology & Atmospheric Sciences
Man-Yau Chan, Xingchao Chen, Jeffrey L. Anderson
Summary: In this study, the potential benefits of using a bi-Gaussian extension of the ensemble Kalman filter (BGEnKF) to address the uncertainty of clouds in weather prediction are demonstrated. The BGEnKF shows better performance than the commonly used ensemble Kalman filter (EnKF) in various weather variables. This study highlights the potential of explicitly handling mixture statistics in improving numerical Earth system predictions.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2023)
Article
Meteorology & Atmospheric Sciences
Xingchao Chen, L. Ruby Leung, Zhe Feng, Qiu Yang
Summary: A high-resolution regional reanalysis is utilized to study the mesoscale processes preceding the formation of Tropical Cyclone Mora. The analysis reveals that mesoscale convective systems persistently occur in the downshear quadrant of the preexisting tropical disturbance, gradually enhancing the meso-a and meso-b scale vortices. Gravity waves from afternoon convection over the Bay of Bengal seem to play a role in modulating the diurnal cycle of pregenesis mesoscale convective systems.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2023)
Article
Meteorology & Atmospheric Sciences
Xiaona Rao, Kefeng Zhu, Kun Zhao, Xingchao Chen, Sheng Hu, Xiantong Liu, Ang Zhou
Summary: This study evaluated the performance of a convection-permitting Weather Research and Forecasting (WRF) model in forecasting nocturnal rainfall in the concave mountainous area of Pearl River Delta. Results showed that the model accurately predicted rainfall over the northern mountainous region but significantly underestimated rainfall near local Huadu Hill and in the foothill area of northern mountains. The study also identified the crucial role of urban-mountain thermal contrast in triggering the nocturnal convection.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Xingchao Chen, L. Ruby Leung, Zhe Feng, Fengfei Song
Summary: This study analyzes the South Asian summer monsoon using a cloud classification and tracking technique, and finds that mesoscale convective systems play a critical role in the vertical transports of the monsoon. Compared to non-MCSs, MCSs have at least 1.5 times stronger mass and energy transports throughout the troposphere, with a much larger contribution from convective updrafts. On a per-event basis, MCSs have vertical transports and net moist static energy exported that are about 70-100 times stronger than non-MCSs. The results provide useful insights into the understanding of the monsoon and advancing the energetic framework.
JOURNAL OF CLIMATE
(2022)