Article
Meteorology & Atmospheric Sciences
Shuguang Wang, Adam H. Sobel
Summary: The Madden-Julian oscillation (MJO) and the boreal summer intraseasonal oscillation (BSISO) are fundamental modes of variability in the tropical atmosphere on the intraseasonal time scale. The horizontal structure and spatial pattern transformation of these modes depend on the magnitude of the meridional moisture gradient.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Minmin Fu, Eli Tziperman
Summary: Surface flux feedback does not contribute significantly to WWB growth, but inhibiting convection and surface evaporation weakens WWBs rapidly. Off-equatorial cyclonic vortices play a crucial role in equatorial WWB winds, while on-equator convection is not important. Tropical cyclones, located more than 5 degrees away from the equator, may be responsible for the majority of WWBs.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Tao Zhu, Jing Yang
Summary: Two types of mid-high-latitude low-frequency intraseasonal oscillations (LF-ISOs) have been identified over the Eurasian continent, with eastward and westward propagation paths, showing significant interactions with tropical intraseasonal variations. These LF-ISOs exhibit different decadal preferences before and after 2000, attributed to changes in intraseasonal efficient kinetic energy and background flow associated with the North Atlantic Oscillation/Arctic Oscillation.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Lei Zhou, Ruomei Ruan, Raghu Murtugudde
Summary: Madden-Julian oscillations (MJOs) have two paths across the Maritime Continent, detoured and nondetoured, with significantly different impacts on the South Pacific convergence zone (SPCZ). Detoured MJOs trigger strong cross-equatorial meridional winds, while nondetoured MJOs have weaker impacts on either hemisphere. Further studies on these processes are expected to enhance understanding of extreme climate and natural disasters in the southern Pacific and Indian Oceans.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Weixin Xu, Steven A. Rutledge, Kyle Chudler
Summary: Using 17 years of spaceborne precipitation radar measurements, this study investigates how diurnal cycles of rainfall and convective characteristics over the South China Sea region are modulated by the boreal summer intraseasonal oscillation (BSISO). Generally, the diurnal cycles change significantly between suppressed and active BSISO periods. Over the Philippines and Indochina, diurnal cycles of rainfall and many convective properties are enhanced during suppressed periods, while over Borneo, diurnal cycles are stronger during active periods.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Chi-Cherng Hong, Chi-Chun Chang, Kuan-Chieh Chen, Chih-Hua Tsou
Summary: This study found that the intensification of tropical cyclones to major cyclones in the western North Pacific region has shown a significant difference between autumn and summer since the early 2000s. The ratio of major cyclones to the total number of cyclones has been increasing continuously in autumn but not in summer. The increase in the ratio of major cyclones in autumn is associated with interdecadal variability in cyclone activity and intraseasonal oscillations. The location of cyclone genesis and intraseasonal oscillations shifted westward in autumn, resulting in enhanced interaction and energy conversion between cyclones and oscillations.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Wenting Hu, Anmin Duan, Bian He, Sai Hao
Summary: This study investigates the effects of the Tibetan and Iranian Plateaus on the northward propagation of the boreal summer intraseasonal oscillation (BSISO). The study finds that the Tibetan Plateau has a significant impact on the northward propagation of the BSISO through its influence on vertical wind shear and moisture gradient, while the Iranian Plateau has a relatively limited effect.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Joshua Talib, Christopher M. Taylor, Bethan L. Harris, Caroline M. Wainwright
Summary: In semi-arid environments, rainfall-induced soil moisture fluctuations have a significant impact on surface turbulent fluxes, influencing regional circulations. This study investigates whether rainfall variability induced by the MJO triggers land-atmosphere feedbacks across East Africa. The results show that surface fluxes during the East African wet seasons are sensitive to MJO-induced precipitation variations, affecting surface temperatures, sensible heat fluxes, and evapotranspiration. This work highlights the importance of considering intraseasonal land-atmosphere interactions in climate modeling.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2023)
Article
Meteorology & Atmospheric Sciences
Tianyi Wang, Tim Li
Summary: This study examined the diversity of the Madden-Julian oscillation (MJO) in terms of its maximum intensity, zonal extent, and phase speed using a cluster analysis method. The results showed significant correlations between zonal extent and phase speed, as well as connections between these diversities and interannual sea surface temperature anomalies and associated moisture and circulation patterns over the equatorial Pacific. An El Nino-like background SSTA was found to be a key factor influencing the behavior of MJO in terms of zonal extent, phase speed, and intensity.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Jing Yang, Siyu Li, Tao Zhu, Xin Qi, Jiping Liu, Seong-Joong Kim, Daoyi Gong
Summary: Understanding the intraseasonal variations of Arctic sea ice is crucial for predicting climate variations and trans-Arctic shipping. This study found that the dominant periodicity of sea ice change in the Northern Barents Sea during summer is 30-60 days, modulated by circumpolar clockwise-propagating atmospheric waves. These atmospheric waves induce meridional thermal advection, modulating surface temperature and atmospheric moisture, causing changes in sensible heat and longwave radiative fluxes, and ultimately regulating the sea ice variations. The mechanism highlights the importance of accurately predicting atmospheric fields for more accurate sea ice subseasonal prediction.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Akshaya C. Nikumbh, Arindam Chakraborty, G. S. Bhat, Dargan M. W. Frierson
Summary: The Indian summer monsoon rainfall variability is primarily influenced by the MISO and LPSs. This study focused on analyzing LPSs that produce extreme rainfall events in central India, finding that dynamic characteristics differ between LPSs triggering different sizes of events. Larger EREs are associated with slower, moister, and more intense LPSs occurring during the positive phase of MISO.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Jing Cui, Tim Li, Lijuan Wang
Summary: The origin of mid-high-latitude intraseasonal oscillations (ISOs) was investigated and it was found that maximum intraseasonal variability centers appear near 60 degrees N. The ISO along 60 degrees N is characterized by a tight coupling among moisture and precipitation and circulation.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Ke Xu, Riyu Lu
Summary: The study identifies the characteristics of all break events of the western North Pacific summer monsoon, indicating that suppressed convection, anticyclonic anomalies, and cyclonic convergence play important roles in the occurrence of breaks.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Yifeng Cheng, Lu Wang, Tim Li
Summary: This study investigated large-scale circulation anomalies associated with persistent heavy rainfall events in the middle and lower reaches of the Yangtze River Valley during the boreal summer. Two distinct types of events, PSAH and NSAH, were identified based on anomalies in the western Pacific subtropical high and South Asian high. Both types are characterized by mei-yu frontal systems, with lower-level circulation anomalies playing a crucial role in initiating rainfall through different processes.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Qinghan Xu, Shuangyan Yang
Summary: Using NCEP-NCAR reanalysis data, this study examines the atmospheric intraseasonal oscillation (ISO) over the mid-high latitudes in the Southern Hemisphere during austral summer. Two types of 10-30-day eastward- and westward-propagating ISO are identified using extended empirical orthogonal functions. The wave activity flux analysis reveals the energy sources for the two wave trains, with the eastward-propagating wave train originating in the southwest Pacific and southern Indian Ocean, while the westward-propagating wave train is located over the east coast of South America. The zonal gradient of ISO relative vorticity guided by mean zonal wind plays a significant role in the eastward propagation, while the meridional gradient of mean relative vorticity and geostrophic vorticity guided by ISO meridional wind drives the westward propagation. Surface air temperature and precipitation over South America are influenced by both types of ISO. The forecasting skills for the eastward- and westward-propagating types reach up to 17 days, with potential improvements to 20 and 19 days, respectively.
JOURNAL OF CLIMATE
(2023)
Article
Geosciences, Multidisciplinary
Ganning Zhou, Jianjie Wang, Yan Yin, Xiuqing Hu, Husi Letu, Byung-Ju Sohn, Yuk L. Yung, Chao Liu
Summary: This study introduces an efficient algorithm to detect supercooled water clouds and validates its high accuracy through experimental comparisons. Supercooled water clouds are mainly found over mid- to high-latitude oceans with a global occurrence frequency of around 8% in cloudy skies. The algorithm utilizes channels commonly available in current operational satellite radiometers, making it easy to implement and operate.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Jiazheng Li, Murthy S. Gudipati, Yogeshwar N. Mishra, Mao-Chang Liang, Yuk L. Yung
Summary: A chemistry-transport model was built to simulate chemical processes in ice during irradiation by 10 keV electrons and to describe the formation, transportation, and distribution of chemical species of interest in the ice. The simulated H2O2 mixing ratio agrees well with experimental results, indicating the model's potential for estimating oxidant generation in ice and evaluating the potential habitability of icy satellites such as Europa. Further experimental studies are needed to constrain critical parameters.
Article
Multidisciplinary Sciences
Siteng Fan, Peter Gao, Xi Zhang, Danica J. Adams, Nicholas W. Kutsop, Carver J. Bierson, Chao Liu, Jiani Yang, Leslie A. Young, Andrew F. Cheng, Yuk L. Yung
Summary: Pluto, Titan, and Triton are unique solar system bodies with icy surfaces and chemically reducing atmospheres. Studies show that their haze particles are bimodally distributed, indicating complex physical and chemical processes in their atmospheres. Further research is encouraged to reanalyze observations of hazes on Titan and Triton.
NATURE COMMUNICATIONS
(2022)
Article
Astronomy & Astrophysics
Ronald Albright, Abigail Corbett, Xun Jiang, Ellen Creecy, Sally Newman, King-Fai Li, Mao-Chang Liang, Yuk L. Yung
Summary: This article uses OCO-2 SW to investigate photosynthetic activity in different seasons in the Amazon region and found a positive correlation between precipitation and photosynthesis, as well as a decrease in photosynthetic activity during the dry/fire season, leading to an increase in atmospheric CO2.
EARTH AND SPACE SCIENCE
(2022)
Article
Environmental Sciences
Liyin He, Jing Wei, Yuan Wang, Quanbiao Shang, Junjie Liu, Yi Yin, Christian Frankenberg, Jonathan H. Jiang, Zhanqing Li, Yuk L. Yung
Summary: The study reveals the critical role of particulate and ozone pollution in regulating interannual variations of crop yields in China. Despite the increase in ozone levels in the North China Plain, particulate pollution mitigation during 2010-2018 outweighed the negative impacts of climate change, resulting in a nationwide net yield increase of 0.5%-1.9%. However, looking to the future, the impacts of climate change, particularly surface temperature increase, will dominate and significantly reduce maize and rice yields.
Article
Astronomy & Astrophysics
Danica Adams, Yangcheng Luo, Yuk L. Yung
Summary: Titan has a similar atmosphere to that of an early Earth-like world, with the potential for relevant prebiotic chemistry. Exo-Titan worlds at close-in orbits also have the conditions suitable for habitability. The study finds that increased incident radiation leads to faster reaction rates. Higher temperatures and a larger H-2 abundance promote cycling and chemical reactions.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Optics
V. Natraj, R. Spurr, A. Gao, T. Le, Z. C. Zeng, S. Fan, Y. L. Yung
Summary: This article introduces a new radiative transfer model that can accurately calculate in vertically inhomogeneous atmospheres, with spherical capability and linearization features, making it particularly useful for remote sensing retrieval applications.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2023)
Article
Astronomy & Astrophysics
Xun Jiang, Ronald Albright, Ellen Creecy, King-Fai Li, Mao-Chang Liang, Sally Newman, Xinyue Wang, Thishan Dharshana Karandana Gamalathge, Yuk L. Yung
Summary: Using satellite observations, it has been found that carbon dioxide levels over the Congo basin are 2 ppm higher than the regional background during the dry season due to biomass burning and reduced photosynthesis. The contribution from biomass burning during this season is larger than that from the biosphere, and better seasonal fire management is crucial for reducing global carbon emissions as per international agreements.
EARTH AND SPACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Zhao-Cheng Zeng, Thomas Pongetti, Sally Newman, Tomohiro Oda, Kevin Gurney, Paul I. Palmer, Yuk L. Yung, Stanley P. Sander
Summary: This study uses atmospheric remote sensing data to demonstrate a decreasing trend in methane emissions in the Los Angeles area from 2011 to 2020. These findings provide important guidance for efforts to reduce methane emissions.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Ji-Won Kim, Jin-Yi Yu, Baijun Tian
Summary: Previous studies have overemphasized the role of a strong El Nino in the formation of multi-year La Nina events. However, observational analyses reveal that most of these events do not require a preceding strong El Nino, but are influenced by the negative phase of the North Pacific Meridional Mode.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Yuan Wang, Xiaojian Zheng, Xiquan Dong, Baike Xi, Yuk L. Yung
Summary: In this study, the warm-cloud physics parameterizations in the NCAR Community Atmospheric Model version 6 and 5 (SCAM6 and SCAM5) are evaluated using measurements from the ARM Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign. The results show that both SCAM6 and SCAM5 can simulate the structure and properties of marine boundary layer clouds, but they underestimate cloud liquid water content, cloud droplet size, and rain liquid water content while overestimating surface rainfall. The study emphasizes the importance of understanding biases in cloud physics parameterizations through combining single-column modeling with in situ observations.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Astronomy & Astrophysics
Jingyu Wang, Siteng Fan, Chao Liu, Vijay Natraj, Leslie A. Young, Yuk L. Yung
Summary: The flyby of the New Horizons spacecraft in 2015 July revealed Pluto's unexpected cold atmosphere and confirmed the existence of its atmospheric haze. This study investigates the influence of organic ice components in Pluto's haze on its scattering properties by comparing observations and simulated particle scattering properties. The results suggest that organic ice can affect Pluto's haze chemistry and optical properties, but additional scattering sources/mechanisms are still required to fully explain the observed scattering observations.
PLANETARY SCIENCE JOURNAL
(2023)
Article
Meteorology & Atmospheric Sciences
Weiming Ma, Gang Chen, Bin Guan, Christine A. Shields, Baijun Tian, Emilio Yanez
Summary: This study developed an AR detection algorithm for satellite observations and evaluated the representation of ARs and AR-induced precipitation in reanalysis products. The results showed that reanalysis products consistently underestimated AR-related precipitation and had excessive precipitation in low latitude regions. These findings can help improve the representation of ARs and associated precipitation in reanalyses and climate models.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Review
Optics
Yuk L. Yung
Summary: This article discusses Professor Goody's illustrious scientific career, which can be divided into three pivotal phases. The article highlights Professor Goody's insights and wisdom as a scientist, which provide invaluable lessons for both emerging scientists and seasoned professionals.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2023)