Article
Meteorology & Atmospheric Sciences
Shuo Li, Wei Mei, Shang-Ping Xie
Summary: This study quantifies the contributions of tropical sea surface temperature (SST) variations during the boreal warm season to the interannual-to-decadal variability in tropical cyclone genesis frequency (TCGF) over the Northern Hemisphere ocean basins. The study finds that the dominant SST modes affecting TCGF vary among different basins and are related to ENSO, GW, PMM, AMO, PDO, and AMM. These modes explain a portion of the variance in TCGF in the North Atlantic, northeast Pacific, and northwest Pacific Oceans.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Kerry Emanuel
Summary: This study investigates the relationship between the seed frequency and transition probability of tropical cyclone occurrence rates. The results demonstrate that the partitioning of this relationship is dependent on the definition of seeds and does not resolve the issue of controlling factors for tropical cyclone frequency. The author argues that tropical cyclone climatology is primarily controlled by regional environment and the global response to uniform radiative forcing may be more influenced by regional response than the average response.
JOURNAL OF CLIMATE
(2022)
Article
Engineering, Marine
Jianmin Yu, Haibin Lv, Simei Tan, Yuntao Wang
Summary: This study investigates the sea surface temperature (SST) changes caused by 96 tropical cyclones (TCs) in the northern Indian Ocean (NIO) over an 18-year period. It reveals that within a radius of 300 km from the TC center, SST decreases were observed at 86% of locations, with an average SST response of -0.46 degrees C and a maximum decrease of -2.07 degrees C. The most significant reduction in SST typically occurred two days after the passage of TCs, followed by a gradual recovery period exceeding 15 days for the SSTs to return to their initial values. Stronger and slower-moving TCs induced more substantial cooling effects.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Oceanography
J. S. Saranya, M. K. Roxy, Panini Dasgupta, Ajay Anand
Summary: This study investigates the genesis and trend of marine heatwaves (MHWs) in the Indian Ocean from 1982 to 2018 and their impact on the Indian summer monsoon. The findings suggest that the rapid warming in the Indian Ocean plays a critical role in increasing the number of MHWs, while El Nino has a prominent influence on their occurrence during the monsoon.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Geosciences, Multidisciplinary
Hao-Yan Liu, Masaki Satoh, Jian-Feng Gu, Lili Lei, Jianping Tang, Zhe-Min Tan, Yuqing Wang, Jing Xu
Summary: This study aimed to explore the predictability of tropical cyclone Freddy in the southern tropical Indian Ocean, and identified three key factors contributing to its limited predictability.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Rui Jin, Hui Yu, Zhiwei Wu, Peng Zhang
Summary: Previous studies have focused on intense tropical cyclones (TCs) in the central-southeastern western North Pacific. However, the modulators for weak TCs (WTCs) are not well understood. This research highlights the potential impact of the early spring North Atlantic tripole sea surface temperature anomaly on WTC frequency and develops a physical-based empirical model to predict WTC frequency.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Md Wahiduzzaman, Kevin Cheung, Jing-Jia Luo, Prasad Kumar Bhaskaran, Shaolei Tang, Chaoxia Yuan
Summary: This study examined the predictive skill of a statistical Generalised Additive Model (GAM) by considering the impact of the Indian Ocean Dipole (IOD). The results show that IOD is a good predictor for tropical cyclone activity and landfall probability. The GAM approach has a potential skill of approximately 72% in matching predicted landfall with observations.
Article
Geosciences, Multidisciplinary
Leying Zhang, Xiting Yang, Jiuwei Zhao
Summary: The study finds that the spring North Atlantic Oscillation (NAO) has cross-basin impacts on summer and autumn tropical cyclone genesis frequency (TCGF) over the whole North Hemisphere. The positive NAO suppresses the TCGF in the North Atlantic but promotes it in the North Pacific, and vice versa. This impact is achieved by modulating the large-scale environment parameters.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Meteorology & Atmospheric Sciences
Md Wahiduzzaman, Kevin K. Cheung, Jing-Jia Luo, Prasad K. Bhaskaran
Summary: This study has developed a regional scale spatial statistical model to analyze the relationship between tropical cyclones (TCs) and sea surface temperature (SST) and tropical cyclone heat potential (TCHP) in the North Indian Ocean region. The study found that using a geographically weighted regression (GWR) method, the contribution of SST and TCHP to TC intensity can be determined, and the model has been validated.
WEATHER AND CLIMATE EXTREMES
(2022)
Article
Meteorology & Atmospheric Sciences
Wei Mei, Shuo Li
Summary: Using atmospheric simulations forced with observed sea surface temperatures, the study investigates the variability and predictability of tropical cyclone genesis frequency (TCGF) in the northwest Pacific. Results show that the model can reproduce the observed TCGF variability in certain sub-basin regions, but has limited skill in other regions. Above-normal TCGF is linked to enhanced relative SST.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Qun Zhou, Runyu Zhang
Summary: The study reveals a positive correlation between the spring SIOD events and the frequency of tropical cyclone genesis over the WNP in the following summer. It shows how the intensification of the WNP monsoon trough, enhanced vorticity, reduced vertical wind shear, increased humidity, and vertical velocity under positive SIOD conditions contribute to the generation of more TCs. Additionally, the strengthening of the Mascarene high and Australian high in a positive SIOD year plays a role in maintaining SIOD-related SST dipole anomalies and inducing cyclonic anomalies over the WNP.
INTERNATIONAL JOURNAL OF CLIMATOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Indrajit Ghosh, Sukhen Das, Nabajit Chakravarty
Summary: This study develops a model to investigate the anomaly temperature in tropical cyclones and discovers its relationship with cyclone velocity. By analogically equating the cyclonic structure to a rotating hollow cylinder, the study provides insights into other critical factors for cyclone development. The empirical approach used in addressing tropical cyclone stability allows for the validation of the model using observational data.
Article
Meteorology & Atmospheric Sciences
Ping Zhang, Anmin Duan, Jun Hu
Summary: This study reveals the individual and combined effects of the Indian Ocean basin mode (IOBM) and tropical North Atlantic (TNA) sea surface temperature anomalies (SSTAs) on the interannual variability of Tibetan Plateau precipitation. The warm SSTAs in the Indian Ocean induce an anomalous anticyclone over the Bay of Bengal and trigger a positive precipitation anomaly over the southeastern Tibetan Plateau. The TNA SSTAs further strengthen this effect by inducing easterly winds and a suppressed convection over the central Pacific, resulting in a significant positive precipitation anomaly over the southeastern Tibetan Plateau.
JOURNAL OF CLIMATE
(2022)
Article
Geosciences, Multidisciplinary
Franz Philip Tuchen, Renellys C. Perez, Gregory R. Foltz, Peter Brandt, Rick Lumpkin
Summary: Tropical Instability Waves (TIWs) are the dominant source of intraseasonal variability in the central equatorial Atlantic and play a crucial role in redistributing heat in the upper ocean. A study using multidecadal records of various oceanic variables has shown a long-term intensification of intraseasonal variability, particularly due to increased TIW activity. This pattern is driven by enhanced barotropic energy conversion from the covariance of horizontal current fluctuations.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Guang Yang, Xia Zhao, Dongliang Yuan, Yazhou Zhang, Lin Liu, Shiqiu Peng
Summary: Previous studies have shown that the sea surface temperature anomalies (SSTA) in the tropical Atlantic or Indian Ocean during boreal winter-to-spring can lead to central-Pacific (CP) type El Nino-Southern Oscillation (ENSO) events in the following winter. This study uses observational data and CMIP5 model simulations to demonstrate the strong relationship between the winter-to-spring north tropical Atlantic (NTA) SSTA or Indian Ocean Basin (IOB) mode and CP ENSO events. The synergistic effect of IOB and NTA SSTA can lead to more severe CP ENSO events in the subsequent winter through adjustments in the Walker circulation.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Vikas Singh, Shweta Singh, Akash Biswal
Summary: Fine particulate matter (PM2.5) is the leading environmental risk factor that requires regular monitoring and analysis for effective air quality management. Among the five Indian megacities, Delhi is found to be the most polluted city with a decreasing trend in PM2.5 concentration. Variations in PM2.5 levels are observed due to different site locations and local meteorology, with distinct diurnal, seasonal, and monthly patterns.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Khaiwal Ravindra, Tanbir Singh, Akash Biswal, Vikas Singh, Suman Mor
Summary: The study explored the impact of COVID-19 lockdown phases on PM2.5 concentration in five Indian megacities, showing significant reductions during lockdown with the most notable decrease in Kolkata and Mumbai. During the unlocking phase, all cities except Chennai experienced lower PM2.5 levels compared to lockdown, mostly due to monsoon rains. This research provides valuable insights for future air pollution reduction strategies and highlights the potential for strengthening air pollution control policies based on the findings.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
Satyaban B. Ratna, Annalisa Cherchi, Timothy J. Osborn, Manoj Joshi, Umakanth Uppara
Summary: The extremely positive Indian Ocean Dipole (IOD) event in 2019 had a significant influence on the Indian Summer Monsoon (ISM) rainfall, particularly towards the end of the season. However, warm sea surface temperature anomalies in the central equatorial Pacific also played a role in affecting rainfall patterns over India.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Chaithanya D. Jain, B. L. Madhavan, Vikas Singh, P. Prasad, A. Sai Krishnaveni, V. Ravi Kiran, M. Venkat Ratnam
Summary: This study investigated the variations in different aerosols, radiation, and trace gases over a tropical rural site in India during the COVID-19 lockdown. The levels of anthropogenic emission species decreased significantly during the lockdown period, leading to impacts on the levels and diurnal variability of other species. The study provides insights into rural atmospheric chemistry and its connections with precursor concentrations and dynamics.
ENVIRONMENTAL RESEARCH
(2021)
Article
Mechanics
Harish Varma, Karthikeyan Jagadeesan, Vagesh D. Narasimhamurthy, Amit P. Kesarkar, Helge Andersson
Summary: The fully developed turbulent channel flow with symmetrically roughened walls is studied at two Reynolds numbers to investigate the statistical quantities, near-wall dynamical structures and turbulence anisotropy, revealing variations in flow behavior with Reynolds number changes.
Article
Environmental Sciences
Yubeen Jeong, SungHyun Nam, Jae-Il Kwon, Umakanth Uppara, Young-Heon Jo
Summary: The surface warming trend in the East Sea stalled from 2000 to 2014, while the subsurface warming trend continued. The strengthened northwesterly/northerly wind in the central part of the sea contributed to a positive/negative wind stress curl, resulting in an anticyclonic/cyclonic circulation in the west/east. The negative wind stress in the west enhanced the northward penetration of the East Korean Warm Current and caused a slowdown in its eastward meandering around 38 degrees N, leading to warm water accumulation in the west and peak warm anomaly at greater depth compared to cold anomaly in the east.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Engineering, Aerospace
A. Munsi, A. P. Kesarkar, J. N. Bhate, V. P. M. Rajasree, G. Kutty
Summary: This study analyzed the helical properties of three tropical cyclones (Fani, Luban, and Ockhi) formed over the north Indian Ocean. The findings showed that when the secondary overturning circulation tangled with the primary tangential circulation in a moist convective environment, the tropical cyclones exhibited helical features, indicating the start of a self-sustained helical feedback process. Therefore, considering helicity analysis is essential for analyzing the intensification and dissipation of tropical cyclones.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Oceanography
A. Munsi, A. P. Kesarkar, J. N. Bhate, K. Singh, A. Panchal, G. Kutty, M. M. Ali, Ashish Routray, R. K. Giri
Summary: This study investigates the evolution of ocean thermal parameters during the intensification of three rare cases of rapidly intensified long-duration tropical cyclones formed over the North Indian Ocean. The study finds that the ultimate storm intensities of the cyclones were significantly impacted by ocean mean temperature rather than sea surface temperature. Moreover, the passage of the cyclones after rapid intensification also causes cooling in sea surface temperature, but the reduction in ocean mean temperature is smaller due to the availability of more thermal energy in the upper layers.
JOURNAL OF OCEANOGRAPHY
(2023)
Article
Meteorology & Atmospheric Sciences
Jyoti Bhate, Amit Kesarkar, Arpita Munsi, Kasturi Singh, Asish Ghosh, Abhishek Panchal, Ramkumar Giri, M. M. Ali
Summary: The study examines the rapid intensification features of super cyclonic storm Amphan using the WRF mesoscale model. Observations and forecasts show reliable predictions, revealing the factors contributing to the rapid intensification of Amphan.
METEOROLOGY AND ATMOSPHERIC PHYSICS
(2023)
Article
Environmental Sciences
Bo-Wen Shen, Roger Pielke Sr, Xubin Zeng, Jialin Cui, Sara Faghih-Naini, Wei Paxson, Amit Kesarkar, Xiping Zeng, Robert Atlas
Summary: Based on an analysis of Lorenz models, it is found that weather has both chaotic and orderly characteristics, with limited predictability for chaotic solutions and unlimited predictability for non-chaotic solutions. This revised view is supported by examples and previous research.
Article
Environmental Sciences
Sandeep Devaliya, Jyoti N. Bhate, Ramya Sunder Raman, Kaushik Muduchuru, Arushi Sharma, Vikas Singh, Amit P. Kesarkar, Chandra Venkataraman
Summary: This study investigates the sensitivity of climate model predictions to atmospheric aerosols and meteorological data assimilation using the WRF-Chem model. The results show that aerosols can cause a decrease in incoming shortwave radiation over the Indian landmass and a slight increase over the surrounding oceanic region. The effects of aerosols are also observed in other meteorological parameters such as outgoing longwave radiation, 2-m temperature, relative humidity, and planetary boundary layer height. The inclusion of aerosols in the data assimilation simulations improves the prediction of incoming shortwave radiation but deteriorates some of the meteorological parameters.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Physics, Fluids & Plasmas
Harish Varma, Karthikeyan Jagadeesan, Vagesh D. Narasimhamurthy, Amit P. Kesarkar
Summary: Fully developed turbulent flows through ribbed channels have been simulated using direct numerical simulation (DNS). Two configurations, a two-dimensional (2D) configuration and a three-dimensional (3D) configuration, were investigated. In the 3D configuration, a unique phenomenon of secondary roll cells with a strong updraft in the smooth half of the channel was observed. This affected the flow negatively and attenuated the turbulence significantly. Comparisons were made with a smooth channel at the same friction Reynolds number, revealing that the rough half of the 3D configuration was more turbulent due to momentum transfer from the smooth half.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Environmental Sciences
Umakanth Uppara, Jae-Hong Moon, Chan Joo Jang, Young-Heon Jo
Summary: In this study, an ensemble empirical mode decomposition (EEMD) approach is used to derive the residual sea level anomaly (SLA) by removing high-frequency variations, including interannual and interdecadal variations. It is found that the weakening of the overall trend in SLA during 1993-2020 is mainly caused by interdecadal variations in the tropical Northwest Pacific (NWP). There is also an in-phase connection observed between the interannual and interdecadal variations of SLA associated with La Nina.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Kavita Patnaik, Amit P. Kesarkar, Subhrajit Rath, Jyoti N. Bhate, Anantharaman Chandrasekar
Summary: This paper tests the accuracy of the 1-D hybrid model in simulating the diurnal cycle of trace gases and finds that it shows good agreement with the CAMS model.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Arpita Munsi, Amit Kesarkar, Jyoti Bhate, Kasturi Singh, Abhishek Panchal, Govindan Kutty, Ramkumar Giri
Summary: This study investigates the life cycle dynamics and intensification processes of three long-duration tropical cyclones formed over the North Indian Ocean through high-resolution mesoscale analysis. The release of CAPE and increased relative humidity in the middle-level leads to intense diabatic heating and triggers rapid intensification. The strengthening of relative vorticity is attributed to vertical stretching and middle tropospheric advection. Increase or decrease in upper-tropospheric divergence have different effects on intensification. The RI causes the vortex of three cyclones to extend up to the upper troposphere.
JOURNAL OF EARTH SYSTEM SCIENCE
(2022)