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Ensemble Sensitivity Analysis of an Extreme Rainfall Event over the Himalayas in June 2013 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2021-01-27 Babitha George; Govindan Kutty
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Effect of offshore troughs on the South India erratic summer monsoon rainfall in June 2017 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Rakesh Teja Konduru; Mrudula G
The onset and advance of southwest monsoon are accompanied by the appearance of the offshore trough along the southwest coast of India. This offshore trough escorts a deluge of rainfall to the southwest coast, and sometimes rainfall band moves eastward further into south India. These broad observations were noticed during the summer monsoon of June 2017. Meteorological agencies and media had reported
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Synoptic and dynamic analysis of a flash flood-inducing heavy rainfall event in arid and semi-arid central-northern Iran and its simulation using the WRF model Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2021-01-02 S. Khansalari; A. Ranjbar-Saadatabadi; F. Fazel-Rastgar; T. Raziei
The synoptic and dynamic aspects of heavy rainfall occurred on 5th May 2017 and caused flash flooding in arid and semi-arid central-northern Iran is analyzed by the Weather Research and Forecasting (WRF) model. This system synoptically is attributed to a surface low-pressure centered over southern Iran extended to the central parts, linking to a mid-tropospheric tilted-trough over western Iran, and
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Impact of terrain complexity on the turbulence drag coefficient: A case study from the Indian Himalayan region Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2021-01-13 Priyanka Lohani; Sandipan Mukherjee
The aerodynamic drag coefficient (CD) is conjectured to change (or remains almost uniform) with the horizontal wind speed (U) over a flexible (or fixed) surface element, which is represented with the surface roughness (z0). This conjecture is tested for the near neutral atmospheric turbulence (i.e. when surface stability z/L is almost equal to 0, where z is the measurement height and L is Obukhov length)
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Role of External Forcing on the Seasonal and Interannual Variability of Mixed Layer Depth over the Bay of Bengal using Reanalysis Datasets during 1980 to 2015 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2021-01-13 Biplab Sadhukhan; Arun Chakraborty; Abhishek Kumar
The monsoon reversal winds in different seasons and high influx of freshwater from various rivers make the Bay of Bengal (BoB) a unique region. Thus, the knowledge of the dynamics of the mixed layer over this region is very important to assess the climatic variation of the Indian subcontinent. A comprehensive study of the role of external forcing on the seasonal and interannual mixed layer depth (MLD)
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Sensitivity evaluation of the different physical parameterizations schemes in regional climate model RegCM4.5 for simulation of air temperature and precipitation over North and West of Iran Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2021-01-05 Fatemeh KhayatianYazdi; Gholamali Kamali; Seyyed Majid Mirrokni; Mohammad Hossein Memarian
In this research the dynamic downscaling method by Regional Climate Model (RegCM4.5) was used to assess the performance and sensitivity of seasonal simulated North and West of Iran (NI&WI) climate factors to different convection schemes, and transforms the large-scale simulated climate variables into land surface states over the North of Iran (NI) and West of Iran (WI). A 30-year (1986–2015) numerical
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Effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries over the North Indian Ocean Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Md. Jalal Uddin; Zahan Most. Nasrin; Yubin Li
Tropical cyclone (TC) rainfall asymmetry is often influenced by vertical wind shear and storm motion. This study examined the effects of environmental vertical wind shear (200-850 hPa) and storm motion on TC rainfall asymmetry over the North Indian Ocean (NIO): the Bay of Bengal (BoB) and the Arabian Sea (AS). Four TC groups were used in this study: Cyclonic Storm (CS), Severe Cyclonic Storm (SCS)
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IMPROVED WIND DRAG FORMULATION FOR NUMERICAL STORM WAVE AND SURGE MODELING Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 C. Gowri Shankar; Manasa Ranjan Behera
The study proposes an enhanced method of computing wind drag coefficient (Cd) for extreme hurricane wind conditions which can be applied to precisely estimate the hurricane induced storm wave and surge. Thirty different tropical cyclone/hurricane conditions were chosen and modeled using the enhanced Wave Boundary Layer Model (WBLM) to estimate Cd based on air-sea interaction concept and are then subjected
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Climatic analysis of tropopause during the northwestern Indian Ocean tropical cyclones Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Nafiseh Pegahfar
In this research, tropopause temperature (TT) and tropopause geopotential height (TGH) over the inner-core and environmental regions of all tropical cyclones (TCs) over the northwest of the Indian Ocean (NWIO) from 1990 to 2019 were investigated. To this aim, observational/analysis/reanalysis data and also simulated data from both historical and Representative Concentration Pathway 8.5 (RCP8.5) experiments
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Fast responses of Northern Hemisphere winter daily circulation to anthropogenic aerosols Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Jiechun Deng; Jing Ma; Leying Zhang; Dorina Chyi
Anthropogenic aerosols (AA) have significantly caused anomalous winter mean atmospheric circulation over the Northern Hemisphere, but the main daily patterns of winter large-scale circulation change are not well understood. Here a self-organizing map analysis is applied to identify the leading patterns in AA-induced winter daily geopotential height (Z) anomaly fields simulated by three atmospheric
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Determining the source of dust storms with use of coupling WRF and HYSPLIT models: A case study of Yazd province in central desert of Iran Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Fatemeh Iraji; Mohammad Hossein Memarian; Mohammad Joghataei; Hamid Reza Ghafarian Malamiri
Dust storm, which has a significant impact on regional air quality, is one of the most hazardous meteorological phenomena in the arid areas. Yazd province is one of the arid areas in Iran that is exposed to dust storms. In this study, two cases of dust storms of Yazd province are studied with the use of coupling numerical models and aerosol optical depth (AOD) from MODIS data. We investigated synoptic
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Inter-comparison of long-term wave power potential in the Black Sea based on the SWAN wave model forced with two different wind fields Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-31 Fulya Islek; Yalcin Yuksel
In this study, a long-term comparative assessment of the potential of wave power in the Black Sea was conducted using the calibrated and validated SWAN (Simulating WAves Nearshore) model forced by two well-known wind fields. The European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim and National Centers for Environmental Prediction/Climate Forecast System Reanalysis (NCEP/CFSR) wind
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On the analytical solution for two-dimensional convective plume and analytical modeling of the entrainment zone thickness Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-30 Cristian V. Vraciu
Analytical solution for two-dimensional thermal plume updraft velocity is obtained under the assumption of a uniform temperature excess inside the plume. In this way, the thermal plume motion is modeled in both mixed layer and entrainment zone. Also, a semi-analytical solution is obtained using an empirical model for the plume temperature excess in the mixed layer. In addition, an analytical model
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Self-localized solitons of the nonlinear wave blocking problem Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-30 Cihan Bayındır
In this paper, we propose a numerical framework to study the shapes, dynamics, and stabilities of the self-localized solutions of the nonlinear wave blocking problem. To our best knowledge, blocking of the solitons in the marine environment has not been studied before in the existing literature. With this motivation, we use the nonlinear Schrödinger equation (NLSE) derived by Smith as a model for the
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Atmospheric driving mechanisms of extreme precipitation events in July of 2017 and 2018 in western Japan Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-25 Sridhara Nayak; Tetsuya Takemi
The occurrence of extreme precipitation events is now a serious concern in recent years in Japan. This study explores the atmospheric driving mechanisms of two extreme precipitation events occurred during 5–6 July 2017 and 5–8 July 2018 over western Japan. We identified that the atmospheric transport of large amounts of moisture and wind streams with wind speed of minimum 15 m s−1 from south of Japan
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Hydrographic effects of an intense “medicane” over the central-eastern Mediterranean Sea in 2018 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-12-15 Dimitris Kassis; George Varlas
The formation of cyclones over the sea surface is driven by air-sea interaction with feedbacks on wave generation, thermohaline structures, and biochemical properties of upper-ocean layers. In the Mediterranean basin, strong cyclonic systems having tropical-like characteristics are called “medicanes”. The consequences of such events are usually assessed over the land, however, hydrographic effects
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Evaluation of the assimilation of conventional and satellite-based observations in simulating heavy rainfall event using WRFDA over the North-West Himalayan region Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-11-19 Sachin Budakoti; Charu Singh; P.K. Pal; Ashish Navale
Present work elucidates the impact of 3DVAR data assimilation technique for the simulation of one of the heavy rainfall events reported over Kotdwara region in the North-West Himalayan (NWH) region on 4th August 2017. We have examined the impact of conventional and satellite-based radiance datasets on the simulated results with and without assimilating the observations into the Weather Research and
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Seasonal variability of air-sea fluxes in two contrasting basins of the North Indian Ocean Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-11-13 Samar Kumar Ghose; Debadatta Swain; Simi Mathew; R. Venkatesan
Latent Heat Flux (LHF) and Sensible Heat Flux (SHF) are the two important parameters in air-sea interactions and hence have significant implications for any coupled ocean-atmospheric model. These two fluxes are conventionally computed from met-ocean parameters using bulk aerodynamic formulations; or the Coupled Ocean Atmosphere Response Experiment (COARE) bulk flux algorithms. Here COARE 3.5 algorithm
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Identifying future climate change and drought detection using CanESM2 in the upper Siem Reap River, Cambodia Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-11-14 Kosal Chim; Jon Tunnicliffe; Asaad Shamseldin; Chan Kakkada
Cambodia is one of the most vulnerable countries to climate change impacts such as floods and droughts. Study of future climate change and drought conditions in the upper Siem Reap River catchment is vital because this river plays a crucial role in maintaining the Angkor Temple Complex and livelihood of the local population since 12th century. The resolution of climate data from Global Circulation
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Ocean surface hidden structures in the Lofoten area of the Norwegian Sea Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-09-30 M. Bakhoday-Paskyabi
We investigate the structure of surface lateral mixing in the Lofoten area in the Norwegian Sea using surface velocity field derived from a 1/12o reanalysis data. We compute a Lagrangian diagnostic based on the evolution of Finite Time Lyapunov Exponents (FTLEs) by advecting (backward in time) a large number of particles to quantify the hidden skeleton of different dynamical regions in the study area
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Long-term analysis of extreme wave characteristics based on the SWAN hindcasts over the Black Sea using two different wind fields Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-09-06 Fulya Islek; Yalcin Yuksel; Cihan Sahin; H. Anil Ari Guner
The long-term variations of wave characteristics in the Black Sea are evaluated by using a third-generation wave model (Simulating WAves Nearshore, SWAN), forced by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim and National Centers for Environmental Prediction/Climate Forecast System Reanalysis (NCEP/CFSR) wind data, covering the period of 1979-2018. The model results were
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Accuracy of the deep convection intensity from a limited number of casts Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-08-29 Aleksandr M. Fedorov, Igor L. Bashmachnikov
Deep convection is one of the key components of the Atlantic Meridional Overturning Circulation. The intensity of deep convection (DC) is traditionally estimated as the maximum mixed layer depth (MMLD). In this study, we developed a criterion of the minimum number of casts needed for obtaining the MMLD in the Greenland Sea with a pre-defined accuracy. The criterion depends on convection intensity.
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Diurnal Sea surface temperature response to tropical cyclone Dahlia in the Eastern tropical Indian Ocean in 2017 revealed by the Bailong buoy Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-08-24 Yang Yang, Lin Liu, Kuiping Li, Weidong Yu, Haiyuan Wang
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Simulation of a mesoscale convective system over Northern India: Sensitivity to convection partitioning in a regional NWP model Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-08-23 Timmy Francis, A. Jayakumar, Saji Mohandas, Jisesh Sethunadh, M. Venkatarami Reddy, T. Arulalan, E.N. Rajagopal
Simulations of a mesoscale convective system (MCS), which propagated across Northern India on 2nd May 2018 - leading to many fatalities when the gust front knocked down homes and tore apart building roofs - have been performed using the National Centre for Medium Range Weather Forecasting (NCMRWF) Unified Model – Regional (4 km horizontal grid spacing), to evaluate the model’s convective treatments
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Submesoscale fronts observed by satellites over the Northern South China Sea shelf Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-08-16 Jihai Dong, Yisen Zhong
Fronts are ubiquitous dynamic processes in the ocean, which play a significant role in the ocean dynamical and ecological environments. In this paper strong temperature fronts are investigated on the shelf of the Northern South China Sea using high resolution satellite data. These fronts have large horizontal gradients exceeding 1 °C km−1 with spatial scales around several kilometers. The fronts generate
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Diurnal cycle of precipitation over the Maritime Continent simulated by a spectral cumulus parameterization Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-07-16 Yuya Baba
The validity of a spectral cumulus parameterization (spectral scheme) for simulating a diurnal cycle of precipitation over the Maritime Continent (MC) was examined using a regional atmospheric model. The impacts of entrainment parameterization and each type of convective closure, i.e., non-equilibrium (or equilibrium) closure for deep convection, mid-level, and shallow convective closures, were also
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Spontaneous superharmonic internal wave excitation by modal interactions in uniform and nonuniform stratifications Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-07-15 Dheeraj Varma, Vamsi K. Chalamalla, Manikandan Mathur
Internal waves in the ocean are well-recognized to play an important role in the global energy budget. Triadic resonance is one mechanism via which these internal waves transfer their energy to other spatial and temporal scales before dissipation, at locations blue both near and away from their generation sites. In this paper, we perform a combined theoretical and numerical study of triadic resonance
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The effect of wind and temperature to phytoplankton biomass during blooming season in Barents Sea Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-07-07 Bo Qu, Xiao Liu
The Barents Sea is the most productive sea in the Arctic. The main causes of phytoplankton spring blooms are studied for a decadal time period of 2003–2013 at the region of (70 °N-80 °N, 30 °E-40 °E) in Barents Sea. Due to the rapidly ice melt in the southern region (70 °N-75 °N), almost no ice left after year 2005, sea surface temperature (SST) and wind speed (WIND) are two main dominant factors influencing
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NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-07-02 Saji Mohandas, Timmy Francis, Vivek Singh, A. Jayakumar, John P. George, A. Sandeep, Prince Xavier, E.N. Rajagopal
In depth examination of the extreme precipitation over Kerala during 15–17th August 2018 – triggering major flood episode in the peninsular Indian state - have been made via the National Centre for Medium Range Weather Forecasting (NCMRWF) Unified Model. A rare alignment of an intense low pressure area (LPA) over head Bay of Bengal (BoB) and a couple of typhoons over South China Sea and West Pacific
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Distinct intensification pathways for a shallow-water vortex subjected to asymmetric “diabatic” forcing Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-06-14 David A. Schecter
Observational studies and cloud resolving numerical simulations have shown that developing tropical cyclones often have markedly asymmetric distributions of moist convection. The present study uses a shallow-water model on the f-plane to gain further insight into the variety of vortex intensification pathways that may exist under such conditions. The diabatic forcing associated with asymmetric convection
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A coupled modeling study of mechanical and thermodynamical air-ocean interface processes under sea storm conditions Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-05-21 Christos Stathopoulos, George Galanis, George Kallos
The interaction mechanisms between the lower part of the atmosphere and the ocean surface comprise of a complicated issue with many parameters to be studied. Heat, moisture and momentum exchanges in the air-sea system exert a significant role on both lower atmosphere and sea state conditions. Working towards the understanding of how wave characteristics link the atmosphere with the ocean, an atmospheric
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The unique, well posed reduced system for atmospheric flows: Robustness in the presence of small scale surface irregularities Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-05-21 G.L. Browning
It is well known that the primitive equations (the atmospheric equations of motion under the additional assumption of hydrostatic equilibrium for large scale motions) are ill posed when used in a limited area on the globe. Yet the atmospheric equations of motion for large scale motions are essentially a hyperbolic system that with appropriate boundary conditions should lead to a well posed system in
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Low latitude dynamical response to vortex split sudden stratospheric warming: An Eliassen Palm Flux perspective Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-05-15 Bhagavathiammal G.J.
The present work extensively describes the tropical dynamical changes during the Vortex split Major Stratospheric Warming (V-MSW) event occurred in recent decades. For better visualization of high latitude influence of tropical atmosphere, in this study, we have utilized three successive major vortex split warming events occurred in winters 1984/85, 1988/89 and 2008/09. The realistic visualization
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Inertia and diurnal oscillations of Ekman layers in atmosphere and ocean Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-05-08 Wen-Yih Sun, Oliver M. Sun
A 1D model, including a time variation of eddy viscosity and mixed layer depth, is applied to study Ekman spirals. It simulates a weak velocity in the atmosphere but a jet in the upper oceanic mixed layer during daytime; and a strong velocity in the atmosphere but a weak, uniform velocity in the ocean at night. The mean spirals in both atmosphere and ocean are close to the average spirals at midday
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Subseasonal coupling between subsurface subtropical front and overlying atmosphere in North pacific in winter Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-04-21 FeiFei Chen, HaiBo Hu, Haokun Bai
At least two main oceanic fronts (the subarctic and subtropical fronts) exist in the North Pacific. Especially in the subtropical frontal zone (STFZ), the sea subsurface temperature gradient is significantly larger than that of the surface layer in winter. Subseasonal interaction between the subsurface subtropical front and overlaying atmosphere is revealed by using empirical orthogonal function (EOF)
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Asymmetry in the tropical Indian Ocean subsurface temperature variability Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-04-06 Rashmi Kakatkar, C. Gnanaseelan, J.S. Chowdary
The empirical orthogonal function (EOF) analysis of subsurface temperature shows a dominant north-south mode of interannual variability in the Tropical Indian Ocean (TIO) at around 100 m depth (thermocline). This subsurface mode (SSM) of variability evolves in September-November (SON) as a response to Indian Ocean Dipole and intensifies during December-February (DJF) reinforced by El Niño and Southern
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The influence of the Madden-Julian oscillation on high-latitude surface air temperature during boreal winter Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-03-20 Jing Cui, Shuangyan Yang, Tim Li
By analyzing NCEP-NCAR reanalysis daily data for 1979–2016, the modulation by Madden-Julian Oscillation (MJO) of the wintertime surface air temperature (SAT) over high latitude is examined. The real-time multivariate MJO (RMM) index, which divides the MJO into eight phases, is used. It is found that a significantly negative SAT anomaly over the northern high latitude region of (180°–60 °W, 60°–90 °N)
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Spatiotemporal long-term trends of extreme wind characteristics over the Black Sea Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-02-29 Fulya Islek, Yalcin Yuksel, Cihan Sahin
In this study, long-term change of wind characteristics on the Black Sea has been investigated using two widely used data sources, i.e., European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim and National Centers for Environmental Prediction/Climate Forecast System Reanalysis (NCEP/CFSR), spanning 40 years between 1979 and 2018. Spatial and seasonal variability of climatic features
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Study of the climatological behaviors of Euro-Atlantic and West Asia blockings in the period of 1959–2018 Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-02-01 Sara Fahimi, Farhang Ahmadi-Givi, Amir Hussain Meshkatee, Majid Mazraeh Farahani
In this study, comparison of blocking climatological behaviors is presented for the two periods of 1959–1988 and 1989–2018 in a part of the Northern Hemisphere including the Atlantic Ocean, Europe and West Asia regions. Blocking events were detected using a modified blocking index that is based on vertically integrated potential vorticity. By applying this index, the characteristics of detected blocking
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Solitary waves of two-layer quasi-geostrophic flow and analytical solutions with scalar nonlinearity Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-01-19 Baojun Zhao, Li Cheng, Wenjin Sun
In this paper we investigate the instability of two-layer quasi-geostrophic model with scalar nonlinearity, which is a geophysical fluid dynamics model, and give a nonlinear stability criterion. Furthermore, the analytical solutions of the two-layer quasi-geostrophic model are obtained via the Jacobi elliptic periodic function transform method and symbolic computation. It is efficient in solving a
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Characteristics and vertical structure of oceanic mesoscale eddies in the Bay of Bengal Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2020-01-13 Venkata Sai Gulakaram, Naresh Krishna Vissa, Prasad Kumar Bhaskaran
The signatures of mesoscale eddies induced surface and subsurface changes have not been comprehensively quantified for the Bay of Bengal (BoB) region. This study quantifies the statistical properties and three-dimensional (3D) eddy structures in the BoB. To accomplish this, the satellite altimetry data combined with automated eddy detection and tracking algorithm is used. Horizontal distribution of
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Tropical cyclone structure in the South China Sea based on high-resolution reanalysis data and comparison with that of ‘bogus’ vortices Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-12-19 Yanyan Huang, Bin Zheng
Based on high-resolution reanalysis data of the European Centre for Medium-Range Weather Forecasts, several samples of tropical cyclones (TCs), including tropical storms, severe tropical storms, and typhoons, in the South China Sea (SCS), were selected for composite analysis. The structures of these three types of vortices and their differences with ‘bogus’ vortices were investigated. Results showed
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Integrating remote sensing data with WRF model for improved 2-m temperature and humidity simulations in China Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-12-02 Dongdong Yan, Tianya Liu, Wenjie Dong, Xiaohan Liao, Siqiong Luo, Kai Wu, Xian Zhu, Zhiyuan Zheng, Xiaohang Wen
The default green vegetation fraction (GVF) in the Weather Research and Forecasting (WRF) Model version 3.7.1 was derived between 1985 and 1990 from the 1990s Normalized Difference Vegetation Index (NDVI) achieved from the NOAA Advanced Very High Resolution Radiometer (AVHRR), and its representation is deteriorating when used to simulate recent weather and climate events. In this study, we applied
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An ocean wind-wave climatology for the Southern Brazilian Shelf. Part I: Problem presentation and model validation Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-11-22 R.O. Cecilio, S.R. Dillenburg
Geomorphological features and sparse visual wave measurements, presented in previous works, point out to the possible existence of alongshore wave energy gradients over the Southern Brazilian Shelf (SBS). After describing the two numerical models utilized and the model grids and settings, the present study evaluated the proposed validation of the basin-scale results against orbital altimetry and the
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Resonance of baroclinic waves in the tropical oceans: The Indian Ocean and the far western Pacific Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-11-12 Jean-Louis Pinault
The Indian Ocean has a particularity, its width is close to half the wavelength of a Rossby wave of biannual frequency, this coincidence having been capitalized on by several authors to give the observations a physical basis. The purpose of this article is to show that this is not the case since the resonance of tropical baroclinic waves occurs in all three oceans. This is because the westward-propagating
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Dynamics of vortical structures in the Baltic Sea Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-09-30 Bijan Dargahi
A fully calibrated and validated 3D hydrodynamic model is applied to the Baltic Sea to investigate the vortical structures in the Baltic Sea in the period 2000–2009. The novelty of the study is the detection and dynamics of large scale mesoscale vortices both in horizontal and vertical planes by using the instantaneous velocity vectors. This study provides some new insights into the type and dynamics
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Analysis of long-term precipitation changes in West Bengal, India: An approach to detect monotonic trends influenced by autocorrelations Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-09-28 Pritha Datta, Soumik Das
The precipitation of the entire Indian sub-continent is primarily driven by the monsoon wind system, which throws a tough challenge to model changes due to its natural variabilities. Additionally, the unique geographical location and diverse climatic condition of the Indian state of West Bengal (WB) accelerates this challenge even more. Such a situation can be more complicated if the assumption of
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An ocean wind-wave climatology for the Southern Brazilian Shelf. Part II: Variability in space and time Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-09-10 R.O. Cecilio, S.R. Dillenburg
Previously validated model results were used to characterize the wave climate over the Southern Brazilian Shelf (SBS). The low mean significant wave height over the western South Atlantic shelves was shown together with examples of cyclone-induced extreme wave fields and other typical wave conditions. The mean offshore spectra showed a bimodal shape with a predominance of S/SSW and ENE/E waves with
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Evaluation of 2-m temperature and precipitation products of the Climate Forecast System version 2 over Iran Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-08-29 Omid Alizadeh-Choobari, Morteza Qadimi, Sajedeh Marjani
Using a continuous multi-decadal simulations over the period 1981–2010, subseasonal to seasonal simulations of the Climate Forecast System version 2 (CFSv2) over Iran against the Climatic Research Unit (CRU) dataset are evaluated. CFSv2 shows cold biases over northern hillsides of the Alborz Mountains with the Mediterranean climate and warm biases over northern regions of the Persian Gulf and the Oman
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Characteristics and evolution of a coastal mesoscale eddy in the Western Bay of Bengal monitored by high-frequency radars Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-08-29 Samiran Mandal, Sourav Sil, Saikat Pramanik, Arunraj K.S., Basanta Kumar Jena
Evolution of a coastal cyclonic eddy has been investigated using surface current observations from high-frequency radar (HFR) along the western Bay of Bengal (BoB) near Andhra Pradesh coast during October-December 2015. The HFRs tracked the genesis of the cyclonic eddy from early October, which persisted throughout November and dissipated after mid-December within the shelf-slope regions of HFR domain
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Performance assessment of WRF model in simulating the very severe cyclonic storm “TITLI” in the Bay of Bengal: A case study Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-08-26 B.K. Mahala, P.K. Mohanty, M. Das, A. Routray
The present study has been conducted to assess the performance of the Weather Research and Forecasting – Advanced Research (WRF-ARW, hereinafter named as WRF) model in simulating the very severe cyclonic storm (VSCS) “Titli” which formed over the Bay of Bengal during 08–13 October, 2018. The simulated meteorological variables viz. 10-m wind vectors, surface latent heat flux, rainfall, track and intensity
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Evaluation of the CORDEX regional climate models performance in simulating climate conditions of two catchments in Upper Blue Nile Basin Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-08-15 Wakjira T. Dibaba, Konrad Miegel, Tamene A. Demissie
This study was targeted at evaluating the performance of six Regional Climate Models (RCMs) used in Coordinated Regional Climate Downscaling Experiment (CORDEX). The evaluation is on the bases of how well the RCMs simulate the seasonal mean climatology, interannual variability and annual cycles of rainfall, maximum and minimum temperature over two catchments in western Ethiopia during the period 1990–2008
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Latitudinal dependence of the dry air effect on tropical cyclone development Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-08-10 Donglei Shi, Xuyang Ge, Melinda Peng
The impacts of dry air on tropical cyclone (TC) development at different latitudes with no mean flows are investigated with idealized simulations. It is found that the effective radius of the dry air is sensitive to its vertical distribution and the background earth rotation. The effect of low-level dry-air layer in inhibiting TC development decreases with increasing latitude. At lower latitudes, the
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Negative relationship between Korea landfalling tropical cyclone activity and Pacific Decadal Oscillation Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-07-12 Jae-Won Choi, Hae-Dong Kim
The present study discovered a strong negative correlation between Korea-landfalling tropical cyclone (TC) frequency and Pacific Decadal Oscillation (PDO) in the summer. Thus, the present study selected years that had the highest PDO index (positive PDO years) and years that had the lowest PDO index (negative PDO years) to analyze a mean difference between the two phases in order to determine the reason
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Asymmetric effects of atmospheric circulation on the South China Sea summer monsoon onset Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-07-06 Chunhui Li, Zhengbin Zheng, Dejun Gu, Ailan Lin
Observational analyses suggest a significant positive correlation between the year-to-year convection over the South China Sea (SCS)/western Pacific (WP) and the SCS summer monsoon (SCSSM) onset date. An investigation shows that there is an asymmetric relationship between the area-mean outgoing longwave radiation and the SCSSM onset date index. The analysis found that the influence of the intraseasonal
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Simulation of location-specific severe thunderstorm events using high resolution land data assimilation Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-06-28 Anshul Sisodiya, S. Pattnaik, H. Baisya, G.S. Bhat, A.G. Turner
In this study, the impact of different land initial conditions on the simulation of thunderstorms and monsoon depressions is investigated using the Weather Research and Forecasting (WRF) model. A control run (CNTL) and a simulation with an improved land state (soil moisture and temperature) using the High Resolution Land Data Assimilation System (HRLDAS, experiment name: EHRLDAS) are compared for three
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The cause of the spring strengthening of the Antarctic polar vortex Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-06-25 Vladimir V. Zuev, Ekaterina Savelieva
The stratospheric polar vortex strengthening from late winter to spring plays a crucial role in polar ozone depletion. The Arctic polar vortex reaches its peak intensity in mid-winter, whereas the Antarctic vortex usually strengthens in early spring. As a result, the strong ozone depletion is observed every year over the Antarctic, while over the Arctic short-term ozone loss occasionally occurs in
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NPZ response to eddy-induced upwelling in a Brazil Current ring: A theoretical approach Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-06-08 Filipe Pereira, Ilson C.A. da Silveira, Glenn R. Flierl, Amit Tandon
This work explores the effect of a cyclonic mesoscale feature of the Brazil Current (BC) moving northward off SE Brazil (20° S–23° S) in the Nutrients-Phytoplankton-Zooplankton (NPZ) dynamics. We employ the contour dynamics technique in a quasi-geostrophic, inviscid, 1½-layer model set as a meridional jet flowing southward along a rigid western boundary. This hydrodynamical model is coupled to a conventional
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Low frequency variations in currents on the southern continental shelf of the Caspian Sea Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-06-01 Mina Masoud, Rich Pawlowicz, Masoud Montazeri Namin
The Caspian Sea (CS) is the largest enclosed basin in the world, located inside the Eurasian continent in the Northern Hemisphere. Although there have been few studies of the dynamics of the coastal zone in the CS, observations show that oscillations with periods from 2–3 days to 1–3 weeks dominate. These oscillations are presumed to be related to the synoptic variability of direct wind impact and
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Probabilistic comparison between turbulence closure model and Bulk Richardson Number approach for ABL height estimation using copula Math. Comput. Simul. Dyn. Atmos. Ocean. (IF 1.592) Pub Date : 2019-05-20 Shikhar Upadhyay, Sarit K. Das, C.S.P. Ojha
In this paper, a numerical study has been carried out to assess changes in Atmospheric Boundary Layer (ABL) height under changing hydro-climatic conditions. ABL height is estimated by using the data from experiments conducted at three different sites- LAnd Surface Process EXperiment (LASPEX-97) in Sabarmati river basin, Gujarat, India, during 1997; Boundary Layer Late Afternoon and Sunset Turbulence
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