scholarly journals Systematic Variation in Wintertime Precipitation in East Asia by MJO-Induced Extratropical Vertical Motion

2008 ◽  
Vol 21 (4) ◽  
pp. 788-801 ◽  
Author(s):  
Jee-Hoon Jeong ◽  
Baek-Min Kim ◽  
Chang-Hoi Ho ◽  
Yeon-Hee Noh
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Diabatic Heating ◽  
Daily Precipitation ◽  
Lower Troposphere ◽  
Vertical Motion ◽  
Mean Value ◽  
Asian Countries ◽  
The Indian Ocean ◽  
Omega Equation

Abstract The variations in the wintertime precipitation over East Asia and the related large-scale circulation associated with the Madden–Julian oscillation (MJO) are examined. By analyzing the observed daily precipitation for the period 1974–2000, it is found that the MJO significantly modulates the distribution of precipitation over four East Asian countries; the precipitation rate difference between wet and dry periods over East Asia, when the centers of MJO convective activities are located over the Indian Ocean and western Pacific, respectively, reaches 3–4 mm day−1, which corresponds to the climatological winter-mean value. Composite analysis with respect to the MJO suggests that the MJO–precipitation relation is mostly explained by the strong vertical motion anomalies near an entrance region of the East Asia upper-tropospheric jet and moisture supply in the lower troposphere. To elucidate different dynamic origins of the vertical motion generated by the MJO, diagnostic analysis of a generalized omega equation is adopted. It is revealed that about half of the vertical motion anomalies in East Asia are induced by the quasigeostrophic forcings by the MJO, while diabatic heating forcings explain a very small fraction, less than 10% of total anomalies.

Parts of South-east Asia may adopt nuclear post-2030

2021 ◽  
Keyword(s):  
East Asia ◽  
Nuclear Power ◽  
Large Scale ◽  
East Asian ◽  
Energy Development ◽  
South East Asia ◽  
Asian Countries ◽  
Content Type ◽  
Electricity Grid ◽  
Renewable Energy Development

Significance It is the only country in South-east Asia with a large-scale nuclear plant, although this was never loaded with fuel. Other countries in the region have tentative plans to develop nuclear power programmes. Impacts The current absence of nuclear power programmes will help avert the diversion of capital from renewable energy development in the region. South-east Asian countries with small, non-power reactors, built for research, will try to maintain these facilities. Across the region, the need for electricity grid investment will increase as more decentralised generation sources are deployed.

scholarly journals OZO v.1.0: software for solving a generalised omega equation and the Zwack–Okossi height tendency equation using WRF model output

2017 ◽  
Vol 10 (2) ◽  
pp. 827-841 ◽  
Author(s):  
Mika Rantanen ◽  
Jouni Räisänen ◽  
Juha Lento ◽  
Oleg Stepanyuk ◽  
Olle Räty ◽  
...  
Keyword(s):  
Diabatic Heating ◽  
Physical Mechanism ◽  
Wrf Model ◽  
Vertical Motion ◽  
Weather Research And Forecasting ◽  
Cartesian Geometry ◽  
Diabatic Processes ◽  
Research And Education ◽  
The Individual ◽  
Omega Equation

Abstract. A software package (OZO, Omega–Zwack–Okossi) was developed to diagnose the processes that affect vertical motions and geopotential height tendencies in weather systems simulated by the Weather Research and Forecasting (WRF) model. First, this software solves a generalised omega equation to calculate the vertical motions associated with different physical forcings: vorticity advection, thermal advection, friction, diabatic heating, and an imbalance term between vorticity and temperature tendencies. After this, the corresponding height tendencies are calculated with the Zwack–Okossi tendency equation. The resulting height tendency components thus contain both the direct effect from the forcing itself and the indirect effects (related to the vertical motion induced by the same forcing) of each physical mechanism. This approach has an advantage compared with previous studies with the Zwack–Okossi equation, in which vertical motions were used as an independent forcing but were typically found to compensate the effects of other forcings.The software is currently tailored to use input from WRF simulations with Cartesian geometry. As an illustration, results for an idealised 10-day baroclinic wave simulation are presented. An excellent agreement is found between OZO and the direct WRF output for both the vertical motion and the height tendency fields. The individual vertical motion and height tendency components demonstrate the importance of both adiabatic and diabatic processes for the simulated cyclone. OZO is an open-source tool for both research and education, and the distribution of the software will be supported by the authors.

scholarly journals OZO v.1.0: Software for solving a generalized omega equation and the Zwack-Okossi height tendency equation using WRF model output

2016 ◽  
Author(s):  
Mika Rantanen ◽  
Jouni Räisänen ◽  
Juha Lento ◽  
Oleg Stepanyuk ◽  
Olle Räty ◽  
...  
Keyword(s):  
Diabatic Heating ◽  
Physical Mechanism ◽  
Wrf Model ◽  
Vertical Motion ◽  
Weather Research And Forecasting ◽  
Cartesian Geometry ◽  
Diabatic Processes ◽  
Research And Education ◽  
The Individual ◽  
Omega Equation

Abstract. A software package (OZO, Omega-Zwack-Okossi) was developed to diagnose the processes that affect vertical motions and geopotential height tendencies in weather systems simulated by the Weather Research and Forecasting (WRF) model. First, this software solves a generalized omega equation to calculate the vertical motions associated with different physical forcings: vorticity advection, thermal advection, friction, diabatic heating, and an imbalance term between vorticity and temperature tendencies. After this, the corresponding height tendencies are calculated with the Zwack-Okossi tendency equation. The resulting height tendency components thus contain both the direct effect from the forcing itself and the indirect effects (related to the vertical motion induced by the same forcing) of each physical mechanism. This approach has an advantage compared with previous studies with the Zwack-Okossi equation, in which vertical motions were used as an independent forcing but were typically found to compensate the effects of other forcings. The software is tailored to use input from WRF simulations with Cartesian geometry. As an illustration, results for an idealized 10-day baroclinic wave simulation are presented. An excellent agreement is found between OZO and the direct WRF output for both the vertical motion (correlation 0.97 in the midtroposphere) and the height tendency fields (correlation 0.95–0.98 in the whole troposphere). The individual vertical motion and height tendency components demonstrate the importance of both adiabatic and diabatic processes for the simulated cyclone. OZO is an open source tool for both research and education, and the distribution of the software will be supported by the authors.

scholarly journals Application of the Compressible, Nonhydrostatic, Balanced Omega Equation in Estimating Diabatic Forcing for Parameterization of Inertia–Gravity Waves: Case Study of Moist Baroclinic Waves Using WRF

2019 ◽  
Vol 77 (1) ◽  
pp. 113-129
Author(s):  
Mahnoosh Haghighatnasab ◽  
Mohammad Mirzaei ◽  
Ali R. Mohebalhojeh ◽  
Christoph Zülicke ◽  
Riwal Plougonven
Keyword(s):  
Gravity Waves ◽  
General Circulation ◽  
Diabatic Heating ◽  
Wrf Model ◽  
Vertical Motion ◽  
General Circulation Models ◽  
Baroclinic Waves ◽  
Diabatic Forcing ◽  
Omega Equation ◽  
Inertia Gravity Waves

Abstract The parameterization of inertia–gravity waves (IGWs) is of considerable importance in general circulation models. Among the challenging issues faced in studies concerned with parameterization of IGWs is the estimation of diabatic forcing in a way independent of the physics parameterization schemes, in particular, convection. The requirement is to estimate the diabatic heating associated with balanced motion. This can be done by comparing estimates of balanced vertical motion with and without diabatic effects. The omega equation provides the natural method of estimating balanced vertical motion without diabatic effects, and several methods for including diabatic effects are compared. To this end, the assumption of spatial-scale separation between IGWs and balanced flows is combined with a suitable form of the balanced omega equation. To test the methods constructed for estimating diabatic heating, an idealized numerical simulation of the moist baroclinic waves is performed using the Weather Research and Forecasting (WRF) Model in a channel on the f plane. In overall agreement with the diabatic heating of the WRF Model, in the omega-equation-based estimates, the maxima of heating appear in the warm sector of the baroclinic wave and in the exit region of the upper-level jet. The omega-equation-based method with spatial smoothing for estimating balanced vertical motion is thus presented as the proper way to evaluate diabatic forcing for parameterization of IGWs.

scholarly journals Regional Simulation of the October and November MJO Events Observed during the CINDY/DYNAMO Field Campaign at Gray Zone Resolution

2015 ◽  
Vol 28 (6) ◽  
pp. 2097-2119 ◽  
Author(s):  
Shuguang Wang ◽  
Adam H. Sobel ◽  
Fuqing Zhang ◽  
Y. Qiang Sun ◽  
Ying Yue ◽  
...  
Keyword(s):  
Large Scale ◽  
Model Simulation ◽  
Lower Troposphere ◽  
Vertical Motion ◽  
Longwave Radiation ◽  
Leading Edge ◽  
Active Phase ◽  
Surface Fluxes ◽  
Field Campaign ◽  
Surface Precipitation

Abstract This study investigates the October and November MJO events observed during the Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011 (CINDY)/Dynamics of the MJO (DYNAMO) field campaign through cloud-permitting numerical simulations. The simulations are compared to multiple observational datasets. The control simulation at 9-km horizontal grid spacing captures the slow eastward progression of both the October and November MJO events in surface precipitation, outgoing longwave radiation, zonal wind, humidity, and large-scale vertical motion. The vertical motion shows weak ascent in the leading edge of the MJO envelope, followed by deep ascent during the peak precipitation stage and trailed by a broad second baroclinic mode structure with ascent in the upper troposphere and descent in the lower troposphere. Both the simulation and the observations also show slow northward propagation components and tropical cyclone–like vortices after the passage of the MJO active phase. Comparison with synthesized observations from the northern sounding array shows that the model simulates the passage of the two MJO events over the sounding array region well. Sensitivity experiments to SST indicate that daily SST plays an important role for the November MJO event, but much less so for the October event. Analysis of the moist static energy (MSE) budget shows that both advection and diabatic processes (i.e., surface fluxes and radiation) contribute to the development of the positive MSE anomaly in the active phase, but their contributions differ by how much they lead the precipitation peak. In comparison to the observational datasets used here, the model simulation may have a stronger surface flux feedback and a weaker radiative feedback. The normalized gross moist stability in the simulations shows an increase from near-zero values to ~0.8 during the active phase, similar to what is found in the observational datasets.

scholarly journals Modeling the Interaction between Quasigeostrophic Vertical Motion and Convection in a Single Column

2016 ◽  
Vol 73 (3) ◽  
pp. 1101-1117 ◽  
Author(s):  
Ji Nie ◽  
Adam H. Sobel
Keyword(s):  
Large Scale ◽  
Diabatic Heating ◽  
Vertical Motion ◽  
Large Set ◽  
Strongly Coupled ◽  
Column Model ◽  
Single Column ◽  
Single Column Model ◽  
Cloud Resolving Model ◽  
The Stability

Abstract A single-column modeling approach is proposed to study the interaction between convection and large-scale dynamics using the quasigeostrophic (QG) framework. This approach extends the notion of “parameterization of large-scale dynamics,” previously applied in the tropics via the weak temperature gradient approximation and other comparable methods, to the extratropics, where balanced adiabatic dynamics plays a larger role in inducing large-scale vertical motion. The diabatic heating in an air column is resolved numerically by a single-column model or a cloud-resolving model. The large-scale vertical velocity, which controls vertical advection of temperature and moisture, is computed through the QG omega equation including the dry adiabatic terms and the diabatic heating term. The component due to diabatic heating can be thought of as geostrophic adjustment to that heating and couples the convection to the large-scale vertical motion. The approach is demonstrated using two representations of convection: a single-column model and linear response functions derived by Z. Kuang from a large set of cloud-resolving simulations. The results are qualitatively similar in both cases. The behavior of convection that is strongly coupled to large-scale dynamics is significantly different from that in the uncoupled case. The positive feedback of the diabatic heating on the large-scale vertical motion reduces the stability of the system, extends the decay time scale after initial perturbations, and increases the amplitude of convective responses to transient large-scale perturbations or imposed forcings. The diabatic feedback of convection on vertical motion is strongest for horizontal wavelengths on the order of the Rossby deformation radius.

scholarly journals The characteristics and structure of extra-tropical cyclones in a warmer climate

2020 ◽  
Vol 1 (1) ◽  
pp. 1-25 ◽  
Author(s):  
Victoria A. Sinclair ◽  
Mika Rantanen ◽  
Päivi Haapanala ◽  
Jouni Räisänen ◽  
Heikki Järvinen
Keyword(s):  
Tropical Cyclones ◽  
Diabatic Heating ◽  
Vertical Motion ◽  
Atmospheric Model ◽  
Sea Surface ◽  
Intermediate Step ◽  
Thermal Advection ◽  
Vorticity Advection ◽  
Omega Equation ◽  
Total Column

Abstract. Little is known about how the structure of extra-tropical cyclones will change in the future. In this study aqua-planet simulations are performed with a full-complexity atmospheric model. These experiments can be considered an intermediate step towards increasing knowledge of how, and why, extra-tropical cyclones respond to warming. A control simulation and a warm simulation in which the sea surface temperatures are increased uniformly by 4 K are run for 11 years. Extra-tropical cyclones are tracked, cyclone composites created, and the omega equation applied to assess causes of changes in vertical motion. Warming leads to a 3.3 % decrease in the number of extra-tropical cyclones, with no change to the median intensity or lifetime of extra-tropical cyclones but to a broadening of the intensity distribution resulting in both more stronger and more weaker storms. Composites of the strongest extra-tropical cyclones show that total column water vapour increases everywhere relative to the cyclone centre and that precipitation increases by up to 50 % with the 4 K warming. The spatial structure of the composite cyclone changes with warming: the 900–700 hPa layer averaged potential vorticity, 700 hPa ascent, and precipitation maximums associated with the warm front all move polewards and downstream, and the area of ascent expands in the downstream direction. Increases in ascent forced by diabatic heating and thermal advection are responsible for the displacement, whereas increases in ascent due to vorticity advection lead to the downstream expansion. Finally, maximum values of ascent due to vorticity advection and thermal advection weaken slightly with warming, whereas those attributed to diabatic heating increase. Thus, cyclones in warmer climates are more diabatically driven.

scholarly journals Vertical Motion of Air over the Indian Ocean and the Climate in East Asia

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2641
Author(s):  
Rongxiang Tian ◽  
Yaoming Ma ◽  
Weiqiang Ma
Keyword(s):  
Indian Ocean ◽  
Tibetan Plateau ◽  
East Asia ◽  
Yangtze River Basin ◽  
Vertical Motion ◽  
The Tibetan Plateau ◽  
Comprehensive Understanding ◽  
Clockwise Rotation ◽  
The Yangtze River Basin ◽  
The Indian Ocean

The Indian Ocean and East Asia are the most famous monsoonal regions, and the climate of East Asia is affected by the change in wind direction due to monsoons. The vertical motion of the atmosphere is closely related to the amount of precipitation in whichever particular region. Climate diagnosis and statistical analysis were used to study the vertical motion of air over the Indian Ocean and its relationship with the climate in East Asia. The vertical motion of air over the Indian Ocean had a significant correlation with the climate in China—especially with precipitation in the Tibetan Plateau and the Yangtze River Basin—as a result of the interaction of the vertical motion of air from the Indian Ocean, the Tibetan Plateau and the subpolar region in the Northern Hemisphere. The vertical motion over the Indian Ocean was weakened from 1981 to 2010, except at a height of 500 hPa in winter. The vertical motion of air over the Indian Ocean had a period of 7–9 years in summer and 9–12 years in winter. An ascending motion was dominant over most of the Indian Ocean throughout the year and the central axis of the ascending motion changed from a clockwise rotation from winter to summer to a counterclockwise rotation from summer to winter as a result of the monsoonal circulation over the Indian Ocean. These results will provide a theoretical reference for a comprehensive understanding of the climate in Asia and contribute to work on climate prediction in these regions.

scholarly journals Implications of a Decadal Climate Shift over East Asia in Winter: A Modeling Study

2010 ◽  
Vol 23 (18) ◽  
pp. 4989-5001 ◽  
Author(s):  
Song-You Hong ◽  
Yoo-Bin Yhang
Keyword(s):  
Climate Change ◽  
East Asia ◽  
Large Scale ◽  
Hydrological Cycle ◽  
East Asian ◽  
Lower Troposphere ◽  
Large Scale Circulation ◽  
Winter Climate ◽  
Climate Shift ◽  
Decadal Climate

Abstract This study investigates a decadal climate shift over East Asia in winter, focusing on the changes in hydrological cycle as well as large-scale circulation using the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM). The RSM is forced by perfect boundary conditions for winter (December–February) from 1979 to 2007. Analyses for two separate periods (1979–87 and 1999–2007) are performed to investigate the regional climate model’s ability to simulate climate change in precipitation as well as large-scale circulation. The RSM reproduces differences in large-scale features associated with winter climate change over East Asia when the winter monsoon is modulated on decadal time scales with its weakening pattern observed since the late 1980s. The model adequately reproduces a weakening of the Siberian high and shallowness of the Aleutian low in the lower troposphere and a weakened East Asian coastal trough and East Asian jet in the upper troposphere during 1999–2007, as compared to the first nine winters of 1979–87. Conversely, the decadal shift in precipitation is not well reproduced by the model. The model is capable of reproducing the power spectrum of daily precipitation with maxima at 8.5 days and 45 days in 1979–87, whereas widely spread peaks in 1999–2007 are not captured. The increase of precipitation due to parameterized convection is prominent. This study shows that the dynamical numerical model has a limited capability to reproduce the wintertime hydrological climate over East Asia associated with global warming in recent years.

scholarly journals <i>Brief communication</i> "Calabria daily rainfall from 1970 to 2006"

2010 ◽  
Vol 10 (4) ◽  
pp. 717-722 ◽  
Author(s):  
S. Federico ◽  
L. Pasqualoni ◽  
E. Avolio ◽  
C. Bellecci
Keyword(s):  
Large Scale ◽  
Daily Precipitation ◽  
Daily Rainfall ◽  
Mean Value ◽  
Precipitation Trend ◽  
Teleconnection Patterns ◽  
Rain Gauges ◽  
The Mediterranean ◽  
Mediterranean Oscillation ◽  
Controlled Precipitation

Abstract. This brief communication introduces a new quality-controlled precipitation database for Calabria, shows the precipitation trend for the period considered, and correlates daily rainfall with some common teleconnection patterns. The database consists of daily accumulated precipitation collected by 61 rain gauges from 1 January 1970 to 31 December 2006. The 37-year trend in yearly rainfall shows a decrease of 4.7 mm/y, with a 17% reduction in the yearly mean value. The correlation of the daily rainfall with large-scale patterns shows that the Mediterranean Oscillation Index (MOI a/c) is a useful predictor of daily precipitation over Calabria.

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