scholarly journals Internal Interannual Variability of the Troposphere–Stratosphere Coupled System in a Simple Global Circulation Model. Part I: Parameter Sweep Experiment

2002 ◽  
Vol 59 (21) ◽  
pp. 3021-3036 ◽  
Author(s):  
Masakazu Taguchi ◽  
Shigeo Yoden
Keyword(s):  
Interannual Variability ◽  
Circulation Model ◽  
Coupled System ◽  
Global Circulation Model ◽  
Global Circulation

scholarly journals Dynamics of the Stationary Anomalies Associated with the Interannual Variability of the Midwinter Pacific Storm Track—The Roles of Tropical Heating and Remote Eddy Forcing

2007 ◽  
Vol 64 (7) ◽  
pp. 2442-2461 ◽  
Author(s):  
Edmund K. M. Chang ◽  
Yanjuan Guo
Keyword(s):  
Interannual Variability ◽  
Storm Track ◽  
Circulation Model ◽  
Wave Model ◽  
Stationary Wave ◽  
Global Circulation Model ◽  
Global Circulation ◽  
The Pacific ◽  
Eddy Fluxes ◽  
Tropical Heating

Abstract The leading mode of interannual variability of the midwinter Pacific storm track is such that the storm track is weaker during the winters when the Pacific jet is strong, and stronger when the jet is weak. In this paper, experiments are conducted using a stationary wave model as well as an idealized global circulation model to explore the roles of anomalous tropical heating and eddy fluxes in forcing the observed Pacific jet anomalies. It is found that enhanced tropical heating over the region 60°E to the date line, 25°S to 25°N, acts to force a stronger and narrower Pacific jet. On average, tropical heating may account for about one-third of the strong jet anomaly, but there is significant year-to-year variability. Moreover, tropical heating does not appear to contribute to the weak jet anomaly. Much of the Pacific jet anomalies are forced by anomalous eddy fluxes. By examining the regional contributions from the Pacific, the Atlantic, and Asia, it is found that local eddy feedback over the Pacific only acts to force part of the stationary anomaly, while much of the signal is forced by remote eddy forcings from the Atlantic and Asia. Since significant parts of the jet anomalies are forced by anomalous tropical heating and remote eddy fluxes, it is concluded that the observed Pacific jet/storm-track variability is not a pure local wave–mean flow interaction mode internal to the Pacific basin. Both stationary wave model diagnostics and idealized global circulation model experiments suggest that stronger eddy activity over the Atlantic may force a weaker Pacific jet and stronger Pacific eddies. On the other hand, changes in eddy activity over the Pacific may also act to force changes in the Atlantic storm track. There are also indications that tropical heating anomalies may force a simultaneous weakening of both storm tracks. These possibilities may be some of the factors behind the observed significant correlation between the Pacific and Atlantic storm tracks and should be further explored in more realistic GCM experiments.

scholarly journals A Comparative Evaluation of a Mesoscale Model and Atmospheric Global Circulation Model for Air Quality Simulation: A Multiscale, Multisite Evaluation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
P. Goswami ◽  
J. Baruah
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Large City ◽  
Circulation Model ◽  
Urban Pollution ◽  
Atmospheric Pollutants ◽  
Scale Model ◽  
Global Circulation Model ◽  
Global Circulation ◽  
Meso Scale

Concentrations of atmospheric pollutants are strongly influenced by meteorological parameters like rainfall, relative humidity and wind advection. Thus accurate specifications of the meteorological fields, and their effects on pollutants, are critical requirements for successful modelling of air pollution. In terms of their applications, pollutant concentration models can be used in different ways; in one, short term high resolution forecasts are generated to predict and manage urban pollution. Another application of dynamical pollution models is to generate outlook for a given airbasin, such as over a large city. An important question is application-specific model configuration for the meteorological simulations. While a meso-scale model provides a high-resolution configuration, a global model allows better simulation of large-sale fields through its global environment. Our objective is to comparatively evaluate a meso-scale atmospheric model (MM5) and atmospheric global circulation model (AGCM) in simulating different species of pollutants over different airbasins. In this study we consider four locations: ITO (Central Delhi), Sirifort (South Delhi), Bandra (Mumbai) and Karve Road (Pune). The results show that both the model configurations provide comparable skills in simulation of monthly and annual loads, although the skill of the meso-scale model is somewhat higher, especially at shorter time scales.

scholarly journals THOR: A NEW AND FLEXIBLE GLOBAL CIRCULATION MODEL TO EXPLORE PLANETARY ATMOSPHERES

2016 ◽  
Vol 829 (2) ◽  
pp. 115 ◽  
Author(s):  
João M. Mendonça ◽  
Simon L. Grimm ◽  
Luc Grosheintz ◽  
Kevin Heng
Keyword(s):  
Circulation Model ◽  
Planetary Atmospheres ◽  
Global Circulation Model ◽  
Global Circulation

scholarly journals True dipole wander

2018 ◽  
Vol 215 (3) ◽  
pp. 1523-1529
Author(s):  
Peter Olson ◽  
Maylis Landeau ◽  
Evan Reynolds
Keyword(s):  
Circulation Model ◽  
Global Circulation Model ◽  
Polar Wander ◽  
Global Circulation ◽  
True Polar Wander ◽  
Symmetric Pattern ◽  
Asymmetric Pattern ◽  
Heterogeneous Mantle ◽  
Geocentric Axial Dipole ◽  
Geomagnetic Dipole

SUMMARY A fundamental assumption in palaeomagnetism is that the geomagnetic field closely approximates a geocentric axial dipole in time average. Here we use numerical dynamos driven by heterogeneous core–mantle boundary heat flux from a mantle global circulation model to demonstrate how mantle convection produces true dipole wander, rotation of the geomagnetic dipole on geologic timescales. Our heterogeneous mantle-driven dynamos show a dipole rotation about a near-equatorial axis in response to the transition in lower mantle heterogeneity from a highly asymmetric pattern at the time of supercontinent Pangea to a more symmetric pattern today. This predicted dipole rotation overlaps with a palaeomagnetically inferred rotation in the opposite direction and suggests that some events previously interpreted as true polar wander also include true dipole wander.

scholarly journals The Use of Radiocarbon Measurements in Atmospheric Studies

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 37-58 ◽  
Author(s):  
M R Manning ◽  
D C Lowe ◽  
W H Melhuish ◽  
R J Sparks ◽  
Gavin Wallace ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Circulation Model ◽  
Current Data ◽  
Atmospheric Methane ◽  
Global Circulation Model ◽  
Fossil Carbon ◽  
Global Circulation ◽  
Methane Source ◽  
Clean Air ◽  
Source Current

14C measured in trace gases in clean air helps to determine the sources of such gases, their long-range transport in the atmosphere, and their exchange with other carbon cycle reservoirs. In order to separate sources, transport and exchange, it is necessary to interpret measurements using models of these processes. We present atmospheric 14CO2 measurements made in New Zealand since 1954 and at various Pacific Ocean sites for shorter periods. We analyze these for latitudinal and seasonal variation, the latter being consistent with a seasonally varying exchange rate between the stratosphere and troposphere. The observed seasonal cycle does not agree with that predicted by a zonally averaged global circulation model. We discuss recent accelerator mass spectrometry measurements of atmospheric 14CH4 and the problems involved in determining the fossil fuel methane source. Current data imply a fossil carbon contribution of ca 25%, and the major sources of uncertainty in this number are the uncertainty in the nuclear power source of 14CH4, and in the measured value for δ14C in atmospheric methane.

Sign in / Sign up

Export Citation Format

Share Document