Bibliography - Shian-Jiann Lin
- Zhao, Ming, Isaac Held, Shian-Jiann Lin, and G A Vecchi, in press: Simulations of global hurricane climatology, interannual variability, and response to global warming using a 50km resolution GCM. Journal of Climate. 1/09.
- Law, R M., W Peters, C Aulagnier, D J Bergmann, Song-Miao Fan, and Shian-Jiann Lin, et al., 2008: TransCom model simulations of hourly atmospheric CO2: Experimental overview and diurnal cycle results for 2002. Global Biogeochemical Cycles, 22, GB3009, doi:10.1029/2007GB003050.
[ Abstract ]A
forward atmospheric transport modeling experiment has been coordinated by
the TransCom group to investigate synoptic and diurnal variations in CO2 .
Model simulations were run for biospheric, fossil, and air-sea exchange of
CO2
and for SF6
and radon for 2000–2003. Twenty-five models or model variants participated
in the comparison. Hourly concentration time series were submitted for 280
sites along with vertical profiles, fluxes, and meteorological variables at
100 sites. The submitted results have been analyzed for diurnal variations
and are compared with observed CO2 in 2002. Mean summer diurnal cycles vary widely in amplitude across models.
The choice of sampling location and model level account for part of the
spread suggesting that representation errors in these types of models are
potentially large. Despite the model spread, most models simulate the
relative variation in diurnal amplitude between sites reasonably well. The
modeled diurnal amplitude only shows a weak relationship with vertical
resolution across models; differences in near-surface transport simulation
appear to play a major role. Examples are also presented where there is
evidence that the models show useful skill in simulating seasonal and
synoptic changes in diurnal amplitude.
- Ming, Yi, Paul Ginoux, Leo J Donner, Stuart Freidenreich, Larry Horowitz, Ming Zhao, J-C Golaz, and Shian-Jiann Lin, in press: Transport of European Air Pollution influences Arctic climate. Science. 8/08.
[ Abstract ]Arctic climate is changing at a pace faster than the global average in the recent decades (1, 2). Arctic haze (3) - an accumulation of long-range transported aerosols - enhances longwave emissivity of liquid water clouds both
by reducing droplet size (4–6) and by increasing liquid condensate, thus exerting substantial surface warming in winter. The formation of Arctic haze and its influence on local climate are poorly understood, and constitutes an important missing piece of the Arctic climate puzzle. Here we find, with the help of a state-of-the-art global climate model with explicit treatment of pollutant transport and aerosol-cloud interactions, that the poleward transport of European air pollution is controlled strongly by the fluctuation in the second climate mode of the North Atlantic - European region. Though accounting for a smaller fraction of the region’s overall climate variability than the first mode (namely the North Atlantic Oscillation), the second mode has its impacts on Arctic climate amplified through modulating the amount of aerosols reaching the Arctic. This is supported by the fact that the surface aerosol concentrations and longwave downward radiative flux measured at locations lying in the model-projected transport pathway show strong correlation with the second mode. A shift of the mode from negative to positive phases doubles the abundance of Arctic haze, and the resulting increase in cloud liquid condensate alone is estimated to warm the surface by 1.8 K or to reduce the wintertime sea ice by 0.16 m. This finding is essential for understanding Arctic climate variability and change.
- Patra, P K., Song-Miao Fan, and Shian-Jiann Lin, et al., December 2008: TransCom model simulations of hourly atmospheric CO2 : Analysis of synoptic-scale variations for the period 2002-2003. Global Biogeochemical Cycles, 22, GB4013, doi:10.1029/2007GB003081.
[ Abstract ]The
ability to reliably estimate CO2
fluxes from current in situ atmospheric CO2
measurements and future satellite CO2
measurements is dependent on transport model performance at synoptic and
shorter timescales. The TransCom continuous experiment was designed to
evaluate the performance of forward transport model simulations at hourly,
daily, and synoptic timescales, and we focus on the latter two in this
paper. Twenty-five transport models or model variants submitted hourly time
series of nine predetermined tracers (seven for CO2 )
at 280 locations. We extracted synoptic-scale variability from daily
averaged CO2
time series using a digital filter and analyzed the results by comparing
them to atmospheric measurements at 35 locations. The correlations between
modeled and observed synoptic CO2
variabilities were almost always largest with zero time lag and
statistically significant for most models and most locations. Generally, the
model results using diurnally varying land fluxes were closer to the
observations compared to those obtained using monthly mean or daily average
fluxes, and winter was often better simulated than summer. Model results at
higher spatial resolution compared better with observations, mostly because
these models were able to sample closer to the measurement site location.
The amplitude and correlation of model-data variability is strongly model
and season dependent. Overall similarity in modeled synoptic CO2
variability suggests that the first-order transport mechanisms are fairly
well parameterized in the models, and no clear distinction was found between
the meteorological analyses in capturing the synoptic-scale dynamics.
- Putman, W M., and Shian-Jiann Lin, 2007: Finite-volume transport on various cubed-sphere grids. Journal of Computational Physics, 227(1), 55-78.
[ Abstract PDF ]The performance of a multidimensional finite-volume transport scheme is evaluated on the cubed-sphere geometry. Advection tests with prescribed winds are used to evaluate a variety of cubed-sphere projections and grid modifications including the gnomonic and conformal mappings, as well as two numerically generated grids by an elliptic solver and spring dynamics. We explore the impact of grid non-orthogonality on advection tests over the corner singularities of the cubed-sphere grids, using some variations of the transport scheme, including the piecewise parabolic method with alternative monotonicity constraints. The advection tests revealed comparable or better accuracy to those of the original latitudinal–longitudinal grid implementation. It is found that slight deviations from orthogonality on the modified cubed-sphere (quasi-orthogonal) grids do not negatively impact the accuracy. In fact, the more uniform version of the quasi-orthogonal cubed-sphere grids provided better overall accuracy than the most orthogonal (and therefore, much less uniform) conformal grid. It is also shown that a simple non-orthogonal extension to the transport equation enables the use of the highly non-orthogonal and computationally more efficient gnomonic grid with acceptable accuracy.
- Collins, W D., P J Rasch, B A Boville, J J Hack, J R McCaa, D L W Briegleb, C M Bitz, Shian-Jiann Lin, and M Zhang, 2006: The formulation and atmospheric simulation of the Community Atmosphere Model Version 3 (CAM3). Journal of Climate, 19(11), doi:10.1175/JCLI3760.1.
[ Abstract ]A new version of the Community Atmosphere Model (CAM) has been developed and released to the climate community. CAM Version 3 (CAM3) is an atmospheric general circulation model that includes the Community Land Model (CLM3), an optional slab ocean model, and a thermodynamic sea ice model. The dynamics and physics in CAM3 have been changed substantially compared to implementations in previous versions. CAM3 includes options for Eulerian spectral, semi-Lagrangian, and finite-volume formulations of the dynamical equations. It supports coupled simulations using either finite-volume or Eulerian dynamics through an explicit set of adjustable parameters governing the model time step, cloud parameterizations, and condensation processes. The model includes major modifications to the parameterizations of moist processes, radiation processes, and aerosols. These changes have improved several aspects of the simulated climate, including more realistic tropical tropopause temperatures, boreal winter land surface temperatures, surface insolation, and clear-sky surface radiation in polar regions. The variation of cloud radiative forcing during ENSO events exhibits much better agreement with satellite observations. Despite these improvements, several systematic biases reduce the fidelity of the simulations. These biases include underestimation of tropical variability, errors in tropical oceanic surface fluxes, underestimation of implied ocean heat transport in the Southern Hemisphere, excessive surface stress in the storm tracks, and offsets in the 500-mb height field and the Aleutian low.
- Delworth, Thomas L., Anthony J Broccoli, Anthony Rosati, Ronald J Stouffer, Ventakramani Balaji, J A Beesley, W F Cooke, Keith W Dixon, John Dunne, Krista A Dunne, J W Durachta, Kirsten L Findell, Paul Ginoux, Anand Gnanadesikan, C Tony Gordon, Stephen Griffies, Rich Gudgel, Matthew J Harrison, Isaac Held, Richard S Hemler, Larry Horowitz, Stephen A Klein, Thomas R Knutson, P J Kushner, A R Langenhorst, H C Lee, Shian-Jiann Lin, Jian Lu, S Malyshev, P C D Milly, V Ramaswamy, J L Russell, M Daniel Schwarzkopf, Elena Shevliakova, Joseph J Sirutis, Michael J Spelman, William F Stern, Michael Winton, Andrew T Wittenberg, Bruce Wyman, Fanrong Zeng, and Rong Zhang, 2006: GFDL's CM2 Global Coupled Climate Models. Part I: Formulation and Simulation Characteristics. Journal of Climate, 19(5), doi:10.1175/JCLI3629.1.
[ Abstract ]The formulation and simulation characteristics of two new global coupled climate models developed at NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) are described. The models were designed to simulate atmospheric and oceanic climate and variability from the diurnal time scale through multicentury climate change, given our computational constraints. In particular, an important goal was to use the same model for both experimental seasonal to interannual forecasting and the study of multicentury global climate change, and this goal has been achieved.
Two versions of the coupled model are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and ocean components. For both coupled models, the resolution of the land and atmospheric components is 2° latitude × 2.5° longitude; the atmospheric model has 24 vertical levels. The ocean resolution is 1° in latitude and longitude, with meridional resolution equatorward of 30° becoming progressively finer, such that the meridional resolution is 1/3° at the equator. There are 50 vertical levels in the ocean, with 22 evenly spaced levels within the top 220 m. The ocean component has poles over North America and Eurasia to avoid polar filtering. Neither coupled model employs flux adjustments.
The control simulations have stable, realistic climates when integrated over multiple centuries. Both models have simulations of ENSO that are substantially improved relative to previous GFDL coupled models. The CM2.0 model has been further evaluated as an ENSO forecast model and has good skill (CM2.1 has not been evaluated as an ENSO forecast model). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in oceanic gyre circulations; 2) changes in cloud tuning and the land model, both of which act to increase the net surface shortwave radiation in CM2.1, thereby reducing an overall cold bias present in CM2.0; and 3) a reduction of ocean lateral viscosity in the extratropics in CM2.1, which reduces sea ice biases in the North Atlantic.
Both models have been used to conduct a suite of climate change simulations for the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment report and are able to simulate the main features of the observed warming of the twentieth century. The climate sensitivities of the CM2.0 and CM2.1 models are 2.9 and 3.4 K, respectively. These sensitivities are defined by coupling the atmospheric components of CM2.0 and CM2.1 to a slab ocean model and allowing the model to come into equilibrium with a doubling of atmospheric CO2. The output from a suite of integrations conducted with these models is freely available online (see http://nomads.gfdl.noaa.gov/).
Manuscript received 8 December 2004, in final form 18 March 2005
- Rasch, P J., D B Coleman, N Mahowald, D L Williamson, Shian-Jiann Lin, B A Boville, and P G Hess, 2006: Characteristics of atmospheric transport using three numerical formulations for atmospheric dynamics in a single GCM framework. Journal of Climate, 19(11), doi:10.1175/JCLI3763.1.
[ Abstract ]This study examines the sensitivity of a number of important archetypical tracer problems to the numerical method used to solve the equations of tracer transport and atmospheric dynamics. The tracers' scenarios were constructed to exercise the model for a variety of problems relevant to understanding and modeling the physical, dynamical, and chemical aspects of the climate system. The use of spectral, semi-Lagrangian, and finite volume (FV) numerical methods for the equations is explored. All subgrid-scale physical parameterizations were the same in all model simulations.
The model behavior with a few short simulations with passive tracers is explored, and with much longer simulations of radon, SF6, ozone, a tracer designed to mimic some aspects of a biospheric source/sink of CO2, and a suite of tracers designed around the conservation laws for thermodynamics and mass in the model.
Large differences were seen near the tropopause in the model, where the FV core shows a much reduced level of vertical and meridional mixing. There was also evidence that the subtropical subsidence regions are more isolated from Tropics and midlatitudes in the FV core than seen in the other model simulations. There are also big differences in the stratosphere, particularly for age of air in the stratosphere and ozone. A comparison with estimated age of air from CO2 and SF6 measurements in the stratosphere suggest that the FV core is behaving most realistically.
A neutral biosphere (NB) test case is used to explore issues of diurnal and seasonal rectification of a tracer with sources and sinks at the surface. The sources and sinks have a zero annual average, and the rectification is associated with temporal correlations between the sources and sinks, and transport. The test suggests that the rectification is strongly influenced by the resolved-scale dynamics (i.e., the dynamical core) and that the numerical formulation for dynamics and transport still plays a critical role in the distribution of NB-like species. Since the distribution of species driven by these processes have a strong influence on the interpretation of the “missing sink” for CO2 and the interpretation of climate change associated with anthropogenic forcing herein, these issues should not be neglected.
The spectral core showed the largest departures from the predicted nonlinear relationship required by the equations for thermodynamics and mass conservations. The FV and semi-Lagrangian dynamics (SLD) models both produced errors a factor of 2 lower. The SLD model shows a small but systematic bias in its ability to maintain this relationship that was not present in the FV simulation.
The results of the study indicate that for virtually all of these problems, the model numerics still have a large role in influencing the model solutions. It was frequently the case that the differences in solutions resulting from varying the numerics still exceed the differences in the simulations resulting from significant physical perturbations (like changes in greenhouse gas forcing). This does not mean that the response of the system to physical changes is not correct. When results are consistent using different numerical formulations for dynamics and transport it lends confidence to one's conclusions, but it does indicate that some caution is required in interpreting the results.
The results from this study favor use of the FV core for tracer transport and model dynamics. The FV core is, unlike the others, conservative, less diffusive (e.g., maintains strong gradients better), and maintains the nonlinear relationships among variables required by thermodynamic and mass conservation constraints more accurately.
- Shen, B-W, R Atlas, O Reale, Shian-Jiann Lin, T Lee, J Chang, and J-D Chern, 2006: The 0.125 degree finite-volume general circulation model on the NASA Columbia supercomputer: Preliminary simulations of mesoscale vortices. Geophysical Research Letters, 33, L05801, doi:10.1029/2005GL024594.
[ Abstract ]The NASA Columbia supercomputer was ranked second on the TOP500 List in November, 2004. Such a quantum jump in computing power provides unprecedented opportunities to conduct ultra-high resolution simulations with the finite-volume General Circulation Model (fvGCM). During 2004, the model was run in realtime experimentally at 0.25 degree resolution producing remarkable hurricane forecasts (Atlas et al., 2005). In 2005, the horizontal resolution was further doubled, which makes the fvGCM comparable to the first mesoscale resolving General Circulation Model at the Earth Simulator Center (Ohfuchi et al., 2004). Nine 5-day 0.125 degree simulations of three hurricanes in 2004 are presented first for model validation. Then it is shown how the model can simulate the formation of the Catalina eddies and Hawaiian lee vortices, which are generated by the interaction of the synoptic-scale flow with surface forcing, and have never been reproduced in a GCM before.
- Shen, B-W, R Atlas, O Reale, Shian-Jiann Lin, J-D Chern, J Chang, C Henze, and J-L Li, 2006: Hurricane forecasts with a global mesoscale-resolving model: Preliminary results with Hurricane Katrina (2005). Geophysical Research Letters, 33, L13813, doi:10.1029/2006GL026143.
[ Abstract ]It is known that General Circulation Models (GCMs) have insufficient resolution to accurately simulate hurricane near-eye structure and intensity. The increasing capabilities of high-end computers have changed this. The mesoscale-resolving finite-volume GCM (fvGCM) has been experimentally deployed on the NASA Columbia supercomputer, and its performance is evaluated in this study by choosing hurricane Katrina as an example. In late August 2005, Katrina underwent two stages of rapid intensification, and became the sixth most intense hurricane in the Atlantic. Six 5-day simulations of Katrina at both 0.25° and 0.125° show comparable track forecasts but the 0.125° runs provide much better intensity forecasts, producing the center pressure with errors of only ±12 hPa. In the runs examined in this study, the 0.125° simulates better near-eye wind distributions and a more realistic average intensification rate. To contribute to the ongoing research on the effects of disabling convection parameterization (CP), we present promising results by comparing 0.125° runs with disabled CPs against runs with enabled CPs.
- Sud, Y C., D Mocko, and Shian-Jiann Lin, 2006: Performance of two cloud-radiation parameterization schemes in the finite volume general circulation model for anomalously wet May and June 2003 over the continental United States and Amazonia. Journal of Geophysical Research, 111, D06201, doi:10.1029/2005JD006246.
[ Abstract ]An objective assessment of the impact of a new cloud scheme, called Microphysics of Clouds with Relaxed Arakawa-Schubert Scheme (McRAS) (together with its radiation modules), on the finite volume general circulation model (fvGCM) was made with a set of ensemble forecasts that invoke performance evaluation over both weather and climate timescales. The performance of McRAS (and its radiation modules) was compared with that of the National Center for Atmospheric Research Community Climate Model (NCAR CCM3) cloud scheme (with its NCAR physics radiation). We specifically chose the boreal summer months of May and June 2003, which were characterized by an anomalously wet eastern half of the continental United States as well as northern regions of Amazonia. The evaluation employed an ensemble of 70 daily 10-day forecasts covering the 61 days of the study period. Each forecast was started from the analyzed initial state of the atmosphere and spun-up soil moisture from the first-day forecasts with the model. Monthly statistics of these forecasts with up to 10-day lead time provided a robust estimate of the behavior of the simulated monthly rainfall anomalies. Patterns of simulated versus observed rainfall, 500-hPa heights, and top-of-the-atmosphere net radiation were recast into regional anomaly correlations. The correlations were compared among the simulations with each of the schemes. The results show that fvGCM with McRAS and its radiation package performed discernibly better than the original fvGCM with CCM3 cloud physics plus its radiation package. The McRAS cloud scheme also showed a reasonably positive response to the observed sea surface temperature on mean monthly rainfall fields at different time leads. This analysis represents a method for helpful systematic evaluation prior to selection of a new scheme in a global model.
- Lin, Shian-Jiann, 2004: A "vertically Lagrangian" finite-volume dynamical core for global models. Monthly Weather Review, 132(10), 2293-2307.
[ Abstract PDF ]A finite-volume dynamical core with a terrain-following Lagrangian control-volume discretization is described. The vertically Lagrangian discretization reduces the dimensionality of the physical problem from three to two with the resulting dynamical system closely resembling that of the shallow water system. The 2D horizontal-to-Lagrangian-surface transport and dynamical processes are then discretized using the genuinely conservative flux-form semi-Lagrangian algorithm. Time marching is split-explicit, with large time steps for scalar transport, and small fractional steps for the Lagrangian dynamics, which permits the accurate propagation of fast waves. A mass, momentum, and total energy conserving algorithm is developed for remapping the state variables periodically from the floating Lagrangian control-volume to an Eulerian terrain-following coordinate for dealing with "physical parameterizations" and to prevent severe distortion of the Lagrangian surfaces. Deterministic baroclinic wave-growth tests and long-term integrations using the Held–Suarez forcing are presented. Impact of the monotonicity constraint is discussed.
- Lin, Shian-Jiann, R Atlas, and K-S Yeh, 2004: Global Weather Prediction and High-End Computing at NASA. Computing in Science and Engineering, 6(1), 29-35.
[ Abstract PDF ]The authors demonstrate the current capabilities of NASA's finite-volume General Circulation Model in high-resolution global weather prediction and discuss its development path in the foreseeable future. This model is a prototype of a future NASA Earth-modeling system intended to unify development activities across various disciplines within NASA's Earth Science Enterprise.
- Coy, L, I Stajner, A Da Silva, J Joiner, R B Rood, S Pawson, and Shian-Jiann Lin, 2003: High-frequency planetary waves in the Polar middle atmosphere as seen in a data assimilation system. Journal of the Atmospheric Sciences, 60(24), 2975-2992.
[ Abstract PDF ]The 4-day wave often dominates the large-scale wind, temperature, and constituent variability in the high-latitude Southern Hemisphere winter near the stratopause. This study examines the winter Southern Hemisphere vortex of 1998 using 4-times-daily output from a data assimilation system to focus on the polar 2-day, wavenumber-2 component of the 4-day wave. The data assimilation system products are from a test version of the finite volume data assimilation system (fvDAS) being developed at the Goddard Space Flight Center (GSFC) and include an ozone assimilation system. Results show that the polar 2-day wave in temperature and ozone dominates over other planetary-scale disturbances during July 1998 at 70°S. The period of the quasi-2-day wave is somewhat shorter than 2 days (about 1.7 days) during July 1998 with an average perturbation temperature amplitude for the month of over 2.5 K. The 2-day wave propagates more slowly than the zonal mean zonal wind, consistent with Rossby wave theory, and has Eliassen–Palm (EP) flux divergence regions associated with regions of negative horizontal potential vorticity gradients, as expected from linear instability theory. Results for the assimilation-produced ozone mixing ratio show that the 2-day wave represents a major source of ozone variation in this region. The ozone wave in the assimilation system is in good agreement with the wave seen in the Polar Ozone and Aerosol Measurement (POAM) ozone observations for the same time period. Some differences from linear instability theory are noted, as well as spectral peaks in the ozone field, not seen in the temperature field, that may be a consequence of advection.
- Ginoux, Paul, M Chin, I Tegen, J M Prospero, B Holben, O Dubovik, and Shian-Jiann Lin, 2001: Sources and distributions of dust aerosols simulated with the GOCART model. Journal of Geophysical Research, 106(D17), 20,255-20,273.
[ Abstract PDF ]The global distribution of dust aerosol is simulated with the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. In, this model all topographic lows with bare ground surface are assumed to have accumulated sediments which are potential dust sources. The uplifting of dust particles is expressed as a function of surface wind speed and wetness. The GOCART model is driven by the assimilated meteorological fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS) which facilitates direct comparison with observations. The model includes seven size classes of mineral dust ranging from 0.1-6 mum radius. The total annual emission is estimated to be between 1604 and 1960 Tg yr(-1) in a 5-year simulation. The model has been evaluated by comparing simulation results with ground-based measurements and satellite data. The evaluation has been performed by comparing surface concentrations, vertical distributions, deposition rates, optical thickness, and size distributions. The comparisons show that the model results generally agree with the observations without the necessity of invoking any contribution from anthropogenic disturbances to soils. However, the model overpredicts the transport of dust from the Asian sources to the North Pacific. This discrepancy is attributed to an overestimate of small particle emission from the Asian sources.
- Lin, Shian-Jiann, and R T Pierrehumbert, 1988: Does Ekman friction suppress baroclinic instability? Journal of the Atmospheric Sciences, 45(20), 2920-2933.
[ Abstract PDF ]The effect of Ekman friction on baroclinic instability is reexamined in order to address questions raised by Farrell concerning the existence of normal mode instability in the atmosphere. As the degree of meridional confinement is central to the result, a linearized two-dimensional (latitude-height) quasi- geostrophic model is used to obviate the arbitrariness inherent in choosing a channel width in one-dimensional (vertical shear only) models. The two-dimensional eigenvalue problem was solved by pseudospectral method using rational Chebyshev expansions in both vertical and meridional directions. It is concluded that the instability can be eliminated only by the combination of strong Ekman friction with weak large-scale wind shear. Estimates of Ekman friction based on a realistic boundary-layer model indicate that such conditions can prevail over land when the boundary layer is neutrally stratified. For values of Ekman friction appropriate to the open ocean, friction can reduce the growth rate of the most unstable mode by at most a factor of two but cannot eliminate the instability.
By reducing the growth rate and shifting the most unstable mode to lower zonal wavenumbers, viscous effects make the heat and momentum fluxes of the most unstable mode deeper and less meridionally confined than in the inviscid case. Nevertheless, linear theory still underestimates the penetration depth of the momentum fluxes, as compared to observations and nonlinear numerical models.
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