A comparison of the microphysics dependency on the reproducibility of the MJO under different resolutions using NICAM

2021 ◽  
Author(s):  
Tamaki Suematsu ◽  
Yohei Yamada ◽  
Chihiro Kodama ◽  
Tomoki Miyakawa
Keyword(s):  
General Circulation ◽  
Atmospheric Model ◽  
Cloud Microphysics ◽  
Horizontal Resolution ◽  
Madden Julian Oscillation ◽  
Atmospheric Models ◽  
Highly Sensitive ◽  
Resolution Model ◽  
Intercomparison Project ◽  
High Resolution Model

<p>Simulation of the Madden-Julian Oscillation (MJO) has been notoriously difficult in atmospheric models. This is partly due to the fact that the reproducibility of the MJO is highly sensitive to parameters that are difficult to fix from observation or theory, and require empirical tuning based on model behaviors. Parameters regards to the cloud-microphysics are some of such parameters that simulations of the MJO are especially sensitive to.</p><p>To address this problem, we conducted a set of cloud-microphysics parameter-sweep experiments on a convection-permitting model, NICAM (Nonhydrostatic ICosahedral Atmospheric Model) at 14 km horizontal resolution to seek for a setting which best represents the MJO (MJO-tuned). We then compared the performance of the NICAM in reproducing the MJO using MJO-tuned setting with the standard NICAM setting employed for high resolution model intercomparison project (High Res MIP)-type experiments. The comparison was conducted for 14 km resolution, and for 3.5 km resolution experiments using DYAMOND (DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains) data, which is based on the MJO-tuned setting.</p><p>The comparison indicated that in the 14 km resolutions, the MJO-tuned setting reduces the excessive development of convection over the Maritime Continents which was apparent in the High Res MIP-setting. However, for the 3.5 km experiments convective activities of the MJO appeared to successfully reach the dateline for both the MJO-tuned setting and the High Res MIP-setting. The results of this study implies that a sufficient increase in the horizontal resolution has the potential to reduce the dependency of the microphysics setting on the reproducibility of the MJO, at least in the first few weeks of the simulations on NICAM.</p>

scholarly journals High Resolution Model Intercomparison Project (HighResMIP)

2016 ◽  
Author(s):  
R. J. Haarsma ◽  
M. Roberts ◽  
P. L. Vidale ◽  
C. A. Senior ◽  
A. Bellucci ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Computational Cost ◽  
Horizontal Resolution ◽  
Small Scale ◽  
Model Intercomparison ◽  
Resolution Model ◽  
Intercomparison Project ◽  
High Resolution Model ◽  
The Impact

Abstract. Robust projections and predictions of climate variability and change, particularly at regional scales, rely on the driving processes being represented with fidelity in model simulations. The role of enhanced horizontal resolution in improved process representation in all components of the climate system is of growing interest, particularly as some recent simulations suggest the possibility for significant changes in both large-scale aspects of circulation, as well as improvements in small-scale processes and extremes. However, such high resolution global simulations at climate time scales, with resolutions of at least 50 km in the atmosphere and 0.25° in the ocean, have been performed at relatively few research centers and generally without overall coordination, primarily due to their computational cost. Assessing the robustness of the response of simulated climate to model resolution requires a large multi-model ensemble using a coordinated set of experiments. The Coupled Model Intercomparison Project 6 (CMIP6) is the ideal framework within which to conduct such a study, due to the strong link to models being developed for the CMIP DECK experiments and other MIPs. Increases in High Performance Computing (HPC) resources, as well as the revised experimental design for CMIP6, now enables a detailed investigation of the impact of increased resolution up to synoptic weather scales on the simulated mean climate and its variability. The High Resolution Model Intercomparison Project (HighResMIP) presented in this paper applies, for the first time, a multi-model approach to the systematic investigation of the impact of horizontal resolution. A coordinated set of experiments has been designed to assess both a standard and an enhanced horizontal resolution simulation in the atmosphere and ocean. The set of HighResMIP experiments is divided into three tiers consisting of atmosphere-only and coupled runs and spanning the period 1950-2050, with the possibility to extend to 2100, together with some additional targeted experiments. This paper describes the experimental set-up of HighResMIP, the analysis plan, the connection with the other CMIP6 endorsed MIPs, as well as the DECK and CMIP6 historical simulation. HighResMIP thereby focuses on one of the CMIP6 broad questions: “what are the origins and consequences of systematic model biases?”, but we also discuss how it addresses the World Climate Research Program (WCRP) grand challenges.

scholarly journals High Resolution Model Intercomparison Project (HighResMIP v1.0) for CMIP6

2016 ◽  
Vol 9 (11) ◽  
pp. 4185-4208 ◽  
Author(s):  
Reindert J. Haarsma ◽  
Malcolm J. Roberts ◽  
Pier Luigi Vidale ◽  
Catherine A. Senior ◽  
Alessio Bellucci ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Computational Cost ◽  
Horizontal Resolution ◽  
Small Scale ◽  
Model Intercomparison ◽  
Resolution Model ◽  
Intercomparison Project ◽  
High Resolution Model ◽  
The Impact

Abstract. Robust projections and predictions of climate variability and change, particularly at regional scales, rely on the driving processes being represented with fidelity in model simulations. The role of enhanced horizontal resolution in improved process representation in all components of the climate system is of growing interest, particularly as some recent simulations suggest both the possibility of significant changes in large-scale aspects of circulation as well as improvements in small-scale processes and extremes. However, such high-resolution global simulations at climate timescales, with resolutions of at least 50 km in the atmosphere and 0.25° in the ocean, have been performed at relatively few research centres and generally without overall coordination, primarily due to their computational cost. Assessing the robustness of the response of simulated climate to model resolution requires a large multi-model ensemble using a coordinated set of experiments. The Coupled Model Intercomparison Project 6 (CMIP6) is the ideal framework within which to conduct such a study, due to the strong link to models being developed for the CMIP DECK experiments and other model intercomparison projects (MIPs). Increases in high-performance computing (HPC) resources, as well as the revised experimental design for CMIP6, now enable a detailed investigation of the impact of increased resolution up to synoptic weather scales on the simulated mean climate and its variability. The High Resolution Model Intercomparison Project (HighResMIP) presented in this paper applies, for the first time, a multi-model approach to the systematic investigation of the impact of horizontal resolution. A coordinated set of experiments has been designed to assess both a standard and an enhanced horizontal-resolution simulation in the atmosphere and ocean. The set of HighResMIP experiments is divided into three tiers consisting of atmosphere-only and coupled runs and spanning the period 1950–2050, with the possibility of extending to 2100, together with some additional targeted experiments. This paper describes the experimental set-up of HighResMIP, the analysis plan, the connection with the other CMIP6 endorsed MIPs, as well as the DECK and CMIP6 historical simulations. HighResMIP thereby focuses on one of the CMIP6 broad questions, “what are the origins and consequences of systematic model biases?”, but we also discuss how it addresses the World Climate Research Program (WCRP) grand challenges.

scholarly journals Towards Direct Simulation of Future Tropical Cyclone Statistics in a High-Resolution Global Atmospheric Model

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Michael F. Wehner ◽  
G. Bala ◽  
Phillip Duffy ◽  
Arthur A. Mirin ◽  
Raquel Romano
Keyword(s):  
High Resolution ◽  
Radiative Forcing ◽  
General Circulation ◽  
Circulation Model ◽  
Atmospheric Model ◽  
Tropical Storm ◽  
Model Studies ◽  
The North ◽  
Resolution Model ◽  
High Resolution Model

We present a set of high-resolution global atmospheric general circulation model (AGCM) simulations focusing on the model's ability to represent tropical storms and their statistics. We find that the model produces storms of hurricane strength with realistic dynamical features. We also find that tropical storm statistics are reasonable, both globally and in the north Atlantic, when compared to recent observations. The sensitivity of simulated tropical storm statistics to increases in sea surface temperature (SST) is also investigated, revealing that a credible late 21st century SST increase produced increases in simulated tropical storm numbers and intensities in all ocean basins. While this paper supports previous high-resolution model and theoretical findings that the frequency of very intense storms will increase in a warmer climate, it differs notably from previous medium and high-resolution model studies that show a global reduction in total tropical storm frequency. However, we are quick to point out that this particular model finding remains speculative due to a lack of radiative forcing changes in our time-slice experiments as well as a focus on the Northern hemisphere tropical storm seasons.

scholarly journals Effect of Horizontal Resolution on the Simulation of Tropical Cyclones in the Chinese Academy of Sciences FGOALS-f3 Climate System Model

2021 ◽  
Author(s):  
Jinxiao Li ◽  
Qing Bao ◽  
Yimin Liu ◽  
Lei Wang ◽  
Jing Yang ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclones ◽  
Horizontal Resolution ◽  
System Model ◽  
Climate System Model ◽  
Chinese Academy Of Sciences ◽  
Resolution Model ◽  
Intercomparison Project ◽  
High Resolution Model ◽  
Academy Of Sciences

Abstract. The effects of horizontal resolution on the simulation of tropical cyclones were studied using the Chinese Academy of Sciences FGOALS-f3 climate system model from the High-Resolution Model Intercomparison Project (HighResMIP) for the Coupled Model Intercomparison Project Phase 6 (CMIP6). Both the low-resolution (approximately 100 km resolution) FGOALS-f3 model (FGOALS-f3-L) and the high-resolution (approximately 25 km resolution) FGOALS-f3 (FGOALS-f3-H) model were used to achieve the standard Tier1 experiment required by the HighResMIP. FGOALS-f3-L and FGOALS-f3-H have the same model parameterizations with exactly the same parameters. The only differences between the two models are the horizontal resolution and the time step. The performance of FGOALS-f3-H and FGOALS-f3-L in simulating tropical cyclones was evaluated with the observation firstly. FGOALS-f3-H (25 km resolution) simulated more realistic distributions of the formation, movement and intensity of the climatology of tropical cyclones than FGOALS-f3-L at 100 km resolution. The seasonal cycles of the number of tropical cyclones increased by about 50 % at the higher resolution and better matched the observed values in the peak month, especially in the eastern Pacific, northern Atlantic, southern Indian and southern Pacific oceans. The simulated variabilities of the number of tropical cyclones and the accumulated cyclone energy were both significantly improved from FGOALS-f3-L to FGOALS-f3-H over most of the ocean basins on the interannual timescale. The characteristics of the tropical cyclones (e.g., the average lifetime, the wind–pressure relationship and the horizontal structure) were more realistic in the simulation using the high-resolution model. The possible physical linkage between the performance of the tropical cyclone simulation and the horizontal resolution were revealed by further analyses. The improvement in the Madden–Julian oscillation from FGOALS-f3-H contributed to the realistic simulation of tropical cyclones. The genesis potential index and the vorticity, relative humidity, maximum potential intensity and the wind shear terms were used to diagnose the effects of the resolution. The current insufficiencies and future directions of improvement for the simulation of tropical cyclones and the potential applications of the FGOALS-f3-H model in the sub-seasonal to seasonal prediction of tropical cyclones are discussed.

scholarly journals Effect of horizontal resolution on the simulation of tropical cyclones in the Chinese Academy of Sciences FGOALS-f3 climate system model

2021 ◽  
Vol 14 (10) ◽  
pp. 6113-6133
Author(s):  
Jinxiao Li ◽  
Qing Bao ◽  
Yimin Liu ◽  
Lei Wang ◽  
Jing Yang ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclones ◽  
Horizontal Resolution ◽  
System Model ◽  
Climate System Model ◽  
Chinese Academy Of Sciences ◽  
Resolution Model ◽  
Intercomparison Project ◽  
High Resolution Model ◽  
Academy Of Sciences

Abstract. The effects of horizontal resolution on the simulation of tropical cyclones were studied using the Chinese Academy of Sciences Flexible Global Ocean–Atmosphere–Land System Finite-Volume version 3 (FGOALS-f3) climate system model from the High-Resolution Model Intercomparison Project (HighResMIP) for the Coupled Model Intercomparison Project phase 6 (CMIP6). Both the low-resolution (about 100 km resolution) FGOALS-f3 model (FGOALS-f3-L) and the high-resolution (about 25 km resolution) FGOALS-f3 (FGOALS-f3-H) models were used to achieve the standard Tier 1 experiment required by HighResMIP. FGOALS-f3-L and FGOALS-f3-H have the same model parameterizations with the exactly the same parameters. The only differences between the two models are the horizontal resolution and the time step. The performance of FGOALS-f3-H and FGOALS-f3-L in simulating tropical cyclones was evaluated using observations. FGOALS-f3-H (25 km resolution) simulated more realistic distributions of the formation, movement and intensity of the climatology of tropical cyclones than FGOALS-f3-L at 100 km resolution. Although the number of tropical cyclones increased by about 50 % at the higher resolution and better matched the observed values in the peak month, both FGOALS-f3-L and FGOALS-f3-H appear to replicate the timing of the seasonal cycle of tropical cyclones. The simulated average and interannual variabilities of the number of tropical cyclones and the accumulated cyclone energy were both significantly improved from FGOALS-f3-L to FGOALS-f3-H over most of the ocean basins. The characteristics of tropical cyclones (e.g., the average lifetime, the wind–pressure relationship and the horizontal structure) were more realistic in the simulation using the high-resolution model. The possible physical linkage between the performance of the tropical cyclone simulation and the horizontal resolution were revealed by further analyses. The improvement in the response between the El Niño–Southern Oscillation and the number of tropical cyclones and the accumulated cyclone energy in FGOALS-f3 contributed to the realistic simulation of tropical cyclones. The genesis potential index and the vorticity, relative humidity, maximum potential intensity and the wind shear terms were used to diagnose the effects of resolution. We discuss the current insufficiencies and future directions of improvement for the simulation of tropical cyclones and the potential applications of the FGOALS-f3-H model in the subseasonal to seasonal prediction of tropical cyclones.

scholarly journals Modeling the Infrared Magnesium and Hydrogen Lines from Quiet and Active Solar Regions

1994 ◽  
Vol 154 ◽  
pp. 323-339
Author(s):  
E. H. Avrett ◽  
E. S. Chang ◽  
R. Loeser
Keyword(s):  
Cross Sections ◽  
Line Emission ◽  
Atmospheric Model ◽  
Atmospheric Temperature ◽  
Atomic Data ◽  
Atmospheric Models ◽  
Spatial Features ◽  
Highly Sensitive ◽  
Hydrogen Lines ◽  
The Continuum

The emission lines of Mg I at 7.4, 12.2, and 12.3 μm are now known to be formed in the upper photosphere; the line emission is due to collisional coupling of higher levels with the continuum together with radiative depopulation of lower levels. These combined effects cause the line source functions of high-lying transitions to exceed the corresponding Planck functions. However, there are uncertainties in a) the relevant atomic data, particularly the collisional rates and ultraviolet photoionization rates, and b) the sensitivity of the calculated results to changes in atmospheric temperature and density. These uncertainties are examined by comparing twelve calculated Mg I line profiles in the range 2.1-12.3 μm with ATMOS satellite observations. We show results based on different rates, and using different atmospheric models representing a range of dark and bright spatial features. The calculated Mg profiles are found to be relatively insensitive to atmospheric model changes, and to depend critically on the choice of collisional and photoionization rates. We find better agreement with the observations using collision rates from van Regemorter (1962) rather than from Seaton (1962). We also compare twelve calculated hydrogen profiles in the range 2.2-12.4 μm with ATMOS observations. The available rates and cross sections for hydrogen seem adequate to account for the observed profiles, while the calculated lines are highly sensitive to atmospheric model changes. These lines are perhaps the best available diagnostics of the temperature and density structure of the photosphere and low chromosphere. Further calculations based on these infrared hydrogen lines should lead to greatly improved models of the solar atmosphere.

scholarly journals Effects of High Resolution and Spinup Time on Modeled North Atlantic Circulation

2019 ◽  
Vol 49 (5) ◽  
pp. 1159-1181 ◽  
Author(s):  
Christopher Danek ◽  
Patrick Scholz ◽  
Gerrit Lohmann
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Horizontal Resolution ◽  
Quasi Equilibrium ◽  
Low Resolution ◽  
The North ◽  
Resolution Model ◽  
High Horizontal Resolution ◽  
High Resolution Model ◽  
The North Atlantic

AbstractThe influence of a high horizontal resolution (5–15 km) on the general circulation and hydrography in the North Atlantic is investigated using the Finite Element Sea Ice–Ocean Model (FESOM). We find a stronger shift of the upper-ocean circulation and water mass properties during the model spinup in the high-resolution model version compared to the low-resolution (~1°) control run. In quasi equilibrium, the high-resolution model is able to reduce typical low-resolution model biases. Especially, it exhibits a weaker salinification of the North Atlantic subpolar gyre and a reduced mixed layer depth in the Labrador Sea. However, during the spinup adjustment, we see that initially improved high-resolution features partially reduce over time: the strength of the Atlantic overturning and the path of the North Atlantic Current are not maintained, and hence hydrographic biases known from low-resolution ocean models return in the high-resolution quasi-equilibrium state. We identify long baroclinic Rossby waves as a potential cause for the strong upper-ocean adjustment of the high-resolution model and conclude that a high horizontal resolution improves the state of the modeled ocean but the model integration length should be chosen carefully.

scholarly journals Forecast Skill of the Madden–Julian Oscillation in Two Canadian Atmospheric Models

2008 ◽  
Vol 136 (11) ◽  
pp. 4130-4149 ◽  
Author(s):  
Hai Lin ◽  
Gilbert Brunet ◽  
Jacques Derome
Keyword(s):  
General Circulation ◽  
Initial Conditions ◽  
Circulation Model ◽  
Skill Score ◽  
Forecast Skill ◽  
Second Phase ◽  
Equatorial Waves ◽  
Madden Julian Oscillation ◽  
Atmospheric Models ◽  
Convectively Coupled Equatorial Waves

Abstract The output of two global atmospheric models participating in the second phase of the Canadian Historical Forecasting Project (HFP2) is utilized to assess the forecast skill of the Madden–Julian oscillation (MJO). The two models are the third generation of the general circulation model (GCM3) of the Canadian Centre for Climate Modeling and Analysis (CCCma) and the Global Environmental Multiscale (GEM) model of Recherche en Prévision Numérique (RPN). Space–time spectral analysis of the daily precipitation in near-equilibrium integrations reveals that GEM has a better representation of the convectively coupled equatorial waves including the MJO, Kelvin, equatorial Rossby (ER), and mixed Rossby–gravity (MRG) waves. An objective of this study is to examine how the MJO forecast skill is influenced by the model’s ability in representing the convectively coupled equatorial waves. The observed MJO signal is measured by a bivariate index that is obtained by projecting the combined fields of the 15°S–15°N meridionally averaged precipitation rate and the zonal winds at 850 and 200 hPa onto the two leading empirical orthogonal function (EOF) structures as derived using the same meridionally averaged variables following a similar approach used recently by Wheeler and Hendon. The forecast MJO index, on the other hand, is calculated by projecting the forecast variables onto the same two EOFs. With the HFP2 hindcast output spanning 35 yr, for the first time the MJO forecast skill of dynamical models is assessed over such a long time period with a significant and robust result. The result shows that the GEM model produces a significantly better level of forecast skill for the MJO in the first 2 weeks. The difference is larger in Northern Hemisphere winter than in summer, when the correlation skill score drops below 0.50 at a lead time of 10 days for GEM whereas it is at 6 days for GCM3. At lead times longer than about 15 days, GCM3 performs slightly better. There are some features that are common for the two models. The forecast skill is better in winter than in summer. Forecasts initialized with a large amplitude for the MJO are found to be more skillful than those with a weak MJO signal in the initial conditions. The forecast skill is dependent on the phase of the MJO at the initial conditions. Forecasts initialized with an MJO that has an active convection in tropical Africa and the Indian Ocean sector have a better level of forecast skill than those initialized with a different phase of the MJO.

scholarly journals Resolution Dependence of European Precipitation in a State-of-the-Art Atmospheric General Circulation Model

2015 ◽  
Vol 28 (13) ◽  
pp. 5134-5149 ◽  
Author(s):  
Ronald van Haren ◽  
Reindert J. Haarsma ◽  
Geert Jan Van Oldenborgh ◽  
Wilco Hazeleger
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Vertical Velocity ◽  
Moisture Transport ◽  
State Of The Art ◽  
Horizontal Resolution ◽  
Accurate Representation ◽  
Medium Resolution ◽  
Resolution Model ◽  
High Resolution Model

Abstract In this study, the authors investigate the effect of GCM spatial resolution on modeled precipitation over Europe. The objectives of the analysis are to determine whether climate models have sufficient spatial resolution to have an accurate representation of the storm tracks that affect precipitation. They investigate if there is a significant statistical difference in modeled precipitation between a medium-resolution (~112-km horizontal resolution) and a high-resolution (~25-km horizontal resolution) version of a state-of-the-art AGCM (EC-EARTH), if either model resolution gives a better representation of precipitation in the current climate, and what processes are responsible for the differences in modeled precipitation. The authors find that the high-resolution model gives a more accurate representation of northern and central European winter precipitation. The medium-resolution model has a larger positive bias in precipitation in most of the northern half of Europe. Storm tracks are better simulated in the high-resolution model, providing for a more accurate horizontal moisture transport and moisture convergence. Using a decomposition of the precipitation difference between the medium- and high-resolution model in a part related and a part unrelated to a difference in the distribution of vertical atmospheric velocity, the authors find that the smaller precipitation bias in central and northern Europe is largely unrelated to a difference in vertical velocity distribution. The smaller precipitation amount in these areas is in agreement with less moisture transport over this area in the high-resolution model. In areas with orography the change in vertical velocity distribution is found to be more important.

Structure of the Madden–Julian Oscillation in the Superparameterized CAM

2009 ◽  
Vol 66 (11) ◽  
pp. 3277-3296 ◽  
Author(s):  
James J. Benedict ◽  
David A. Randall
Keyword(s):  
Boundary Layer ◽  
General Circulation ◽  
Deep Convection ◽  
Circulation Model ◽  
Grid Cell ◽  
Atmospheric Model ◽  
Space Time ◽  
Madden Julian Oscillation ◽  
Moist Convection ◽  
Time Structures

Abstract The detailed dynamic and thermodynamic space–time structures of the Madden–Julian oscillation (MJO) as simulated by the superparameterized Community Atmosphere Model version 3.0 (SP-CAM) are analyzed. Superparameterization involves substituting conventional boundary layer, moist convection, and cloud parameterizations with a configuration of cloud-resolving models (CRMs) embedded in each general circulation model (GCM) grid cell. Unlike most GCMs that implement conventional parameterizations, the SP-CAM displays robust atmospheric variability on intraseasonal space and time (30–60 days) scales. The authors examine a 19-yr SP-CAM simulation based on the Atmospheric Model Intercomparison Project protocol, forced by prescribed sea surface temperatures. Overall, the space–time structures of MJO convective disturbances are very well represented in the SP-CAM. Compared to observations, the model produces a similar vertical progression of increased moisture, warmth, and heating from the boundary layer to the upper troposphere as deep convection matures. Additionally, important advective and convective processes in the SP-CAM compare favorably with those in observations. A deficiency of the SP-CAM is that simulated convective intensity organized on intraseasonal space–time scales is overestimated, particularly in the west Pacific. These simulated convective biases are likely due to several factors including unrealistic boundary layer interactions, a lack of weakening of the simulated disturbance over the Maritime Continent, and mean state differences.

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