GMMIP Global Monsoons Model Intercomparison Project

Global Monsoons Modeling Inter-comparison Project (GMMIP) | MonsoonMIP | Application for CMIP6-Endorsed MIPs

Chairs

Tianjun Zhou, Institute of Atmospheric Physics, Chinese Academy of Sciences, China (zhoutj@lasg.iap.ac.cn)
Andy Turner, University of Reading, UK (a.g.turner@reading.ac.uk)
James Kinter, COLA, George Mason University (ikinter@gmu.edu)

Suggested Members of the Scientific Steering Committee (new members from African and American monsoon communities will be included)

Bin Wang, University of Hawaii, USA (wangbin@hawaii.edu)
Yun Qian, Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, USA (yun.qian@pnnl.gov)
Bin Wang, Institute of Atmospheric Physics, Chinese Academy of Sciences, China (wab@lasg.iap.ac.cn)

Official website

http://www.lasg.ac.cn/gmmip (coming soon)

Proposed by

CLIVAR AAMP, CLIVAR-GEWEX MP, CLIVAR/C20C+, in collaboration with LASG/IAP, China and PNNL, USA

Goals of GMMIP

Changes in the precipitation and atmospheric circulation in the global monsoons are of great scientific and societal importance owing to their impacts on more than two-thirds of the world's population.

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Monsoons occur in various regions around the world. Prediction of the monsoon rainfall change in the coming decades is of deep societal concern and vital for infrastructural planning, water resource management, and sustainable economic development.

The dominant monsoon systems in the world include the Asian-Australian, African, and the American monsoons. Each monsoon system generally has its own unique and specific characteristics in terms of variability. At the same time, the connections in the global divergent circulation necessitated by mass conservation link the various regional monsoons as they evolve through the season. On interannual-to-multidecadal time scales, there is evidence that monsoon precipitation in the Northern Hemisphere (NH) and Southern Hemisphere (SH) varies coherently, driven by ENSO and other global modes of climate variability at the lower boundary of the atmosphere.

The combination of changes in monsoon area and rainfall intensity has led to an overall weakening trend of global land monsoon rainfall accumulation since the 1950s. This decreasing tendency is dominated by the African and South Asian monsoons, due to the significant decreasing tendencies of both rainfall intensity and monsoon coverage. Beginning in the 1980s, however, the NH global monsoon precipitation has shown an upward trend. Understanding the mechanisms of precipitation changes in the global monsoons and identifying the roles of natural and anthropogenic forcing agents have been foci of the monsoon research community.

While all monsoons are large-scale cross-equatorial overturning circulations, major differences between characteristics of the different regional monsoons arise because of the different orography. This is most apparent for the Asia region, due to the TIP/Himalaya. Climate models are useful tools in climate variability and climate change studies. However, the performance of the current state-of-the-art climate models is very poor and needs to be greatly improved over the monsoon domains. The Global Monsoons Model Inter-comparison Project (hereafter GMMIP) aims to improve our understanding of physical processes in global monsoon systems and to better simulate the mean state, interannual variability and long-term change of global monsoons by performing multi-model inter-comparisons. The contributions of internal variability (IPO-Interdecadal Pacific Oscillation, AMO-Atlantic Multidecadal Oscillation) and external anthropogenic forcing to the historical evolution of global monsoons in the 20th and 21st century will be addressed.

Primary Science Questions

What are the relative contributions of internal processes and external forcing that are driving the 20th century historical evolution of global monsoons?
To what extent and how does the atmopshere-ocean interaction contribute to the interannual variability and predictability?
What are the effects of Eurasian orography, in particular the Himalaya/Tibetan Plateau, on the regional/global monsoons?
How well can developing high-resolution models and improving model dynamics and physics help to reliably simulate monsoon precipitation and it variability and change?

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By focusing on addressing these four questions we expect to deepen our understanding of models' capability in reproducing the monsoon mean state and its natural variability as well as the forced response to natural and anthropogenic forcing, which ultimately will help to reduce model uncertainty and improve the credibility of models in projecting future changes in the monsoon. The coordinated experiments will also help advance our physical understanding and prediction of monsoon changes.

Due to the uncertainties in the physical parameterizations in current models, the best way to address these questions is through a multi-model framework. CMIP6 provides a good opportunity for advancement of monsoon modeling and understanding. GMMIP will contribute to four of the five grand challenges of the WCRP, viz. Regional Climate Information, Water Availability, Climate Extremes, and Clouds, Circulation and Climate Sensitivity.

Proposed Experiments

The main experiments of GMMIP will be divided into Tier 1 and Tier 2, with further optional ideas in Tier 3. The total experiments of GMMIP are summarized in Table 1. The Tier-1 experiments will be extended AMIP runs. This is the entry card for GMMIP.

priority	EXP name	integration length	short description and purpose	model type
Tier-1	AMIP20C	1870-2013	Extended AMIP run. All natural and anthropogenic historical forcings as used in CMIP6 historical simulation will be included. AGCM resolutions as CMIP6 historical simulation. The HadISST data will be used. Minimum number of integrations is 1	AGCM
Tier-2	HIST-IPO	1870-2013	Pacemaker 20th century historical run that includes all forcings as used in CMIP6 historical simulation, and the observational historical SST is restored in the tropical lobe of the IPO domain (20°S-20°N, 175°E-75°W), to understand the forcing of IPO-related tropical SST on global monsoon changes. Models' resolutions as CMIP6 historical simulation. The HadISST data will be used. Minimum number of integrations is 1	CGCM with SST restored to model climatology plus observational historical anomaly in the tropical lobe of the IPO domain
Tier-2	HIST-AMO	1870-2013	Pacemaker 20th century historical run that includes all forcings as used in CMIP6 historical simulation, and the observational historical SST is restored in the AMO domain (0-70°N, 70°W-0°), to understand the forcing of AMO-related SST on global monsoon changes. Models' resolutions as CMIP6 historical simulation. The HadISST data will be used. Minimum number of integrations is 1	CGCM with SST restored to model climatology plus observational historical anomaly in the AMO domain
Tier-3	DTIP	1979-2013	The topography of the TIP is modified by setting surface elevations to 500m, to understand the combined thermal and mechanical forcing of the TIP. Same model as DECK. Minimum number of integrations is 1	AGCM
Tier-3	DTIP-DSH	1979-2013	Surface sensible heat released at the elevation above 500m over the TIP is not allowed to heat the atmosphere, to compare the impact of removing thermal effects. Same model as DECK. Minimum number of integrations is 1	AGCM
Tier-3	DHLD	1979-2013	The topography of the highlands in Africa, N. America and S. America TP is modified by setting surface elevations to a certain height (500m). Minimum number of integrations is 1	AGCM

Further details...

The Tier-2 HIST-IPO run is Pacemaker 20th century historical climate simulation that includes all forcing, and the sea surface temperature (SST) restored to the model climatology plus observational historical anomaly in the tropical lobe of the Interdecadal Pacific Oscillation (IPO; Power et al. 1999; Folland et al. 2002) domain (20°S-20°N, 175°E-75°W): the weight=1 in the inner box (15°S-15°N, 180°-80°W), linearly reduced to zero in the buffer zone (zonal and meridional ranges are both 5°) from the inner to outer box.

The Tier-2 HIST-AMO run is Pacemaker 20th century historical climate simulation that includes all forcing, and the SST restored to the model climatology plus observational historical anomaly in the Atlantic Multidecadal Oscillation (AMO; Enfield et al. 2001; Trenberth and Shea 2006) domain (0°-70°N, 70°W-0°): the weight=1 in the inner box (5°N-65°N, 65°W-5°W), linearly reduced to zero in the buffer zone (zonal and meridional ranges are both 5°) from the inner to outer box.

In Tier-3 DTIP run, following Boos and Kuang (2011, 2013) and Wu et al. (2007, 2012), the topography of the Tibetan Plateau (hereafter TIP) (20-60°N, 25-120°E) in the model is modified by levelling off the TIP to a certain height (e.g. 500m), with the surface properties unchanged. Other settings of the integration are same as the standard DECK AMIP run. This experiment represents perturbations to both thermal and mechanical forcing of the TIP with respect to the standard DECK AMIP run.

In Tier-3 DTIP-DSH run, the surface sensible heat flux at elevations above 500m over the TIP is not allowed to heat the atmosphere, i.e., the vertical diffusive heating term in the atmospheric thermodynamic equation is set to zero (Wu et al. 2012).Other settings of the integration are same as the standard DECK AMIP run. The differences between the standard DECK AMIP run and the DTIP-DSH are considered to represent the removal of TIP thermal forcing only and thus the circulation pattern of DTIP-DSH reflects the impacts of mechanical forcing.

Description of the analysis of GMMIP experiments

There are four tasks in the analysis of GMMIP:

Task-1: Understanding 20th century changes of global monsoons
Task-2: The role of Eurasian orography on the regional/global monsoons (Himalaya/Tibetan Plateau experiment)
Task-3: Interannual variability of global monsoon precipitations
Task-4: High resolution modelling of global monsoons

The analysis of the four tasks will use the outputs of GMMIP experiments, DAMIP (Detection and Attribution MIP) experiments, HighResMIP experiments, the CMIP6 Historical Simulation, and the AMIP experiments of DECK.

Connection with DECK and CMIP6 Historical Simulation

The DECK simulations will serve as an entry card for the CMIP6-Endorsed MIPS. The DECK experiments are:

AMIP simulations
Pre-industrial control simulations
1%/yr increase in CO2 concentration
Switch-on 4XCO2

The CMIP6 Historical Simulation experiment is:

Historical simulation of fully coupled models (1850-2014)

The AMIP DECK simulation with the standard CMIP6 resolution will be used in the analysis of GMMIP. The Tier-1 AGCM experiment of GMMIP will specify the specific forcings which are consistent with the historical simulation from 1850-2014, viz. the CMIP6 Historical Simulation.

Connection with other MIPs

DAMIP (Detection and Attribution MIP) The histALL (enlarging ensemble size of historical ALL forcing runs in DECK), histNAT(Historical natural-only run), histGHG (Historical well-mixed GHG-only run), histAER experiments (Historical anthropogenic-Aerosols-only run) of DAMIP will be used in the analysis of Task-1 of GMMIP.

Combinations of histALL, histNAT and histGHG will allow us to understand the observed 20th century global monsoon precipitation and circulation changes in the context of contributions from GHG, the other anthropogenic factors and natural forcing. The contributions of these external forcings will be compared to those from internal variability modes such as IPO and AMO.
HighResMIP The Tier-1 experiments of HighResMIP, which are AMIP runs but with minimum 25-50km at mid-latitudes for high resolution + a standard resolution configuration (1950-2014), will be used in the analysis of Task-4 of GMMIP, which aims to examine the performance of high-resolution models in reproducing both the mean state and year-to-year variability of global monsoons.

The Tier-2 experiments of HighResMIP, which are coupled runs consisting of pairs of both historic runs and control runs using fixed 1950s forcing, will be used in the analysis of Task-3 of GMMIP, which aims to understand the role of air-sea interaction process in the improvement of monsoon mean state and year-by-year variability.

WCRP Grand Challenges

GMMIP will address the grand challenges of the WCRP in the following ways:

Regional Climate Information (rank 1) GMMIP will improve our understanding of the 20th climate changes in global monsoon domains. The contributions of external anthropogenic forcings (GHG, aerosol), natural forcing, and internal variability modes (IPO, AMO) will be identified. These would provide useful information to climate prediction/projections in the highly populated global monsoon domains.
Water Availability (rank 2) The water resources in global monsoon domains are greatly affected by the anomalous activities of monsoons. Understanding the mechanisms of monsoon variability as posed by GMMIP will lead to improvement of monsoon prediction/projection and provide useful information to policymakers in water availability-related decision making.
Climate Extremes (rank 2) Extreme events such as mega-droughts and flooding have been frequently occurred in global monsoon domains. GMMIP is hopefully to identify the useful ways of improving the simulation/prediction of climate extremes in global monsoon domains.
Clouds, Circulation and Climate Sensitivity (rank 2) A reasonable simulation of monsoon circulation and clouds is a prerequisite for a successful simulation of monsoon precipitation. By comparing the performances of climate models with high and normal resolutions, model simulations with/without air-sea interaction processes, the implementation of GMMIP will link the monsoon circulations to monsoon precipitation in the context of reducing model bias and improving model performances.

GEWEX and CLIVAR

Monsoon has been a research focus of GEWEX and CLIVAR. The scientific questions listed in GMMIP were originally identified by the CLIVAR Asian-Australian monsoon panel, the GEWEX/CLIVAR Monsoons Panel, and CLIVAR/C20C+ project. The questions have also been highlighted by the reports of CLIVAR Research Opportunities Tiger Team on "Decadal Variability in the Climate System and its Predictability", and CLIVAR Research Opportunities Tiger Team on "Intra-seasonal, Seasonal and Interannual Variability and Predictability of Monsoon Systems".

Participation

Participation in GMMIP is voluntary and open. GMMIP will be coordinated by a small working group composed of engaged representatives from climate diagnosis, climate change attribution and climate modelling communities. This working group will engage the broadest degree of input and involvement from members of the scientific community.

The Scientific Steering Committee (SSC) of GMMIP will be composed of representatives from CLIVAR & GEWEX monsoon panels, relevant projects and the global monsoon community. The SSC will provide comments and instructions for the analysis of GMMIP with focus on the scientific questions listed in the proposal.

Please contact us for a list of the 15 modelling centers who have expressed their interest.

Proposed timing

Start of the experiments: Beginning of 2016

End of the experiments: No fixed date.

References

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Boos, W. R. &Z. M. Kuang 2010: Dominant control of the South Asian monsoon by orographic insulation versus plateau heating. Nature 463, 218-223.
Boos, W.R. &Z. M. Kuang 2013: Sensitivity of the South Asian monsoon to elevated and non-elevated heating. Sci. Rep. 3, 1192; DOI:10.1038/srep01192.
Cook, B.I., and R. Seager, 2013: The response of the North American Monsoon to increased greenhouse gas forcing. J. Geophys. Res.,118, 1690-1699
Cook, K. H., G. A. Meehl, and J. M. Arblaster, 2012: Monsoon regimes and processes in CCSM4. Part II: African and American monsoon systems. J. Climate, 25, 2609-2621
Enfield, D., A. Mestas-Nuñez, and P. Trimble (2001), The Atlantic Multidecadal Oscillation and its relation to rainfall and river flows in the continental U.S., Geophys. Res. Lett., 28, 2077–2080, doi:10.1029/2000GL012745.
Folland, C. K., J. A. Renwick, M. J. Salinger, and A. B. Mullan (2002), Relative influences of the Interdecadal Pacific Oscillation and ENSO on the South Pacific Convergence Zone, Geophys. Res. Lett., 29(13), 1643, doi:10.1029/ 2001GL014201.
Kitoh, A., H. Endo, K. Krishna Kumar, I.F.A. Cavalcanti, P. Goswami, T. Zhou, 2013: Monsoons in a changing world: a regional perspective in a global context. J. Geophys. Res., 118, 3053-3065,doi:10.1002/jgrd.50258.
Lin R., T. Zhou, Y. Qian, 2014: Evaluation of Global Monsoon Precipitation Changes based on Five Reanalysis Datasets, Journal of Climate,27(3),1271-1289
Liu, J., B. Wang, M.A. Cane, S.-Y. Yim, and J.-Y. Lee, 2013: Divergent global precipitation changes induced by natural versus anthropogenic forcing. Nature, 493, 656-659
Power, S., T. Casey, C. Folland, A. Colman, and V. Mehta (1999), Interdecadal modulation of the impact of ENSO on Australia, Clim. Dyn., 15, 319–324.
Qiu J. 2013: Monsoon Melee. Science, 340 (6139), 1400-1401; DOI:10.1126/science 340.6139.1400.
Song, F., T. Zhou,and Y. Qian (2014), Responses of East Asian summer monsoon to natural and anthropogenic forcings in the 17 latest CMIP5 models, Geophys. Res. Lett., 41,doi:10.1002/2013GL058705
Song, F., T. Zhou, 2014: Interannual Variability of East Asian Summer Monsoon Simulated by CMIP3 and CMIP5 AGCMs: Skill Dependence on Indian Ocean–Western Pacific Anticyclone Teleconnection. J. Climate, 27, 1679-1697
Song F., T. Zhou, 2014: The climatology and inter-annual variability of East Asian summer monsoon in CMIP5 coupled models: Does air-sea coupling improve the simulations? Journal of Climate, doi:10.1175/JCLI-D-14-00396.1
Sperber, K.R., H. Annamalai, I.-S. Kang, A. Kitoh, A. Moise, A. Turner, B. Wang and T. Zhou, 2013: The Asian summer monsoon: an intercomparison of CMIP5 vs. CMIP3 simulations of the late 20th century. Clim. Dynam., 41, 2771-2744, doi:10.1007/s00382-012-1607-6.
Trenberth, K. E., and D. J. Shea (2006), Atlantic hurricanes and natural variability in 2005, Geophys. Res. Lett., 33, L12704, doi:10.1029/2006GL026894.
Wang B., Q. H. Ding, X. H. Fu, I.-S. Kang, K. Jin, J. Shukla, and F. Doblas-Reyes, 2005: Fundamental challenge in simulation and prediction of summer monsoon rainfall. Geophys. Res. Lett., 32, L15711, doi:10.1029/2005GL022734.
Wang, B., J. Liu, H.-J. Kim, P.J. Webster, S.-Y. Yim, and B. Xiang, 2013: Northern Hemisphere summer monsoon intensified by mega-El Niño/southern oscillation and Atlantic multidecadal oscillation. PNAS, 110 (14), 5347-5352, doi:10.1073/pnas.1219405110.
Wang, B., J. Liu, H.-J. Kim, P.J. Webster, and S.-Y. Yim, 2012: Recent Change of the Global Monsoon Precipitation (1979-2008). Clim. Dyn., 39 (5), 1123-1135
Wu, G., Y. Liu, T. Wang, et al., 2007: The Influence of the Mechanical and Thermal Forcing of the Tibetan Plateau on the Asian Climate. J. Hydrometeorology 8: 770-789.
Wu, G., Y. Liu, B. He, Q. Bao, A.Duan& F.-F. Jin, 2012: Thermal Controls on the Asian Summer Monsoon. Sci. Rep. 2, 404; DOI:10.1038/srep00404.
Zhou T., R. Yu, H. Li, and B. Wang, 2008, Ocean Forcing to Changes in Global Monsoon Precipitation over the Recent Half-Century, Journal of Climate, 21(15), 3833–3852
Zhou T., B. Wu, B. Wang, 2009, How Well Do Atmospheric General Circulation Models Capture the Leading Modes of the Interannual Variability of the Asian-Australian Monsoon? Journal of Climate, 22, 1159-1173

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