Improvement of simulated monsoon precipitation over South-Asia with a regionally

coupled model REMO-MPIOM

Pankaj Kumarª, Dmitry Sein², William Cabos³, Daniela Jacobª

ª : Climate Service Center 2.0, Germany ² : Alfred Wegener Institute, Germany ³ : University of Alcalà, Spain

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

Motivation

Regional coupled model setup

Experiment design

Results

Conclusion

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Motivation

Sources Google images

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

Monsoon season JJAS is the most important climatic feature over South-Asia, contributing ca. 70-90% annual rainfall. One of the most complicated phenomenon to be simulate by climate models. A regional coupled atmosphere–ocean model is developed to study the monsoon climate over the CORDEX South Asia domain.

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Experiment Setup

Figure : Grid configuration: the red “rectangle” indicates the coupled domain (REMO model) black lines indicate the grid of the MPIOM/HAMOCC. For the ocean/sea ice grid only every 15th line is shown.

• The REgional atmosphere MOdel REMO with 50km horizontal resolution is coupled to the MPI global ocean – sea ice model MPIOM with increased resolution over the Indian Ocean (up to 20 km).

• The CORDEX south Asia domain is taken as atmospheric model domain (Fig.-1).

• The models are coupled via the OASIS coupler. • The global Hydrological Discharge model HD, which

calculates river runoff (0.5º horizontal grid resolution), is coupled to both the atmosphere and ocean components.

• Hereafter this coupled system will be called as ROM. • Exchange of fields between ocean and atmosphere takes

place every three hours. • Lateral atmospheric and upper oceanic boundary conditions

outside the REMO domain were prescribed using ERA40 reanalysis for the two hindcast simulations as well as with MPI-ESM-LR two historical run

• The total simulation period is 1958-2001.

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

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REMO/ROM CORDEX SA simulation table

RCM Forcing REMO (UnCoupled)

ROM (Coupled: REMO-MPIOM)

Period

ERA Interim √ - 1989-2008 ERA40 √ √ 1958-2001 MPI-ESM_Hist. √ √ 1958-2005 MPI-ESM_rcp26 √ - 2006-2100 MPI-ESM_rcp45 √ - 2006-2100 MPI-ESM_rcp85 √ - 2006-2100 EcEarth_Hist. √ - 1958-2005 EcEarth_rcp26 Under preparation - - EcEarth_rcp45 ,, - - EcEarth_rcp85 ,, - -

Note: REMO CORDEX South-Asia simulation with MPI-ESM data is ready and some data is already uploaded on the ESGF node. Rest of the ready data is likely to be uploaded by the end of next month.

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

Annual, Precipitation (mm/d) 1989-2001, coupled & uncoupled Much better resolve local and large scale precip. structure in ROM

Results

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

Annual Precipitation magnitude difference (mm/d), coupled - uncoupled

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de

WMO CCL TECO 2014, Heidelberg, Germany 30June-2July 2014 contact: pankaj.kumar@hzg.de 8

Conclusion

Within CORDEX framework over South-Asia domain a set of four long regional coupled/uncoupled climate simulations are performed for monsoon studies.

Regional coupled model (ROM) showed substantial improvement over South-Asia for monsoon precipitation climatology, both over land and ocean. Especially over Indonesian region, Bangladesh, plains of northern India, etc.

Indian ocean precipitation is mainly improved due to cooler SST in ROM

Much higher resolved Indian ocean (20-30km) lead’s to locally better resolved SST and precipitation patterns

Preliminary analysis is presented here, next step is to explore more on intraseasonal variability

Thank you for your attention!