South Asian Regional Reanalysis

1. South Asian Regional Reanalysis IMD Station Precipitation (1979-2001) Summer Monsoon Climatology (JJA) Contours: 2, 4, 6, 8 (+4) > 6 mm/day Sumant Nigam University of Maryland (US – Project PI)

2. South Asian Regional Reanalysis OBJECTIVE Generate a high-resolution dynamics-thermodynamics consistent climate dataset from retrospective analysis of in-situ and remotely sensed observations. To advance understanding, modeling and prediction of regional hydroclimate variability and change over this vastly populated subcontinent of complex orography, land-surface types and land-ocean boundaries. Sumant Nigam, University of Maryland, nigam@atmos.umd.edu http://www.atmos.umd.edu/~nigam/Asian.Regional.Reanalysis.pdf

3. South Asian Regional Reanalysis MOTIVATION Consistent description of hydroclimate (precipitation, soil moisture, stream flow, drought indices): Direct societal impact. Climate-change detection and attribution over Asia – home of two large energy-hungry economies. Circulation-hydroclimate consistent records are presently unavailable for a discriminating analysis of climate change: IPCC relevance. Understanding mechanisms that mediate local and remote forcing (aerosols, ENSO, NAO,..) and the monsoon response: Advance basic science. Wide influence of Asian monsoon and Indian ocean: Notably, on ENSO evolution and US summer climate. Teleconnections. Nowcasting and forecasting of regional climate: An Observation-Model bridge. Sumant Nigam, University of Maryland, nigam@atmos.umd.edu http://www.atmos.umd.edu/~nigam/Asian.Regional.Reanalysis.pdf

4. SST Trend in the 20th Century Trend Mode (REEOF3) CI=0.1K Linear Trend CI=0.3K/century Indian Ocean:Only basin exhibiting significant SST-trends at the Equator

5. South Asian Regional Reanalysis SPECIFIC OBJECTIVES Exploit high spatiotemporal resolution satellite data over vast stretches of conventionally unsampled mountainous terrain. Generate unique synthesis of conventional and remotely sensed data with state-of-the-art atmosphere/land-surface models. Develop comprehensive summer and winter monsoon circulation-hydroclimate phenomenologies from closer interaction of observations and models; advancing model validation. Generate a framework for diagnosing the influence of regional anthropogenic aerosols/pollutants on circulation and hydroclimate. Contribute to the development of improved (and rigorous) water resource management and agricultural practice models. Forge strong links between climate programs of South Asian countries,with Indian leadership? Sumant Nigam, University of Maryland, nigam@atmos.umd.edu http://www.atmos.umd.edu/~nigam/Asian.Regional.Reanalysis.pdf

6. South Asian Regional Reanalysis Science CHALLENGES Canonical assimilation of circulation and temperature – as in global reanalyses – has not constrained the hydroclimate. Precipitation, radiances and aerosols need to be additionally assimilated for circulation-hydroclimate consistency. Assimilation strategies that reduce long-term imbalances in regional water and energy budgets in addition to minimizing short-term circulation forecast errors; as in global reanalysis. Aerosol assimilation consistent with radiation balance. The precipitation and radiance assimilating North American Regional Reanalysis offers valuable guidance. Sumant Nigam, University of Maryland, nigam@atmos.umd.edu http://www.atmos.umd.edu/~nigam/Asian.Regional.Reanalysis.pdf

7. Rainfall in Global Reanalysis Summer Monsoon (JJA) Precipitation Climatology (Reanalyses,1979-2001) Contours: 2, 4, 6, 8 (+4) mm/day ERA-40 NCEP > 6 mm/day ERA-40: ECMWF Reanalysis JRA-25: Japanese Reanalysis NCEP: NCEP Reanalysis NCEP2: NCEP-DOE Reanalysis JRA-25 CRU

8. CMAP2 CRU Summer Monsoon (J,J,A) Temporal Correlation of monthly rainfall with IMD data(1979-2001) Correlation contours: .3, .4, .5, … ERA40 NCEP > 0.5 ERA-40: ECMWF Reanalysis JRA-25: Japanese Reanalysis NCEP: NCEP Reanalysis NCEP2: NCEP-DOE Reanalysis JRA25

9. SUMMER WINTER US Precipitation in Regional and Global Reanalyses ●CMAP-2: Precip analysis (Validation) ●NARR: North American Regional Reanalysis (assimilates precipitation) ●ERA-40 & NCEP: Global Reanalysis SUMMER ERA-40 is drier over the central US NCEP, on the other hand, is too wet NARR is on target (not surprisingly) WINTER NCEP and ERA-40 capture the winter rainy season in the Pacific/Northwest but not the winter rainy zone over the Gulf Coast and southeastern states. NARR again is on target.

10. Satellite derived Station data IMD CMAP2 Summer Monsoon (JJA) Precipitation Climatology (Observations,1979-2001) Contours: 2, 4, 6, 8 (+4) mm/day IITM TRMM (1998-06) > 6 mm/day IMD: India Meteorological Dept., New Delhi, MoES IITM: Indian Institute of Tropical Meteorology, Pune, MoES CRU: Climate Research Unit, University of East Anglia CRU

11. Hydroclimate Variability and Change over the South Asian Monsoon Region: The Need for Regional ReanalysisSession A34B at the AGU Fall Meeting 2006 (Conveners: Nigam, Krishnamurti, Ramanathan and Shukla) • S Nigam, Maryland: Session introduction: The need for South Asian Regional Reanalysis • TN Krishnamurti, FSU: Assimilation of precipitation and latent heating profiles • Chung/Ramanathan, UCSD: Aerosols' influence on monsoon circulation and precipitation • William Kuo, NCAR: Influence of COSMIC satellite data on regional reanalysis • Peter Webster, Georgia Tech: Monsoon variability and hydrology of South Asia • Ruby Leung, DOE/PNL: Regional modeling over complex terrains: Hydroclimate challenges over South Asia • William Lau, GSFC: Aerosols' influence on monsoon circulation and hydroclimate • Fedor Mesinger, NCEP: Lessons from the North American Regional Reanalysis project