Summer Monsoon Variability over South and East Asia: Understanding Tele-connections through NCEP/NCAR Reanalysis data R. H. Kripalani A.A.Kulkarni, S.S. Sabade and J.H. Oh * Indian Institute of Tropical Meteorology, Pune 411008, India * Pukyong National University, Busan, South Korea 3 rd WCRP International Conference on Reanalysis: Tokyo, Japan 28 Jan-1 Feb 2008
Data and Methodology Standardized DMI 1960 through 2000 derived from GISST data Seasonal Summer Monsoon Rainfall North China (36-41 0 N, 109-124 0 E) South Korea (34-38 0 N, 126-130 0 E) Southern parts of Japan (31-36 0 N, 130-141 0 E) NCEP-NCAR Reanalysis data 850 hpa vector winds 500 hpa geopotential heights Sea Surface Temperature Sea Level Pressure ( Kripalani et al, 2005: Theoretical Applied Climatology, 82, 81-94 )
Relationship of Seasonal DM Index with Summer Monsoon Rainfall Over South (India) and East Asia (China, Japan, Korea) Indian Institute of Tropical Meteorology
1 0.5 INDIA 0-0.5-1 CORRELATION COEFFICIENT 1 0.5 0-0.5-1 1 0.5 0-0.5 CHINA JAPAN -1 1 0.5 KOREA 0-0.5-1 JJA-1 JJA0 JJA+1 SEASON PRECEDING FOLLOWING Kripalani et al, 2005
EXTREME INDIAN OCEAN DIPOLE PHASES POSITIVE NEGATIVE 1961 1964 1963 1973 1967 1974 1972 1980 1982 1981 1983 1984 1991 1989 1994 1992 1997 1996 2000 1998
Indian Institute of Tropical Meteorology
Main Inference from Correlation and Composite Analysis Summer and Autumn DMI during the preceding year show significant negative relationship with summer monsoon rainfall over Korea and Japan and the adjoining regions Indian Ocean Dipole / Zonal Mode influences East Asian monsoon variability 3 to 4 seasons later
Mean Seasonal Rainfall following Extreme Events For South Korea : Mean KMR 648 mm Following Extreme Positive Events 593 mm Following Extreme Negative Events 753 mm Difference significant at 90% confidence level For Japan : Mean JMR 923 mm Following Extreme Positive Events 885 mm Following Extreme Negative Events 1140 Events Difference significant at 90% confidence level (Kripalani et al 2005)
Indian Ocean East Asian Monsoon connections
Through Northern Hemisphere Mid-Latitudes Monsoon Desert Mechanism
500 hpa Geopotential Height Difference Positive minus Negative DMI Kripalani et al, 2005
Kripalani et al, 2005
Kripalani et al, 2005
Kripalani et al, 2005
Through Southern Channel: Indonesian Through-Flow
850 hpa Vector Wind Difference: Positive minus Negative DMI Kripalani et al, 2005 Indian Institute of Tropical Meteorology
Kripalani et al, 2005 Indian Institute of Tropical Meteorology
Kripalani et al, 2005 Indian Institute of Tropical Meteorology
Kripalani et al, 2005 Indian Institute of Tropical Meteorology
Memory for delayed impact : Eurasian Snow?
Soviet snow depth data product (National Snow and Ice Data Center, Boulder, CO, USA) Data for the 284 stations 70 uniform blocks of 5 0 lat by 10 0 long (Kripalani and Kulkarni, Climate Dynamics,1999, 15:475-489) Indian Institute of Tropical Meteorology
Empirical Approach: Dipole Mode and Eurasian Snow Indian Institute of Tropical Meteorology
Indian Institute of Tropical Meteorology
Indian Institute of Tropical Meteorology
EXTREME SNOW DEPTH: WINTER / SPRING (50-70 0 N, 120-140 0 E: North of Korea-Japan) HEAVY SNOW LIGHT SNOW 1962 1961 1970 1963 1978 1966 1979 1973 1980 1987 WINTER= +1.6 WINTER= -1.5 SPRING= +1.1 SPRING= -0.6
Indian Institute of Tropical Meteorology
Indian Institute of Tropical Meteorology
Indian Institute of Tropical Meteorology
SST Anomalies September 2007 Memory for delayed impact : Sea Surface Temperature?
SST Difference : Positive minus Negative DMI
SST Difference : Positive minus Negative DMI
Indian Institute of Tropical Meteorology
Summary : Possible Mechanisms Eurasian route : heavy snow cold and dry air from north Indonesian Through Flow : Positive SST anomalies West IO East IO West Pacific North Pacific Displacement of NPSH eastwards Weak low level jet / cross equatorial flow Inhibiting moisture supply from Pacific Subdued rainfall activity Seasonal evolution of NCEP/NCAR data sets bring out Tele-connections Indian Institute of Tropical Meteorology
SST Anomalies September 2007
Relationship of ENSO (NINO3 SST) with Summer Monsoon Rainfall Over East Asia (China, Korea, Japan) 0.8 0.6 China China Korea 0.4 0.2 0-0.2-0.4-0.6-0.8 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6-0.8 0.8 0.6 0.4 0.2 0 Kore a Japan i. Significant simultaneous Relationship ii. iii. Inference El Nino favorable (unfavorable) for monsoon activity over Korea Japan (China). La Nina favorable (unfavorable) for monsoon activity over China (Korea- Japan) Japan -0.2-0.4-0.6-0.8 JJA-1 SON-1 DJF0 MAM0 JJA0 SON0 DJF+1 MAM+1 JJA+1 ENSO leads ENSO lags Indian Institute of Tropical Meteorology
Outlook for Summer Monsoon 2008 : Korea Japan Sector Positive dipole over Indian Ocean La Nina phase over the Pacific Deficient Monsoon JJA 2008 over Korea Japan Peninsula?