R. H. Kripalani A.A.Kulkarni, S.S. Sabade and J.H. Oh *

Transcription

1 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 , India * Pukyong National University, Busan, South Korea 3 rd WCRP International Conference on Reanalysis: Tokyo, Japan 28 Jan-1 Feb 2008

2 Data and Methodology Standardized DMI 1960 through 2000 derived from GISST data Seasonal Summer Monsoon Rainfall North China ( N, E) South Korea ( N, E) Southern parts of Japan ( N, 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, )

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4 Relationship of Seasonal DM Index with Summer Monsoon Rainfall Over South (India) and East Asia (China, Japan, Korea) Indian Institute of Tropical Meteorology

5 1 0.5 INDIA CORRELATION COEFFICIENT CHINA JAPAN KOREA JJA-1 JJA0 JJA+1 SEASON PRECEDING FOLLOWING Kripalani et al, 2005

6 EXTREME INDIAN OCEAN DIPOLE PHASES POSITIVE NEGATIVE

7 Indian Institute of Tropical Meteorology

8 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

9 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)

10 Indian Ocean East Asian Monsoon connections

11 Through Northern Hemisphere Mid-Latitudes Monsoon Desert Mechanism

12 500 hpa Geopotential Height Difference Positive minus Negative DMI Kripalani et al, 2005

13 Kripalani et al, 2005

14 Kripalani et al, 2005

15 Kripalani et al, 2005

16 Through Southern Channel: Indonesian Through-Flow

17 850 hpa Vector Wind Difference: Positive minus Negative DMI Kripalani et al, 2005 Indian Institute of Tropical Meteorology

18 Kripalani et al, 2005 Indian Institute of Tropical Meteorology

19 Kripalani et al, 2005 Indian Institute of Tropical Meteorology

20 Kripalani et al, 2005 Indian Institute of Tropical Meteorology

21 Memory for delayed impact : Eurasian Snow?

22 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: ) Indian Institute of Tropical Meteorology

23 Empirical Approach: Dipole Mode and Eurasian Snow Indian Institute of Tropical Meteorology

24 Indian Institute of Tropical Meteorology

25 Indian Institute of Tropical Meteorology

26 EXTREME SNOW DEPTH: WINTER / SPRING ( N, E: North of Korea-Japan) HEAVY SNOW LIGHT SNOW WINTER= +1.6 WINTER= -1.5 SPRING= +1.1 SPRING= -0.6

27 Indian Institute of Tropical Meteorology

28 Indian Institute of Tropical Meteorology

29 Indian Institute of Tropical Meteorology

30 SST Anomalies September 2007 Memory for delayed impact : Sea Surface Temperature?

31 SST Difference : Positive minus Negative DMI

32 SST Difference : Positive minus Negative DMI

33 Indian Institute of Tropical Meteorology

34 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

35 SST Anomalies September 2007

36 Relationship of ENSO (NINO3 SST) with Summer Monsoon Rainfall Over East Asia (China, Korea, Japan) China China Korea 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 JJA-1 SON-1 DJF0 MAM0 JJA0 SON0 DJF+1 MAM+1 JJA+1 ENSO leads ENSO lags Indian Institute of Tropical Meteorology

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38 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?

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