Interannual Covariance between Japan Summer Precipitation and Western North Pacific SST

A statistical analysis is conducted of the covariance between summer precipitation in Japan and concurrent variations of sea surface temperature (SST) in the Western North Pacific (WNP; 120‐160 � E, 0‐60 � N). To this end, a singular value decomposition (SVD) is applied to observed monthly anomalies of the two fields for the period 1961‐1998 (38 summer seasons). The first coupled mode of the SVD explains as much as 71% of the total cross-covariance between WNP SST and Baiu precipitation. It is characterized by a zonally elongated dipole in the SST anomaly with opposite loadings on either side of about 30 � N and a precipitation anomaly with its maximum in southern Japan. The patterns indicate a negative correlation between Japan’s summer precipitation and the sea surface temperature in the East China Sea, Japan Sea and Kuroshio-Oyashio extension. Simpler composite analyses confirm the robustness of the coupling. In a linear regression analysis, the score of the WNP SST explains 30% of the domain mean summer precipitation variance, which is larger than the variance accounted for by lagged and concurrent ENSO-indices. Composites related to the mode’s precipitation score were found to support both directions of the atmosphere‐ocean interaction. On the one hand, the anomalies in radiation and evaporation at the sea surface would be sufficiently large to induce the observed temperature variations in the northern pole of the SST pattern. On the other hand, the possibility for an atmospheric response to the SST is supported by the consistency of anomalies in lower‐tropospheric baroclinicity and moisture flux divergence with the underlying SST distribution.

[1]  K. Lau,et al.  Interannual Variability of the Asian Summer Monsoon: Contrasts between the Indian and the Western North Pacific–East Asian Monsoons* , 2001 .

[2]  M. Rodwell,et al.  Subtropical Anticyclones and Summer Monsoons , 2001 .

[3]  S. Emori,et al.  Numerical Study on the Baiu Front Genesis by Heating Contrast between Land and Ocean , 2001 .

[4]  Bin Wang,et al.  Impact of the Preceding El Niño on the East Asian Summer Atmosphere Circulation , 2001 .

[5]  K. Lau,et al.  Coherent modes of global SST and summer rainfall over China: an assessment of the regional impacts of the 1997-98 El Niño , 2001 .

[6]  W. Collins,et al.  The NCEP–NCAR 50-Year Reanalysis: Monthly Means CD-ROM and Documentation , 2001 .

[7]  Tim Li,et al.  Interannual and Interdecadal Variations of the East Asian Summer Monsoon and Tropical Pacific SSTs. Part I: Roles of the Subtropical Ridge , 2000 .

[8]  H. Storch,et al.  Statistical Analysis in Climate Research , 2000 .

[9]  A. Sumi,et al.  Role of Transients in the Dynamics of East Asian Summer Seasonal Mean Circulation Anomalies—A Study of 1993 and 1994 , 2000 .

[10]  K. Lau,et al.  Dynamical and Boundary Forcing Characteristics of Regional Components of the Asian Summer Monsoon , 2000 .

[11]  Peter A. Rochford,et al.  An optimal definition for ocean mixed layer depth , 2000 .

[12]  P. Jones,et al.  Representing Twentieth-Century Space-Time Climate Variability. Part II: Development of 1901-96 Monthly Grids of Terrestrial Surface Climate , 2000 .

[13]  Bin Wang,et al.  Pacific–East Asian Teleconnection: How Does ENSO Affect East Asian Climate? , 2000 .

[14]  H. Davies,et al.  Covariation of the Mid-Tropospheric Flow and the Sea Surface Temperature of the North Atlantic: A Statistical Analysis , 2000 .

[15]  Y. Xue,et al.  Multi-Scale Summer Rainfall Variability Over China and its Long-Term Link to Global Sea Surface Temp , 1999 .

[16]  K. Lau,et al.  Interannual, Decadal–Interdecadal, and Global Warming Signals in Sea Surface Temperature during 1955–97 , 1999 .

[17]  P. Jones,et al.  Representing Twentieth-Century Space–Time Climate Variability. Part I: Development of a 1961–90 Mean Monthly Terrestrial Climatology , 1999 .

[18]  K. Lau,et al.  Principal Modes of Climatological Seasonal and Intraseasonal Variations of the Asian Summer Monsoon , 1999 .

[19]  T. Ose.  Seasonal Change of Asian Summer Monsoon Circulation and Its Heat Source , 1998 .

[20]  Minoru Tanaka.  Interannual and Interdecadal Variations of the Western North Pacific Monsoon and Baiu Rainfall and t , 1997 .

[21]  Chung-Kyu Park,et al.  On the Nature of the 1994 East Asian Summer Drought , 1997 .

[22]  Zeng‐Zhen Hu,et al.  Summer climate variability in China and its association with 500 hPa height and tropical convection. , 1996 .

[23]  J. Fyfe,et al.  The Coupled Patterns between Sea Level Pressure and Sea Surface Temperature in the Midlatitude North Atlantic. , 1996 .

[24]  Thomas M. Smith,et al.  Reconstruction of Historical Sea Surface Temperatures Using Empirical Orthogonal Functions , 1996 .

[25]  Bin Wang,et al.  Interdecadal changes in El Niño onset in the last four decades , 1995 .

[26]  Jun Matsumoto,et al.  Summer Monsoon over the Asian Continent and Western North Pacific , 1994 .

[27]  Thomas M. Smith,et al.  Improved Global Sea Surface Temperature Analyses Using Optimum Interpolation , 1994 .

[28]  Yasu-masa Kodama,et al.  Large-Scale Common Features of Sub-Tropical Convergence Zones (the Baiu Frontal Zone, the SPCZ, and the SACZ) Part II : Conditions of the Circulations for Generating the STCZs , 1993 .

[29]  Hans von Storch,et al.  The Atmospheric Circulation and Sea Surface Temperature in the North Atlantic Area in Winter: Their Interaction and Relevance for Iberian Precipitation , 1992 .

[30]  Catherine A. Smith,et al.  Singular value decomposition of wintertime sea surface temperature and 500-mb height anomalies , 1992 .

[31]  Catherine A. Smith,et al.  An Intercomparison of Methods for Finding Coupled Patterns in Climate Data , 1992 .

[32]  K. Ninomiya,et al.  Multi-scale Features of Baiu, the Summer Monsoon over Japan and the East Asia , 1992 .

[33]  K. Lau.  East Asian Summer Monsoon Rainfall Variability and Climate Teleconnection , 1992 .

[34]  Ian T. Jolliffe,et al.  Rotation of principal components: Some comments , 1987 .

[35]  Michaf. L. B. Richman.  Rotation of principal components: a reply , 1987 .

[36]  B. Hoskins,et al.  The formation mechanism of the Bonin high in August , 2003 .

[37]  C. Kobayashi,et al.  Precipitation and Moisture Balance of the Asian Summer Monsoon in 1991 Part II: Moisture Transport a , 1999 .

[38]  C. Schär,et al.  The interannual variability as a test ground for regional climate simulations over Japan , 1999 .

[39]  Minoru Tanaka.  Intraseasonal Oscillation and the Onset and Retreat Dates of the Summer Monsoon over East, Southeast , 1992 .

[40]  Yasu-masa Kodama,et al.  Large-Scale Common Features of Subtropical Precipitation Zones (the Baiu Frontal Zone, the SPCZ, and , 1992 .

[41]  T. Nitta,et al.  Recent Warming of Tropical Sea Surface Temperature and Its Relationship to the Northern Hemisphere Circulation , 1989 .

[42]  K. Ninomiya,et al.  Variations of Bain precipitation over Japan in 1951-1980 and large-scale characteristics of wet and dry Baiu , 1987 .

[43]  M. Richman,et al.  Rotation of principal components , 1986 .

[44]  K. Ninomiya,et al.  Characteristics of Baiu Front as a Predominant Subtropical Front in the Summer Northern Hemisphere , 1984 .

[45]  S. Gorshkov,et al.  World ocean atlas , 1976 .

[46]  T. Akiyama.  Southerly Transversal Moisture Flux into the Extremely Heavy Rainfall Zone in the Baiu Season , 1975 .