Trend and Variability of EastAsian Precipitation Linkage to

Trend and Variability of East-Asian Precipitation: Linkage to Sea Surface Temperatures Fanglin Yang Environmental Modeling Center National Centers for Environmental Prediction NOAA 32 nd Climate Diagnostic and Prediction Workshop COAPS/FSU, October 22 -27, 2007 Acknowledgment: This work was support by the NASA Modeling, Analysis and Prediction program while the author worked with William Lau at GFSC/NASA.

Possible causes: 1. South Asian black carbon emission 2. Climate regime shift 3. Global warming 4. Shift of Africa-North China teleconncection 5. SST trend

North China Central China South China

Questions? • To what extent can the observed precipitation variability can be explained by SST variability? • Does the precip-SST relation at the interannual timescale differ from that at the inter-decadal timescale?

Interannual Variability Single Value Decomposition (SVD) applied to 7 year high-pass filtered precipitation and SSTs

MAM SST Precip

JJA SST Precip

SST Variance Precipitation Variance SSTPrecipitation Co-Variance Correlation (PC_sst, PC_precip) MAM SVD 1 31% 27% 0. 57 SVD 2 11% 15% 14% 0. 64 JJA SVD 1 43% 10% 24% – 0. 77 SVD 2 7% 13% 0. 76

JJA, Regressions of wind 850 and Z 700 to PCs SVD Modes JJA Climate, 1951 -1998, NCEP R 1 SST_PC Precip_PC

MAM SST_PC Precip_PC

Decadal Variation and Trend

SST Interannual Mode

Area-Mean Rainfall Projection of Obs to SVD mode Rainfall Interannual Mode

Conclusion Interannual Variability • Precipitation over South China in MAM and North China in JJA ENSO mode of SSTs • • Precipitation over central China in both MAM and JJA season SST in warm pool and northern Indian ocean; Features of the anomalous 850 h. Pa winds and 700 -h. Pa geopotential height corresponding to these modes support a physical mechanism that explains the causal links between the modal variations of precipitation and SSTs. Trend and decadal variation • Upward South China MAM precipitation and downward JJA North China precipitation warming trend of the ENSO-like mode. • Upward JJA central China precipitation warming trend of SSTs over the warm pool and Indian Ocean. • Downward MAM South China precipitation downward central North Pacific SSTs (less robust)