An erratum to this article can be found at http://dx.doi.org/10.1007/s00382-006-0149-

Possible changes in the Asian summer monsoon due to increased atmospheric CO2 are investigated by an MRI global coupled atmosphere-ocean general circulation model. The summer (June-August) monsoon rainfall in India increases significantly with global warming. On the other hand, the monsoon wind shear index, defined as the difference between 850 hPa and 200 hPa zonal winds over the northern Indian Ocean, decreases. At 850 hPa, the westerly wind shifts northward and intensifies from the Sahel to northwest of India, but the monsoon westerly over the Arabian Sea weakens. It is found that increased moisture content in the warmer air leads to larger moisture flux convergence, contributing to the increased rainfall. Therefore, the monsoon wind shear index is not a good indicator for identifying any change of monsoon accompanying global warming. In contrast to the increased rainfall in India, change in rainfall is little over China where soil moisture becomes drier at times of increased CO2. It is also noted that the northern Eurasian continent becomes wetter in the increased-CO2 climate.The magnitude of the interannual variability of the Asian summer monsoon rainfall becomes larger in the CO2 experiment than in the control experiment, particularly in the later stage of the experiment after CO2 doubling. However it should be noted that the interdecadal variation of this interannual variability is also large both in the control and the CO2 experiments.

[1] Using the Simple Ocean Data Assimilation (SODA), NCEP/NCAR reanalysis and the GISST datasets from 1950 -1999, and an atmosphere-ocean coupled general circulation model, we explored the possible existence of decadal Indian Ocean Dipole (IOD) variability for the first time. We find that there are strong decadal IOD events, and that the time series of the decadal IOD and decadal ENSO indices are not well correlated. The simulated decadal signal of the IOD index is highly correlated with the 20°C isotherm depth anomaly, indicating that ocean dynamics is involved in the decadal IOD. It is also associated with the zonal wind anomaly. We suggest that the decadal IOD in the tropics is interpreted as decadal modulation of the interannual IOD events.

A B S T R A C TWe estimated long-term trends of ocean acidification in surface waters in latitudinal zones from 3 • N to 33 • N along the repeat hydrographic line at 137 • E in the western North Pacific Ocean. Estimates were based on the observational records of oceanic CO 2 partial pressure and related surface properties over the last two decades. The computed pH time series both for 25 yr in winter (late January-early February) and for 21 yr in summer (June-July) exhibited significant decreasing trends in the extensive subtropical to equatorial zones, with interannual variations that were larger in summer. The calculated rates of pH decrease ranged from 0.0015 to 0.0021 yr −1 (average, 0.0018 ± 0.0002 yr −1 ) in winter and from 0.0008 to 0.0019 yr −1 (average, 0.0013 ± 0.0005 yr −1 ) in summer. The thermodynamic effects of rising sea surface temperature (SST) accounted for up to 44% (average, 15%) of the trend of pH decrease in the subtropical region in winter, whereas a trend of decreasing SST slowed the pH decrease in the northern subtropical region (around 25 • N) in summer. We used the results from recent trends to evaluate future possible thermodynamic changes in the upper ocean carbonate system.

Unfortunately, author corrections to Figs. 2, 3a, b, and 4a, b were not carried out.The correct versions are shown below.