By using monthly historical sea surface temperature (SST) data for the yearsfrom 1950 to 2000, the Western Pacific Warm Pool (WPWP) climatology and anomalies are studied inthis paper. The analysis of WPWP centroid (WP...By using monthly historical sea surface temperature (SST) data for the yearsfrom 1950 to 2000, the Western Pacific Warm Pool (WPWP) climatology and anomalies are studied inthis paper. The analysis of WPWP centroid (WPWPC) movement anomalies and the Nino-3 region SSTanomalies(SSTA) seems to reveal a close, linear relation between the zonal WPWPC and Nino-3 regionSSTA, which suggests that a 9° anomaly of the zonal displacement from the climatological positionof the WPWPC corresponds to about a 1℃ anomaly in the Nino-3 region area-mean SST. This studyconnects the WPWPC zonal displacement with the Nino-3 SSTA, and it may be helpful in betterunderstanding the fact that the WPWP eastward extension is conducive to the Nino-3 region SSTincrease during an El Nino-Southern Oscillation (ENSO) event.展开更多
Using daily outgoing long-wave radiation (OLR) data from the National Oceanic and Atmospheric Administration (NOAA) and the National Center for Environmental Prediction/National Center for Atmospheric Research (N...Using daily outgoing long-wave radiation (OLR) data from the National Oceanic and Atmospheric Administration (NOAA) and the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data of geopotential height fields for 1979-2006, the relationship between persistent heavy rain events (PHREs) in the Huaihe River valley (HRV) and the distribution pattern of convective activity in the tropical western Pacific warm pool (WPWP) is investigated. Based on nine cases of PHREs in the HRV, common characteristics of the West Pacific subtropical high (WPSH) show that the northern edge of the WPSH continues to lie in the HRV and is associated with the persistent "north weak south strong" distribution pattern of convective activities in the WPWP. Composite analysis of OLR leading the circulation indicates that the response of the WPSH to OLR anomaly patterns lags by about 1-2 days. In order to explain the reason for the effects of the distribution pattern of convective activities in the WPWP on the persistent northern edge of the WPSH in the HRV, four typical persistent heavy and light rain events in the Yangtze River valley (YRV) are contrasted with the PHREs in the HRV. The comparison indicates that when the distribution pattern of the convective activities anomaly behaves in a weak (strong) manner across the whole WPWP, persistent heavy (light) rain tends to occur in the YRV. When the distribution pattern of the convective activities anomaly behaves according to the "north weak south strong" pattern in the WPWP, persistent heavy rain tends to occur in the HRV. The effects of the "north weak south strong" distribution pattern of convective activities on PHREs in the HRV are not obvious over the seasonal mean timescale, perhaps due to the non-extreme status of convective activities in the WPWP.展开更多
Variability of clay mineral assemblages in the Western Pacific Warm Pool(WPWP) over the past 370 ka shows the prominent glacial-interglacial cyclicity.Smectite(62%-91%) is the dominant clay mineral,with decreased cont...Variability of clay mineral assemblages in the Western Pacific Warm Pool(WPWP) over the past 370 ka shows the prominent glacial-interglacial cyclicity.Smectite(62%-91%) is the dominant clay mineral,with decreased contents during interglacials while increased in glacials.In contrast,variations in chlorite(4%-21%),illite(4%-12%),and kaolinite(2%-10%) share a similar pattern with higher contents during interglacials than glacials,mirroring to that of smectite.The results indicate that the smectite-dominated clay minerals derive mainly from the river detrital inputs of New Guinea.The glacial-interglacial cycle of clay mineral assemblages well correspond to the fluctuation of sea level.When the sea level was low,the river materials can travel more easily across the narrow shelf off the island of New Guinea,inject directly into the subsurface currents flowing westwards,then merge into the Equatorial Undercurrent(EUC),and eventually deposit on the central part of WPWP.Precessional periods of the smectite content indicate the intensity of mechanical erosion in its provenance of New Guinea,responding to the river runoff and precipitation,and this could also be linked to the meridional migration of the Intertropical Convergence Zone(ITCZ).展开更多
文摘By using monthly historical sea surface temperature (SST) data for the yearsfrom 1950 to 2000, the Western Pacific Warm Pool (WPWP) climatology and anomalies are studied inthis paper. The analysis of WPWP centroid (WPWPC) movement anomalies and the Nino-3 region SSTanomalies(SSTA) seems to reveal a close, linear relation between the zonal WPWPC and Nino-3 regionSSTA, which suggests that a 9° anomaly of the zonal displacement from the climatological positionof the WPWPC corresponds to about a 1℃ anomaly in the Nino-3 region area-mean SST. This studyconnects the WPWPC zonal displacement with the Nino-3 SSTA, and it may be helpful in betterunderstanding the fact that the WPWP eastward extension is conducive to the Nino-3 region SSTincrease during an El Nino-Southern Oscillation (ENSO) event.
基金This study was supported by the "National Key Programme for Developing Basic Science" projects under Grant No. 2004CB418303the National Natural Science Foundation of China under Grant No. 40705022.
文摘Using daily outgoing long-wave radiation (OLR) data from the National Oceanic and Atmospheric Administration (NOAA) and the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data of geopotential height fields for 1979-2006, the relationship between persistent heavy rain events (PHREs) in the Huaihe River valley (HRV) and the distribution pattern of convective activity in the tropical western Pacific warm pool (WPWP) is investigated. Based on nine cases of PHREs in the HRV, common characteristics of the West Pacific subtropical high (WPSH) show that the northern edge of the WPSH continues to lie in the HRV and is associated with the persistent "north weak south strong" distribution pattern of convective activities in the WPWP. Composite analysis of OLR leading the circulation indicates that the response of the WPSH to OLR anomaly patterns lags by about 1-2 days. In order to explain the reason for the effects of the distribution pattern of convective activities in the WPWP on the persistent northern edge of the WPSH in the HRV, four typical persistent heavy and light rain events in the Yangtze River valley (YRV) are contrasted with the PHREs in the HRV. The comparison indicates that when the distribution pattern of the convective activities anomaly behaves in a weak (strong) manner across the whole WPWP, persistent heavy (light) rain tends to occur in the YRV. When the distribution pattern of the convective activities anomaly behaves according to the "north weak south strong" pattern in the WPWP, persistent heavy rain tends to occur in the HRV. The effects of the "north weak south strong" distribution pattern of convective activities on PHREs in the HRV are not obvious over the seasonal mean timescale, perhaps due to the non-extreme status of convective activities in the WPWP.
基金supported by the National Natural Science Foundation of China (40925008 and 91128206)the National Basic Research Program of China(2007CB815906)
文摘Variability of clay mineral assemblages in the Western Pacific Warm Pool(WPWP) over the past 370 ka shows the prominent glacial-interglacial cyclicity.Smectite(62%-91%) is the dominant clay mineral,with decreased contents during interglacials while increased in glacials.In contrast,variations in chlorite(4%-21%),illite(4%-12%),and kaolinite(2%-10%) share a similar pattern with higher contents during interglacials than glacials,mirroring to that of smectite.The results indicate that the smectite-dominated clay minerals derive mainly from the river detrital inputs of New Guinea.The glacial-interglacial cycle of clay mineral assemblages well correspond to the fluctuation of sea level.When the sea level was low,the river materials can travel more easily across the narrow shelf off the island of New Guinea,inject directly into the subsurface currents flowing westwards,then merge into the Equatorial Undercurrent(EUC),and eventually deposit on the central part of WPWP.Precessional periods of the smectite content indicate the intensity of mechanical erosion in its provenance of New Guinea,responding to the river runoff and precipitation,and this could also be linked to the meridional migration of the Intertropical Convergence Zone(ITCZ).