Analysis of African climate variability at pre-industrial, 4kyr and 6kyr BP simulations by Self-Organizing Maps

摘要: Results from three simulations of the IPSL-CM5A (96 x 96) coupled ocean-atmosphere model modern pre-industrial control (1000-year long) and mid-Holocene at 4kyr (400-year 6kyr (910-year BP have been used to investigate changes in seasonal sub-Saharan rainfall patterns their links with sea surface temperatures (SST) main oceanic basins. Self-organizing maps hierarchical ascendant classifications performed over whole data set highlight anomaly ("monsoon regimes") for each season year. Then, composite SST, mean level pressure low-levels wind anomalies, computed every class patterns. In northern summer, eight monsoon regimes are defined. Three them mostly present period, other last two evenly distributed periods. On hand, period is scattered within all regimes. A discriminant analysis shows that these can be well differentiated by SST modes basins, particular Guinea gulf Mediterranean basin. Similar analyses conducted seasons will presented too. This work has funded French Agency National Research through research project C3A.