Quasi 3-year period response of the rainy season precipitation over the eastern parts of Northwest China to the spring sensible heat flux over the eastern part of the Tibetan Plateau

By using the precipitation data at 39 stations in the eastern parts of Northwest China during 1960－2010 and the NCEP/NCAR reanalysis data, the quasi-periodic cycles of precipitation during the rainy season over the eastern parts of Northwest China, spring sensible heat flux over the eastern part of the Tibetan Plateau and their synergistic coupling are analyzed through the Multi Taper Method-Singular Value Decomposition (MTM-SVD). The results show that both the sensible heat flux and precipitation have a significant quasi 3-year period, and their coupling field also shows a significant 3-year period. When the spring sensible heat flux becomes stronger (weaker) over the eastern part of the Tibetan Plateau, there is more (less) precipitation over the eastern parts of Northwest China during the rainy season. The most significant period of such quasi 3-year period synergistic relationship appears during 1960-1982, and there is an adjustment stage in 1983-1990, with the quasi 3-year period appeared again after 1990s. The continuous heating process of the former can affect the latter, which are mainly embodied in August.