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利用青藏高原东北侧区域平均降水量资料（１９５８～１９９７年）和同期ＮＣＥＰ／ＮＣＡＲ再分析５００ ｈＰａ网格资料（２．５°ｘ ２．５°），分析发现：（１）高原东北侧汛期降水份额最大的７、８、９月３个月近４０年降水明显减少，过去明显存在的准３年周期振荡８０年代以来处于低潮；（２）日本—北太平洋附近位势高度降低，鄂霍茨克海阻高加强是高原东北侧７、８、９月干旱最典型的标志；（３）就干旱流型而言，７月干旱环流与江淮梅雨环流特征十分相似，表现在江淮多梅雨年，一般是高原东北侧重旱年；（４）高原东北侧７～９月的典型旱年流型，实际就是 ＥＩ Ｎｉｎｏ流型；（５） ＥＩ Ｎｉｎｏ事件对高原东北侧降水有明显影响，表现在该区域典型少雨年，一般发生于 ＥＩ Ｎｉｎｏ事件当年。从阶段看，以 ７～９月降水总量与 ＥＩ Ｎｉｎｏ事件相关最为显著，从月际看，尤以 ９月关系最好。
Based on the data of average precipitation in the northeastern Qinghai-Tibet Plateau (1958-1997) and the reanalysis of 500 hPa grid data (2.5 ° x 2.5 °) by NCEP / NCAR in the same period, it is found that: (1) The precipitation with the largest proportion of precipitation in the three months of July, August and September decreased significantly in the past 40 years, and the obvious quasi-3-year periodic oscillation in the past was at a low ebb since the 1980s. (2) The geopotential height near Japan-North Pacific Ocean decreased. (3) For the arid flow pattern, the July drought circulation is very similar to the circulation characteristics of the Meiju meiyu in the Yangtze River and the Yangtze River, showing in the years of the Jianghuai-Meiyu rainy season, (4) The typical dry flow pattern in the northeast of the Plateau from July to September is actually EI Nino flow pattern; (5) EI Nino event has a significant effect on precipitation in the northeast of the plateau, The area is typically drier and generally occurs during the EI Nino event. From the stage of observation, the total precipitation in July-September is most significantly related to the EI Nino event. From an inter-month perspective, the correlation between September and September is the best.