Climate change on the Tibetan Plateau (TP) and its response to the atmosphere circulation has been widely concerned. The extremely cold-dry area of the central-northern TP is vulnerable and particularly sensitive to the variations of Indian Summer Monsoon (ISM) and the Westerlies. However, records from the central-northern TP are still scarce, limiting our understanding of the natural variability of climate on the TP and its response to the atmosphere circulation. Here we present a high resolution palynological record from Buruo Co covering the last 5000 years. The palynological assemblage shows that the Artemisia-steppe predominated the Buruo Co region until it was replaced by the alternant domination of steppe and desert since 900 cal a BP. Our results show that the central-northern TP experienced relatively warm and humid conditions reflected by Artemisia-steppe before 3800 cal a BP linked with stronger ISM. And then, the vegetation variation reveals a stepwise long-term aridification on the central-northern TP, which was influenced by the gradually weakened ISM during 3800–3200 cal a BP. Subsequently, the strengthened dry Westerlies dominated this region since 3200 cal a BP. After 1000 cal a BP, the Buruo Co might slightly expanded, but the catchment still maintained relatively dry conditions, even though this region probably received small amount of external moisture supply under the low evaporation conditions. Besides, four drought intervals (4400–4100, 3850–3650, 3300–3000 and 1900–1400 cal a BP) and two relatively cold periods (3200–2800 and 400 cal a BP-Present) were detected. The climate and vegetation variations since mid-Holocene on the central-northern TP were mainly controlled by the summer insolation at 30°N and the solar activity. Also, it was associated with the position of Intertropical Convergence Zone and the climate oscillations of the North Atlantic mediated by the synergistic effect of ISM and the Westerlies.

青藏高原（TP）的气候变化及其对大气环流的响应已引起广泛关注。中北部TP的极冷地区很脆弱，对印度夏季风（ISM）和西风的变化特别敏感。但是，中北部TP的记录仍然很少，这限制了我们对TP上气候的自然变化及其对大气环流的响应的理解。在这里，我们介绍了Buruo Co过去5000年的高分辨率古生物学记录。孢粉学研究表明，蒿属草原一直统治着Buruo Co地区，直到自900 cal BP以来被草原和沙漠的交替统治所取代。我们的结果表明，中北部TP经历了蒿蒿反映的相对温暖和潮湿的条件-在3800年前校准了与更强的ISM相关的BP。然后，植被变化揭示了中北部TP的逐步长期干旱化，这受3800–3200 cal BP期间ISM逐渐减弱的影响。随后，自3200 cal BP以来，增强的干燥Westerlies主导了该地区。在1000 cal BP后，Buruo Co可能会略有膨胀，但集水区仍保持相对干燥的条件，即使该地区在低蒸发条件下可能会获得少量外部水分供应。此外，还检测到四个干旱间隔（4400–4100、3850–3650、3300–3000和1900–1400 cal a BP）和两个相对寒冷的时期（3200–2800和400 cal a-BP）。中北部新茂中部以来的气候和植被变化主要受夏季30°N的日照和太阳活动的控制。此外，它还与ISM和Westerlies的协同效应介导的热带辐合带的位置和北大西洋的气候振荡有关。