王宁练
论文题目：青藏高原古里雅冰芯中太阳活动记录研究
作者简介：王宁练，男，1966年01月出生，1995年09月师从于中科院寒区旱区环境与工程研究所姚檀栋教授，于2001年08月获博士学位。
摘
要
太阳是地球气候环境变化的一个重要影响因素。然而，系统、较连续的太阳活动观测只有二、三百年的历史，为了更加充分地认识和理解日地关系，必须对于太阳活动的代用指标进行研究，以获得更长时间尺度太阳活动的强弱变化。冰芯不但记录着过去气候环境的变化，而且还记录着影响气候环境的因素（如太阳活动、温室气体、火山活动等）的变化。本论文主要依据青藏高原古里雅冰芯中NOˉ3 和36CL浓度等记录，探讨了过去太阳活动的有关信息，并分析了该冰芯记录的气候变化与太阳活动的关系，并获得以下主要结论：
1. 研究发现近1500a古里雅冰芯中NOˉ3浓度与太阳活动强弱呈正相关，其变化可以揭示太阳活动的信息。造成这一现象的主要原因，是由于受太阳活动影响的高层大气中的NOx是该冰芯中NOˉ3的一个主要来源。
2. 从冰芯研究角度，回答了长期争议的Maunder极小期是否存在及该时期太阳活动特征问题。研究结果表明，太阳活动的Maunder极小期（1645-1715A.D.）是存在的，而且这一时期内太阳活动的周期也是正常的，即存在11a左右的黑子周期，这直接关系到太阳发电机理论的正确性，具有重要的科学意义。
3. 根据古里雅冰芯中NOˉ3浓度变化和其它太阳活动指标，发现太阳活动可能存在36a左右的周期（波动于28-42a之间），该周期的产生与太阳黑子周期长度的变化有关。这对不同地区气候变化中为什么普遍存在Bruckner周期，找到了一种较合理的解释，并对日地关系研究将具有新的启示作用。
4. 证实了37kaBP左右青藏高原古里雅冰芯记录中宇宙成因同位素36CL含量峰值的存在，并且认为该峰值是36CL在大气中产生速率增加导致的。与其它地区10Be及36CL记录的对比，指出这一时期的宇宙成因同位素峰值事件具有全球性，并与全球性的气候变冷事件相拌出现，弱的太阳活动和弱的地磁场是这一事件发生的原因所在。
5. “8.2ka BP事件”是目前国际上古气候研究的一个热点，古里雅冰芯很明显的记录到了这一事件。研究认为，“8.2ka BP事件”发生的主要原因除与北美冰湖溃决导致的北大西洋热盐减弱有关之外，还与弱的太阳活动有关。
6. Milankovitch理论已受到个别冰消期气候变化研究结果的冲击。将古里雅冰芯中δ18O记录与6月份北半球30ºN太阳辐射变化的对比分析，发现末次冰盛期气候的出现滞后于太阳辐射最小值约4ka，冰消期气候变化大概滞后太阳辐射变化约1ka，而全新世气候变化大致与太阳辐射变化同步。这一结论为地球轨道要素影响下的气候变化，增加了新的证据。
7. 对古里雅冰芯记录的进一步研究表明，从18ka BP开始至14ka BP时期气候逐渐升温，这一特征与南半球气候变化特征相似；而14ka BP时出现的突然降温是全球所共有的特征。这说明热带地区的气候变化可能对全球气候存在重要的影响。
关键词： 太阳活动 气候变化 古里雅冰芯 青藏高原
Abstract
The Sun plays an important role in climatic and environmental changes. However, the history of systemic observation about the solar activity is only two or three centuries. In order to understand the solar-terrestrial relationship, it is needed to investigate the indexes of solar activity and extend the time series of the solar activity far back. Ice core records document not only a wide range of environmental parameters that are both measures of and response to climate change (e.g., atmospheric chemistry and circulation, temperature, precipitation) but also many of the causes of climate change (e.g., solar variability, volcanic activity, greenhouse gases). In this thesis, some information of the past solar activity was revealed by NO3- and 36Cl concentrations recorded in the Guliya ice core from the Tibetan Plateau, and the correlationship between climate change and solar activity was studied. The following major conclusions were obtained:
l A positive correlationship was found between the solar activity and NO3- concentration in the Guliya ice core in recent 1500 years, which mean NO3- in this core could reveal the past variability of the Sun. A major reason of this phenomenon is that NO3- in this core came basically from the NOx in high atmosphere which related with the solar activity.
l A long-standing issue of whether the solar activity was very low, and especially whether the solar cycle existed, during the Maunder Minimum (1645-1715AD), was solved by the Guliya ice core record. The results show that the solar activity was indeed low, and solar cycle displayed normal as present, i.e. about 11 years, in that period. This conclusion has important scientific significance for the solar dynamo theory.
l An about 36a cycle (ranging from 28a to 42a) was found by analyses of the various indexes of the solar activity. The occurrence of this cycle is related to the changes in the length of the sunspot cycle. This founding provides a reasonable explanation for the ubiquitous Bruckner cycle in hydrological, meteorological and glacier fluctuation data, and is of importance for the study of the relationship between the sun variability and the Earth climate change.
l A 36Cl peak was found at about 37ka BP in the Guliya ice core. This peak is indicative of enhanced cosmogenic isotope production in the atmosphere, rather than a change in accumulation rate. Comparison with the records 10Be and 36Cl in ice core from bipolar regions indicates that peak of the cosmogenic isotopes are global. The 37ka BP global event coincided with a cold period, and was caused by low solar activity and a weak geomagnetic field.
l “8.2ka BP event” is one of the focal issue in paleoclimatological study at present. This event was revealed obviously by the Guliya ice core record. It was pointed out that the global “8.2ka BP event” was resulted from the weakening of the North Atlantic thermohaline circulation by a catastrophic release of meltwater associated with the final stages of deglaciation of the Laurentide ice sheet, and low solar activity.
l Some evidence indicates that the penultimate deglaciation (Termination 2) occurred thousands of years before the date of about 127ka ago predicted by Milankovitch. This apparent contradiction makes it important to determine precisely when other deglaciations happened. Comparison of δ18O record in the Guliya ice core with precise dating with Northern Hemisphere June insolation at 30oN showed that climate change lagged insolation about 4ka during the last glacial maximum, about 1ka during the last deglaciation, and nearly 0ka during the Holocene. These results agree with Milankovitch.
l δ18O record in the Guliya ice core suggests that temperature over the Tibetan Plateau rose gradually from 18ka BP to 14ka BP, which was similar to climate change in Southern Hemisphere, and rose rapidly at about 14ka BP, which, however ,was similar t climate change in Northern Hemisphere , and dropped abruptly just after 14ka BP, a global feature. All those indicate that the tropics maybe play an important role on global climate change.
Keywords: solar activity , climate change , Guliya ice core, the Tibetan Plateau
