Knowledge Resource Center for Ecological Environment in Arid Area
| 欧亚大陆积雪时空变化特征及其与气候变化的关系 | |
| 其他题名 | Spatiotemporal Variability of Snow Cover and the Relationship between Snow and Climate Change across the Eurasian Continent |
| 钟歆玥 | |
| 出版年 | 2014 |
| 学位类型 | 博士 |
| 导师 | 张廷军 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 欧亚大陆是北半球积雪的主要分布区，冬季积雪覆盖面积广，积雪时间长，积雪特征也因受到气候变化的影响发生显著变化。研究欧亚大陆积雪属性及其变化与气候变化的关系极为重要。本文利用1966-2012年欧亚大陆地面气象台站以及1966-2011年前苏联地区snow course地面积雪观测资料，1966-2010年前苏联地区和中国地面气象台站气温、降水资料，以及1966-2012年北大西洋涛动和北极海冰面积数据资料，分析了欧亚大陆积雪深度、积雪时间、积雪密度和雪水当量的空间分布和时空变化特征，在积雪时间统计分析基础上对欧亚大陆的积雪区类型重新进行了划分，并探讨了冷季（十一月至三月）积雪变化与气候变化、北大西洋涛动（NAO）和北极海冰面积变化的关系。主要结论概括如下： 1) 欧亚大陆积雪深度和积雪时间的空间分布具有显著的纬度地带性，随纬度向北递增，积雪深度逐渐增加，积雪首日出现的时间逐渐提前，积雪末日出现时间逐渐延后，积雪期和积雪天数则随纬度的增加而延长。1966-2011年，积雪深度整体呈现增加趋势，增加率为0.7 cm/ 10 yr。46年来，积雪首次出现的时间延后了约11天，积雪消失的时间提前了约7天，积雪期和积雪天数分别缩减了18天和7天。与积雪天数的变化趋势相比，积雪期受积雪首日和积雪末日年际变化的影响更大。1990s末期至2000s末期，积雪时间发生的变化最为显著，积雪首日、积雪末日、积雪期和积雪天数分别延后、提前或缩短了8-10天。多年平均积雪深度和多年平均最大积雪深度变化最显著的地区主要位于50°N以北的广大地区，逐月平均雪深最明显的变化趋势主要介于50-60°N之间的范围，这些区域雪深变化率均超过±0.6 cm/ yr，个别地区甚至超过±1 cm/ yr。 2) 前苏联地区积雪密度从九月至次年六月呈现增加趋势，但增加率依据不同积雪类型各不相同。其中苔原积雪的积雪密度月变化趋势最小，约为0.0193 g cm-3/mth，短时积雪的变化率最大，约0.0392 g cm-3/mth。1966-2000年，积雪密度呈显著减少趋势，每年约减少0.0005 g cm-3，但2001-2010年，积雪密度有明显增加，增加率为0.0013 g cm-3。雪水当量的长期变化趋势与积雪深度变化相似，但并不显著，而逐月年际变化较为明显。十月至十二月雪水当量有显著减少，尤以十一月减少最多（-0.12 mm/yr），而春季月份雪水当量又有明显增多，其中四月份增加趋势最为显著，增加率约为0.33 mm/yr。雪水当量变化趋势最显著的地区主要集中在50-60°N之间的区域，俄罗斯平原北部，前苏联地区西南部的沙漠地区，以及哈萨克丘陵东南部，这些地区雪水当量每年增加或减少的速率超过0.6 mm。积雪密度和雪水当量随海拔的升高而减少，随纬度的增加而递增。其中，积雪密度受海拔影响较大，海拔每升高100 m，积雪密度会减少0.004 g cm-3。而雪水当量则主要受纬度的影响，纬度每增加1°，雪水当量随之约增加3.14 mm。 3) 以连续积雪天数划分积雪区类型，具有明显的纬度特征，随纬度升高，由不稳定积雪区向稳定积雪区逐渐过渡。欧亚大陆的稳定积雪区主要位于42°N以北的大部分地区；短时不稳定积雪区主要位于中国境内40°N以南的大部分地区。与传统的积雪天数划分积雪类型的方法相比，在对中国积雪区类型的划分上存在显著差异。利用连续积雪天数对积雪类型划分结果显示青藏高原不存在稳定积雪，周期性不稳定积雪区范围明显缩小，而短时不稳定积雪区的范围有显著扩大。 4) 整个冷季（十一月至三月）积雪深度与平均气温有明显的负相关关系，气温每升高1℃，积雪深度减少约0.9 cm。各月平均积雪深度与月平均气温的关系中，十一月两者关系最为紧密，相关系数约0.62。但变化率在三月最大，约为-1.47 cm/℃。积雪深度与月平均气温关系的空间分布具有显著地域特征。显著的负相关关系主要位于俄罗斯平原西部和中国大部，相关系数超过-0.5。由于西西伯利亚平原、中西伯利亚高原以及俄罗斯远东大部分区域冬季气温偏低，因此0℃以下气温的升高不会对积雪深度产生影响。 5) 冷季积雪深度与降水累积量具有显著正相关关系，降水累积值每增加1 cm，积雪深度随之增加0.39 cm。但与气温的关系相比，欧亚大陆冷季积雪深度与降水累积量的关系总体上不如与气温关系密切，总体拟合优度仅为7%。冷季雪深与降水累积量的空间分布具有明显的区域特征。50°N以北的大部分地区十一月至三月积雪深度与降水累积量有很好的正向相关性，随降水累积量的增多，积雪深度逐渐增厚。 6) 前苏联地区积雪累积量与同时期降水累积值的差值偏大，说明前苏联积雪的蒸发量较大。其中俄罗斯平原大部分地区，西西伯利亚平原的东部和南部，俄罗斯远东地区的南部，堪察加半岛以及库页岛的蒸发量最大，降水累积量与积雪累积量的差值均超过150 mm。 7) 整体上，冷季积雪深度与NAO关系并不密切。但NAO在一月的强度最强，因此积雪深度与NAO在一月份的关系在冷季中最为紧密：NAO偏强时，雪深偏厚的年份占52.5%，NAO偏弱时，雪深变浅的年份约占65%。俄罗斯平原西北部地区平均积雪深度随NAO增强，反而在减少，相关系数超过-0.6，而西西伯利亚平原和中西伯利亚高原中部以及内蒙古高原东北部和中国东北平原部分地区雪深随NAO的增强而增厚，两者相关性在0.5以上，表明冷季NAO正相位的增强有助于增加该地区的降雪量从而促进雪深的增厚。 8) 欧亚大陆冷季积雪深度与北极海冰面积在十一月至一月，呈正相关关系，随海冰面积的减少雪深也在变浅，二月和三月两者呈相反的变化趋势，雪深随海冰面积减少反而增厚。冬季北极海冰面积的缩减会改变北极上空水气输送模式，从而导致降水的增多。二、三月随海冰面积缩减，积雪深度增厚的站点显著增多，说明冬季北极海冰面积的减少对雪深变化有滞后影响。 |
| 英文摘要 | Eurasian continent is the main distribution areas of snow cover in the Northern Hemisphere. Large parts of the Eurasian continent are covered by snow each winter, and some areas are covered with snow for more than half a year. The significant changes in snow cover are effected by climate change, therefore, to investigate the climatology and spatiotemporal variations of snow cover properties and the relationship between snow and climate change are very crucial. In our research, daily snow depth data from 1966-2012 and snow course data covering 1966-2011 from ground-base stations were used to investigate spatial and temporal changes in snow depth, snow cover time, snow density and snow water equivalent (SWE) over the Eurasian continent. We proposed to use the number of days with continuous snow cover of 30 days to classify seasonal snow cover as stable or unstable snow cover across the Eurasian Continent. Based on air temperature and precipitation data for the period from 1966-2010, North Atlantic Oscillation (NAO) index and Arctic sea ice area (SIA) data during 1966-2012, the research analyzed the relationships between snow and climate change, NAO and SIA. The main conclusions are summarized as follows: 1） The results showed that there were closely relationships between long-term average (during 1971-2000) of snow depth, snow cover time and the latitude: snow depth increased with the increasing latitude; first day of snow cover started earlier with the increasing latitude; the appearance of last day was deferred with the increasing latitude; duration and number of snow cover days became longer with the increasing latitude. From 1966-2011, there was an obvious increasing trend in snow depth, and the increase rate was 0.07 cm/ yr. First day of snow cover started earlier (11 days), the appearance of last day was deferred about 7 days, and the duration and number of snow cover days decreased about 18 days and 7 days, respectively, during the 46 years. The changes of snow cover duration were mainly affected by the snow cover timing. Snow cover time appeared significant changes from the late 1990s through the late 2000s, and the change rate was about 8-10 days/10 yr. Over the entire Eurasian continents, significant variations in annual mean snow depth and maximum snow depth were found the northward 50o N, and the most significant trends in monthly mean snow depth lay in the areas between 50 and 60o N. The increase rates of snow depth were more than ±0.6 cm/ yr, some of the areas were no less than ±1 cm/ yr. 2） An increasing trend was found in monthly mean snow density from September through June of the next year, but the rate of increase varied with different snow classes. For the six snow classes, the maximum increase rate of monthly snow density was measured in ephemeral snow (0.0392 g cm-3/mth), and the minimum value of 0.0193 g cm-3 per month was seen in taiga snow. There was a significant decreasing trend in snow density and the decrease rate of 0.0005 g cm-3 per year. But it presented an increasing trend during 2000s. Obvious trends of changes in monthly mean SWE can be find from 1966-2010. The maximum decrease rate was found in November, -0.12 mm/yr, and the maximum increasing trend appeared in April, with the change rate of 0.33 mm/yr. Significant variations in SWE were found between 50 and 60o N，the north of Russian Plain, desert areas in the southwest over the former USSR and the southeast of Kazakh Uplands, in which the change rates were more than ±0.6 mm per year. There was a high correlation between snow density and elevation, the rate of snow density decrease was about 0.004 g cm-3 per 100 m increased in elevation. While SWE was highly correlated with latitude, SWE increased about 3.14 mm per 1o increased in latitude. 3） It revealed that there was a significant latitude feature in snow cover classification over the Eurasian Continent. Stable snow cover located in most areas towards the north of 42 o N over the Eurasian |
| 中文关键词 | 欧亚大陆 ; 积雪属性 ; 积雪分类 ; 气候变化 ; 关系研究 |
| 英文关键词 | the Eurasian Continent snow cover property snow cover classification climate change relationship analysis |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287396 |
| 推荐引用方式 GB/T 7714 | 钟歆玥. 欧亚大陆积雪时空变化特征及其与气候变化的关系[D]. 中国科学院大学,2014. |
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