地理科学 ›› 2014, Vol. 34 ›› Issue (5): 635-640.doi: 10.13249/j.cnki.sgs.2014.05.635

• • 上一篇    

1960~2005年西北地区低云量的时空变化及成因分析

王亚敏1,3(), 冯起1,2, 李宗省1,2   

  1. 1.中国科学院寒区旱区环境与工程研究所阿拉善荒漠生态水文试验站, 甘肃 兰州 730000
    2.甘肃省水文水资源工程技术研究中心, 甘肃 兰州 730000
    3.中国科学院大学, 北京 100049
  • 收稿日期:2013-04-28 出版日期:2014-05-10 发布日期:2014-05-10
  • 作者简介:

    王亚敏(1986-),女,甘肃秦安人,博士研究生,研究方向为区域水文水资源与气候变化。E-mail: wangyamin@lzb.ac.cn

  • 基金资助:
    中国科学院重点部署类项目(KZZD-EW-04-05)、甘肃省重大项目(1102FKDA013)、中国博士后科学基金(2012M510219)项目资助。

Analysis of Low Cloud Amount Variations in the Northwest China During 1960-2005

Ya-min WANG1,3(), Qi FENG1,2, Zong-xing LI1,2   

  1. 1.Alashan Desert Eco-hydrology Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China
    2.Gansu Hydrology and Water Resources Engineering Center, Lanzhou, 730000, China
    3.Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-04-28 Online:2014-05-10 Published:2014-05-10

摘要:

基于西北地区177个站点1960~2005年逐日的低云量观测资料,运用地统计学、交叉小波分析和多元回归分析,分析了近46 a来西北地区低云量的时空变化特征及影响因素。结果表明:近46 a来西北地区低云量呈较显著上升趋势,1997年之后上升显著。低云量空间呈自东南向西北递减的趋势。低云量与降水、相对湿度等呈显著的正相关,与昼夜温差、日照时数等呈显著的负相关。低云量存在2~4 a、准6 a、准11 a的周期变化,与宇宙射线在1982~1993年存在5~8 a的共振周期,与NOI指数存在2~4 a、准5 a、准11 a的共振周期,和太阳黑子的共振周期为9~11 a。

关键词: 低云量, 西北地区, 交叉小波分析

Abstract:

Clouds are a visible manifestation of thermo-dynamic processes in the atmosphere. Clouds have a strong influence on climate as a component of water cycle and through radiation budget. Surface based observation of cloud amount is a valuable source of information for the interpretation of the surface radiation budget and for the validation of satellite based retrievals of cloud and radiation properties. The correlation between cosmic rays and low cloud amount (LCA) variations, which led to the introduction of a new scientific subject-‘cosmoclimatology’, was found more than 10 years ago. Although much evidence implying correlations between low cloud amount variations and solar activity, the physical phenomenon explaining this is still poorly pronounced. In this article, we try to analysis spatial and temporal distribution characteristics, annual trend, and seasonal change of cloudiness over the northwest of China. In addition, the correlations among low cloud amount and climate factors, cosmic rays, NOI index and sunspot were discussed, respectively. With trend analysis method, the spatial-temporal variation of low cloud amount is analyzed for 177 stations on the Northwest China during 1960-2005. Analysis of these data reveals that the annual low cloud amount is characterised by high year-to-year variability and shows a weak, statistically significant increase in 1960-2005. A more pronounced increase in 1997-2005 is evident. Analysis indicates that the annual low cloud amount decreases from the southeast to the northwest of the Northwest China. A strong positive correlation is found among low cloud amount and rainfall, annual average temperature, relative humidity and annual low temperature, while a strong negative correlation is found among low cloud amount and average wind speed, diurnal temperature range and Sunshine Duration. The low cloud amount of Jaunary is positive with the relative humidity. However, the low cloud amount of July is positive with the average low temperature, and is negative with average wind speed, diurnal temperature range and sunshine duration, respectively. The cross wavelet transform method is adopted to study the time-frequency characteristics and multitime scale correlations among low cloud amount, cosmic rays, NOI index and sunspot was discussed, respectively. Results show that there are significant periods at scales of 2-4 a, 6 a and 11 a in low cloud amount over Northwest China. There are significant syntonic periods of 5-8 a between low cloud amount and the cosmic rays in 1982-1993, while the multi-time scale correlations between the low cloud amount and NOI index are 2-4 a, 5 a and 11 a syntonic period in 1960-2005 within the 95% of the red noise test, respectively. The low cloud amount and the sunspot number has a significant a syntonic periods 9-11 a, also within the 95% of the red noise test. A strong correlation was found between low cloud amount and cosmic rays, NOI index and sunspot, while the strongest correlation was found between low cloud amount and NOI index.

Key words: low cloud amount, the Northwest China, cross wavelet analysis

中图分类号: 

  • P426.6