分类： 地球科学 >> 大气科学 提交时间： 2017-11-01
摘要： 卷云反射率是天气、气候和地球能量平衡研究中关注的重要参数。卷云反射率的快速算法在遥感反演卷云特性参数中具有重要应用。依据卷云反射率随卷云光学厚度、有效尺度、太阳天顶角、观测天顶角、相对方位角等参数的变化，利用离散坐标法（DISORT）计算卷云反射率，预先建立卷云反射率随相关参数变化的快速查找表，以此建立了卷云反射率的快速算法。将MODIS卫星探测的卷云光学厚度、太阳天顶角、观测天顶角、相对方位角等因素作为输入参数，计算得到了卷云反射率，比较了计算的卷云反射率和MODIS实际测量的卷云反射率值，相关系数达到0.94，平均偏差小于18.5%，说明了卷云快速算法计算合理可行。
分类： 地球科学 >> 空间物理学 提交时间： 2017-10-31
摘要： The thermal structure and energy balance of upper atmosphere are dominated by solar activity. The response of Cold-Point-Mesopause(CPM) to solar activity is an important form. This article presents the response of Temperature-of-CPM(T-CPM) to solar activity using fourteen-year SABER data series over 80°S–80°N regions. These regions are divided into 16 latitude zones with 10° interval, and the spatial areas of 80°S—80°N,180°W—180°E are divided into 96 lattices with 10°(latitude)×60°(longitude) grid. The annual-mean values of T-CPM and F10.7 are calculated. The least squares regression method and correlation analysis are applied to these annual-mean series. First, the results show that the global T-CPM is significantly correlated to solar activity at the 0.05 level of significance with correlation coefficient of 0.90. The global solar response of T-CPM is 4.89±0.67K/100 Solar-Flux-Units(SFU). Then, for each latitude zone, the solar response of T-CPM and its fluctuation are obtained. The solar response of T-CPM becomes stronger with increasing latitude. The fluctuation ranges of solar response at middle latitude regions are smaller than those of equator and high latitude regions, and the global distribution takes on W-shape. The co-relationship analysis shows that the T-CPM is significantly correlated to solar activity at the 0.05 level of significance for each latitude zone. The correlation coefficients at middle latitude regions are higher than those of equator and high latitude regions, and the global distribution takes on M-shape. At last, for each grid cell, the response of T-CPM to solar activity and their correlation coefficient are presented.
分类： 地球科学 >> 大气科学 提交时间： 2017-10-31
摘要： The Trends of the Cold-Point Tropopause CPT are presented using high-resolution radiosonde observations from 77 stations over China during 1979—2014. The latitude region from 18°N to 53°N is divided into 7 latitude zones with every 5° intervals and the spatial area of 18°N—53°N 75°E—135°E is divided into 27 lattices with 5°×10° grids. The annual-mean values of Height-of-CPT H-CPT and Temperature-of-CPT T-CPT are obtained. First by using the least squares regression method it is found that the H-CPT increases with rate of 273m/decade and overall significant cooling rate of -0.70K/decade for the T-CPT over China. Then the trends and latitude distribution of H-CPT and T-CPT for each latitude zone are reached. The change rates even the change direction of H-CPT H-CPT show obviously latitude distribution characteristics. The characteristic difference of H-CPT among latitude distribution is reducing year by year and corresponding T-CTP is enlarging. The H-CPT displays uplift trend between 28°N—53°N latitude region with the positive change rates and corresponding it has decline trend between 18°N—28°N latitude region with the negative change rates. The change rates of T-CPT are negative values for all latitude zones. Third the spatial latitude-longitude distribution of long-term trends of H-CPT T-CPT for each grid are obtained. The change rates of H-CPT T-CPT are not only dependent on latitude but also on longitude. At last the spatial structure of annual fluctuation of H-CPT T-CPT for each grid are obtained. The fluctuation of standard deviations of T-CPT is not only related to spatial distribution but also to economic belt of China.
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