本文利用2007～2010年整四年最新可利用的CloudSat卫星资料,对东亚地区（15°～60°N,70°～150°E）云的微物理量包括冰/液态水含量、冰/液态水路径、云滴数浓度和有效半径等的分布特征和季节变化进行了分析.本文将整...本文利用2007～2010年整四年最新可利用的CloudSat卫星资料,对东亚地区（15°～60°N,70°～150°E）云的微物理量包括冰/液态水含量、冰/液态水路径、云滴数浓度和有效半径等的分布特征和季节变化进行了分析.本文将整个东亚地区划分为北方、南方、西北、青藏高原地区和东部海域五个子区域进行研究,结果显示：东亚地区冰水路径值的范围基本在700 g m-2以下,高值区分布在北纬40度以南区域,在南方地区夏季的平均值最大,为394.3 g m-2,而在西北地区冬季的平均值最小,为78.5 g m-2;而液态水路径的范围基本在600 g m-2以下,冬季在东部海域的值最大,达到300.8 g m-2,夏季最大值为281.5 g m-2,分布在南方地区上空.冰水含量的最高值为170 mg m-3,发生在8km附近,南方地区夏季的值达到最大,青藏高原地区的季节差异最大;而液态水含量在东亚地区的范围小于360 mg m-3,垂直廓线从10km向下基本呈现逐渐增大的趋势,峰值位于1～2 km高度上.冰云云滴数浓度在东亚地区的范围在150 L-1以下,水云云滴数浓度的值小于80 cm-3,垂直廓线的峰值均在夏季最大.冰云有效半径在东亚地区的最大值为90 μm,发生在5km左右;水云有效半径在东亚地区的值分布在10km以下,最大值为10～12 μm,基本位于1～2 km高度上.从概率分布函数来看,东亚地区冰/水云云滴数浓度的分布呈现明显的双峰型,其他量基本为单峰型.本文的结果可以为全球和区域气候模式在东亚地区对以上云微物理量的模拟提供一定的观测参考依据.展开更多
本文首先构建了二流—四流球谐函数谱展开累加辐射传输的新方案,然后将其应用于国家气候中心第二代大气环流模式BCC_AGCM2.0.1的新版本中,并与模式中原有的Eddington累加方案进行了比较。由于新方案本质上是单层Eddington近似方案在四...本文首先构建了二流—四流球谐函数谱展开累加辐射传输的新方案,然后将其应用于国家气候中心第二代大气环流模式BCC_AGCM2.0.1的新版本中,并与模式中原有的Eddington累加方案进行了比较。由于新方案本质上是单层Eddington近似方案在四流上的推广。因此新方案在计算精度上要优于原方案。通过在全球气候模式中的应用与比较,本文发现新方案对气候模拟会产生比较大的影响。在晴空条件下,新方案计算的在南纬30°到60°区间、北大西洋东北部以及非洲北部的撒哈拉沙漠区域的地表向下年平均短波辐射通量要小于原方案结果,最大差别可以达到3.5 W/m2;同时,新方案计算的在南纬30°到60°区间和北大西洋东北部的大气顶向上年平均短波辐射通量要大于原方案结果,最大差别达到3 W/m2。在有云大气情况下,新方案计算的地表向下年平均短波辐射通量要小于原方案结果,并随着纬度的增加,新旧两种方案的差别逐渐变大,在南北极时达到最大5.5 W/m2;同时,新方案计算的在赤道区域的大气顶的年平均短波向上辐射通量要小于原方案结果,最大差别为2.5 W/m2,而在南北纬30°到60°区间,新方案计算的在大气顶的年平均短波向上辐射通量则要大于原方案结果,最大差别为1.5 W/m2。新方案计算的年平均短波加热率普遍高于原方案结果,特别是在800 h Pa到地表之间的低层大气以及50 h Pa到100 h Pa的高层大气,最大差别可达0.03 K/d。因此,新方案有助于改善全球气候模式中普遍存在的赤道平流层中下层的温度冷偏差现象。展开更多
Four editions of the High Resolution Transmission （HITRAN） databases （HITRAN96, HITRAN2K, HITRAN04, and HITRAN08） are compared by using a line-by-line （LBL） radiative model in the long-wave calculation for six t...Four editions of the High Resolution Transmission （HITRAN） databases （HITRAN96, HITRAN2K, HITRAN04, and HITRAN08） are compared by using a line-by-line （LBL） radiative model in the long-wave calculation for six typical atmospheres. The results show that differences in downward radiative fluxes between HITRAN96 and HITRAN08 at the surface can reach a maximum of 1.70 W m-2 for tropical atmospheres. The largest difference in heating rate between HITRAN96 and HITRAN08 can reach 0.1 K day-1 for midlatitude summer atmosphere. Uncertainties caused by line intensity and air-broadened half- widths are also evaluated in this work using the uncertainty codes given in HITRAN08. The uncertainty is found to be 1.92 W m-2 for upward fluxes at the top of the atmosphere （TOA） and 1.97 W m-2 for downward fluxes at the surface. The largest heating rate caused by the uncertainty of line intensity and air-broadened hMf-width can reach 0.5 K day-1. The differences in optical depths between 1300 and 1700 cm-1 caused by different HITRAN versions are larger than those caused by the uncertainties in intensity and air-broadened half-width. This paper suggests that there is inaccurate representation of line parameters over some spectral ranges in HITRAN and more attention should be paid to these ranges in fields such as remote sensing.展开更多
The latest advances in studies on the treatment of cloud overlap and its radiative transfer in global climate models are summarized.Developments with respect to this internationally challenging problem are described f...The latest advances in studies on the treatment of cloud overlap and its radiative transfer in global climate models are summarized.Developments with respect to this internationally challenging problem are described from aspects such as the design of cloud overlap assumptions,the realization of cloud overlap assumptions within climate models,and the data and methods used to obtain consistent observations of cloud overlap structure and radiative transfer in overlapping clouds.To date,there has been an appreciable level of achievement in studies on cloud overlap in climate models,demonstrated by the development of scientific assumptions（e.g.,e-folding overlap） to describe cloud overlap,the invention and broad application of the fast radiative transfer method for overlapped clouds（Monte Carlo Independent Column Approximation）,and the emergence of continuous 3D cloud satellite observation（e.g.,CloudSat/CALIPSO） and cloud-resolving models,which provide numerous data valuable for the exact description of cloud overlap structure in climate models.However,present treatments of cloud overlap and its radiative transfer process are far from complete,and there remain many unsettled problems that need to be explored in the future.展开更多
文摘本文利用2007～2010年整四年最新可利用的CloudSat卫星资料,对东亚地区（15°～60°N,70°～150°E）云的微物理量包括冰/液态水含量、冰/液态水路径、云滴数浓度和有效半径等的分布特征和季节变化进行了分析.本文将整个东亚地区划分为北方、南方、西北、青藏高原地区和东部海域五个子区域进行研究,结果显示：东亚地区冰水路径值的范围基本在700 g m-2以下,高值区分布在北纬40度以南区域,在南方地区夏季的平均值最大,为394.3 g m-2,而在西北地区冬季的平均值最小,为78.5 g m-2;而液态水路径的范围基本在600 g m-2以下,冬季在东部海域的值最大,达到300.8 g m-2,夏季最大值为281.5 g m-2,分布在南方地区上空.冰水含量的最高值为170 mg m-3,发生在8km附近,南方地区夏季的值达到最大,青藏高原地区的季节差异最大;而液态水含量在东亚地区的范围小于360 mg m-3,垂直廓线从10km向下基本呈现逐渐增大的趋势,峰值位于1～2 km高度上.冰云云滴数浓度在东亚地区的范围在150 L-1以下,水云云滴数浓度的值小于80 cm-3,垂直廓线的峰值均在夏季最大.冰云有效半径在东亚地区的最大值为90 μm,发生在5km左右;水云有效半径在东亚地区的值分布在10km以下,最大值为10～12 μm,基本位于1～2 km高度上.从概率分布函数来看,东亚地区冰/水云云滴数浓度的分布呈现明显的双峰型,其他量基本为单峰型.本文的结果可以为全球和区域气候模式在东亚地区对以上云微物理量的模拟提供一定的观测参考依据.
文摘本文首先构建了二流—四流球谐函数谱展开累加辐射传输的新方案,然后将其应用于国家气候中心第二代大气环流模式BCC_AGCM2.0.1的新版本中,并与模式中原有的Eddington累加方案进行了比较。由于新方案本质上是单层Eddington近似方案在四流上的推广。因此新方案在计算精度上要优于原方案。通过在全球气候模式中的应用与比较,本文发现新方案对气候模拟会产生比较大的影响。在晴空条件下,新方案计算的在南纬30°到60°区间、北大西洋东北部以及非洲北部的撒哈拉沙漠区域的地表向下年平均短波辐射通量要小于原方案结果,最大差别可以达到3.5 W/m2;同时,新方案计算的在南纬30°到60°区间和北大西洋东北部的大气顶向上年平均短波辐射通量要大于原方案结果,最大差别达到3 W/m2。在有云大气情况下,新方案计算的地表向下年平均短波辐射通量要小于原方案结果,并随着纬度的增加,新旧两种方案的差别逐渐变大,在南北极时达到最大5.5 W/m2;同时,新方案计算的在赤道区域的大气顶的年平均短波向上辐射通量要小于原方案结果,最大差别为2.5 W/m2,而在南北纬30°到60°区间,新方案计算的在大气顶的年平均短波向上辐射通量则要大于原方案结果,最大差别为1.5 W/m2。新方案计算的年平均短波加热率普遍高于原方案结果,特别是在800 h Pa到地表之间的低层大气以及50 h Pa到100 h Pa的高层大气,最大差别可达0.03 K/d。因此,新方案有助于改善全球气候模式中普遍存在的赤道平流层中下层的温度冷偏差现象。
基金Support Program of China (2007BAC03A01)National Natural Science Foundation of China (41075056)National Basic Research and Development (973) Program of China (2011CB403405)
文摘Four editions of the High Resolution Transmission （HITRAN） databases （HITRAN96, HITRAN2K, HITRAN04, and HITRAN08） are compared by using a line-by-line （LBL） radiative model in the long-wave calculation for six typical atmospheres. The results show that differences in downward radiative fluxes between HITRAN96 and HITRAN08 at the surface can reach a maximum of 1.70 W m-2 for tropical atmospheres. The largest difference in heating rate between HITRAN96 and HITRAN08 can reach 0.1 K day-1 for midlatitude summer atmosphere. Uncertainties caused by line intensity and air-broadened half- widths are also evaluated in this work using the uncertainty codes given in HITRAN08. The uncertainty is found to be 1.92 W m-2 for upward fluxes at the top of the atmosphere （TOA） and 1.97 W m-2 for downward fluxes at the surface. The largest heating rate caused by the uncertainty of line intensity and air-broadened hMf-width can reach 0.5 K day-1. The differences in optical depths between 1300 and 1700 cm-1 caused by different HITRAN versions are larger than those caused by the uncertainties in intensity and air-broadened half-width. This paper suggests that there is inaccurate representation of line parameters over some spectral ranges in HITRAN and more attention should be paid to these ranges in fields such as remote sensing.
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund(GYHY201406023)National Natural Science Foundation of China(41375080)
文摘The latest advances in studies on the treatment of cloud overlap and its radiative transfer in global climate models are summarized.Developments with respect to this internationally challenging problem are described from aspects such as the design of cloud overlap assumptions,the realization of cloud overlap assumptions within climate models,and the data and methods used to obtain consistent observations of cloud overlap structure and radiative transfer in overlapping clouds.To date,there has been an appreciable level of achievement in studies on cloud overlap in climate models,demonstrated by the development of scientific assumptions（e.g.,e-folding overlap） to describe cloud overlap,the invention and broad application of the fast radiative transfer method for overlapped clouds（Monte Carlo Independent Column Approximation）,and the emergence of continuous 3D cloud satellite observation（e.g.,CloudSat/CALIPSO） and cloud-resolving models,which provide numerous data valuable for the exact description of cloud overlap structure in climate models.However,present treatments of cloud overlap and its radiative transfer process are far from complete,and there remain many unsettled problems that need to be explored in the future.
