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1.
线翼截断方式对大气辐射计算的影响 总被引：2，自引：0，他引：2
在大气辐射传输计算方法中,有3种基本方法,即,逐线积分方法,k-分布方法和带模式方法。其中,逐线积分方法是最精确的计算大气透过率的方法,本文根据透过率计算方式的不同,将逐线积分方法分为追线积分法和追点积分法。由于逐线积分计算需要耗费大量的计算时间,在大气遥感和大气探测业务中使用时,必须减少计算成本,提高计算速度。本文在追线积分法的基础上,给出了简化的逐线积分的基本方法,在保证同样计算精度的同时,大大提高了计算速度。对在精确的和简化的逐线积分下,不同线翼截断方式(CUTOFF)对吸收系数、大气透过率和冷却率的影响进行了更详细的探讨。通过数值试验发现,对谱线线翼的截断方式是影响辐射计算精度和计算速度的重要因子。在不同压力下,用CUTOFF=2计算的吸收系数误差最大;对CUTOFF=1,在大多数取样点上误差都小于2%;对CUTOFF=3或4,对绝大多数取样点上计算的吸收系数误差都在5%以内,但所用的计算时间却明显减少。大气低层的透过率对不同的计算方法和不同的线翼截断方式不敏感;对大气高层,无论是对精确的还是简化的逐线积分方法,当CUTOFF=2时的透过率结果与其他线翼截断方式的结果差别较大。通过比较,本文给出线翼截断的优选方案。 相似文献
2.
干旱地区大气与地表特征对辐射加热场的影响 总被引：1，自引：0，他引：1
本文利用美国犹他大学气象系的辐射和云参数化模式，对ＨＥＩＦＥ期间张掖地区１９９１年春、夏、秋、冬四季资料进行了计算，讨论了晴天条件下的大气状况态地表反射率与地表比辐射率等因子对地气系统的太阳辐射收支以及短波加热率与长波冷却率分布的影响；揭示了不同季节的整层大气反射、透过与吸收特征，分析了大气中各主要吸收成分对加热率与冷却率的贡献，同时就辐射模式的垂直分辨率对加热率与冷却率的影响亦作了讨论。 相似文献
3.
文章总结了１９９０－１９９５年对红外窗区大气透过率的观测结果，以实测整层大气透过率与理论模拟计算透过率作了对比，并对大气中的水汽，微量气体和大气污染物对透过率的影响作了初步分析。 相似文献
4.
利用太阳辐射计940nm通道反演大气柱水汽总量 总被引：7，自引：4，他引：7
利用太阳辐射计CE318近红外940nm水汽吸收通道和临近窗区道反演大气柱水汽总量，由于大气在940nm附近有水汽吸收。该通道不能采用通常Langley法处理，而采用改进的Langley法。利用MODTRAN3．7模式模拟出太阳辐射940nm通道透过率与水汽量关系常数，考虑了通道的光谱响应函数和不同大气模式的影响，模拟结果表明穿通道（小于10nm)上述关系常数受大气模式影响不大。总消光剔除气溶胶和分子散射，就得出水汽的透过率，从透过率反演水汽量。处理了敦煌和青海湖辐射校正场1999年7月场大气特征测量兼FY－1C辐射定标期间的数据，反演的平均水汽量与探空水汽积分比较，差异在12％以内。还计算出一天中不同时刻的水汽量，给出了同步观测6天卫星过顶前后15min平均水汽量，该水汽量用于FY－1C卫星遥感器辐射定标时辐射传输模式输入参数。结果表明太阳辐射计是一种便携有效测量水汽量仪器。 相似文献
5.
一种快速高效的逐线积分大气吸收计算方法 总被引：19，自引：4，他引：15
本文发展了一种新的计算大气气体吸收系数以及冷却率的快速数值方法, 并对影响逐线 积分精度和计算时间的各种因子进行了详细研究。以大气主要吸收气体CO-215 μm带的 500～800 cm-1波段为例,将新方法计算的吸收系数、大气透过率和冷却率结果与经 典的逐线积分方法进行了比较。对从地面到100 km范围的整层大气,大气透过率的 误差不超过0.0004;对70 km以下的大气,大气冷却率的误差不超过0.004 K/d,而计算时 间却节省1～2个数量级左右。 相似文献
6.
浑善达克沙地沙尘气溶胶的辐射强迫 总被引：5，自引：7，他引：5
利用2001年春季浑善达克沙地外场观测的辐射资料及大气辐射模式,对沙尘气溶胶的局地辐射强迫进行了分析和模拟估算。计算结果表明,浑善达克沙地大气透过率日变化显著,晴天可达0.80以上,沙尘天气最低在0.01以下;白天沙尘的辐射强迫对地表有冷却作用,夜间起保温作用。观测期间,平均大气透过率为0.6,白天沙尘对地面向下长波辐射的平均强迫增加量为16.76 W.m-2,对地面净辐射能收支的平均强迫减少量为62.76 W.m-2;夜间地表长波辐射净损失量因沙尘作用减少,平均为67.84 W.m-2。 相似文献
7.
文章介绍了一种比较简单实用的地球大气的光谱透过率和到达大气层顶的红外辐射率的计算模型,光谱波长从4 μm到∞ μm,吸收气体H2O、CO2、O3的吸收计算采用Elsasser带模式及其经验参数,H2O的连续吸收公式是美国LOWTRAN-6计算程序的水汽连续吸收经验公式。透过率的计算结果与LOWTRAN计算结果相一致。以这种透过率简化模型为基础,建立了辐射传递正演计算模型,开发了相应软件,并用于卫星遥感射出长波辐射的资料处理中,取得了良好结果。 相似文献
8.
平流层臭氧变化对大气加热率及到达地面紫外辐射的影响 总被引：2，自引：2，他引：2
平流层臭氧的变化对平流层的温度结构，整个大气环流以及到达地面的紫外辐射均有影响。本文采用一个计算臭氧吸收太阳辐射的参数化方法和有关资料，研究了臭氧变化对大气最大加热率和到达地面的紫外辐射通量密度的影响情况。文中给出的参数化方法可直接应用于大气环流模式计算臭氧吸收太阳辐射的加热率。 相似文献
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10.
利用“绿洲系统能量与水分循环过程观测与数值研究”的观测资料和酒泉站的地面和探空气象资料,计算了酒泉绿洲夏季大气边界层的加热（冷却）率,分析了酒泉绿洲近地面层和行星边界层的大气加热（冷却）率逐日变化,研究了不同典型天气下大气加热（冷却）率的变化特征。结果表明,酒泉绿洲近地面层和行星边界层内,大气加热（冷却）率具有明显的逐日变化特征;近地面层和行星边界层及整个大气层白天的大气加热率和夜晚的大气冷却率基本相当,大气能量基本守恒;日照时数、云量和特殊天气过程（如冷空气活动、沙尘天气和降水等）对大气加热（冷却）率有很大影响。 相似文献
11.
SHUMING DU 《Boundary-Layer Meteorology》1997,83(2):207-219
In this paper, we evaluate the Lagrangian velocity structure function constant, C0, in the inertial subrange by comparing experimental diffusion data and simulation results obtained with applicable Lagrangian stochastic models. We find in several different flows (grid turbulence, laboratory boundary-layer flow and the atmospheric surface layer under neutral stratification) the value for C0 is 3.0 ± 0.5. We also identify the reasons responsible for earlier studies having not reached the present result. 相似文献
12.
Sven-Erik Gryning 《Boundary-Layer Meteorology》1999,90(3):479-494
The ability to simulate atmospheric dispersion with models developed for applied use under stable atmospheric stability conditions is discussed. The paper is based on model simulations of three experimental data sets reported in the literature. The Hanford data set covered weakly stable conditions, the Prairie Grass experiments covered both weakly stable and very stable atmospheric conditions, and the Lillestrøm experiment was carried out during very stable conditions. Simulations of these experiments reported in the literature for eight different models are discussed. Applied models based on the Gaussian plume model concept with the spread parameters described in terms of the Pasquill stability classification or Monin–Obukhov similarity relationships are used. Other model types are Lagrangian particle models which also are parameterized in terms of Monin–Obukhov similarity relationships. The applied models describe adequately the dispersion process in a weakly stable atmosphere, but fail during very stable atmospheric conditions. This suggests that Monin–Obukhov similarity theory is an adequate tool for the parameterization of the input parameters to atmospheric dispersion models during weakly stable conditions, but that more detailed parameterisations including other physical processes than those covered by the Monin–Obukhov theory should be developed for the very stable atmosphere. 相似文献
13.
卫星气象的发展——机遇与挑战 总被引：2，自引：0，他引：2
气象卫星和卫星气象发展到今天,正处于一个承上启下,继往开来的关键时期。本文从国内外气象卫星的发展,气象卫星对大气科学的作用和影响这两大方面讨论了它们在不同发展阶段所取得的进展、成就和特点,以及未来的发展趋势和面临的科学、技术问题。在此基础上,提出了卫星气象为适应良好的发展机遇所面临的挑战,它们是：绝对辐射定标和真实性检验、发展快速精确的辐射传输模式、全球模式中同化卫星遥感的水汽和云等资料、在区域模式中同化卫星遥感的高分辨率资料和发展先进的反演算法。 相似文献
14.
Summary An initial value problem is proposed to study the influence of mountains upon atmospheric flows. The normal mode, quasigeostrophic theory of lee cyclogenesis is revisited; in order to model Alpine cyclogenesis, the flow, upon which the mountain acts, should represent a cyclone wave propagating eastward in a sheared zonal current. Two different models are considered in order to describe cyclone waves: an unstable Eady normal mode and a finite amplitude, neutral Rossby mode in the two layer model. It is shown that the topographic modifications proper of normal modes emerge very rapidly from the integration of the initial value problem. It is also shown that an enhanced deepening of the upper level trough can occur when finite amplitude effects are taken into account.With 8 Figures 相似文献
15.
Connection between atmospheric latent energy and energy fluxes simulated by nine CMIP5 models 
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下载免费PDF全文 The atmospheric latent energy and incoming energy fluxes of the atmosphere are analyzed here based on the historical simulations of nine coupled models from the Coupled Model Intercomparison Project Phase 5(CMIP5)and two reanalysis datasets.The globally averaged atmospheric latent energy is found to be highly correlated with several types of energy flux,particularly the surface latent heat flux,atmosphere absorbed solar radiation flux,and surface net radiation flux.On the basis of these connections,a hydrological cycle controlled feedback(HCCF)is hypothesized.Through this feedback,the atmosphere absorbed solar radiation is enhanced and causes intensification of the surface latent heat flux when the atmospheric latent energy is abnormally strong.The representativeness of the HCCF during different periods and over different latitudinal zones is also discussed.Although such a feedback cannot be confirmed by reanalysis,it proves to be a common mechanism for all the models studied. 相似文献
16.
The Response of Arctic Sea Ice to Global Change 总被引：4，自引：0，他引：4
The sea ice-covered polar oceans have received wider attention recently for two reasons. Firstly, the global conveyor belt circulation of the ocean is believed to be forced in the North and South Atlantic through deep water formation, which to a large degree is controlled by the variations of the sea ice margin and especially by the sea ice export to lower latitudes. Secondly, CO2 response experiments with coupled climate models show an enhanced warming in polar regions for increased concentrations of atmospheric greenhouse gases. Whether this large response in high latitudes is due to real physical feedback processes or to unrealistic simplifications of the sea ice model component remains to be determined. Coupled climate models generally use thermodynamic sea ice models or sea ice models with oversimplified dynamics schemes. Realistic dynamic-thermodynamic sea ice models are presently implemented only at a few modeling centers. Sensitivity experiments with thermodynamic and dynamic-thermodynamic sea ice models show that the more sophisticated models are less sensitive to perturbations of the atmospheric and oceanic boundary conditions. Because of the importance of the role of sea ice in mediating between atmosphere and ocean an improved representation of sea ice in global climate models is required. This paper discusses present sea ice modeling as well as the sensitivity of the sea ice cover to changes in the atmospheric boundary conditions. These numerical experiments indicate that the sea ice follows a smooth response function: sea ice thickness and export change by 2% of the mean value per 1 Wm-2 change of the radiative forcing. 相似文献
17.
ON THE RELATIONSHIP BETWEEN PLANETARY AND SURFACE ALBEDO:MODEL’S COMPARISON AND VALIDATION* 下载免费PDF全文
下载免费PDF全文 The simple linear relationship between clear-sky planetary and surface albedo can be adopted for certain accuracy.There are different parameterization schemes of atmospheric correction for different retrieval models.In this paper,several representative retrieval models are compared and tested with observational data from HEIhe basin Field Experiment(HEIFE) in western China.Some evaluations and suggestions on improvement are proposed for models which would be more applicable to plateau and arid areas. 相似文献
18.
ON THE RELATIONSHIP BETWEEN PLANETARY AND SURFACE ALBEDO:MODEL''''S COMPARISON AND VALIDATION 总被引：2，自引：0，他引：2 下载免费PDF全文
下载免费PDF全文 The simple linear relationship between clear-sky planetary and surface albedo can be adopted forcertain accuracy.There are different parameterization schemes of atmospheric correction for differentretrieval models.In this paper,several representative retrieval models are compared and tested withobservational data from HEIhe basin Field Experiment (HEIFE) in western China.Some evaluationsand suggestions on improvement are proposed for models which would be more applicable to plateauand arid areas. 相似文献
19.
A coupled, one-dimensional atmospheric-oceanic boundary layer model based on a single station assessment has been formulated from independent oceanic and atmospheric bulk boundary layer models. Sensitivity analyses are conducted to determine major differences in the responses of the coupled model compared to those of the separate oceanic and atmospheric models. The general behavior of the coupled model atmosphere is not significantly different from that of the atmospheric model over short term simulations (12–24 h). However, large differences may occur under certain limited conditions when winds are light and the lifting condensation level is close to the height of the inversion. Major differences between the predicted evolution of the ocean boundary layer by the ocean model and coupled model are more common, and the short term predictive ability of the ocean model in coupled form is enhanced. 相似文献
20.
利用1961~2000年逐月气温资料计算了东北地区分省和全区玉米的热量指数。通过对热量指数和大气环流资料的统计分析，建立了6个预测玉米热量指数的模型，各模型都能较好地预测东北地区各省及全区的玉米生长发育期间的热量状况。检验结果可以看出，所有模型的准确率较高，且稳定性较好，6个模型预测玉米热量指数的平均相对误差都在7%以下，说明了各模型都具有较好的预测能力。其中辽宁省的相对误差最小，平均在2%以下，预测效果最好，黑龙江省的平均误差最大，也都在4.5%~7%。 相似文献