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991.
为研究我国近百年气温的长程相关规律,通过对我国近百年月平均温度序列的非趋势波动分析。初步得出以下几个结论:我国近百年气温存在内在的长程相关性;标度指数a≌0.66;尽管大于18a尺度区间的α与小于18a尺度区间的α有所不同,但可能由于所分析的温度序列长度受到限制,没有足够充分的理由认为18a是个交叉点。 相似文献
992.
George Ohring 《Pure and Applied Geophysics》1979,117(5):851-864
The effect of atmospheric aerosols on the temperatures of a zonal average climate model is investigated. This is done by introducing into the climate model the results of extensive calculations of the effect of aerosols on the partitioning of solar radiation. Calculations are performed for a non-absorbing and a sloghtly absorbing aerosol, for average and for heavy aerosol amounts. The results indicate that the presence of atmospheric aerosols causes a cooling of the earth's surface and atmosphere, at all latitudes, with aerosol amounts, especially for the absorbing aerosols. The results are compared with some of the previous estimates of aerosol effects on climate. 相似文献
993.
The effect of cloud feedback on the response of a radiative-convective model to a change in cloud model parameters, atmospheric CO2 concentration, and solar constant has been studied using two different parameterization schemes. The method for simulating the vertical distribution of both cloud cover and cloud optical thickness, which depends on the relative humidity and on the saturation mixing ratio of water vapor, respectively, is the same in both approaches, but the schemes differ with respect to modeling the water vapor profile. In scheme I atmospheric water vapor is coupled to surface parameters, while in scheme II an explicit balance equation for water vapor in the individual atmospheric layers is used. For both models the combined effect of feedbacks due to variations in lapse rate, cloud cover, and cloud optical thickness results in different relationships between changes in surface temperature, planetary temperature, and cloud cover. Specifically, for a CO2 doubling and a 2% increase in solar constant, in both models the surface warming is reduced by cloud feedback, in contrast to no feedback, with the greater reduction in scheme I as compared to that of scheme II. 相似文献
994.
The dispersal of an ash plume as it propagates downwind with the ash settling under gravity is presented. It is shown that wind shear, the initial plume height and the plume grain size distribution have an important role in the dispersal of the ash, in particular in determining the evolution of the upper surface and the leading edge of the ash cloud. Once the ash has thermally equilibrated with the atmosphere, the temperature of the upper surface of the ash plume is directly related to its altitude. As a result we can use the model to interpret satellite images of the temperature of the upper surface of ash plumes. These calculations are compared with new analyses of satellite data from the 18 May 1980 eruptions of Mount St Helens in which both thermal infra-red and visible GOES satellite data were examined. In accord with the data, the model is able to predict the rate at which the Mount St Helens ash plume propagated downwind through a combination of the wind shear and gravitational settling of different size particles. The model is also able to explain the observed thermal structure of the upper surface of the ash plume, in which the temperature initially decreases, but then increases with downwind distance as the ash falls through the tropopause. 相似文献
995.
996.
青藏高原岩石圈热状态及其东西部差异 总被引:11,自引:0,他引:11
分析青藏高原几条地球物理研究剖面,并对其地表大地热流和岩石圈温度场进行计算。结果表明:青藏高原温度场分布具南北分带、东西分块的特征。进一步论述了青藏高原东西部的地质构造差异、热差异及其地球动力学意义。 相似文献
997.
Physikalische,chemische und hydrographische Untersuchungen eines Mittelgebirgsbaches: Ein Beitrag zur Typisierung kleiner Fließgewässer 总被引:1,自引:0,他引:1
E. Meyer J. Schwoerbel G. C. Tillmanns 《Aquatic Sciences - Research Across Boundaries》1990,52(3):236-255
Temperature, discharge, and chemical parameters were studied in the upper reach of a Black Forest stream over a three-year period. Additionally, investigations of the upstream tributaries and of downstream sites were conducted at some occasions. While monthly and annual means of water temperature exhibited only little year-to-year variations, average annual discharge differed considerably. Total suspended organic matter was correlated to total supended solids and discharge, orthophosphate and ammonium to temperature. Phosphorus was the only nutrient with a strong seasonal dynamic. Cumulative surface runoff of the upstream tributaries was inversely correlated to total discharge at the gauging station. Concentrations of Ca2+ and Mg2+ and accordingly specific conductivity increase in the longitudinal course of the stream, due to tributaries originating in the adjacent shell limestone and red marl formations.Mit finanzieller Unterstützung der Deutschen Forschungsgemeinschaft, Az. Schw. 63/27-1, 2, 3. 相似文献
998.
We evaluate the time-course of deaths and evidence of periods of increased mortality (i.e., critical periods) in laboratory populations of larval flatfish. First, we make the distinction between age-at-death and abundance-at-time data for fish larvae, the latter being typical in studies of natural populations. Next, we describe an experimental investigation of age- and temperature-dependent mortality in larval winter flounder, Pseudopleuronectes americanus. The survivorship curves of these populations differed significantly in both the magnitude and time-course of mortality among the four water temperatures evaluated (7, 10, 13, and 16°C). Mortality was highest in the cooler temperatures and concentrated in the third quarter of larval life, largely concurrent with settlement of surviving members of the cohort. Among the statistical methods for analysing survival data, the proportional-hazards model with time-varying covariates proved best at capturing the patterns of age-specific mortalities. We conclude that fair appraisals of recruitment hypotheses which are predicated on periods of high, age-specific mortality that vary with environmental conditions (e.g., Hjort's critical period hypothesis) will require: (1) data that are based on age, not time; (2) data that are of higher temporal resolution than commonly available at present and (3) analytical methods that are sensitive to irregularities in survivorship curves. We suggest four research approaches for evaluating critical periods in nature. 相似文献
999.
提出了一种简单的用红外辐射计获得海表面温度的方法。该方法应用了一个快速、均匀搅拌的水浴与一支精密的水银温度计,获取海表面温度的反演系数(又称等效比辐射率),避开了海水辐射率、大气温度和红外辐射计的响应函数等问题。在未知辐射率、大气温度、响应函数的情况下,仍可得到高于0.2℃的精度。 相似文献
1000.
西北太平洋副热带高压等在渤海冬季气温预报中的应用 总被引:1,自引:0,他引:1
本文首先对渤海冬季温分为冷年的暖年,而后对西北太平洋副热带高压(简称副高,下同)强度指,亚洲极涡面积指数,赤道东太平洋海温与冷,暖年的关系进行了分析,得出:当渤海冬季气温属暖年时,其前期西北太平洋副热带高压偏强,亚洲极涡面积指数偏低,赤道东太平洋海温偏高,属冷年时,情况相反。 相似文献