Doppler Detection of Hydroxyl Column Abundance in the Middle Atmosphere: 2. Measurement for Three Years and Comparison with a 1D Model

The hydroxyl column abundance in the middle atmosphere is measured for 3 years in Tokyo by ground-based uv absorption spectroscopy utilizing the Doppler shift of the solar spectrum due to the solar rotation. The diurnal and seasonal variations of the measured column abundance are found to be reproduced qualitatively by a one-dimensional photochemical-diffusive model; however, the measured column abundances are smaller than the calculated by 20 to 30% systematically.     

遵义市太阳能资源分布推算及其利用评估

为了给遵义市太阳能资源利用提供科学依据,该文根据行业标准《太阳能资源评估方法》,整理了遵义气象台30a的太阳辐射观测资料,建立了两种回归模式,分别推算了各县市、各乡镇的太阳总辐射,分析了全市太阳总辐射的时空分布特征,评估了太阳辐射的利用价值,并提出了太阳能利用的对策建议。     

Measurements of chemically and biologically effective radiation reaching the ground

Solar ultraviolet radiation at the surface has been measured at Potsdam on cloudless days by spectrometer OL 752/10. The measurements are compared with broad-band filter measurements and with model calculations using a modified version of Green's model, which is independent of the measurements. Input data to the model such as atmospheric ozone and aerosol optical thicknesses were measured by a Dobson and Brewer spectrophotometer as well as a Linke Feussner pyrheliometer, respectively. Differences between the model and the measurements are discussed in terms of uncertainties in the calibration and errors of instruments as well as uncertainties in the model calculations including the errors of input data. It is demonstrated that different chemically and biologically effective radiances can be determined from only one set of measured spectral irradiance components, i.e. global radiation and diffuse downward and upward directed radiation. Examples of diurnal variations of the photochemical production of ozone and hydroxyl radicals as determined from spectral irradiance measurements and measured concentrations of relevant trace gases are given.It is shown from the measured irradiance that relations between different effects of radiation to the biosphere depend on solar zenith angle, and to a certain extent also on atmospheric ozone. This has to be taken into account when adverse effects of changing UV radiation are evaluated. Radiation Amplification Factors derived from measurements correspond to those determined from model calculations.     

Models for obtaining daily global solar irradiation from air temperature data

The study presents a critical assessment of the possibility of global solar irradiation computation by using air temperature instead of sunshine duration with the classical Ångström equations. The reason for this approach comes from the fact that, although the air temperature is a worldwide measured meteorological parameter, this is rarely used in solar radiation estimation techniques. More than that, the literature is very silent concerning the testing of such models in Eastern Europe. Two new global solar irradiation models (to be called AEAT) related to solar irradiation under clear sky conditions and having the minimum and maximum daily air temperature as input parameters were tested and compared with others from the literature against data measured at five stations in Romania in the year 2000. The accuracy of AEAT is acceptable and comparable to that of the models which use sunshine duration or cloud amount as input parameters. Since temperature-based Ångström correlations are strongly sensitive to origin, the approach for AEAT as a tool for potential users is presented in detail. Additionally reported is a new method to increase the generality of AEAT concerning the extension of the geographical application area. Based on overall results it was concluded that air temperature successfully substitutes sunshine duration in the estimation of the available solar energy.     

Numerical stochastic simulation of the solar cycle and quasi-biennial oscillation of wind speed in the equatorial stratosphere

A problem of simulation of a stationary random process (SRP) is studied. A computer program is developed for modeling SRP, should the parameters required be estimated beforehand. The programming methods used are well known, but the numerical scheme of modeling the SRP needs some explanations; therefore, it is considered in detail in the article, being its basic subject for consideration, although basic characteristic features of the program are also considered. Examples show how the program is used to simulate the solar cycle and the quasi-biennial oscillation of the solar wind in the equatorial stratosphere (QBO). A distinguishing feature of this work, compared with the previous one, is also simulation of the solar cycle taking into account the variability of the sunspot dispersion. The SRP parameters are estimated for the QBO. It is found that the annual mean wind speed variation behavior is similar to the SRP.     

CORRECTION METHODS FOR THERMAL OFFSET ERRORS IN TBQ-2-B PYRANOMETERS

Due to the existence of thermal offsets, global solar irradiances measured by pyranometers are smaller than actual values, and errors are larger in the daytime. Until now, there is no universally-recognized correction method for thermal offset errors. Therefore, it is imperative to identify a convenient and effective correction method. Five correction methods were evaluated based on the data measured from a field experiment from 23 January to 15 November, 2011. Results have shown: 1) Temporal variation characteristics of thermal offsets in the four tested pyranometers are consistent. 2) Among the five methods, non-dimensional quantity method is suggested for use to correct thermal offsets, because it is convenient and no modification of instruments is required. If collocated net longwave radiation and wind speed data are available and their uncertainties are small, the historical solar radiation datasets can also be corrected. And correction effects by the method are better.     

东太平洋冷舌区海表面温度日变化特征的模拟研究

本文通过分辨太阳辐射日变化, 利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室 (LASG/IAP) 气候系统海洋环流模式 (LICOM), 模拟了东太平洋冷舌区海表面温度 (SST) 的日变化特征并研究了弱混合对其影响。采用理想的太阳辐射日变化强迫上层垂向分辨率为10 m的海洋模式LICOM, 模拟出了SST日变化一些特征, 同时海洋的上层流场也产生明显日变化。模拟的SST日变化振幅水平分布与观测接近, 且受太阳辐射日变化振幅水平分布调制。在赤道中东太平洋区, 模拟的SST日变化振幅 (约为0.3～0.4℃) 比观测偏小约0.1～0.2℃。模拟的SST日变化峰值出现在15～16 时 (当地标准时间), 落后于太阳辐射峰值2～3个小时, 接近观测。进一步减弱混合后, 模拟的日变化振幅增加约0.1℃, 更接近观测。这说明在东太平洋冷舌区SST日变化主要受太阳辐射日变化和垂直混合影响。此外, 混合减小后, 在太阳辐射日变化调制下, 平均态 (如混合层、温度和流场) 也出现明显变化。在赤道东太平洋冷舌区北侧, 弱混合导致混合层变浅, 变浅使热量堆积进而使平均SST升高约0.3℃; 在赤道东太平洋冷舌南侧, 经向平流加强导致平均SST降低约0.2℃。     

Variations of Total Nitrogen Oxide Content in the Atmosphere over the North Caucasus

The data are presented on total nitrogen dioxide (NO₂) content in the atmosphere from 1979 to 2009 at the high-mountain scientific station located in the unpolluted area in the North Caucasus at the height of 2070 m above the sea level (43.7° N, 42.7° E). The total content of NO₂ was measured on the basis of attenuation of direct solar radiation over slope pathways after the sunrise and before the sunset. Characteristics features are analyzed of temporal variability of total NO₂ content in the atmosphere related to its diurnal and seasonal variations, 11-year solar activity, volcanic eruptions, quasi-biennial oscillations of tropical circulation, and the El Niño effect.     

利用探空资料计算云层对辐射的影响

本文对两次江淮流域的梅雨天气过程作了辐射特征分析。着重考虑了云层对太阳辐射和大气长波辐射的影响。计算时假设云层随高度的分布由大气的湿度决定,方案考虑了大气中云层随高度的分布,所得结果能反映实际大气中各种云的辐射特征。     

Assessing the performance of global solar radiation empirical formulations in Kampala, Uganda

Summary Solar radiation incident on the Earth’s surface is a determining factor of climate on Earth, hence having a proper solar radiation database is crucial in understanding climate processes in the Earth’s atmosphere. Solar radiation data may be used in the development of insolation maps, analysis of crop growth and in the simulation of solar systems. Unfortunately, measured solar radiation data may not be available in locations where it is most needed. An alternative to obtaining observed data is to estimate it using an appropriate solar radiation model. The purpose of this study is to assess the performance of thirteen global solar radiation empirical formulations, in Kampala, Uganda, located in an African Equatorial region. The best performing formulations were determined using the ranking method. The mean bias error, root mean square error and t-statistic value were calculated and utilized in the ranking process. Results have shown that the formulation: is ranked the highest and therefore is the recommended empirical equation for the estimation of the monthly mean global solar irradiation in Kampala, Uganda and in other African Equatorial locations with similar climate and terrain.     

In-situ Formation of Light-Absorbing Organic Matter in Cloud Water

Current climate models seem to underestimate the flux of solar energy absorbed by the global troposphere. All of these models are constrained with the assumption that cloud droplets consist of pure water. Here we demonstrate in a simple laboratory experiment that aromatic hydroxy-acids which are found in continental fine aerosol can react with hydroxyl radicals under typical conditions prevalent in cloud water influenced by biomass burning. The reactions yield colored organic species which do absorb solar radiation. We also suggest that the products of such reactions may be humic-like substances whose presence in continental aerosol has been confirmed but their source mechanisms are still much sought after. We also attempt to give a first order estimate of the enhancement of water absorption at a visible wavelength under atmospheric conditions.     

Evaluation of support vector machine for estimation of solar radiation from measured meteorological variables

Solar radiation is an essential and important variable to many models. However, it is measured at a very limited number of meteorological stations in the world. Developing method for accurate estimation of solar radiation from measured meteorological variables has been a focus and challenging task. This paper presents the method of solar radiation estimation using support vector machine (SVM). The main objective of this work is to examine the feasibility of SVM and explore its potential in solar radiation estimation. A total of 20 SVM models using different combinations of sunshine ratio, maximum and minimum air temperature, relative humidity, and atmospheric water vapor pressure as input attributes are explored using meteorological data at 15 stations in China. These models significantly outperform the empirical models with an average 14 % higher accuracy. When sunshine duration data are available, model SVM2 using sunshine ratio and air temperature range is proposed. It significantly outperforms the empirical models with an average 26 % higher accuracy. When sunshine duration data are not available, model SVM19 using maximum temperature, minimum temperature and atmospheric water vapor pressure is proposed. It significantly outperforms the temperature-based empirical models with an average of 18 % higher accuracy. The remarkable improvement indicates that the SVM method would be a promising alternative over traditional approaches for estimation of solar radiation at any locations.     

A survey of possible effects of long-lasting absence of solar activity on climate and some speculations on possible mechanisms

This paper deals with the prolonged lack (or existence) of solar activity, such as the Maunder or Spörer minima, since considerable climatic changes barely occur within a shorter time interval. For this aim, first the possible influences of the present-day 11-yr solar cycle are considered for higher atmospheric regions, and found scarcely to be responsible for inducing climatic changes. On the other hand, solar activity-generated changes of the solar parameter in the visible spectrum are estimated too. The results of these simple considerations indicate that the external manifestations of the solar cycle hardly can cause observable change in the tropospheric weather (and so the long-lasting solar quiets seem not climatically significant), and seem indirectly to support the possibility, that the Milankovitch mechanism plays an important role in forcing the ice-age oscillations at least during the Quaternary period. Besides it can be concluded, that greater (≥ 0.1%, measured from satellite platform) solar parameter variations cannot be in close connection with the known forms of solar activity, which suggest that the possible, significant secular solar luminosity changes could be generated deep inside the Sun and/or could not be closely related to the sunspot cycle.     

Retrieving daily global solar radiation from routine climate variables

Solar radiation is an important variable for studies related to solar energy applications, meteorology, climatology, hydrology, and agricultural meteorology. However, solar radiation is not routinely measured at meteorological stations; therefore, it is often required to estimate it using other techniques such as retrieving from satellite data or estimating using other geophysical variables. Over the years, many models have been developed to estimate solar radiation from other geophysical variables such as temperature, rainfall, and sunshine duration. The aim of this study was to evaluate six of these models using data measured at four independent worldwide networks. The dataset included 13 stations from Australia, 25 stations from Germany, 12 stations from Saudi Arabia, and 48 stations from the USA. The models require either sunshine duration hours (Ångstrom) or daily range of air temperature (Bristow and Campbell, Donatelli and Bellocchi, Donatelli and Campbell, Hargreaves, and Hargreaves and Samani) as input. According to the statistical parameters, Ångstrom and Bristow and Campbell indicated a better performance than the other models. The bias and root mean square error for the Ångstrom model were less than 0.25 MJ m² day^?1 and 2.25 MJ m² day^?1, respectively, and the correlation coefficient was always greater than 95 %. Statistical analysis using Student’s t test indicated that the residuals for Ångstrom, Bristow and Campbell, Hargreaves, and Hargreaves and Samani are not statistically significant at the 5 % level. In other words, the estimated values by these models are statistically consistent with the measured data. Overall, given the simplicity and performance, the Ångstrom model is the best choice for estimating solar radiation when sunshine duration measurements are available; otherwise, Bristow and Campbell can be used to estimate solar radiation using daily range of air temperature.     

广州地区太阳分光辐射的某些变化特征

利用广州地区1985—1990年的太阳分光辐射的连续观测资料（观测角度为23°11′），研究了广州地区紫外辐射、可见光辐射（光合有效辐射）、近红外辐射的某些特征。结果指出，每年7—10月份各分光辐射及总辐射总量较大。月总辐射中可见光辐射占总辐射的百分比年平均为47.3%，相应的紫外辐射和近红外辐射分别占7.1%和45.6%。文中还分析了晴天条件下分光辐射的变化和1990年紫外辐射变化的某些特征，并分析和讨论了分光辐射与云量、日照时间等因子的相关。     

藏北高原五道梁地区的气溶胶特征

通过对藏北高原五道梁地区的大气气溶胶光学厚度分析发现,该地区气溶胶光学厚度有明显的日变化及季节变化特征,气溶胶光学厚度增大时月平均气温与年平均气温减小。     

上甸子大气本底站太阳辐射观测数据的质量评价

采用了基准地面辐射观测网络(BSRN)推荐的辐射观测数据质量评价方法,对2005年上甸子大气本底站太阳辐射观测数据进行了质量评价,并通过分析晴空地面太阳总辐射观测值与计算值之间的均方根误差和变差系数来替换BSRN质量评价方法中的"辐射观测值序列的目视"检验步骤.结果表明,通过前3步检验的直接、散射和地面太阳总辐射数据的百分比,除7月和8月外其他月份均在95%以上;地面向上辐射除3、4、7、8和11月在74.7%～85.5%之间外,其他月份均在91%以上.通过前3步检验的晴空地面太阳总辐射观测值与计算值之间的均方根误差均在23.5 W·m-2以下,除11月和12月外其他月份的变差系数均在0.05以下.     

内蒙古自治区太阳总辐射的气候学计算及其时空分布特征

通过对比分析国内外太阳总辐射的气候学计算方法,最终给出内蒙古太阳辐射最佳计算公式。根据内蒙古及周边地区24个太阳辐射观测站历年各月的总辐射和日照百分率,采用最小二乘法拟合出公式中的经验系数,并在分区基础上通过内插将a、b系数推广到内蒙古108个气象站点上,从而建立了内蒙古太阳总辐射计算模型。结果表明：内蒙古太阳总辐射年际变化总体呈下降趋势,但不显著,而且不同区域在减小速率上差异明显。年变化则表现为单峰型变化趋势,以5月辐射量最大,6、7月次之,12月最小。全年和各月总辐射的空间分布形态一致,总的分布趋势由东北向西南逐渐递增。全区年总辐射在4633～6616 MJ·m^-2之间,太阳能资源丰富程度均在丰富级别以上,而且大部分地区属于资源最丰富区和很丰富区,太阳能开发利用潜力巨大。     

紫外线强度的计算及预报方法研究

利用一般常规的辐射观测资料 ,通过经验公式计算紫外辐射的方法 ,讨论了紫外辐射强度的月际变化特征 ,并给出应用实例 ,对开展紫外线强度指数预报有一定的参考意义     

中层大气臭氧的全日盘掩日测量

本文研究了日盘张角对掩日测量的影响,引进了日盘光辐射空间变化特性这一先验信息,提出了从全日盘掩日测量反演中层大气臭氧含量的新方法.数值模拟试验指出,这一方法可以满意地给出25—65km高度范围内大气臭氧的垂直分布。当测量吸收比的均方根噪声为0.01时,其反演误差小于10％.利用这一方法,可以大大简化探测系统、降低测量对遥感平台的要求.