Solar Altitude Angle Research Articles

서울·대구 ASOS 지점에서 건물에 의한 일조 차단 영향

In this study, the observational environment for sunshine duration at Seoul and Daegu Automated Synoptic Observing Systems (ASOSs) was analyzed using a numerical model. In order to analyze the effects of topography and buildings on observational environment for sunshine duration, the model domains including the elevated building and mountainous areas around Seoul and Daegu ASOSs were considered. Three dimensional topography and buildings used as input data for the numerical model were constructed using a geographic information system (GIS) data. Solar azimuth and altitude angles calculated for the analysis period (one-week for each season in 2008) in this study were validated against those by Korea Astronomy and Space Science Institute (KASI). The starting and ending times of sunshine duration observed at ASOSs largely differed from the respective sunrise and sunset times simply calculated using solar angles and information of ASOSs' latitude and longitude, because uneven topography and elevated buildings around ASOSs cut off sunshine duration right after the sunrise and right before the sunset. The model produced the sunshine indices for Seoul and Daegu ASOSs with the time interval of one minute and the period of one week for each season and we compared the hourly averaged indices with those observed at the ASOSs. One week of which the cloudiness is lowest for each season is selected for analysis. Not only the adjacent buildings but also distant buildings and mountain cut off sunshine duration right after the sunrise and right before the sunset. The buildings and topography cutting off sunshine duration were found for each analyzing date. It was suggested that, in order to evaluate the observational environment for sunshine duration, we need to consider even the information of topography and/or building far away from ASOSs. This study also showed that the analyzing method considering the GIS data is very useful for evaluation of observational environment for sunshine duration.

수질 매개변수 추정에 있어서 항공 초분광영상의 가용성 고찰

This study reviewed an application of water quality estimation using an Airborne Hyperspectral Imagery (A-HSI) and tested a part of Han River water quality (especially suspended solid) estimation with available in-situ data. The estimation of water quality was processed two methods. One is using observation data as downwelling radiance to water surface and as scattering and reflectance into water body. Other is linear regression analysis with water quality in-situ measurement and upwelling data as at-sensor radiance (or reflectance). Both methods drive meaningful results of RS estimation. However it has more effects on the auxiliary dataset as water quality in-situ measurement and water body scattering measurement. The test processed a part of Han River located Paldang-dam downstream. We applied linear regression analysis with AISA eagle hyperspectral sensor data and water quality measurement in-situ data. The result of linear regression for a meaningful band combination shows -24.847 + 0.013 L560 as 560 nm in radiance (L) with 0.985 R-square. To comparison with Multispectral Imagery (MSI) case, we make simulated Landsat TM by spectral resampling. The regression using MSI shows -55.932 + 33.881 (TM 1/ TM 3) as radiance with 0.968 R-square. Suspended Solid (SS) concentration was about 3.75 mg/l at in-situ data and estimated SS concentration by A-HIS was about 3.65 mg/l, and about 5.85mg/l with MSI with same location. It shows overestimation trends case of estimating using MSI. In order to upgrade value for practical use and to estimate more precisely, it needs that minimizing sun glint effect into whole image, constructing elaborate flight plan considering solar altitude angle, and making good pre-processing and calibration system. We found some limitations and restrictions such as precise atmospheric correction, sample count of water quality measurement, retrieve spectral bands into A-HSI, adequate linear regression model selection, and quantitative calibration/validation method through the literature review and test adopted general methods.

A study on use of miniature dielectric compound parabolic concentrator (dCPC) for daylighting control application

Low-concentration solid dielectric compound parabolic concentrator (dCPC) and its variations have been widely regarded as an attractive solution to reduce the cost of a photovoltaic (PV) system, particularly for building-integrated application. Different from a mirror CPC, a dCPC allows the light beyond its acceptance angle to penetrate through its lateral surface. This escaped light could be actually used for daylighting, so the dCPC offers a potential for combined PV and daylighting application suitable for the atrium buildings or large green houses. In the modern buildings, an advanced daylighting system such as prismatic panels is used to balance between harvesting daylight and preventing excessive solar heat gain. In contrast, this study aims to evaluate the advantage of the miniature solid dCPC over common prismatic structures according to their daylight transmittance values under both standard and real sky conditions. A commercial optical analysis software PHOTOPIA is firstly used to compare the daylighting control performance between a dCPC rod and two common prismatic elements. The effect of solar altitude and azimuth angles changing with time is considered. A preliminary test under a solar simulator and a real sky condition is also introduced to provide experimental evidence regarding the advantageous feature of a dCPC rod for daylighting control.

小麦LAI-2000观测值对辐亮度变化的响应

利用LAI-2000植物冠层分析仪和ASD光谱仪，通过固定点拔节期冬小麦叶面积指数（LAI）观测实验和同步光谱辐亮度实验，测量了晴天条件下，固定点冬小麦从中午至傍晚24个不同时刻的LAI值及对应的辐亮度。继之分析了此段时间内测得的定点冬小麦LAI值分别与对应时刻可见光和近红外谱段的天空光辐亮度、总辐亮度和太阳直射辐亮度值之间的相关性。结果表明，无论波长小于490nm的谱段，还是波长大于490 nm的谱段，LAI与天空光辐亮度、总辐亮度和太阳直射辐亮度都呈负相关，相关系数（<em>R</em>²）高达0.8左右；尤其LAI与天空光辐亮度的负相关性最高，这种相关性随着波长的增大而减小。LAI与各谱段天空光辐亮度的相关性特征可为LAI-2000晴天观测的LAI值归一化修正处理提供一种新思路和技术途径，以消除太阳直射光的影响，从而解决LAI-2000只能在晴天观测的局限性，拓展LAI-2000在晴天观测条件下的适用性。;The radiance from the sun and the sky is varying with solar altitude angle, and the solar altitude angle is varying with time. That is to say the radiance is varying with time. The LAI-2000 measures the canopy light interception at five view angles using a fisheye optical sensor. From all the above, it can be inferred that the LAI is related to the radiance. And then, a fixed plot observation experiment of winter wheat was conducted from 12:15 to 17:40 on sunny with LAI-2000 plant canopy analyzer and ASD spectrometer to explain that inference. In this experiment, the wheat LAI and the radiance were measured continuously at 24 different moments which were corresponding to 24 different solar altitude angles. And then the wheat LAI measured at different moments was computed with FV-2200. The total radiance and sky radiance was got by ASD spectrometer. After that, the direct solar radiance was got by the total radiance subtracting the sky radiance. Next, the radiance in 380-430 nm spectrum region, 430-470 nm spectrum region, 470-490 nm spectrum region, 500-560 nm spectrum region, 620-760 nm spectrum region and 760-1000 nm spectrum region were extracted. At last, the correlation between wheat LAI and the sky radiance, the total radiance and the direct solar radiance was separately analyzed at different spectrum regions. The results of the study showed that either in spectrum regions below 490 nm or above 490 nm, the <em>R</em>² between LAI and the sky radiance, the total radiance and the direct solar radiance were all high which were up to 0.8. In addition, the <em>R</em>² between LAI and the sky radiance was highest among each spectrum regions, while the <em>R</em>² between LAI and the direct solar was lowest. Moreover, the <em>R</em>² between LAI and the sky radiance decreased with the increasing of wavelength, while the <em>R</em>² between LAI and the total radiance and the direct solar radiance increased with the increasing of wavelength. And the results of the study also showed that LAI-2000 would be affected greatly by the direct sunlight and caused large error on sunny condition. Therefore, it is necessary that the LAI measured on sunny condition should be corrected. This research provided a thought and a technological approach for the normalization and correction of the LAI measured with LAI-2000 on sunny condition. And then the influence of the direct sunlight could be eliminated, which was benefit of getting over the limits of weather condition for LAI-2000's use, and the suitability of using LAI-2000 under sunny condition could also be expanded.

Study on land-surface albedo over different types of underlying surfaces in North China

Land-surface albedo reflects the ability that land surface reflects solar radiation and plays a very important role in surface energy balance. By picking 10 different underlying surfaces including bare soil, cropland and grassland, the differences in the diurnal variation of land surface radiation and energy processes over North China are investigated using the data measured during July and September, 2008, provided by the Experimental Co-observation and Integral Research in Semi-arid and Arid Regions over North China, the characteristic of land-surface albedo and the response to precipitation are analyzed, and the relationships between land-surface albedo and solar altitude angle and soil humidity are studied. According to the average albedo, the sequence of albedo over all the underlying surfaces are arid meadow in the northeast of China&gt;alpine meadow in the northwest of China&gt;oasis farmland in the northwest&gt;natural vegetation on the Loess Plateau&gt;semi-arid meadow in the northeast of China&gt;farmland in the northeast of China&gt;fruit bearing forest in the northeast of China. And the albedo is smaller when the precipitation is much while it is bigger when the precipitation is less on the whole. The diurnal variation curves of albedo have three types: symmetric type, bigger in the morning and smaller in the noon and afternoon, biggest in the afternoon and smallest in the morning. In the selected 6 stations, the valley of albedo basically occurs on rainy days and the peak occurs on days which are not rainy but have strong solar radiation. The land-surface albedo decreases with the solar altitude angle increasing and tends to remain when the solar altitude angle is bigger than 40°. The land-surface albedo decreases obviously with soil moisture increasing in Yuzhong and farmland of Tongyu, then the grassland of Tongyu. And the land-surface albedos of Maqu, Miyun, Jinzhou have no significant change with the soil moisture.

도시지역 유인관측소 일조 관측환경 평가 모델 개발

In this study, the numerical model was developed to evaluate the observational environment of sunshine duration and, for evaluating the accuracy and utility of the model, it was verified against the observational data measured at Dae-gu Automated Synoptic Observing System (ASOS) located in an urban area. Three-dimensional topography and building configuration as the surface input data of the model were constructed using a Geographic Information System (GIS) data. First, the accuracy of the computing planetary positions suggested by Paul Schlyter was verified against the data provided by Korea Astronomy and Space Science Institute (KASI) and the results showed that the numerical model predicted the Sun's position (the solar azimuth and altitude angles) quite precisely. Then, this model was applied to reproduce the sunshine duration at the Dae-gu ASOS. The observed and calculated sunshine durations were similar to each other. However, the observed and calculated sunrise (sunset) times were delayed (curtailed), compared to those provided by KASI that considered just the ASOS's position information such as latitude, longitude, and elevation height but did not consider the building and topography information. Further investigation showed that this was caused by not only the topographic characteristic (higher in the east and lower in the west) but also the buildings located in the southeast near the sunrise and the southwest near the sunset. It was found that higher building resolution increased the accuracy of the model. It was concluded that, for the accurate evaluation of the sunshine duration, detailed building and topography information around the observing sites was required and the numerical model developed in this study was successful to predict and/or the sunshine duration of the ASOS located in an urban area.

Numerical simulation of solar radiation transmission process for the solar tower power plant: From the heliostat field to the pressurized volumetric receiver

In the present work, a concentrating and collecting subsystem optical model for the solar tower power plant is fully developed and the corresponding solar radiation transmission process from heliostat field to the pressurized volumetric receiver (PVR) is simulated by the in-house developed Monte Carlo Ray Tracing (MCRT) code. Based on the above model, the optical efficiency of heliostat field and the local heat flux distribution within the SiC absorber are calculated, and then the influences of time and date, receiver mounting height and heliostats tracking error on the radiation transmission and absorption process are also investigated. The computation results show that, the heat flux distribution within the SiC absorber exhibits a great non-uniform characteristic, while the maximum heat flux density at the top area of the absorber is up to 2.58 × 109 W/m3. The variation tendencies of the field efficiency and the maximum heat flux density of the absorber are similar to that of the solar altitude angle during a day or a year. Furthermore, the annual mean field efficiency and the maximum heat flux of the absorber exhibit a rapid decreasing trend as the tracking error increases, but show a little increasing trend as the receiver mounting height increases.

Calculation and Distributive Characteristics of Solar Radiation in Henan Province

Taking factors such as astronomy, atmosphere, microgeography and local landscape that comprehensively affect solar radiation into account, we established a direct solar radiation (DSR) model on the accidented topography. Dynamics of DSR on accidented topography in Henan province were also statistically analyzed. Modeling results showed that highest DSR in Henan occurred between May and July, while lowest DSR occurred between December and February of the next year, and the multi-annual mean DSR in Henan province was 2127.7MJ/ m2. Impacts of local landscape on DSR on accidented topography in Henan province differs in different seasons. In winter half year, during which solar altitude angle is relatively low, this impact is more significant.

Determination of time and sun position system

Accurate calculations and recording of time either in local clock time or true solar time in regular daytime measurements of sun and sky radiation and light, in computer programs evaluating solar irradiance or sunlight and skylight illuminance currently apply differently defined solar hour angles as well as angularly determined solar altitude and azimuth coordinates. The historical basis of solar geometry used to construct sundials for the measurements of true solar time were gradually replaced during Middle Ages by spherical trigonometry relations of solar altitude and azimuth angles including solar declination, local geographical latitude and time changes in better precision. However, in different scientific and practical applications like in solar energy or daylight calculations are currently used several systems and formulae defining sun position and time which need to be unified and standardised in computer programs or measurement evaluations. Potential confusion and inconsistent results should be avoided, possible mistakes have to be checked and corrected after the valid ISO international standard. This paper discusses various approaches considering time and sun coordinates in different systems.

Design of Parabolic Trough Solar Collector (PTC) and Numerical Simulation for Improving the Efficiency

This research focus on two PTC designs, one in Runzhen-school, China (latitude 36.5°N, longitude110°E and 386m altitude) and the second PTC with tracking system. The study showed that, using one tube concentrate in the focal point with fixed PTC gives lower efficiency compared with using two vacuum tubes, as the variation of solar altitude angle is large. So using two focal points results a better heating. The new system uses PTC with sun tracking system to maximize solar radiation absorptions, that leading to increase the hot water temperature and has higher system efficiency. In addition, this system supplies two batteries by electricity coming from two solar-cells and it’s produced for the tracking system working during hours of sunlight. The photovoltaic electricity provided is stored in batteries and then used for tracking motion. The tracing motion receives orders from a control unit, which works at different voltage in two solar cells.

Performance comparison of a double-axis sun tracking versus fixed PV system

In the present study, performance results of two double axis sun tracking photovoltaic (PV) systems are analyzed after one year of operation. Two identical 7.9kWp PV systems with the same modules and inverters were installed at Mugla University campus in October 2009. Measured data of the PV systems are compared with the simulated data. The performance measurements of the PV systems were carried out first when the PV systems were in a fixed position and then the PV systems were controlled while tracking the sun in two axis (on azimuth and solar altitude angles) and the necessary measurements were performed. Annual PV electricity yield is calculated as 11.53MWh with 1459kWh/kWp energy rating for 28 fixed tilt angle for each system. It is calculated that 30.79% more PV electricity is obtained in the double axis sun-tracking system when compared to the latitude tilt fixed system. The annual PV electricity fed to grid is 15.07MWh with 1908kWh/kWp for the double axis sun-tracking PV system between April-2010 and March-2011. The difference between the simulated and measured energy values are less than 5%. The results also allow the comparison of different solutions and the calculation of the electricity output.

Photopia를 이용한 추적식 디쉬형 집광기의 배광분포 분석 및 자연채광 성능 예측

A set of candela distribution curves(CDCs) were generated for a fiber optic dish daylighting system by Photopia under clear sky conditions at different solar altitudes. The candela distribution curves were then exported to Radiance for photometric analysis of a windowless lecture room. Observations were made on the Radiance rendered illuminance images, which provided photo realistic scenes varying with solar altitudes. If no tracking error were assumed, the daylight collection efficiency of the system remained at a constant value of 68.4% during its operation. Higher the solar altitude angle, greater in photometric quantities were observed, which are represented by candela(cd) and total lumens(lm). In all cases considered, however, the angle of light distribution remained fixed reflecting the solar tracking feature of the system. The illuminance uniformity on the workplane lingered around 0.12, which is quite low. This is quite a contrast to its average value of 0.68 of the area directly below the terminal device (diffuser) of the system. The maximum illuminance of 1,340lux was obtained at a solar altitude of 80 degrees.

Based on High Resolution of Remote Sensing Data Mining Houses Information Extraction Methods Research

High resolution remote sensing images generally refer to image to the spatial resolution within 10m aerospace、aviation remote sensing images. The emergence of high-resolution images strengthened the ability to recognize the large scale features, especially for the extraction of houses information in mining area. High spatial resolution image has rich delicate texture feature, it is urgent to solution the problem of how to extract the features. The technology is very useful for statistic houses information、village relocation assessment and research of pressure coal status, providing important data basis for village relocation, statistics, assessment. Taking henan as a mining area for example, houses information extraction methods are discussed. This paper mainly research contents as followings: It is combined with the space texture information of high resolution imaging rich, using different methods to extract building information, including followings: First, ordinary image segmentation technology; this method is simple and feasible, but extracted housing information is not accurate. Second, the object-oriented method of feature extraction technology, visualization degree and extracting accuracy of this method is higher; Third, it has conducted the preliminary height extraction of the houses; according to the solar altitude angles and the shadow of the houses to calculate the height of the houses. And considering the influence of undulating terrain, using the terrain DEM data to analyze study area, finally determined the shadow length, and then used solar altitude angles to calculate houses height. Based on the verification, accuracy evaluation results show that houses contour information extraction accuracy is: accuracy of the number and area is over 80%, the total rate of wrong classifications is lower. Houses highly information extraction accuracy is within the 85%. The research methods are effective.

Design and Implementation on a Novel of Solar Double-Direction Tracking-Device

The development of solar energy tracking technology has important practical significance for promoting solar energy application. In the paper, double-direction tracking-device was designed based on the theory of calendar check tracking and worm gear mechanism, gear transmission mechanism, cam push-rod mechanism was used to achieve the function of “single driving, double-direction tracking” . So, the function of tracking solar azimuth and solar altitude angles was cleverly realized through controlling a single power. In the paper, design and manufacture of the device were completed by Solidworks software. Through the debugging experiment, the device’s advantages were proved of low energy consumption, high reliability, strong anti-interference ability, easy maintenance and suitable for a variety of small solar installations.

Design Issues and Contribution to Building Energy of Photovoltaic Roof

Building-integrated photovoltaics (BIPV) is a relatively recent new application of photovoltaic (PV) energy technologies whose energy output is affected by many design-related factors including PV module technologies, installation orientation, tilt and shadow range of solar panels. The shading analysis of a residential house’s PV roof in Beijing was conducted by using building analysis program Autodesk Ecotect 2010. Analysis result shows that there is no shadow on the PV roof from 9a.m to 4p.m in winter solstice when the solar altitude angle reaches minimum, which ensures almost no shading losses for the PV modules over the year. The differences in monthly energy output were compared in the case of different installation tilt of solar panels and PV module technologies. Finally, the contribution to the building energy of the PV roof was discussed. The results show that appropriate design and selection of PV modules can compensate for the energy requirements for building heating and cooling to some extent.

지형 효과를 고려한 지표면 태양광 분포

지형 효과가 포함된 태양복사 모델(GWNU)을 이용한 한반도의 태양광 자원지도를 개발하였다. 태양복사 모델의 입력 자료는 위성 관측 자료(MODIS, OMI, MTSAT-1R)와 수치 모델(RDAPS) 자료를 사용하였으며 특히 고해상도 지형 자료를 이용하여 지형 효과에 따른 한반도의 지표면 태양광 변화를 계산하였다. 계산 결과를 월 및 연 누적하여 분석하였을 때 여름철은 태양 고도각이 높아 지형 효과에 영향이 10% 이하로 적은 반면 겨울철은 20% 이상의 큰 차이가 나타났다. 또한 4 km 해상도의 지표면 태양광의 경우보다 1 km 해상도의 경우 지형 효과 포함에 따른 태양광 차이가 약 2배 정도 크게 나타났다. 즉 지표면에 도달하는 태양광을 정확히 모델링하기 위해서는 입력 자료뿐만 아니라 정확하고 고해상도의 지형 자료가 필연적이며 지형효과는 더욱 뚜렷이 나타나 실제와 유사할 것이다. A photovoltaic energy map that included a topography effect on the Korean peninsula was developed using the Gangneung-Wonju National University (GWNU) solar radiation model. The satellites data (MODIS, OMI and MTSAT-1R) and output data from the Regional Data Assimilation Prediction System (RDAPS) model by the Korea Meteorological Administration (KMA) were used as input data for the GWNU model. Photovoltaic energy distributions were calculated by applying high resolution Digital Elevation Model (DEM) to the topography effect. The distributions of monthly accumulated solar energy indicated that differences caused by the topography effect are more important in winter than in summer because of the dependency on the solar altitude angle. The topography effect on photovoltaic energy is two times larger with 1 km resolution than with 4 km resolution. Therefore, an accurate calculation of the solar energy on the surface requires high-resolution topological data as well as high quality input data.

Dust direct radiative effects on the earth-atmosphere system over east Asia: Early spring cooling and late spring warming

Focusing on three dust storms occurring in spring 2001, we developed a detailed aerosol parameterization scheme and integrated it in a radiative transfer model to characterize possible impacts of solar altitude angle on dust direct radiative effects over China desert regions and the North Pacific, using actual daily solar altitude angles. Increasing solar altitude angle from early spring (or winter) to late spring (or summer) leads to increase of positive clear sky radiative forcing, and decrease of negative radiative forcing due to dust aerosols at the top of the atmosphere. Because solar altitude angle increases from early to late spring, dust-clear sky radiative forcing may change from negative to positive at the top of atmosphere, showing a change from cooling to heating of the earth-atmosphere system over high-albedo deserts and nearby regions. Over low-albedo ocean negative clear sky radiative forcing by dust may decrease, suggesting a change from strong to weak cooling on the earth-atmosphere system. The impacts of solar altitude angle on cloudy sky radiative forcing due to dust are similar to those of clear sky. Impacts of low cloud on dust radiative forcing are the same as increasing surface albedo. This causes the transition of dust cooling effects into heating effects over deserts to occur earlier, and causes decrease of negative radiative forcing over the ocean and even cause a change from weak negative radiative forcing to weak positive forcing over local areas. Even in the same East Asian desert regions and nearby areas, the strength and sign of the radiative forcings depend on storm dates and thus solar altitude angle. The nearer to early spring (or winter) a dust storm occurs, the easier it leads to negative radiative forcing at the top of atmosphere, which indicates cooling effects on the earth-atmosphere system. In contrast, the nearer to late spring (or summer) a dust storm occurs, the easier it leads to positive radiative forcing at the top of atmosphere, showing heating effects. Over East Asian deserts and nearby regions, dust layers may be regarded as cooling sources in early spring (winter) and warming sources in late spring (summer).

SOLAR ENERGY FLUX INCIDENT ON A HORIZONTAL PLANE OF DIFFERENT EGYPTIAN LOCATIONS FOR AGRICULTURAL APPLICATIONS

Solar energy is the main parameter, which affects both photovoltaic pumps and crops evapo-transpiration. A micro computer program derived for mapping the incident solar energy over Egypt (22o to 32o and 24o to 38o latitude and longitude angles, respectively). The derived model transforms the solar altitude angle to solar radiation intensity, which integrated between sunrise and sunset to compute the incident solar energy. The model was validated with the measured solar energy with average deviation percent of -3.5 %. The daily average solar energy flux incident on a horizontal plane was 5.72 kWh/m2/day.

Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements

Relative humidity (RH) measurements from Vaisala RS92 radiosondes are widely used in research and operational applications, but their accuracy is not well characterized as a function of height, RH, and time of day (or solar altitude angle). This study compares RS92 RH measurements to simultaneous water vapor measurements from three reference instruments of known accuracy. Cryogenic frost point hygrometer measurements are used to characterize the RS92 accuracy above the 700‐mbar level, microwave radiometer measurements characterize the RS92 accuracy averaged over essentially the lower troposphere, and the RS92 accuracy at the surface is characterized by a system of 6 RH probes with National Institute of Standards and Technology–traceable calibrations. The three RS92 accuracy assessments are combined to yield a detailed estimate of RS92 accuracy for all RH conditions from the surface to the lowermost stratosphere. An empirical correction is derived to remove the mean bias error, yielding corrected RS92 measurements whose bias uncertainty is independent of height or RH and is estimated to be ±4% of the measured RH value for nighttime soundings and ±5% for daytime soundings, plus an RH offset uncertainty of ±0.5% RH that is significant for dry conditions. The accuracy of an individual RS92 sounding is further characterized by the 1‐σ “random production variability,” estimated to be ±1.5% of the measured RH value. The daytime bias correction must be used with caution, as it is only accurate for clear‐sky or near‐clear conditions owing to the complicated effect of clouds on the solar radiation error.

A study on parameterization of surface albedo over grassland surface in the northern Tibetan Plateau

The relationship of surface albedo with the solar altitude angle and soil moisture is analyzed based on two-year (January 2002 to December 2003) observational data from the AWS (Automatic Weather Station) at MS3478 in the northern Tibetan Plateau during the experimental period of CEOP/CAMP-Tibet (Coordinated Enhanced Observing Period Asia-Australia Monsoon Project on the Tibetan Plateau). As a double-variable (solar altitude angle and soil moisture) function, surface albedo varies inconspicuously with any single factor. By using the method of approximately separating the double-variable function into two, one-factor functions (product and addition), the relationship of albedo with these two factors presents much better. The product and additional empirical formulae of albedo are then preliminarily fitted based on long-term experimental data. By comparison with observed values, it is found that the parameterization formulae fitted by using observational data are mostly reliable and their correlation coefficients are both over 0.6. The empirical formulae of albedo though, for the northern Tibetan Plateau, need to be tested by much more representative observational data with the help of numerical models and the retrieval of remote sensing data. It is practical until it is changed into effective parameterization formulae representing a grid scale in models.