The 1997 North American Interagency Intercomparison of Ultraviolet Spectroradiometers Including Narrowband Filter Radiometers

The fourth North American Intercomparison of Ultraviolet Monitoring Spectroradiometers was held September 15 to 25, 1997 at Table Mountain outside of Boulder, Colorado, USA. Concern over stratospheric ozone depletion has prompted several government agencies in North America to establish networks of spectroradiometers for monitoring solar ultraviolet irradiance at the surface of the Earth. The main purpose of the Intercomparison was to assess the ability of spectroradiometers to accurately measure solar ultraviolet irradiance, and to compare the results between instruments of different monitoring networks. This Intercomparison was coordinated by NIST and NOAA, and included participants from the ASRC, EPA, NIST, NSF, SERC, USDA, and YES. The UV measuring instruments included scanning spectroradiometers, spectrographs, narrow band multi-filter radiometers, and broadband radiometers. Instruments were characterized for wavelength accuracy, bandwidth, stray-light rejection, and spectral irradiance responsivity. The spectral irradiance responsivity was determined two to three times outdoors to assess temporal stability. Synchronized spectral scans of the solar irradiance were performed over several days. Using the spectral irradiance responsivities determined with the NIST traceable standard lamp, and a simple convolution technique with a Gaussian slit-scattering function to account for the different bandwidths of the instruments, the measured solar irradiance from the spectroradiometers excluding the filter radiometers at 16.5 h UTC had a relative standard deviation of ±4 % for wavelengths greater than 305 nm. The relative standard deviation for the solar irradiance at 16.5 h UTC including the filter radiometer was ±4 % for filter functions above 300 nm.     

Sugarcane model intercomparison: Structural differences and uncertainties under current and potential future climates

Sugarcane is one of the world's main carbohydrates sources. We analysed the APSIM-Sugar (AS) and DSSAT/CANEGRO (DC) models to determine their structural differences, and how these differences affect their predictions of crop growth and production. The AS model under predicted yield at the hotter sites, because the algorithm for computing the degree-days is based in only one upper cardinal temperature. The models did not accurately predict canopy and stalk development through time using growth parameters values developed from observed data, in combination with previously determined RUE for the cultivars. In response to elevated CO₂, both predicted higher yields, although AS showed higher sensitivity to CO₂ concentration, rainfall and temperature than DC. The Mean of simulations from both models produced better estimations than predictions from either model individually. Thus, applying the two models (in their current form) is likely to give the more accurate predictions than focusing on one model alone.     

国产珠状温度传感器对比分析

通过比对试验,采取同球比对施放方式,选择德国GRAW探空仪作为比对标准,使用总共12次同球比对数据,对中国长峰、华云和大桥3种型号探空仪的珠状电阻温度传感器开展比对分析.经典型个例分析与统计分析表明:3个型号国产探空仪高空温度廓线与德国GRAW探空仪具有较好的整体一致性,温度测量夜间性能均好于白天;长峰探空仪温度探测性能随高度变化比较稳定,而华云探空仪与大桥探空仪性能相仿,均随高度性能下降,尤其是30km以上高空;长峰探空仪温度探测整体性能最好,相对系统误差在0.2℃左右;而华云探空仪与大桥探空仪误差可达1℃,且均表现为整体上温度测值偏低.体积较小的珠状温度传感器将是未来高空温度探测的一个好的选择,下一步需要改善华云探空仪与大桥探空仪温度传感器表面涂层工艺,两者的温度辐射订正算法也需要进一步完善.     

The 1996 North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers

Concern over stratospheric ozone depletion has prompted several government agencies in North America to establish networks of spectroradiometers for monitoring solar ultraviolet irradiance at the surface of the Earth. To assess the ability of spectroradiometers to accurately measure solar ultraviolet irradiance, and to compare the results between instruments of different monitoring networks, the third North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers was held June 17–25, 1996 at Table Mountain outside Boulder, Colorado, USA. This Intercomparison was coordinated by the National Institute of Standards and Technology (NIST) and the National Oceanic and Atmospheric Administration (NOAA). Participating agencies were the Environmental Protection Agency; the National Science Foundation; the Smithsonian Environmental Research Center; the Department of Agriculture; and the Atmospheric Environment Service, Canada. The spectral irradiances of participants’ calibrated standard lamps were measured at NIST prior to the Intercomparison. The spectral irradiance scales used by the participants agreed with the NIST scale within the combined uncertainties, and for all lamps the spectral irradiance in the horizontal position was lower than that in the vertical position. Instruments were characterized for wavelength uncertainty, bandwidth, stray-light rejection, and spectral irradiance responsivity, the latter with NIST standard lamps operating in specially designed field calibration units. The spectral irradiance responsivity demonstrated instabilities for some instruments. Synchronized spectral scans of the solar irradiance were performed over several days. Using the spectral irradiance responsivities determined with the NIST standard lamps, the measured solar irradiances had some unexplained systematic differences between instruments.     

上海SSDL参加国际剂量比对总结（1983—1994）

文章总结了上海ＳＳＤＬ自１９８３年至１９９４年期间参加国际原子能机构组织的各种剂量比对活动的目的、方法和结果．十多年来的比对数据表明，上海ＳＳＤＬ在放射治疗水平、辐射加工水平和个人剂量防护水平及对Ｘ、γ射线吸收剂量测量和控制等方面以满意的量值准确度与国际标准量值相统一。文章对测量误差进行了讨论．     

Calibration of Radon-222 Reference Instrument in Sweden

A simple procedure to calibrate and characterize a recently developed radon-222 reference instrument is described. The system, which is now used as the official national Swedish reference, is quick and easy to use. Systematic as well as random errors are smaller than in an earlier system and compare well with other systems, as has been shown in a number of international intercomparison measurements.     

Intramural Comparison of NIST Laser and Optical Fiber Power Calibrations

The responsivity of two optical detectors was determined by the method of direct substitution in four different NIST measurement facilities. The measurements were intended to demonstrate the determination of absolute responsivity as provided by NIST calibration services at laser and optical-communication wavelengths; nominally 633 nm, 850 nm, 1060 nm, 1310 nm, and 1550 nm. The optical detectors have been designated as checks standards for the purpose of routine intramural comparison of our calibration services and to meet requirements of the NIST quality system, based on ISO 17025. The check standards are two optical-trap detectors, one based on silicon and the other on indium gallium arsenide photodiodes. The four measurement services are based on: (1) the laser optimized cryogenic radiometer (LOCR) and free field collimated laser light; (2) the C-series isoperibol calorimeter and free-field collimated laser light; (3) the electrically calibrated pyroelectric radiometer and fiber-coupled laser light; (4) the pyroelectric wedge trap detector, which measures light from a lamp source and monochromator. The results indicate that the responsivity of the check standards, as determined independently using the four services, agree to within the published expanded uncertainty ranging from approximately 0.02 % to 1.24 %.     

An intercomparison study of the determination of glyphosate, chlormequat and mepiquat residues in wheat

An intercomparison study of the determinations of glyphosate, chlormequat and mepiquat residues in cereals was performed. Four samples comprising one blank, two incurred and one spiked sample were sent to six participating laboratories. For glyphosate, two laboratories reported considerably lower results than the other four. One of the two laboratories with low results also reported low recoveries. The results of a sample spiked with 0.80 mg kg^-1 glyphosate and an incurred sample, ranged from 0.23-0.87 mg kg^-1 and 0.11-0.25 mg kg^-1 respectively. The strong correlation between the two samples (r² = 0.95) indicates a systematic between-laboratory variation. Several different principles were used for the analysis of glyphosate using different clean-up techniques and GC/MS, HPLC-fluorescence or LC/MS for detection. The results of the chlormequat residues showed more consistency. All but one laboratory obtained comparable results. However the correlation between the results for the sample spiked with 0.38 mg kg^-1 (range: 0.26-0.65 mg kg^-1) and the incurred samples (range: 0.19-0.45 and 0.15-0.23 mg kg^-1, respectively) again showed a strong correlation (r² = 0.99 and 0.88) indicating a systematic component. For mepiquat, results above the limit of quantification were only reported for the spiked sample. The results ranged from 0.29-0.92 mg kg^-1 (spiked concentration = 0.38 mg kg^-1). Three laboratories had results that deviated less than 25% from the fortified concentration. Two laboratories reported results 38% and 141% above the fortified concentration, respectively.     

建材中放射性核素含量比对测量结果

介绍了参加建材样品中放射性核素含量检测比对的测量和质控方法及结果。用高纯锗谱仪测量比对样品,检测结果与参考值符合较好,比对合格。证明了本实验室检测方法是可靠的,检测结果是可信的。