Scintillometer Intercomparison Study—Continued

An earlier study by one of the authors reported significant differences of up to 21% in linear regression slopes between six Kipp & Zonen large-aperture scintillometers. In this note, the consistency of this increasingly popular instrument for measuring sensible heat fluxes at the km scale was quantified by comparing measurements from four Scintec boundary-layer scintillometers and one large-aperture scintillometer over nearly identical transects. The Kipp & Zonen instrument’s sensible heat fluxes were more than 20% larger than those from the Scintec instruments, while the difference in regression slopes amongst the Scintec instruments was 3% or less.     

Evaluation of Modeled Spatially and Temporarily Highly Resolved Emission Inventories of Photosmog Precursors for the City of Augsburg: The Experiment EVA and Its Major Results

Emission inventories of NO_x, CO, and individual volatile organic compounds (VOC), highly resolved in space and time, belong to the most important input parameters for chemistry and transport models (CTM) used for ozone prediction. Because of the decisive influence of the input quality on the outcome of CTM simulations, the quality of emission inventories has to be assessed. This paper presents an experimental evaluation of the highly resolved emission inventories for the city of Augsburg. The emissions of the city, determined in March and October 1998 using mass balance and tracer techniques, and derived from the measured receptor concentration ratios, were compared with emissions modeled from an emission inventory. The modeled CO emissions were in agreement with the measured ones within the combined experimental and model uncertainties. More detailed CO emission model simulations suggest that the tendency of calculated CO emissions being smaller than the measured ones may be due to higher traffic activity in Augsburg. Modeled NO_x emissions were in agreement with the measured ones within the combined experimental and model uncertainties. Large deviations between modeled and measured values have been found for some individual NMHC compounds. The measured NMHC emission fingerprints were dominated by mobile sources. Substantial model predicted NMHC emissions from the solvent use could not be detected by measurements suggesting that they may not be correctly represented by the emission model.     

Atmospheric and Coupled Model Intercomparison in Terms of Amplitude—Phase Characteristics of Surface Air Temperature Annual Cycle

1. Introduction In spite of the progress achieved in global climatemodelling during the last few decades, the models stillshow considerable errors even for the surface air tem-perature ?eld (Covey et al., 2000; IPCC, 2001; Lam-bert and Boer, 2001). As i…     

Intercomparison of remote measurements of stratospheric NO and NO2

During the 1982 and 1983 Balloon Intercomparison Campaigns, the vertical profile of stratospheric NO₂ was measured remotely by nine instruments and that of NO by two. Total overhead columns were measured by two more instruments. Between 30 and 35km, where measurements overlapped, agreement between NO profiles was within ±30%, which is better than the accuracies claimed by the experimenters. Between 35 and 40km there was similarly good agreement between NO₂ profiles, but below 30km, differences of greater than a factor three were found. In the second Campaign, NO₂ values from most instruments agreed within their quoted errors, except that the Oxford radiometer gave much lower values; but the first Campaign and the column measurements show a more uniform spread of results.These differences below 30km could not be resolved, but new laboratory measurements are planned which should do so.     

Intercomparison of Boron Isotope and Concentration Measurements. Part II: Evaluation of Results

The Istituto di Geoscienze e Georisorse (IGG), on behalf and with the support of the International Atomic Energy Agency (IAEA), prepared eight geological materials (three natural waters and five rocks and minerals), intended for a blind interlaboratory comparison of measurements of boron isotopic composition and concentration. The materials were distributed to twenty seven laboratories - virtually all those performing geochemical boron isotope analyses in the world -which agreed to participate in the intercomparison exercise. Only fifteen laboratories, however, ultimately submitted the isotopic and/or concentration results they obtained on the intercomparison materials. The results demonstrate that interlaboratory reproducibility is not well reflected by the precision values reported by the individual laboratories and this observation holds true for both boron concentration and isotopic composition. The reasons for the discrepancies include fractionations due to the chemical matrix of materials, relative shift of the zero position on the δ¹¹B scale and a lack of well characterized materials for calibrating absolute boron content measurements. The intercomparison materials are now available at the IAEA (solid materials) and IGG (waters) for future distribution.     

The Balloon Intercomparison Campaigns an introduction and overview

The Balloon Intercomparison Campaigns of 1982 and 1983 compared balloon-borne sensors of HCl, HNO3, NO2, NO and O3, and measured many other stratospheric constituents. Most sensors were remote rather than in-situ. In the 1982 campaign, three large gondolas were successfully launched from Palestine, Texas on the same day; in the 1983 campaign, four gondolas were launched within 3 days. Accompanying papers describe the results of these successful intercomparisons.