Evaluation of thermal indices for their applicability in obstacle-resolving meteorology models

A thermally comfortable design of outdoor spaces favors social interaction and outdoor activities and thus contributes to the overall well-being of urban dwellers. To assess such a design, obstacle-resolving models (ORM) combined with thermal indices may be used. This paper reviews existing thermal indices to identify those suitable for thermal comfort assessment with ORMs. For the identification, 11 criteria and six index features are derived from literature analysis focusing on the characteristics of human environmental heat exchange, of outdoor urban environments, and of ORMs. An air temperature weighted world population distribution is calculated to derive the minimal air temperature range; a thermal index should cover to be applicable to 95% of the world population. The criteria are applied to 165 thermal indices by reviewing their original publications. Results show that only four thermal indices are suitable to be applied globally in their current form to various outdoor urban environments and also fulfill the requirements of ORMs. The evaluation of the index features shows that they differ with respect to the comprehensiveness of the thermophysiological model, the assessed human response, the treatment of clothing and activity, and the computational costs. Furthermore, they differ in their total application frequency in past ORM studies and in their application frequency for different climatic zones, as a systematic literature analysis of thermal comfort studies employing ORMs showed. By depicting the differences of the thermal indices, this paper provides guidance to select an appropriate thermal index for thermal comfort studies with ORMs

05/18/1993 - Eastern\u27s 1993 All Student Show Winner Laura Brahos.pdf

This paper reports on the stages forming a model evaluation protocol for urban flow and dispersion models proposed within the COST Action 732 on "Quality Assurance and Improvement of Micro-Scale Meteorological Models". It discusses the different components forming model evaluation with emphasis on validation and implementation of the protocol for the test case Mock Urban Setting Test (MUST). The protocol was proposed with building-resolving models in mind, but integral models have also been included. The suggested approach can be used for further micro-scale model evaluation and for the standardisation of their applications

The Fragmented Mitochondrial Ribosomal RNAs of Plasmodium falciparum

The mitochondrial genome in the human malaria parasite Plasmodium falciparum is most unusual. Over half the genome is composed of the genes for three classic mitochondrial proteins: cytochrome oxidase subunits I and III and apocytochrome b. The remainder encodes numerous small RNAs, ranging in size from 23 to 190 nt. Previous analysis revealed that some of these transcripts have significant sequence identity with highly conserved regions of large and small subunit rRNAs, and can form the expected secondary structures. However, these rRNA fragments are not encoded in linear order; instead, they are intermixed with one another and the protein coding genes, and are coded on both strands of the genome. This unorthodox arrangement hindered the identification of transcripts corresponding to other regions of rRNA that are highly conserved and/or are known to participate directly in protein synthesis.The identification of 14 additional small mitochondrial transcripts from P. falciparum and the assignment of 27 small RNAs (12 SSU RNAs totaling 804 nt, 15 LSU RNAs totaling 1233 nt) to specific regions of rRNA are supported by multiple lines of evidence. The regions now represented are highly similar to those of the small but contiguous mitochondrial rRNAs of Caenorhabditis elegans. The P. falciparum rRNA fragments cluster on the interfaces of the two ribosomal subunits in the three-dimensional structure of the ribosome.All of the rRNA fragments are now presumed to have been identified with experimental methods, and nearly all of these have been mapped onto the SSU and LSU rRNAs. Conversely, all regions of the rRNAs that are known to be directly associated with protein synthesis have been identified in the P. falciparum mitochondrial genome and RNA transcripts. The fragmentation of the rRNA in the P. falciparum mitochondrion is the most extreme example of any rRNA fragmentation discovered

Numerical Dispersion of Gravity Waves

When atmospheric gravity waves are simulated in numerical models, they are not only dispersive for physical but also for numerical reasons. Their wave properties (e. g., damping or propagation speed and direction) can depend on grid spacing as well as on the numerical schemes. In this work numerical dispersion relations for atmospheric gravity waves are theoretically derived as well as experimentally measured using the anelastic Mesoscale Transport and Stream model (METRAS). Both the theoretical solution and the numerical model show a retardation of gravity waves with decreasing grid resolution. Furthermore, the influence of a Shapiro seven-point filter is analyzed. The Shapiro seven-point filter causes damping of the shorter waves. Therefore, shorter waves can better be simulated without the seven-point filter. The influence of different advection schemes is analyzed by prescribing a background wind. A first-order upstream scheme and second- and third-order flux integrated essentially nonoscillatory (FIENO) schemes are used. As expected, the damping is the smaller the higher the order of the scheme. The numerical dispersion has severe consequences, when nonuniform grid spacing is used. Waves moving from the fine grid to the coarse are reflected because of numerical dispersion if they are only poorly resolved on the coarse grid. In tests with different refinement factors and wave lengths the reflection is found to be the larger the greater the refinement factor. The results show that refinement factors larger than 3 should not be used with nonuniform grid spacing or two-way nested grids

Evaluation of a Mesoscale Model with Different Surface Parameterizations and Vertical Resolutions for the Bay of Valencia

Two different setups of the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) are used and the results of 71 forecasts are evaluated with a focus on the accuracy of meteorological surface data including wind, temperature, dewpoint temperature, and pressure. The forecasts, which cover the Valencia coastal region with a 3-km grid, are nested into two coarser grids of 9- and 27-km mesh size. The integration time is 18 h. The ability to correctly simulate the sea breeze plays a major role for this area. Different model setups are used: in the M1 simulations 34 atmospheric vertical sigma levels combined with a five-layer land surface model (5L LSM) are applied for the first half of the year 2006. In total, 52 atmospheric vertical sigma levels and the Noah LSM are used for the second half of 2006 (setup M2). The accuracy improves for all meteorological parameters except pressure with the M2 setup. However, negative biases of temperature, dewpoint temperature, and wind speed worsen. Detailed analysis of results for 4 days simulated with all combinations of vertical resolutions and LSMs shows that the increase of vertical resolution is responsible for the improved forecast performance. The Noah LSM generally improves temperature performance, but reduces the performance of all other parameters, especially for days with sea-breeze conditions. The Noah LSM performs better than the 5L LSM scheme only for a day driven by synoptic changes

The influence of emission changes on ozone concentrations and nitrogen deposition into the southern North Sea

The impact of changes in amount of emission for NOx (Nitrogen monoxide NO + Nitrogen dioxide NO2) and NMVOC (Non Methane Volatile Organic Compounds) on concentrations of ozone (O-3), NOx, nitric acid (HNO3) and on nitrogen deposition in the area of the southern North Sea are investigated. One reference case for the period 16 June till 20 June, 1998 and six emission scenarios are calculated. Spatial and temporal emission patterns are kept and overall emission factors are used that correspond to years 1998 (reference), 1970 and 2010. Some more artificial emission scenarios are constructed to investigate the effect of a changed ratio of NOx to NMVOC emissions. The meteorology is unchanged for all scenarios. The studies are performed with the meteorology/chemistry model M-SYS (METRAS/MECTM) including a simple aerosol chemistry and using a horizontal resolution of 8 km. Changes in emissions of NMVOC and NOx cause non-linear changes in O-3, NOx and HNO3 concentrations. The concentration changes depend on emission changes and on changes in the ratio of NMVOC to NOx emissions. The whole area, over land and water, turns out to be in the NMVOC limited regime. Ozone scenario concentrations linearly depend on the ratio of NMVOC to NOx emissions. NOx concentrations linearly depend on changes in the total emissions of NOx and NMVOC. They are inversely related to changes in the ratio of NMVOC to NOx emissions. HNO3 concentrations mainly depend on the total emission changes with NOx emission changes being of doubled relevance compared to NMVOC emission changes. The same relation is found for nitrogen deposition. Compared to mean ozone concentrations from the reference case, higher (lower) NOx emissions reduce (increase) ozone concentrations, while HNO3 concentrations are increased (reduced). In contrast, reduced (increased) NMVOC emissions reduce (increase) both, ozone and HNO3 concentrations and, in addition, the nitrogen deposition

A statistical model for the urban heat island and its application to a climate change scenario

A linear statistical model relating the nocturnal urban heat island (UHI) intensity of Hamburg with meteorological conditions is constructed from observations taken by the German Meteorological Service (DWD). To find the appropriate predictors the relationship between different meteorological variables and the UHI of Hamburg is analyzed. Results and physical plausibility suggest that cloud cover, wind speed and relative humidity are the relevant variables and can be used to construct a statistical model. The parameters for the statistical model are determined with the generalized least square method. With the help of the statistical model up to 42% of the UHI variance can be explained. The statistical model is then used to statistically downscale results from climate runs of the regional climate models (RCM) REMO and CLM. Both RCMs were driven with the A1B SRES emission scenario runs of the global climate model ECHAM5/MPI-OM. The resulting values for the future UHI are analyzed with respect to monthly averages and the frequency distribution. Results show that changes in the UHI are different for the different months. Significant change (decrease of UHI) in the results of both RCMs and for both realizations of the A1B scenario can be found for April in at the middle and the end of the century and in December at the end of the century. For the summer months which are most relevant to the development of adaption strategies the results differ between the RCMs. REMO results show no significant changes for the summer, while analyses of CLM suggest significant increase in July and August. The frequency distribution of the summer UHI shows no significant changes for REMO and only in one realization of CLM a significant increase in moderate and strong UHI days can be found for the end of the century. Copyright (C) 2011 Royal Meteorological Societ

Long-term changes and regional differences in temperature and precipitation in the metropolitan area of Hamburg

Climate changes and the urban climate of the 'green city' Hamburg and its metropolitan region are analyzed using observational data for temperature and precipitation. Values for Hamburg's synoptic site HH-Fuhlsbuttel start in 1891 and are used to determine climate changes. Additional data from up to 45 climate stations are used to analyze the different aspects of the regional climate and urban effects on the temperature [urban heat island (UHI)] and precipitation [urban precipitation impact (UPI)]. The analysis of the long-term data shows that the climate has already changed. Annual precipitation significantly increases similar to 0.8 mm/year when focusing on years 1891-2007 and similar to 1.3 mm/year for 1948-2007. Precipitation increases are largest in November through March and March as well as June for 1978-2007. For April and July of this period, a precipitation decrease is found. The precipitation distribution shows that moderate daily precipitation amounts (10 mm/day have increased by 20% in the same period. Average temperatures significantly increase by 0.07 K/decade (1891-2007), 0.19 K/decade (1948-2007). 0.6 K/decade (1978-2007) with largest significant increases in fall. For the UHI, it is found that the average temperature is higher up to 1.1 K in the densely build-up city area than outside. Values are about halved for more green urban areas but also depend on more local impacts. The minimum temperatures are up to 3 K higher and maximum temperatures slightly lower in the inner city than in the rural during summer. The winter temperatures are higher throughout the urban area. The UHI differences depend on wind speed; this dependence is best described by using the inverse square root of the wind speed. Classification using different wind directions shows that the precipitation is significantly higher (5-20%) for downwind of urban areas compared with the upwind side. Copyright (C) 2009 Royal Meteorological Societ