TM5 and MOCAGE), CHIMERE has higher horizontal resolution and presents a more comprehensive chemical mechanism that is only similar, as VOCs and their oxidation products are concerned, to the one used in MOCAGE. Low vegetation with superfi- cial roots probably underwent water deficit during spring–summer 2003, which is ex- pected to strongly decrease stomatal ozone uptake. Since such dependence was not
Correct boundary conditions are very important to ac- curately calculate UK surface ozone and previous work has demonstrated that European transport and trans-Atlantic transport are well simulated by the EMEP model (e.g. Jon- son et al., 2006). Figures 17 and 18 show that the import of ozone from outside the UK was typically the most im- portant factor contributing to the very high surface ozone in SE England during August 2003. Import is important on different days at different locations (Fig. 18). This is evi- dent for the 6 and 10 August (Fig. 18) when localised in- cursions ofEuropean-emitted precursors and/or ozone itself were present. This agrees with Solberg et al. (2008), who re- ported that the higher values of ozone observed over SE Eng- land were often the result of import from the continent. How- ever, one ofthe conclusions in Solberg et al. (2008) was that Portuguese forest fires were a possible cause for the unusu- ally high surface ozone over Europe. The EMEP4UK model was able to simulate high surface ozone without emissions from forest fires, further development ofthe EMEP model to include forest fire emissions should be undertaken in order to properly assess their impact on ozone over the UK.
Due to its mean tropospheric lifetime of about 2 months, CO can be transported globally and is often used as a tracer for long-range pollution transport (e.g. Li et al., 2002; Liu et al., 2003; Duncan and Bey, 2004; Law and Stohl, 2007; Shindell et al., 2008; Drori et al., 2012; Cristofanelli et al., 2013). Tropospheric CO builds up over the Northern Hemi- sphere (NH) during wintertime, when emissions are high and photochemical activity is low. The surface CO mixing ratios peak around March, with typical values measured at back- ground stations of around 150 ppb. Above and downwind of strongly polluted areas in East Asia, North America, or Eu- rope, wintertime mixing ratios are significantly higher. Val- ues above 1000 ppb have been reported over eastern China (e.g. Wang et al., 2004; Gao et al., 2005). Summertime mix- ing ratios are significantly lower, with NH background val- ues going down to 100 ppb due to the faster photochemical depletion of CO. In some regions, the highest mixing ratios are measured from August to October, largely influenced by emissions from biomass burning (Worden et al., 2013). Trop- ical and Southern Hemisphere (SH) mixing ratios are gener- ally lower (values as low as 35–40 ppb have been observed in remote areas) due to the lower amount of anthropogenic emissions and the large ocean surface (Novelli et al., 1998; Duncan et al., 2007).
Abstract. We present an overview ofthe coordinated global numerical modelling experiments performed during 2012– 2016 by the Task Force on Hemispheric Transport ofAirPollution (TF HTAP), the regional experiments by theAir Quality Model Evaluation International Initiative (AQMEII) over Europe and North America, and theModel Intercom- parison Study for Asia (MICS-Asia). To improve model es- timates ofthe impacts of intercontinental transport ofairpollution on climate, ecosystems, and human health and to answer a set of policy-relevant questions, these three ini- tiatives performed emission perturbation modelling experi- ments consistent across theglobal, hemispheric, and conti- nental/regional scales. In all three initiatives, model results are extensively compared against monitoring data for a range of variables (meteorological, trace gas concentrations, and aerosol mass and composition) from different measurement platforms (ground measurements, vertical profiles, airborne measurements) collected from a number of sources. Ap- proximately 10 to 25 modelling groups have contributed to each initiative, and model results have been managed cen- trally through three data hubs maintained by each initiative.
smoke plume. Wildfire aerosols participate to increase the atmospheric stability and to enhance hot and dry conditions during summer 2003 (Pace et al., 2005; Hodzic et al., 2007). The objective of this paper is to investigate for the first time the vertical extension and the origins of pollutants dur- ing the2003heatwave with a set of 162 profiles of ozone, carbon monoxide and relative humidity performed from 16 July to 31 August 2003 by 3 MOZAIC airliners over Frank- furt (Measurements of OZone, water vapour, carbon monox- ide and nitrogen oxides by Airbus In-service airCraft, http:// mozaic.aero.obs-mip.fr/web/), (Marenco et al., 1998). First, the main characteristics and the anomalies of meteorological parameters (temperature, wind speed, relative humidity) and of reactive gas concentrations (ozone, carbon monoxide and total nitrogen oxide) in vertical profiles above Frankfurt are investigated in relation to the meteorological situation and to the climatology. Then a Lagrangian dispersive model is used to investigate the origins ofthe main anomalies of pol- lutants duringthe episode. Section 2 describes the methods and measurements used in this paper. The meteorological situation is described in Sect. 3. Based on MOZAIC mea- surements and back-trajectory calculations, a description ofthe vertical extension of chemical tracers is documented in Sect. 4 together with the investigation of their origins. Sec- tion 5 provides a discussion on the relative contribution of forest fires versus other anthropogenic emissions to the CO levels observed by the MOZAIC aircraft in Frankfurt.
Simulationsof atmospheric POP transport were made using the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998, 2005; Stohl and Thomson, 1999). FLEX- PART was driven with analyses from theEuropean Centre for Medium-Range Weather Forecasts (ECMWF, 1995) with 1 ◦ ×1 ◦ resolution (derived from T319 spectral truncation). Analyses at 00:00, 06:00, 12:00 and 18:00 UTC, and 3-h forecasts at 03:00, 09:00, 15:00 and 21:00 UTC were used. There are 23 ECMWF model levels below 3000 m, and 91 in total. FLEXPART calculates the trajectories of so-called tracer particles and accounts for turbulence, convection, de- position (wet and dry) and atmospheric reaction by hydroxyl (OH) radicals (Eckhardt et al., 2009). It was run in backward mode, in order to identify the source regions ofair pollu- tants at a particular site (Stohl et al., 2003; Seibert and Frank, 2004). These were found by following all 4 million particles equally released over the sample duration, 20 days backward in time. These source regions are expressed as emission sen- sitivities (ES) in the footprint layer (0–100 m above ground) during each deployment period at different sites. The ES unit is nanoseconds per cubic meter, which is the residence time ofair masses normalized by the volume. The ES maps for the footprint layer thus illustrates were theair mass had the abil- ity to collect pollutants from sources near the ground. Mul- tiplying this ES with emission fluxes from the PCB-28 emis- sion inventory (Breivik et al., 2007) yields the geographical distribution of sources contributing to the simulated concen- tration at the given measurement site. Emission contributions (EC), which gives the simulated air concentration at the re- ceptor, may then be obtained by areal integration. For further details we refer to the original publications listed above.
The following initial assumptions were adopted: the sen- sible heat production to the chicken is uniform and constant; the latent heat produced by the chicken is uniform and con- stant; sensible heat gained by mechanical, electrical and other sources, such as motor and lights are negligible; the sensible heat resulting from the absorption of solar irradiation in the interior ofthe installation is negligible; the sensible heat transferred through the building construction, such as roof, walls, doors, etc, are negligible, theheat transferred to the floor through the region near the building perimeter is neg- ligible; the mass air flow is constant, and the cooling sys- tem works in a uniform and constant way.
The NAO exerts a clear influence on the atmospheric dis- tribution of aerosol pollution. The NAO phase strongly af- fects the magnitude and direction of moisture transport, in- cluding water-soluble aerosols emitted in North America and Europe, over the Atlantic Ocean. The NAO also affects the location and extent ofthe spatial pattern of precipitation. During high NAO index periods, drier than average condi- tions occur over much of central and southern Europe, the Mediterranean and parts ofthe Middle East, whereas more precipitation than average falls over a region from Iceland through Scandinavia (Hurrell, 1995). As precipitation is the main mode of removal of water-soluble aerosols from the atmosphere, the distribution of particulate pollutants, espe- cially from Europe, is indirectly influenced by the NAO. The response ofthe aerosols is relatively strong, as they are in- fluenced both by NAO-related transport and wet deposition anomalies, whereas CO is unaffected by precipitation.
The high rate ofthe population growth has challenged the metropolitan’s infrastructure enormously. In this context, transportation has been recognized as a highest problem and it is now being discussed in order to cope with the increasing population growth. Phoenix has been described as an automotive centered city by primarily focusing on creating a grid of streets for automobiles. It seemed like a phenomenal idea to the time ofthe invention ofthe car. Today with the fight against the urban traffic emitted greenhouse gases, city leaders search for alternative solutions in order to decrease airpollution and also keep up with the increasing population. In 2005, the cities of Phoenix, Mesa and Tempe have started a Transit-Oriented Development program, in order to create a more pedestrian friendly environment in those areas with all three aspects of sustainability in mind - environmental, economic and social. This program involved a 20 mile light rail track stretching from Mesa across Tempe into Central Phoenix. The project initially showed extreme economic and social benefits by a heavy increase of development around the light rail. An expansion ofthe light rail further into Phoenix, Mesa and even Scottsdale might not be a bad idea seeing the benefits the Transit-Oriented Development program brought (MICHAEL; UPCHURCH, 2004).
WRF-ARW ver. 2.2.1 (Skamarock et al., 2005) is used to prepare meteorological fields. NCEP Final Analysis data are used to provide initial and boundary conditions, and to per- form grid nudging. CMAQ ver. 4.6 (Byun et al., 2006) is used to simulate pollutant concentrations in the atmosphere. The default datasets provided with CMAQ are used as initial concentrations in all domains and boundary concentrations in East Asia domain. Simulations are started one month be- fore the observation campaign as a spin-up period to elim- inate influence of initial concentrations. SAPRC99 (Carter, 2000) is chosen for the chemical mechanism. Table 1 shows relationships between the species measured in the observa- tion campaign and the SAPRC99 species which react with OH. Measured species are allocated to one ofthe SAPRC99 species. These SAPRC99 species are further merged into species groups - abbreviated as AVOC, BVOC and OVOC – as shown in Table 1. However, no measured species are allo- cated to the SAPRC99 species listed in the “missing sinks” group in Table 1, which are treated as missing sinks in this paper.
If the source current density (the channel ofthe unspeci- fied lightning discharge in the neutral atmosphere) is paral- lel to the lower “boundary” ofthe ionosphere, this kind of source generates directly a UWB signal (an upward propa- gating whistler) in the magnetoionic medium, reaching the LEO satellite and propagating through the plasmasphere (Ferencz et al., 2001). This is typical in the case of cloud- to-cloud lightnings, and of large horizontal discharges in mesoscale convective complexes. If the source current den- sity is closely perpendicular to the boundary surfaces ofthe Earth and the plasma environment, then this source will not directly excite the signal in the magnetoionic medium above at all, however, it generates guided wave modes propagating in the EIWG (Ferencz, 2004a). This happens predominantly by cloud-to-ground lightnings. (Note that the above descrip- tion captures only one fundamental geometric aspect of im- pulse generation by lightnings in the atmosphere. Both the orientation and the linear character of a tortuous discharg-
The objective of URBAIR was to develop Action Plans for air quality improvement in the four Asian cities that were studied. The action plans where to be based upon cost-benefit or cost-effectiveness anal- ysis, so that theair quality could be improved to a certain target level at least cost. The concept com- bined air quality assessment based upon monitoring data and modelling ofairpollution and exposure, as- sessment ofthe health damage (using dose-response relationships) and the related costs (based upon local cost data), analysis of control options and their costs, and prioritising the control measures through com- parison of control costs and the related reduced health costs, choosing the measures with the highest bene- fit/cost ratio .
documented at high altitudes ofthe south-facing Himalayan slopes (e.g., Marinoni et al., 2010, 2013; Decesari et al., 2010) which are sometimes directly exposed to atmospheric brown clouds (ABC) (Ramanathan et al., 2007b; Bonasoni et al., 2010). Brown clouds have been defined as “huge blankets or layers of haze generally composed of light- absorbing submicrometer-sized carbonaceous aerosol parti- cles” (Engling and Gelencser, 2010). Areas that are partic- ularly affected by brown clouds, so-called ABC hotspots, are characterized by an anthropogenic aerosol optical depth (AOD) larger than 0.3 and an absorbing aerosol optical depth (AAOD) greater than 0.03 for at least one season (Ra- manathan et al., 2007a). Such conditions are frequently ob- served on the southern side ofthe Himalayas, especially over the Indo-Gangetic Plain (IGP) duringthe dry months (November to May). BC transported from this regional hotspot might thus contribute to the retreat of Himalayan glaciers (Engling and Gelencser, 2010). Furthermore, recent studies show BC observations on snow and in ice even fur- ther north on the Tibetan Plateau (TP) (e.g., Xu et al., 2009; Qian et al., 2011; Ming et al., 2013; Kaspari et al., 2011) and springtime episodes with large amounts of pollutants ob- served on the TP have been reported (Engling et al., 2011; Xia et al., 2011). As a consequence of such episodes, BC concentrations on glaciers could significantly increase on the TP and affect the surface albedo (Zhao et al., 2013).
In summary the State plays an important part in guiding economic activity towards sustainability, in this case environmental sustainability – for the short-term and long-term. While aerial pollution is a worrying issue, it is seen that wealth-creation does not necessarily mean ever-increasing pollution indefinitely. Through incentivizing the use and development of alternative technology and techniques by having the economic agents internalize the cost ofpollution, the market can be guided to provide higher living standards while at the same time lowering pollution-levels. This would not happen organically, hence the need for State intervention. TheEuropean Union has made very significant strides in this sense, and it’s safe to say it is the preeminent organization when it comes to such matters. Portugal, being a part of it, benefits immensely from its legislature and funds. While the heavy investment in renewable energies is commendable, there is still a lot of work to be done inasmuch as three major urban areas (Lisbon, Oporto and Braga) have aerial pollution levels above the EU’s quality standards. The fact that environmental tax revenue as % of GDP is so high in comparison to industrial giants such as Germany is also concerning and must be investigated, along with alternative policies to cover polluting activities with higher precision.
based on fundamental equations and gives a numerical solution validated by experimental results (Factor and Grossman, 1980; Fumo and Goswami, 2002; Gandhidasan, 2004). For optimum design of desic- cant cooling systems and annual energy performance analyses, it is most desirable to obtain an analytical solution to the general differential equations. For example, in Hellmann and Grossman’s model (1995), the solution film heat and mass transfer resistances were introduced in their model equations. The outer surface ofthe tube banks was assumed to be uni- formly wetted and the Lewis factor was assumed to be equal to unity. Chengqin et al. (2006) rearranged the general differential equations and an analytical solution was developed. For the four possible flow arrangements ofthe parallel/counter flow configura- tions and three types of commonly used liquid desiccant solutions, the results of analytical solutions were compared with those of numerical integration over a wide range of operating conditions and the agreement was found to be quite satisfactory. Chen et al. (2006) presented an integrated analytical solution of adiabatic heat and mass transfer in packed-type liquid desiccant equipment based on proposed mathematical models in both parallel-flow and counter- flow configurations. In the derivation process, the desiccant concentration at the inlet and outlet ofthe absorber was assumed to be constant. Babakhani (2009) presented an analytical solution of simultane- ous heat and mass transfer processes in a packed bed liquid desiccant dehumidifier/regenerator. Various dimensionless parameters and reliable assumptions were used in order to develop this solution. Longo and Gasparella (2005) presented the experimental tests and the theoretical analysis ofthe chemical dehumidification ofair by a liquid desiccant and desiccant regeneration in an absorption/desorption column with random packing. Liu et al. (2007) presented analytical solutions oftheair and desiccant parameters that affect theheat and mass transfer performance. Many researchers have developed mathematical models ofthe coupled heat and mass transfer processes in the dehumidifier or regenerator, and most ofthe models were solved numerically. Compared with numerical solutions, analytical solutions have advantages in analyzing the parameters that affect theheat and mass transfer performance. For this purpose, in the current study, an analytical approach based on the Laplace method for the mathematical modelofthe coupled heat and mass transfer process in air dehumidification has been presented. The analytical results have been compared with experimental data (2004) and show good agreement.
3.2 Permafrost distribution in historical simulation The simulated permafrost in JULES is shown in Fig. 7, along with observations from the Circum-Arctic map of permafrost and ground-ice conditions (Brown et al., 1998) (Sect. 2.4.6). The observed map shows areas with continuous, discontin- uous and sporadic permafrost and isolated patches. There is no equivalent of discontinuous permafrost in JULES be- cause each grid box has only a single soil column, so in or- der to compare the two maps we assume that a deeper active layer in JULES may correspond to discontinuous or sporadic permafrost. With this assumption, all thesimulations match the observations fairly well in most areas. We can see that introducing themodel developments brings in much more spatial variability in ALT, which generally matches with the patterns of continuous/discontinuous permafrost. The corre- lation between the ALT in JULES and the percentage cover of permafrost from (Brown et al., 1998) (100 % for continu- ous, 90 % for discontinuous, 50 % for sporadic and 10 % for isolated patches) is high, ranging between −0.37 and −0.51. However, there are still places where continuous per- mafrost is observed but JULES does not simulate permafrost. Figure 8 shows that in most of these areas, JULES simulates far too much snow, which will mean too much insulation in winter leading to soils that are too warm. This is particularly noticeable in north-east Canada and two areas in north-west Russia. In north-east Canada, however, it has been shown that the GlobSnow data set underestimates the SWE (Langlois et al., 2014), so the over-estimation in JULES may not be as large as Fig. 8 suggests. However, the permafrost in this re- gion is unstable to thawing (Thibault and Payette, 2009), so a small bias in themodel could make the difference between simulating permafrost or not. For most ofthe remaining land surface, JULES slightly underestimates the SWE. Hancock et al. (2014) showed that JULES generally underestimates SWE when driven by reanalysis data sets.
The true color image from the Moderate Resolution Imag- ing Spectro-radiometer (MODIS) Aqua instrument, Fig. 6, shows both dust events over the EM. Figure 7 shows the daily average, vertically integrated dust load over the EM region for both dust events and HYSPLIT (http://ready.arl. noaa.gov/) backward trajectories, which show the pathways oftheair masses that reached the CUT-TEPAK station on 22 and 28 September 2011. The HYSPLIT trajectories are driven by NCEP (National Center for Environmental Pre- diction) reanalysis data that appear to be consistent with our model calculations. The streamlines and the velocity vectors refer to an elevation of about 2.5 km (700 hPa) and show the maximum dust concentration during atmospheric transport. In the dust outflow-1 event (Fig. 7, upper panels) the low- pressure system (not shown here) over Cyprus resulted in cyclonic activity that enhanced dust transport from the Sa- hara and airpollution and moisture transport from central and southern Europe. The cyclonic activity of 21 Septem- ber then advected eastwards. The backward trajectories show that air masses reached the CUT-TEPAK station at differ- ent times from different sources; air masses carrying dust from Egypt and from Tunisia. Theair masses from Egypt started at a lower elevation and were then lifted during trans- port across the Mediterranean, while the dust from Tunisia was transported over a long distance and at higher eleva-
As it was observed in theModel 7 with the conventional reflection event, the Figure 6A showed a residual local minimum region for the PS reflection event. In the Figure 6B, there is no local minimum region. Thus, the approximation showed a unimodal behavior for the converted wave reflection event oftheModel 8. Similar to the Figure 3B, the local minimum region is completely suppressed and presents a homogeneous objective function structure. The PS wave reflection event oftheModel 9 (Fig. 6C) showed an extremely homogeneous topographic structure ofthe objective function with no local minimum region. Concerning theglobal minimum region, it becomes larger as the local minimum region disappears. It can also be observed that the difference between the maximum regions and theglobal minimum region became smaller as the structure becomes softer. It was also observed that with the increase ofthe depth ofthe interface where occurs the reflection, there is a decrease ofthe complexity ofthe topography. There is an attenuation and after a suppression ofthe local minimum region, and also a homogenization ofthe structure. For the PS event, the attenuation ofthe local minimum region starts occur strongly in theModel 5
In the context ofthe population-based case---control study called Childhood Autism Risks from Genetics and Envi- ronment (CHARGE), Shelton et al. explored, in California, the possible association between proximity of residence to agricultural pesticides during gestation and ASD or devel- opmental delay (DD). For 970 participants, aged 2---5 years, commercial pesticide application data collected using the California Pesticide Use Report (from 1997 to 2008) were connected with the addresses during gestation. The pounds of active ingredient applied regarding organophophates, organochlorines, pyrethroids, and carbamates (four pesti- cide families selected by the authors) were aggregated within buffer distances of 1.25-km, 1.5-km, and 1.75-km from the residence. The authors used multinomial logistic regression to calculate the exposure odds ratio compar- ing cases affected by ASD (486, diagnosed according to both ADI-R and ADOS), or by DD (168, assessed by the Mullen Scales of Early Learning and the Vineland Adap- tive Behavioral Scale), with normal controls (316) frequency matched to the ASD cases by sex, age, and the regional catchment area. Data were adjusted for education ofthe father, home ownership, birthplace ofthe mother, child race/ethnicity, maternal prenatal vitamin intake, and year of birth. During pregnancy, about one-third ofthe moth- ers lived within 1.5 km of an application of agricultural pesticides. Living near organophosphates at some time dur- ing pregnancy was associated with 60% increased ASD risk, higher for third-trimester exposure to organophosphates overall, and for second-trimester applications of chlorpyri- fos (an organophosphate explored independently). Children of mothers living near applications of pyrethroids duringthe preconception period or pregnancy at third trimester were at higher risk of both ASD and DD. DD risk was higher in those living near applications of carbamates, with no specific vulnerable periods. The authors concluded that their study supports the association between pesticide exposure during pregnancy, particularly organophosphates, and neurodevel- opmental disorders, as well as providing novel findings about the associations of pyrethroids and carbamates with ASD and DD. 21