Regime Diagrams for <Emphasis Type="Italic">K</Emphasis>-Theory Dispersion

In atmospheric dispersion, the “non-Gaussian” effects of gravitational settling, the vertical gradient in diffusivity and the surface deposition do not enter uniformly but rather break up parameter space into several discrete regimes. Here, we describe regime diagrams that are constructed for K-theory dispersion of effluent from a surface line source in unsheared inhomogeneous turbulence, using a previously derived Fourier–Hankel method. This K-theory formulation differs from the traditional one by keeping a non-zero diffusivity at the ground. This change allows for turbulent exchange between the canopy and the atmosphere and allows new natural length scales to emerge. The axes on the regime diagrams are non-dimensional distance defined as the ratio of downwind distance to the characteristic length scale for each effect. For each value of the ratio of settling speed to the K gradient, two to four regimes are found. Concentration formulae are given for each regime. The regime diagrams allow real dispersion problems to be categorized and the validity of end-state concentration formulae to be judged.     

A modified moist ageostrophic <Emphasis Type="Italic">Q</Emphasis> vector

The quasi-geostrophic Q vector is an important rainfall associated with large-scale weather systems diagnostic tool for studying development of surface and is calculated using data at single vertical level. When ageostrophic Q vector was introduced, it required data at two vertical levels. In this study, moist ageostrophic Q vector is modified so that it can be calculated using data at a single vertical level. The comparison study between the original and modified moist ageostrophic Q vectors is conducted using the data from 5 to 6 July 1991 during the torrential rainfall event associated with the Changjiang-Huaihe mei-yu front in China. The results reveal that divergences of original and modified moist ageostrophic Q vectors have similar horizontal distributions and their centers are almost located in the precipitation centers. This indicates that modified moist ageostrophic Q vector can be used to diagnose convective development with reasonable accuracy.     

NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> change over China and its influences

A 3-D chemical transport model (OSLO CTM2) is used to investigate the impact of the increase of NOx emission over China. The model is capable to reproduce basically the seasonal variation of surface NOx and ozone over eastern China. NOx emission data and observations reveal that NOx over eastern China increases quite quickly with the economic development of China. Model results indicate that NOx concentration over eastern China increasingly rises with the increase of NOx emission over China, and accelerates to increase in winter. When the NOx emission increases from 1995 to its double, the ratio of NO2/NOx abruptly drops in winter over northern China. Ozone at the surface decreases in winter with the continual enhancement of the NOx level over eastern China, but increases over southern China in summertime. It is noticeable that peak ozone over northern China increases in summer although mean ozone changes little. In summer, ozone increases in the free troposphere dominantly below 500 hPa.Moreover, the increases of total ozone over eastern China are proportional to the increases of NOx emission.In a word, the model results suggest that the relationship between NOx and ozone at the surface would change with NOx increase.     

Climate,development and malaria: an application of <Emphasis Type="Italic">FUND</Emphasis>

Climate change may well increase malaria morbidity and mortality. This would slow economic growth through increased spending on health care, reduced production, and less effective education. Slower economic growth would increase the incidence of malaria morbidity and mortality. The integrated assessment model FUND is used to estimate the strength of this negative feedback. Although climate-change-induced health problems may well substantially affect the projected growth path of developing regions, it is unlikely that climate change would reverse economic growth due to the impacts considered here. Even in sub-Saharan Africa, an area thought to be very sensitive to climate change and associated health effect, the impact, while detectable, is small and unlikely to reverse economic growth.     

Assimilation of <Emphasis Type="Italic">HY-2A</Emphasis> scatterometer ambiguous winds based on feature thinning

This paper focuses on the data assimilation methods for sea surface winds, based on the level-2B HY-2A satellite microwave scatterometer wind products. We propose a new feature thinning method, which is herein used to screen scatterometer winds while maintaining the key structure of the wind field in the process of data thinning for highresolution satellite observations. We also accomplish feeding the ambiguous wind solutions directly into the data assimilation system, thus making better use of the retrieved information while simplifying the assimilation process of the scatterometer products. A numerical simulation experiment involving Typhoon Danas shows that our method gives better results than the traditional approach. This method may be a valuable alternative for operational satellite data assimilation.     

Improvement of radar quantitative precipitation estimation based on real-time adjustments to <Emphasis Type="Italic">Z-R</Emphasis> relationships and inverse distance weighting correction schemes

The errors in radar quantitative precipitation estimations consist not only of systematic biases caused by random noises but also spatially nonuniform biases in radar rainfall at individual rain-gauge stations.In this study,a real-time adjustment to the radar reflectivity-rainfall rates(Z-R) relationship scheme and the gauge-corrected,radar-based,estimation scheme with inverse distance weighting interpolation was developed.Based on the characteristics of the two schemes,the two-step correction technique of radar quantitative precipitation estimation is proposed.To minimize the errors between radar quantitative precipitation estimations and rain gauge observations,a real-time adjustment to the Z-R relationship scheme is used to remove systematic bias on the time-domain.The gauge-corrected,radar-based,estimation scheme is then used to eliminate non-uniform errors in space.Based on radar data and rain gauge observations near the Huaihe River,the two-step correction technique was evaluated using two heavy-precipitation events.The results show that the proposed scheme improved not only in the underestimation of rainfall but also reduced the root-mean-square error and the mean relative error of radar-rain gauge pairs.     

On the Angular Momentum Loss of Tropical Cyclones: An <Emphasis Type="Italic">f</Emphasis>-Plane Approximation

The angular momentum for ideal axisymmetric tropical cyclones on the f-plane is investigated with a focus on the total-volume integrated quantity. Budget analysis of the momentum equation at cylindrical coordinates shows that a tropical cyclone loses angular momentum during its development and mature stages due to the dynamical difference between the viscous inward-flow near the surface and the angular momentum conserving outward-flow aloft. The total relative angular momentum of a tropical cyclone, as a result, can be negative (i.e., implying anticyclonic rotation as a whole) despite intense cyclonic wind in the tropospheric layers. This anticyclonic rotation was measured in terms of the super-rotation ratio, the ratio of total relative angular momentum to the planetary angular momentum. Simulations with the numerical model of Weather Research and Forecasting (WRF) version 3.4.1 was found to be in favor of the theoretical angular-momentum budget analysis. It was revealed in the numerical simulations that the super-rotation ratio was negative, indicating a sub-rotation, as was predicted by analysis. The sub-rotation ratio was found to be less than one percent for typical tropical cyclones. To show the angular momentum decrease even in the decaying stage, numerical simulations where the thermal forcing by sea surface temperature switched off in the mature stage were carried out. In support of the angular momentum budget analysis, the results indicated that the angular momentum also decreases for a while soon after the forcing was eliminated.     

Diagnostic analyses and application of the moist ageostrophic vector<Emphasis Type="Italic">Q</Emphasis>

Considering the main thermal forcing factor, which is critical for the development of synoptic systems,the concept of the moist ageostrophic vector Q is introduced. A formula of the moist ageostrophic Q and the ageostrophic diabatic equation, in which the divergence of the moist ageostrophic Q is taken as a single forcing term, is derived. Meanwhile, the moist ageostrophic Q is applied to diagnose a torrential rain process in North China. The results suggest that the moist ageostrophic Q can clearly reveal the system development during the torrential rain process; the corresponding relationship between the divergence of the moist ageostrophic Q and the rainfall area is better than that of the vertical velocity (ω) and the divergence of the dry Q; the 6-h rainfall region can be correctly drawn according to the negative area of the divergence of the moist ageostrophic Q, and its precipitation is positively correlated to the magnitude of the divergence of the moist ageostrophic Q. The research provides valuable information for improving short-term weather forecast.     

<Emphasis Type="Italic">Boeing 737-800</Emphasis> crash: Weather conditions in Rostov-on-Don on March 19, 2016

Weather conditions at night on March 19, 2016, when Boeing 737-800 crashed in Rostov-on-Don, are analyzed using the data of aerodrome observations and radiosounding, satellite data on cloudiness and cloud top temperature, and the data of synoptic and calculated charts of maximum wind.     

Halogenation processes linked to red wood ant nests (<Emphasis Type="Italic">Formica</Emphasis> spp.) and tectonics

We investigated and evaluated the occurrence of fault zone tracer gases (CO₂, He, Rn), volatile organohalogens (CH₃Cl, CHCl₃, CHBr₃), alkanes and limonene in soil and nest gases of red wood ants (RWA) in comparison to ambient air, in a seismically active area. In this new approach, we compared RWA-free areas to RWA-areas by combining different investigation and analytical methods. In soil gas, the fault zone tracer gas Rn was surprisingly highly correlated to limonene, suggesting a combination of biotic production of limonene and abiotic degassing of Rn in a seismically active area; moderate correlations were found with trihalomethanes and other halocarbons. In RWA nests a variety of elevated concentrations of haloforms were found, while remaining below the atmospheric background values in RWA-free areas. The evidence of CHCl₃ in RWA nests is the first record. Its average concentrations in nests of F. rufa and F. polyctena were up to 3 fold higher than atmospheric background and up to 28–70 fold higher compared to e.g. volcanic emissions being considered as one of its main geogenic sources. Thus, RWA nests could possibly be an additional source for CHCl₃ liberation. Consequently, apart from RWA being bioindicators for seismically active degassing faults, they might also be used as bioindicators for CHCl₃ formation in forest soils. Although we cannot yet differentiate between a geogenic/abiotic and a biotic formation. RWA nests will have to be reconsidered for halocarbon formation in future quantifications of geochemical cycles at global scale, since they impact organic soil chemistry through biotic and/or abiotic pathways. Therefore, further larger-scale research in different tectonic settings but also in well-known CHCl₃ “hot spot” study areas such as the Klosterhede area (Denmark) should focus directly on gas sampling from confirmed active fault systems. Nests of other ant species should be addressed to compare seasonal, diurnal and nocturnal variations of degassing procedures in relation to earth tides, different geologic settings, and tectonic events such as earthquakes and on quantifying the fluxes to the atmosphere.     

Ecophysiological responses to elevated CO<Subscript>2</Subscript> and temperature in <Emphasis Type="Italic">Cystoseira tamariscifolia</Emphasis> (Phaeophyceae)

Ocean acidification increases the amount of dissolved inorganic carbon (DIC) available in seawater which can benefit photosynthesis in those algae that are currently carbon limited, leading to shifts in the structure and function of seaweed communities. Recent studies have shown that ocean acidification-driven shifts in seaweed community dominance will depend on interactions with other factors such as light and nutrients. The study of interactive effects of ocean acidification and warming can help elucidate the likely effects of climate change on marine primary producers. In this study, we investigated the ecophysiological responses of Cystoseira tamariscifolia (Hudson) Papenfuss. This large brown macroalga plays an important structural role in coastal Mediterranean communities. Algae were collected from both oligotrophic and ultraoligotrophic waters in southern Spain. They were then incubated in tanks at ambient (ca. 400–500 ppm) and high CO₂ (ca. 1200–1300 ppm), and at 20 °C (ambient temperature) and 24 °C (ambient temperature +4 °C). Increased CO₂ levels benefited the algae from both origins. Biomass increased in elevated CO₂ treatments and was similar in algae from both origins. The maximal electron transport rate (ETR_max), used to estimate photosynthetic capacity, increased in ambient temperature/high CO₂ treatments. The highest polyphenol content and antioxidant activity were observed in ambient temperature/high CO₂ conditions in algae from both origins; phenol content was higher in algae from ultraoligotrophic waters (1.5–3.0%) than that from oligotrophic waters (1.0–2.2%). Our study shows that ongoing ocean acidification can be expected to increase algal productivity (ETR_max), boost antioxidant activity (EC ₅₀ ), and increase production of photoprotective phenols. Cystoseira tamariscifolia collected from oligotrophic and ultraoligotrophic waters were able to benefit from increases in DIC at ambient temperatures. Warming, not acidification, may be the key stressor for this habitat as CO₂ levels continue to rise.     

Effects of climate change on the phenology of <Emphasis Type="Italic">Osmia cornifrons</Emphasis>: implications for population management

The phenology of many ecological processes including pollination service is modulated by surface air temperature, making them potentially sensitive to climatic change. The Japanese hornfaced bee, Osmia cornifrons (Hymenoptera: Megachilidae), was introduced into the USA in the 1970s and has been used as a key pollinator of spring blooming fruit crops such as apple and blueberry. This study examined the effects of future climate change on three key phenological events of O. cornifrons: date for adult emergence (female and male) in spring, date for completion of egg and larval development, and duration for the development in the Eastern USA. We used daily temperature data obtained from 21 models in Coupled Model Intercomparison Project Phase 5 for 2006–2100 under the two future climate scenarios of Representative Concentration Pathways (RCPs 4.5 and 8.5). We estimated the Julian dates (JDs) of spring emergence and development of O. cornifrons using the phenological parameters derived from temperature-dependent biophysical models. The JDs for the bee emergence and development are projected to be significantly advanced in the Eastern USA under the RCP 4.5 and 8.5 scenarios. The number of days for bee development is projected to be longer in the southern region (+?0.57 days/decade) and shorter in the central (??0.27 days/decade) and northern (??0.65 days/decade) regions of the Eastern USA (all the p values <?0.01). The significantly longer duration of bee development under future climate change could pose a risk to the bee due to the longer period of being exposed to its pests. Implications for management of O. cornifrons population were discussed in this article.     

Historical climatology, <Emphasis Type="Italic">Climatic Change</Emphasis>, and implications for climate science in the twenty-first century

Historical climatology is the use of documentary evidence for the reconstruction of past climate. This paper gives a brief personal view of the development of the discipline from early times to the present day. Although several papers have been published on the importance of carefully analysing and evaluating all historical sources before they are used in climate reconstructions, several of them in Climatic Change, the use of unreliable, unanalysed data still persists. This may lead to false impressions of the climate of the past. In these times, when climate data are being used for political, as well as purely scientific ends, the cause of accuracy, as championed by Climatic Change, will best be served by emphasising, yet again, the importance of using only reliable data. A number of examples are given which illustrate these points. These include discussions on wine growing in England in medieval times, the Norse settlement of Greenland, and comments on the climate history of the past thousand years.     

BVOC emissions from mechanical wounding of leaves and branches of <Emphasis Type="Italic">Eucalyptus sideroxylon</Emphasis> (red ironbark)

Emissions of biogenic volatile organic compounds (BVOCs) from mechanical wounding of leaves and branches of plants can contribute to the atmospheric burden of volatile organic compounds (VOCs) in both (a) urban airsheds (from urban garden maintenance) and (b) the global atmosphere (from large scale forest harvesting). These emissions of BVOCs are poorly understood and quantified, and their role in urban and global emissions inventories neglected. This paper presents measurements of the magnitude, duration and composition of emissions of BVOCs, carbon dioxide (CO₂) and methane (CH₄) from freshly cut leaf mulch and wood chips derived from a common eucalypt tree, Eucalyptus sideroxylon (red ironbark), found in southeastern Australian forests and gardens. The emissions of BVOCs from freshly cut and shredded leaves and wood of E. sideroxylon were found to be 2.3 ± 0.6 and 0.05 ± 0.04 mg g^-1 DM (Dry Mass) from leaf mulch and wood chips respectively and to last typically for 1 day following cutting. Three sampling techniques were used for VOC speciation and the 12 most abundant BVOCs released from the mulch materials were identified. The specific BVOCs emitted in order of decreasing abundance from leaf mulch are: (a) stored plant oils, 1,8-cineole, α–pinene and o-cymene which make up the major part of the emissions, (b) a minor contribution from chemicals associated with environmental stress and wound defence, (Z)–3–hexenyl acetate, (E)-2-hexenal and (Z)-3-hexen-1-ol, and (c) a second minor contribution from metabolic products, acetaldehyde and acetone. The observed integrated emissions of BVOCs from leaves following mulching are equivalent to more than half and perhaps all of the likely stored plant oils in the leaves. For the two comparable studies available, one of a plant with stored oils (this study) and one of a plant without stored plant oils, the emissions of leaf wound defence BVOCs are in the same range for both plants. In the plant with stored plant oils, the plant oil emissions are about a factor of 11 larger in emission rate than the plant wound defence BVOCs. A compilation of available leaf wounding BVOC emission studies indicates that for plants with stored plant oils, plant oil emissions dominate, whereas with other plants, leaf wound defence BVOCs dominate the emissions.     

Biomonitoring of heavy metals by <Emphasis Type="Italic">Pseudevernia furfuracea</Emphasis> (L.) Zopf in Ankara (Turkey)

The objective of this study was to determine the air pollution level of Ankara and to generate the air pollution map of this city by using Pseudevernia furfuracea (L.) Zopf as a biomonitor. Lichen samples were collected from unpolluted area at Yaprakli Mountains, Cankiri in November 2002 and transplanted to 27 localities in Ankara. Lichen samples were retrieved following an exposure of 3 and 6 months. Heavy metal, Cu, Mn, Ni, Pb and Zn, contents were determined by using inductively coupled plasma spectrometry (ICP). The chlorophyll a and b contents were determined by using DMSO method. The increase in Ni, Pb, Zn and chlorophyll a content of the specimens were statistically important. All the increases and decreases in the variables could be explained by the environmental stress like pollution, but it is hard to say that this is the only reason of these changes, also climatic conditions, seasons, strength of the light and the physiological status of the plant itself effective on these changes. According to the results of heavy metal analysis Pseudevernia furfuracea continued to accumulate heavy metals and worked well as a biomonitor. The air pollution level of Ankara shows great variations because of the great area of the city.     

Effect of temperature on the methyl chloride production rate in a marine phytoplankton, <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis>

Methyl halides such as methyl chloride (CH₃Cl) are known to be important carriers of halogen from the ocean to the atmosphere, and the halogens they release into the stratosphere by photolysis catalyze ozone depletion. Marine phytoplankton have been reported as a source of CH₃Cl, but the effects of environmental temperature on the CH₃Cl production by phytoplankton have not been investigated. In this study, we investigated the effects of temperature on the production of CH₃Cl in the culture of a marine diatom, Phaeodactylum tricornutum CCMP 630, incubated at 10, 15, 20, 25, and 30 °C. CH₃Cl concentrations in cultured samples were determined using purge and trap gas chromatograph–mass spectrometry. Phytoplankton growth was monitored by measuring the chlorophyll a concentrations. CH₃Cl production was observed for several weeks at four different temperatures ranging from 10 to 25 °C. The CH₃Cl production from P. tricornutum was increased with increasing temperature from 10 to 25 °C, and the maximum production rate for CH₃Cl was 0.21~0.26 μmol (g chlorophyll a)^?1 d^?1 at 25 °C, which was several times higher than that at 10 °C (~0.03 μmol (g chlorophyll a)^?1 d^?1). The Arrhenius equation was successfully used to characterize the effects of temperature on the production rates of CH₃Cl in the culture of P. tricornutum. Our results suggest that water temperature directly affects CH₃Cl production derived from P. tricornutum and that water temperature would be a significant factor for estimating the emissions of CH₃Cl from marine environments.     

Effects of changing precipitation and warming on functional traits of zonal <Emphasis Type="Italic">Stipa</Emphasis> plants from Inner Mongolian grassland

The mechanisms driving changes in dominant plant species are the key for understanding how grassland ecosystems respond to climate change. In this study, we examined plant functional traits (morphological characteristics: plant height, leaf area, and leaf number; biomasses: aboveground, belowground, and total; and growth indices: root-to-shoot ratio, specific leaf area, and leaf mass ratio) of four zonal Stipa species (S. baicalensis, S. bungeana, S. grandis, and S. breviflora) from Inner Mongolian grassland in response to warming (control, +1.5, +2.0, +4.0, and +6.0?), changing precipitation (-30%, -15%, control, +15%, and +30%), and their combined effects via climate control chambers. The results showed that warming and changing precipitation had significant interactive effects, different from the accumulation of single-factor effects, on functional traits of Stipa species. The correlation and sensitivity of different plant functional traits to temperature and precipitation differed. Among the four species, the accumulation and variability of functional traits had greater partial correlation with precipitation than temperature, except for leaf number, leaf area, and specific leaf area, in S. breviflora, S. bungeana, and S. grandis. For S. baicalensis, the accumulation and variability of plant height, aboveground biomass, and root-to-shoot ratio only had significant partial correlation with precipitation. However, the variability of morphological characteristics, biomasses, and some growth indices, was more sensitive to temperature than precipitation in S. bungeana, S. grandis, and S. breviflora—except for aboveground biomass and plant height. These results reveal that precipitation is the key factor determining the growth and changes in plant functional traits in Stipa species, and that temperature mainly influences the quantitative fluctuations of the changes in functional traits.     

The Hydrogen Kinetic Isotope Effects of the Reactions of <Emphasis Type="Italic">n</Emphasis>-Alkanes with Chlorine Atoms in the Gas Phase

The stable-hydrogen kinetic isotope effects (KIEs) for a series of n-alkanes in reaction with chlorine atoms in the gas phase were studied in a 25-L PTFE reaction chamber at 298 K. The time dependence of both the stable hydrogen isotope ratios and the concentrations was determined using a gas chromatography pyrolysis isotope ratio mass spectrometry (GC-P-IRMS) system. The following KIE values, in per mil (‰), were obtained: 39.6 ± 2.7 (n-butane), 28.2 ± 0.9 (n-pentane), 24.6 ± 1.0 (n-hexane), 24.0 ± 1.2 (n-heptane), 17.9 ± 3.3 (n-octane), 15.1 ± 0.7 (n-nonane), and 14.9 ± 1.8 (n-decane). The errors given are the ±1σ standard errors. These measured values were used to derive structure–reactivity relationship (SRRs), which allow for the calculation of the KIEs for the reaction of n-alkanes with Cl atoms. The results of the calculations agree with the measurements within few per mil or better. The site specific stable hydrogen isotope fractionation effects for methyl groups are approximately a factor of 3 larger than those for methylene group, a finding which is qualitatively similar to site-specific stable hydrogen isotope effects reported in literature for reactions of alkanes with the OH radical. Because n-alkanes with close to natural isotope ratios (i.e. neither artificially labeled, nor enriched or depleted) were used, the KIE data are directly applicable to atmospheric studies. Based on these KIE values, the impact of Cl-atom reactions of the stable hydrogen isotope ratio on alkanes are estimated for different levels of Cl-atom concentrations. On average in the troposphere, the impact of Cl-atom reactions of the stable hydrogen isotope ratio of n-alkanes will be small. However, in regions of the troposphere with high concentrations of Cl atoms, such as the tropospheric ozone depletion episodes during polar sunrise, the impact of Cl-atom reactions is substantial. An erratum to this article is available at .     

Liquid water path retrieval using the lowest frequency channels of <Emphasis Type="Italic">Fengyun-3C</Emphasis> Microwave Radiation Imager (MWRI)

The Microwave Radiation Imager (MWRI) on board Chinese Fengyun-3 (FY-3) satellites provides measurements at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with both horizontal and vertical polarization channels. Brightness temperature measurements of those channels with their central frequencies higher than 19 GHz from satellite-based microwave imager radiometers had traditionally been used to retrieve cloud liquid water path (LWP) over ocean. The results show that the lowest frequency channels are the most appropriate for retrieving LWP when its values are large. Therefore, a modified LWP retrieval algorithm is developed for retrieving LWP of different magnitudes involving not only the high frequency channels but also the lowest frequency channels of FY-3 MWRI. The theoretical estimates of the LWP retrieval errors are between 0.11 and 0.06 mm for 10.65- and 18.7-GHz channels and between 0.02 and 0.04 mm for 36.5- and 89.0-GHz channels. It is also shown that the brightness temperature observations at 10.65 GHz can be utilized to better retrieve the LWP greater than 3 mm in the eyewall region of Super Typhoon Neoguri (2014). The spiral structure of clouds within and around Typhoon Neoguri can be well captured by combining the LWP retrievals from different frequency channels.