北京发布最严停工令:采暖季城六区停止土方作业

日前,北京市住建委发布《2017-2018年秋冬季建设系统施工现场扬尘治理攻坚行动方案》,从今年11月15日至2018年3月15日的采暖季期间,东城区、西城区、朝阳区、海淀区、丰台区、石景山区全部区域;通州区、大兴区、房山区、门头沟区、延庆区、昌平区、怀柔区、密云区、平谷区、顺义区、亦庄经济技术开发区城区及建成区要停止各类道路工程、水利工程等土石方作业和房屋拆迁施工等.

Impacts of Environmental Factors on the Structure Characteristics of Avian Community in Shanghai Woodlots in Spring

From March to May, 2004, we selected 8 typical parks or green lands in Shanghai downtown as the study sites to conduct a ornithological research. During this study, total 55 species of birds were recorded, which included 31 resident and 24 migratory species. With statistics methodology, we analyzed the avian communities with 10 major environmental factors covering the park area, water percentage, vegetation species, canopy cover, shrub cover, grass cover, hill number, location condition, human quantity, path width, the study results indicated that: (1) the following 7 environmental factors were important to impact the structures of the avian community, they were park area, vegetation species, shrub coverage, grass coverage, hill number, location condition of the parks and path width; (2) the avian community of theses urban parks tended to deteriorate in the bird number and diversity; the man-made lake which was currently promoted in the park designing and planning process would not be good to attract the birds.

PRELIMINARY STUDY OF INDOOR FEATURES OF TEMPERATURE AND HUMIDITY FOR ROOMS FACING NORTH-SOUTH IN WINTER IN A LOW-LATITUDE PLATEAU CITY

Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.

Human Behavior in Downtown Public Spaces during Cooling Periods in Winter Cities

There is an urban design problem that outdoor public spaces are not used for long periods of time within a year due to coldness and snow cover in cities with severe winter climates （winter cities）. Therefore, an urban design that promotes activities in these spaces is required for winter cities. The purpose of this paper is to clarify the relationship between outdoor environmental conditions and the behaviors of people in outdoor public spaces. This six-month study conducted a field survey in six kinds of public spaces in downtown Sapporo and analyzed the changes of microclimates and sitting behaviors in these spaces. The analysis revealed that sitting behaviors decreased with temperature drops during the cooling period （20 ~C-8 ~C）, that sunlight could suppress the reduction in the number of sitting behaviors, and that wind speed could suppress the reduction in the duration of sitting behaviors.

Observations of Aerosol Optical Properties in the Beijing Urban Area in Summer

To investigate aerosol optical properties in the Beijing metropolitan area, aerosol absorption coefficient （Ab）, scattering coefficient （So）, and fine particulate matter （PM2.5） were measured in the Beijing urban area from 20 May to 30 August 2009. The average Ab, So, single scat- tering albedo （SSA）, and PM2.5 concentration were 58.0±39.5 M m^-1, 343.5±353.7 M m 1, 0.80±0.10 and 63.6＋50.0 μg m^-3, respectively, during the observation period. Ab, Sc, and SSA all showed single peak diurnal variations, with their maximum values being measured at 0500, 1000, and 1300 local time, respectively. Ab and Sc had a strong positive correlation with PM2.5, and Ab, Sc, and PM25 all had positive correlations with relative humidity and negative correlations with wind speed.

Seasonal variations of rotifers from a high altitude urban shallow water body, La Cantera Oriente (Mexico City, Mexico)

La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （Schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.

Sensitivity experiments of impacts of large-scale urbanization in East China on East Asian winter monsoon

By using the global atmospheric general circulation model CAM4.0 including an urban canopy parameterization scheme,the possible impacts of large-scale urbanization in East China on East Asian winter monsoon was investigated via idealized numerical experiments.Results suggest that large-scale urbanization can cause a significant warming effect in both surface temperature and air temperature near the surface over most areas of East China.Meanwhile,large-scale urbanization also alters the surface energy balance,causing evident increases in net surface long-wave radiation and sensible heat flux as well as intensified surface thermal heating to the atmosphere.Forced by the surface thermal heating anomalies induced by the large-scale urban expansion,East Asian winter monsoon circulation exhibits distinct changes.Overall,the extensive urbanization over East China will weaken East Asian winter monsoon,but intensify winter monsoon in northeast China.

Niche segregation, competition, and urbanization

Urbanization of species is an ongoing process where successful urban colonizers usually obtain large fitness benefits. Mechanisms proposed to explain associations between urbanization and lifehistory traits are based on behavioral flexibility in food and habitat use and reduced fear responses. We test the novel hypothesis that interspecific competition for proximity to humans is driving ur- banization. We recorded the distance during the breeding season to human habitation for 50 pairs of closely related bird species, where one was closely associated with humans while the other species was not. The degree of urbanization was larger as was range size and abundance in the species more closely associated to humans. Flight initiation distance was shorter, and species closely associated with humans were more abundant in ancestral rural habitats. Likewise, species more closely associated with humans reproduced earlier and during longer periods. These results are consistent with the hypothesis that urbanization is promoted by interspecific competition. Resulting isolation by urban habitat may further facilitate contemporary adaptation to urban environments.