2011, 16(6):679-689. DOI: 10.3878/j.issn.1006-9585.2011.06.01
Abstract:The Weather Research and Forecasting (WRF) model coupled with a singlelayer Urban Canopy Model (UCM) is used to simulate the Urban Heat Island (UHI) features in Shanghai and Nanjing, two different cities in China. Results show that the horizontal distribution of UHI is determined by largescale surface wind, which causes high air temperature of downstream rural area. Cross sections of the difference of air temperature between the urban and rural surfaces are analyzed, the model suggests that more heat is transported from the land to the air over urban area, which leads to the continuous transportation of heat to the downstream rural surface under the control of the steady largescale wind. It is concluded that the effect of largescale surface wind on UHI can increase the downstream rural air temperature, which shouldn’t be ignored.
2011, 16(6):690-696. DOI: 10.3878/j.issn.1006-9585.2011.06.02
Abstract:One dusthaze episode occurring from North China to Northeast China plains during 4-6 Nov 2010 has been analyzed, using MODIS data, air pollution monitoring data, weather chart, and backward trajectory method. Preliminary result shows that this dusthaze episode in Northeast China is inherently related to that in North China, and the former is influenced by the transportation of air pollution form the latter. The air pollutant transportation channel between Northeast China and North China is the Bohai Bay and its neighborhood Liaohe Plain. This conclusion was proved by MODIS image, backward trajectory analysis and the phase delay of PM10(inhalable particulate) concentration upspring along the transportation route. This brings forward a challenge to the air pollution regional control strategy.
2011, 16(6):697-706. DOI: 10.3878/j.issn.1006-9585.2011.06.03
Abstract:Using the conventional sounding data at Beijing meteorological station(ID:54511) during May to September in 2007 and 2008, the reliability of quantitative applications of the sounding constructed from the temperature and humidity data detected by microwave radiometer and the wind data obtained by wind profiler(hereinafter referred to as special sounding) at the same station was analyzed. Results showed that the special and conventional sounding had a more consistent trend of any element, since the special sounding could effectively compensate for the low temporal resolution of conventional sounding in qualitative analysis. But in the quantitative use, the different performance of different elements should be paid attention to and the systematic bias should be revised. Firstly, the error of humidity of microwave radiometer was greater, which resulted in the poor consistency and the greater value of the dewpoint temperature of special sounding, while the small mean error and the slightly high value of the temperatures. The error of zonal wind detected by wind profiler increases as the height increases, but the error of meridional wind is smaller. So, the temperature and wind profile had a better quantitative value relatively. Secondly, the performance differencs of various elements and heights between conventional sounding and the special sounding were very different. The consistency at 0800 LST and 2000 LST was better than that at 0200 LST and 1400 LST. The average errors of dewpoint temperature and zonal wind increased significantly as the altitude increasesd, but those of the temperature and meridional wind had a little change. Finally, for the physical parameters calculated from the two kinds of sounding, the most had a consistent trend between two kinds of sounding except the Richardson index and Δθse, so they had a good qualitative value. However, for quantitative use, the error of the base elements must be considered. The humidityrelated parameters had different degrees of error, such as CAPE(Convective Available Potential Energy), Δθse(difference of pseudoeguivalent potential temperature between 850 hpa and 500 hpa), K index, vertical gradient of humidity and the dewpoint temperature difference. But, the parameters only related to the temperature or the lowlevel wind profile had high quantitative values because of the smaller absolute errors, such as the vertical temperature gradient, 0 °C and -20 °C layer height, lowlevel vertical wind shear.
2011, 16(6):707-716. DOI: 10.3878/j.issn.1006-9585.2011.06.04
Abstract:Based on the Landsat TM remote sensing images from 1990 to 2006, the relationship between different types of underlying surfaces and Urban Heat Island (UHI) by analyzing various underlying surfaces from different radius circular buffer zones (with Hefei Weather Station as their center) and their corresponding air temperatures (annual average temperaeure, maximum temperaeure,minimum temperaeure, and fixed time data). It is found that a very strong positive correlation between construction land and UHI and a negative correlation between woodland/grassland and UHI. There is a relatively strong positive correlation between water body and UHI at night. The influence of different types of underlying surfaces on UHI varies with different hours everyday. As far as range of influence is concerned, construction land is within 6 km; woodland/grassland is within 4 km; farmland influence reaches its peak at 4 km; influence of water body reaches 8 km slowly. At the same time, through analyzing the relationship between yearly Land Use and Land Cover Change (LUCC) and UHI, the authors give more evidence of the vital effect laid by city development on UHI. There is a relatively strong correlation between the maximum temperature and the annual variation of heat island intensity at 1400 LST and the yearly variation of LUCC. By the way, UHI decreases dramatically after the moving out of Hefei Weather Station. At last, the possible reasons for how the correlation between different underlying surfaces and UHI can be formed are discussed.
2011, 16(6):717-722. DOI: 10.3878/j.issn.1006-9585.2011.06.05
Abstract:The population, energy consumption，and the climate forcing for anthropogenic heat release (AHR) in China and in different provinces and areas were analyzed, as well as the relationship among them. Besides, the climate forcing for AHR in the future was predicted. The result shows that the climate forcing for AHR has greatly increased during recent 30 years. In 1978, the climate forcing for AHR is only 0.07 W·m-2, while it has increased to 0.28 W·m-2 in 2008.The distribution of AHR has regional characteristics in China，that is, the climate forcing for AHR in the northwestern part of China,they is very little, while in North China, Central China, East China，and South China,they are much higher than other regions. The distribution of the climate forcing for AHR is nonuniform，and it may be very high in some regions. It may influence the regional climate，as well as the climate of China, even the world climate.
2011, 16(6):723-732. DOI: 10.3878/j.issn.1006-9585.2011.06.06
Abstract:Using the monthly mean precipitation data at 67 stations over the Tibetan Plateau during 1967 to 2008, the spatial and temporal distribution characteristics of rainfall in flood season (from May to September) are analyzed through linear trend analysis, EOF, and Morlet wavelet transformation. The results indicate that there are distinct spatial variations of rainfall in the flood season in the Tibetan Plateau, which are concluded as three main patterns based on the EOF decomposition: The northsouth reverse type, the whole region consistent type, and the southeastnorthwest reverse type. Otherwise, the northsouth reverse type has an interannual oscillation cycle of quasifour years and a decadal oscillation cycle of quasi11 years, while the whole region consistent type has a cycle of 5-6 years. The precipitation in the northern part of the Tibetan Plateau shows a decreasing trend, but the precipitation in the southern part of the plateau shows an increasing trend.
2011, 16(6):733-741. DOI: 10.3878/j.issn.1006-9585.2011.06.07
Abstract:A field performance of Doppler wind lidar Windcube (released by Leosphere Company) was conducted by Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS) and Leosphere Company (from France) at the 325m meteorological tower site (a part of IAP, located between 3rd North Ring Road and 4th North Ring Road) from 11 December to 14 December 2007. The intercomparison of wind speed and wind direction obtained by Windcube and wind cup anemometers (fixed in the meteorological tower) shows that：1) 10min averaged wind speed is highly consistent between two types of wind data at six matched levels (63 m, 80 m, 100 m, 120 m, 160 m, and 200 m), the correlation coefficients all equal or exceed 0.98. 2) 10min averaged wind direction is calculated with the vector method, the correlation coefficients of averaged wind direction at the six levels are 0.99. 3) In comparison with domestic Doppler wind lidar, Windcube performs slightly better in wind speed measuring, and equally well in wind direction measuring. The intercomparison indicates that Windcube is a reliable and swift mobile system measuring wind profile at low levels.
2011, 16(6):742-752. DOI: 10.3878/j.issn.1006-9585.2011.06.08
Abstract:Using the upperair and surface observation data and sandstorm instrumental data of Inner Mongolian sandstorm monitoring stations, a severe sandstorm which lasted in the period from 19 Jan to 20 Jan 2010 was observed and analyzed. The result show that: Before the occurrence of this sandstorm, the stability of atmosphere was not conducive to the development of convection. However, the difference advection between from 700 hPa to 500 hPa and below 850 hPa was favorable for the increasing of temperature lapse rate. The strong cold advection caused a thermal convective instability which formed at the levels below its center and was favorable for the sandstorm burst. When dryconvective storm started and led to a sandstorm, the instable energy was released, which made the layer of the atmosphere tends to be a neutral stratification, namely the mixed layer. This layer may be an equilibrium state during the whole process. To some extent, the strength, location, and level of the cold advection in the middle and lower troposphere influenced the thickness of the mixed layer and the intensity of the sandstorm. During the process, due to both of the quick droppings of the temperature in the layers below the mixed layer and the heating effect of shortwave radiation at the top of sandstorm, there formed a temperature inversion cap at the top of the mixed layer (about 500 hPa). The strong cold air activity was the main reason for sandstorm occurrence which accompanied by the sharp dropping of land surface temperature and relative humidity, as well as by the rising of air pressure. The surface wind speed directly affected the strength of sandstorm. PM10(inhalable particle matter) value can reflect and describe the change of the sandstorm intensity in a better level. The change trend of the particles scattering coefficient was highly consistent with PM10 value: During the sandstorm, the scattering coefficient was generally above 1000 Mm-1; while the sandstorm being a strong one, it was mainly above 2000 Mm-1.
2011, 16(6):753-759. DOI: 10.3878/j.issn.1006-9585.2011.06.09
Abstract:The influence of the longterm linear trends on the seasonal forecast skill of the surface air temperature in summer and winter over China is investigated using both observations and ensemble seasonal forecast output from the numerical model IAP AGCM （Atmospheric General Circulation Model from the Institute of Atmospheric Physics, Chinese Academy of Sciences）during the period from 1979 to 2004. The results show that the temperature during the 26 years show a warming trend over most of China while the warming trend in winter is more significant than that in summer. IAP AGCM ensemble forecasts cannot reasonably capture the characteristics of the longterm liner climate trends. Further study shows that the seasonal forecast skill of the surface air temperature over China can be significantly improved if the numerical model can perfectly capture the longterm linear trends in the forecasts.
2011, 16(6):760-766. DOI: 10.3878/j.issn.1006-9585.2011.06.10
Abstract:Analyses of Characteristics and Trend of Air Temperature Variation along the Brahmaputra Valley
2011, 16(6):767-773. DOI: 10.3878/j.issn.1006-9585.2011.06.11
Abstract:The Manas River valley, which is the typical inland river formed from glaciermelted water in the Central Asia, was chosen as the sample. The trend and periodic fluctuation of climate change during the past five decades was analyzed, and the phenophase change and the response to climate change of locally main woody plants was illustrated. The results showed that the climate in Manas River valley generally trended to be warm and humid in the recent five decades. The degree of temperature rise was larger in the noncrop growing season than that in crop growing season, while the increment of precipitation was larger in crop growing season. The annual temperature exhibited a circular alternation from higher period to lower period under the scale of ten years, and the number of points of abrupt climate change increased, which indicated the complexity and uncertainty in the shortperiod climate fluctuation existing in this region. The inclination rate between the deciduous end and growing season in the main woody plants, for example Lombardy poplar, willows, Xinjiang poplar, and elm, is positive, which indicated phenological phenomena of woody plant occurred early. The regression coefficients between woody plants and climate factors were established to indicate that woody plant kept the same change trend with the temperature, precipitation, and sunshine hours.
2011, 16(6):774-778. DOI: 10.3878/j.issn.1006-9585.2011.06.12
Abstract:The lightning disaster risk of the six regions in Xiamen city are evaluated using fuzzy comprehensive evaluation method with the densities of earthstroked lightning, output value, and population as three evaluation indices. The lightning disaster risks in different regions of Xiamen city show that the Siming district, Xiangan district, and the other four districts belong to high risk area, low risk area, and medium risk areas, respectively, due to the discrepancies of ground flash, economy, and population. It is a more detailed reference to help the Xiamen lightning protection department to make scientific, appropriate, and economic lightning protection programs for the local situations.
2011, 16(6):779-788. DOI: 10.3878/j.issn.1006-9585.2011.06.13
Abstract:Using the data of 81 weather stations of Anhui Province, the characteristics of temperature series were analyzed. The selected 46 stations were classified into urban stations (US), rural stations(RS), and basic/reference stations (BS). The seasonal and annual variations of mean, maximum, and minimum temperatures at the 46 stations were analyzed during 1966-2005. The results show that warming rate of temperature, warming rate of urban heat island (UHI), and contributive rate of UHI at US, BS, and RS were the maximum, the second, and the minimum, respectively. The contribution rates of UHI effect on annual mean temperature fluctuated from 21.1% to 37.8%. With the UHI effect on the seasonal warming, the maximum warming rates of UHI at US and BS occurred in autumn, followed by spring and summer, and the minimum occurred in winter; the maximum contributive rates of UHI at US and BS occurred in summer, followed by autumn, and in winter and spring they were a little smaller. It is suggested that the impacts of the variation of UHI intensity on temperature series are complicated and cannot be ignored in Anhui Province.
2011, 16(6):789-804. DOI: 10.3878/j.issn.1006-9585.2011.06.14
Abstract:The longest cold snap since 1981, as well as snowy weather, which began in December 2009 across Europe like Britain, continued into January 2010. On 27 February 2010， a strong Atlantic cyclonic depression named Xynthia tore northeastward across coastal western Europe with hurricane force winds and heavy rains. Pakistan suffered the worst flood for 80 years during the monsoon season. The extreme heat wave accompanied by severe drought led to destructive forest fires in Russia during July and August. Parts of the Amazon basin were badly affected by drought during the later part of 2010. Super typhoon Megi struck the northern Philippines, southern part of China. Xinjiang experienced the most severe snow disaster for 60 years in January 2010. Parts of southwestern China experienced severe drought through late 2009 and early 2010. The extreme high temperature hit the northeastern part of China in June. In Zhouqu County of Gansu Province, China，several villages were leveled by landslides triggered by the heavy rainfall on 8 August. Heavy rains over Hainan Province, China led to the worst flooding in that region in nearly half a century. Extreme events of weather and climate happened frequently over the world in 2010.
2011, 16(6):805-814. DOI: 10.3878/j.issn.1006-9585.2011.06.15
Abstract:The current understanding about the effects of climate change on air quality is reviewed. It has been found that the increase of surface air temperature can accelerate the natural source emission of the precursors(eg. VOCs) of some air pollutions (eg. O3); it can change the vertical mixing and diffusion rate by modifying the chemical reaction rate, the height of Planetary Boundary Layer (PBL), and the occurrence frequency of weather systems; it can also alter the atmospheric circulation and thereby change the manner of pollution transport. Climate change can affect not only the outdoor air quality but also the indoor air quality, hence there might be a threat to human health. Thus, climate change can impact the regional or local outdoor and indoor air quality, on which most scholars have reached an agreement. However，these impacts still have some major uncertainties: The trend and intensity of future climate change, the future emission of air pollutions and their precursors, the correlation between atmospheric pollution and climate change factors, and the physical and chemical mechanisms of atmospheric constituents in the diverse meteorological conditions. The topic on the effect of climate change on air quality is still at the initial stage in China. Therefore, the authors suggest discreetly that the research projects on this topic, especially, on the impacts of climate change on airpollutionrelated public health, should be launched in China.