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1.
Following the Balloon Intercomparison Campaigns carried out from the NSBF, Palestine, Texas, in the fall of 1982 (BIC1) and spring of 1983 (BIC2), three instruments have reported infrared measurements (one in emission and two in absorption) from which results on the concentration of methane between 20 and 40 km altitude have been deduced. While the absorption-retrieved concentration profiles are in excellent agreement, the results from the emission measurements are significantly lower. Recent methane profiles obtained by satellite and from Spacelab 1 are in satisfactory agreement with the absorption data reported here. 相似文献
2.
C. B. Farmer B. Carli A. Bonetti M. Carlotti B. M. Dinelli H. Fast W. F. J. Evans N. Louisnard C. Alamichel W. Mankin M. Coffey I. G. Nolt D. G. Murcray A. Goldman G. M. Stokes D. W. Johnson W. A. Traub K. V. Chance R. Zander G. Roland L. Delbouille 《Journal of Atmospheric Chemistry》1990,10(2):237-272
All of the techniques used to measure stratospheric HCl during the two BIC campaigns involved high resolution infrared spectroscopy. The balloon-borne instruments included five different spectrometers, three operating in the solar absorption mode and two in emission (at distinctly different wavelengths). Ground-based and aircraft correlative measurements were made close to the balloon locations, again by near-infrared spectroscopy.Within this set of results, comparisons between different techniques (absorption vs emission) viewing the same airmass (i.e., on the same gondola) were possible, as were comparisons between the same technique used on different gondolas spaced closely in time and location. The final results yield a mean profile of concentration of HC1 between 18 and 40 km altitude; an envelope of ±15% centered on this profile encompasses all of the results within one standard deviation of their individual mean values. The absolute accuracy of the final profile is estimated to be no worse than 10%. It is concluded also that the measurement techniques for HCl have reached a level of performance where a precision of 10% to 15% can be confidently expected. 相似文献
3.
D. Murcray A. Goldman J. Kosters R. Zander W. Evans N. Louisnard C. Alamichel M. Bangham S. Pollitt B. Carli B. Dinelli S. Piccioli A. Volboni W. Traub K. Chance 《Journal of Atmospheric Chemistry》1990,10(2):159-179
The Balloon Intercomparison Campaign (BIC) was set up to intercompare remote sensing measurements of a number of compounds other than water vapor; however, water vapor has strong absorption features throughout the infrared and mm wave regions of the spectrum. Therefore many of the investigators involved in BIC have absorption or emission features due to water vapor in the data they obtained during the balloon flights made under the campaign. These features have been used by the investigators to determine the stratospheric water vapor profiles which are compared in this paper. The profiles allow comparison of a wide range of remote sensing techniques involving both emission and absorption in the mid-infrared and emission techniques in the far infrared. 相似文献
4.
基于WRF中尺度模式,采用集合卡尔曼滤波方法同化中国岸基多普勒天气雷达径向速度资料,对2015年登陆台风彩虹（1522）进行数值试验。从台风强度、路径、结构等方面验证了同化效果,并对不同区域雷达观测资料的同化敏感性进行讨论。试验结果表明:在同化窗内同化分析场台风位置误差相比未同化平均减小15 km,最多时刻减小38 km,同化资料时次越多,确定性预报路径误差越小。同化雷达资料后较好地反映出台风彩虹（1522）近海加强过程,台风中心最低气压同化分析和预报误差相比未同化最大减小超过25 hPa,台风眼的尺度、眼墙处对流非对称结构相比未同化与观测更加接近。试验还表明:台风内核100 km范围内的雷达观测对同化效果影响最大,仅同化这部分资料（约占总量的20%）各方面效果与同化全部资料相近,而仅同化100 km以外资料效果明显不及同化所有资料。仅同化台风内核雷达观测资料可以在不影响同化效果的前提下,使集合同化计算机时减小为原来的1/3,该策略可为台风实际业务预报提供一定参考。 相似文献
5.
基于北京地区快速更新循环同化预报系统 (BJ-RUC)、WRF-Chem模式和优选的能见度参数化方案,建立了北京区域环境气象数值预报系统。对2014年全年PM2.5浓度、能见度和APEC (Asia-Pacific Economic Cooperation) 期间预报效果检验结果表明:该系统对京津冀及周边地区PM2.5浓度的预报效果较好,大部分站点的相关系数在0.6以上,特别是北京的部分站点可达0.8以上,预报结果相比观测总体偏低,随着预报时效的延长,24 h之后预报效果略有下降。相比人工观测,能见度预报结果与自动观测能见度更加接近,对持续性低能见度过程预报与实况吻合较好,对于小时能见度低于10 km的分级检验显示,预报准确率从77%左右逐级下降,2 km以下在40%左右。2014年APEC期间,系统很好地预报出北京地区空气质量指数、PM2.5浓度和能见度的时空演变特征,为APEC期间环境气象预报服务提供了有力的技术支撑。 相似文献
6.
Compact two-channel IR radiometers for solar occultation experiments have been constructed in order to measure concentration profiles of stratospheric trace gases. The instruments can be used as filter-or gas correlation-type radiometers depending on the trace gas under investigation. Within the LIMS correlative measurement program, balloon flights were performed with a payload of up to four of these two-channel radiometers. From the gas correlation-type measurements, profiles of the trace gas NO2 are inferred for the altitude region between about 20 km and the balloon float level. The data evaluation also includes a comprehensive analysis of the error sources and their effect on the accuracy of the NO2 profiles. The derived profiles are compared among themselves and are assessed against the observations of other authors by accounting for the diurnal, latitudinal and seasonal changes of NO2. As a by-product of our measurements, the mean absorption of the O2 collision-induced band at 6.4 m was determined within the range of the interference filter used and compared with calculations based on known absorption coefficients. 相似文献
7.
8.
广州站能见度数据质量评估及其参数化研究 总被引：1，自引：0，他引：1
利用广州地面观测站（简称广州站）的两种能见度仪和人工观测的能见度资料,分析两种观测方法之间的一致性和差异性,并对广州站能见度建立参数化模型。研究结果表明,不同的能见度范围和观测时次,两者均有较好的一致性;当能见度为3 km以下及10 km以上时,两者一致率较高;在5次正点观测的器测和目测值一致率均高达90%以上。10~30 km范围内的平均相对误差较低,其余范围均高于20%。在11、14和17时的相对误差低于10%,08和20时的相对误差较高。能见度在1~10 km范围内,随着能见度的增大,器测与目测平均相对误差增大,仪器粗差率增大。另外,基于大气相对湿度、颗粒物数浓度建立广州站能见度参数化模型,能较准确模拟出能见度变化的趋势。实际检验表明,模拟值与实况误差基本小于3 km。因此,该模型可以预报广州站的能见度,为准确判断广州市能见度变化提供一定的参考依据。 相似文献
9.
为了进一步提高国家气象中心区域模式台风数值预报系统（GRAPES_TYM）的预报能力,2016年对模式参考大气廓线以及涡旋初始化方案进行了改进:由模式初始场水平方向平均的一维参考大气代替原来的等温大气,涡旋初始化方案取消了原涡旋重定位并将涡旋强度调整半径由原来的12°减小到4°。对2014—2016年的生命史超过3 d的所有台风进行了回算,路径及近地面最大风速统计误差分析表明:参考大气的改进可以减小模式对台风预报路径预报的系统北偏和平均路径误差,尤其是140°E以东的转向台风。涡旋初始化方案中强度调整半径的减小会进一步减小模式预报路径的北偏趋势,从而进一步减小平均误差。同业务系统预报结果相比,改进后的GRAPES_TYM（包括参考大气和涡旋初始化）可以使平均路径误差分别减小10%（24 h）,12%（48 h）,16%（72 h）,14%（96 h）以及15%（120 h）。同美国NCEP全球模式路径预报相比,GRAPES_TYM在西行、西北行登陆我国的台风路径预报有一定优势。 相似文献
10.
An Examination of ENSO''s Effect on the Monthly and Seasonal Climate of Hong Kong from a Statistical Perspective 
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下载免费PDF全文 This study aims to examine the effect of El Ni~no and La Ni~na on the monthly and seasonal climate
of Hong Kong against the ENSO-neutral situation from a statistical perspective. Monthly and seasonal
temperature and rainfall of Hong Kong and monthly number of tropical cyclones (TCs) coming within 500
km of the city over the 59-yr (1950-2008) period are examined under three ENSO situations, namely El Ni~no,
La Ni~na, and ENSO-neutral. It is found that, compared with the ENSO-neutral situation, El Ni~no tends
to be associated with wetter winter (December-February) and spring (March-May) while La Ni~na tends
to be associated with cooler autumn (September-November) and winter. El Ni~no tends to be associated
with a later start of the tropical cyclone season of Hong Kong while La Ni~na tends to be associated with
more TCs coming within 500 km of Hong Kong in August-October. It is also found that, for April and
June-December, although the monthly number of TCs coming within 500 km of Hong Kong during El Ni~no
is generally lower than that under the ENSO-neutral situation, the difference is not statistically significant
based on the current data sample size. 相似文献
11.
北京奥运会期间NO2浓度降低原因分析 总被引：1，自引：0，他引：1
2002～2008年,北京市城区和近郊8月的NO2月均浓度大体呈现逐年下降趋势,其中前5年二者均以每年约10%的降幅下降,2008年发生显著下降,降幅达40%左右。利用嵌套网格空气质量模式系统(NAQPM/IAP),采用敏感性试验方法,评估了气象条件与污染控制措施对北京奥运会期间大气NO2浓度降低的影响,评估不同污染控制措施对NO2浓度降低的作用。研究结果表明,污染控制措施是NO2浓度降低的主要影响因素,其中面源的污染控制措施对于NO2浓度降低的作用最明显。 相似文献
12.
William G. Mankin M. T. Coffey K. V. Chance W. A. Traub B. Carli F. Mencaraglia S. Piccioli I. G. Nolt J. V. Radostitz R. Zander G. Roland Douglas W. Johnson Gerald M. Stokes C. B. Farmer R. K. Seals 《Journal of Atmospheric Chemistry》1990,10(2):219-236
Observations of the vertical profile of hydrogen fluoride (HF) vapor in the stratosphere and of the vertical column amounts of HF above certain altitudes were made using a variety of spectroscopic instruments in the 1982 and 1983 Balloon Intercomparison Campaigns. Both emission instruments working in the far infrared spectral region and absorption instruments using solar occultation in the 2.5m region were employed. No systematic differences were seen in results from the two spectral regions. A mean profile from 20–45 km is presented, with uncertainties ranging from 20% to 50%. Total columns measured from ground and from 12 km are consistent with the profile if the mixing ratio for HF is small in the tropophere and low stratosphere. 相似文献
13.
Globally-coupled climate models are generally capable of reproducing the observed trends in the globally averaged atmospheric temperature or mean sea level. However, the global models do not perform as well on regional/local scales. Here, we present results from four 100-year ocean model experiments for the Western Baltic Sea. In order to simulate storm surges in this region, we have used the General Estuarine Transport Model (GETM) as a high-resolution local model (spatial resolution ≈ 1?km), nested into a regional atmospheric and regional oceanic model in a fully baroclinic downscaling approach. The downscaling is based on the global model ECHAM5/MPI-OM. The projections are imbedded into two greenhouse-gas emission scenarios, A1B and B1, for the period 2000–2100, each with two realisations. Two control runs from 1960 to 2000 are used for validation. We use this modelling system to statistically reproduce the present distribution of surge extremes. The usage of the high-resolution local model leads to an improvement in surge heights of at least 10% compared to the driving model. To quantify uncertainties associated with climate projections, we investigate the impact of enhanced wind velocities and changes in mean sea levels. The analysis revealed a linear dependence of surge height and mean sea level, although the slope parameter is spatially varying. Furthermore, the modelling system is used to project possible changes within the next century. The results show that the sea level rise has greater potential to increase surge levels than does increased wind speed. The simulations further indicate that the changes in storm surge height in the scenarios can be consistently explained by the increase in mean sea level and variation in wind speed. 相似文献
14.
应用大气化学模式WRF-Chem(Weather Research and Forecast-Chemistry),分别选用亚洲排放源清单INTEX-B(Intercontinental Chemical Transport Experiment-Phase B)、REASv2.1(Regional Emission inventory in Asia version 2.1)以及全球排放源清单HTAP_v2(Hemispheric Transport of Air Pollution version 2),对浙江省2013年12月进行模拟,分别记为IN、RE和HT试验,研究人为源排放清单对大气污染物浓度数值模拟的影响。结果表明,3组试验合理的反映出PM2.5(空气动力学当量直径小于等于2.5μm的颗粒物,即细颗粒物)、PM10(空气动力学当量直径小于等于10μm的颗粒物,即可吸入颗粒物)和NO_2近地面浓度的时空分布特征,相关系数为0.5~0.8,85%以上的模拟值落在观测值的0.5~2倍范围内,但对SO_2近地面浓度模拟较差。IN、RE、HT试验对PM2.5和PM10的模拟偏差均成递减趋势,约为30%、16%和6%,HT试验的模拟值更加接近观测。INTEX-B清单中PM2.5的一次排放与二次气溶胶前提物SO_2均高于REAS与HTAP清单,因此会导致更多的硫酸盐生成,从而进一步增加PM2.5浓度。HTAP_v2清单中较低的NH3排放会抑制硝酸盐的生成,从而有助于降低PM2.5浓度。3个清单的基准年与模拟年的差异对SO_2浓度模拟的准确性影响更大,INTEX-B清单中SO_2排放量明显高于REASv2.1与HTAP_v2清单,尤其在浙北和沿海工业发达地区,导致IN试验模拟的SO_2在这些地区存在明显高估。3组试验模拟的NO_2浓度偏差最小且更为接近(-8%~4%),主要原因是3个清单在浙江省的NOx排放十分一致。从3组试验结果之间的差异程度来看,浙江省范围内PM2.5、PM10、SO_2和NO_2逐日浓度模拟值之间的平均差异程度分别约为14%、15%、51%和16%,最大差异程度分别为69%、78%、137%和132%。月均浓度与逐日浓度的平均差异程度基本一致,但最大差异程度明显更低。总体来看3组试验模拟的PM2.5、PM10与NO_2的差异程度明显低于SO_2。 相似文献
15.
本文从实验气溶胶样品、实验技术和分析方法三个方面对以往的实验室研究结果进行综合分析, 归纳总结出适合东亚地区沙尘气溶胶的非均相吸附系数γ的参考值, 并利用区域大气化学模式, 模拟研究了非均相吸附系数γ的不确定性对东亚地区沙尘气溶胶非均相化学过程的影响。为了研究非均相反应对γ的敏感性, 针对其中四种物质(HNO3、N2O5、O3和SO2) 的γ上限值和下限值, 分别进行了T-up (上限值) 和T-low(下限值)两个敏感实验; 针对相对湿度对HNO3和N2O5非均相吸附系数的影响进行了T-rh敏感实验。模拟结果与观测资料进行了对比分析, 结果表明模式可以比较好地反映气态物质、气溶胶浓度的演变过程和非均相反应过程。考虑非均相反应后模拟的硫酸盐和硝酸盐浓度与观测值更接近一些。采用γ参考值的模拟结果总体上比采用γ上限值和γ下限值更合理, 把γ系数作为相对湿度的函数来处理比作为常数处理更合理。沙尘气溶胶通过非均相化学反应, 可以使模拟区域内SO2、NOx和O3的平均浓度下降, 使硫酸盐和硝酸盐颗粒物浓度增加, 采用γ参考值计算得到3 km以下的上述物质的变化率分别为－3.44%、－5.92%、－1.75%、5.22%和23.25%, 显示沙尘表面非均相化学反应对大气化学成分特别是气溶胶有较大的影响; 不同γ取值对上述物质变化率有一定影响, 其中对硝酸盐和臭氧的影响较大, T-up和T-low 模拟结果之间可以相差13.4%和10.1%。 相似文献
16.
航空运输是交通领域CO2排放增长最快速的部门。文中选择中国民航使用频率较高的超大型、大型、中型和小型飞机的典型机型,基于不同飞机在起飞、爬升、巡航、接近和滑行阶段引擎油耗速率、运行时间和油耗量的变化,计算航空飞机CO2排放因子。同时结合各机型碳排放因子、额定载客量与客座率评估旅客搭乘不同飞机时的人均CO2排放量（即单位客运周转量CO2排放因子)。结果显示,超大型飞机、大型飞机、中型飞机和小型飞机在其航程区间内的平均CO2排放因子分别为49.8、31.7、16.2和8.5 kg CO2/km;满载条件下单位客运周转量CO2排放因子均值分别为102.6、95.2、81.7和112.4 g CO2/(人∙km)。起飞和爬升阶段引擎油耗速率约为巡航阶段油耗速率的2.6~3.4倍和2.0~2.8倍,飞机CO2排放因子随飞行里程的提高而降低。航空运输是高碳客运方式,相同里程条件下,航空单位客运周转量CO2排放因子显著高于高铁、道路机动车等其他客运方式。提升燃油效率、减少短途航运、合理安排航线以提高客座率并减少中途转机是降低航空碳排放量的有效途径。 相似文献
17.
GRAPES模式中的坡地辐射方案及其对短期天气过程模拟的影响 总被引：10，自引：4，他引：6
为了改进太阳短波辐射参数化, 在非静力中尺度模式GRAPES (全球/区域同化和预报系统) 中考虑了坡地辐射 (SLOPE), 并着重讨论其在不同分辨率情况下对我国短期天气过程的影响.数值试验结果表明: 地形坡度和坡向对地表短波辐射 (GSW) 计算有较大的影响, 与没有考虑坡地作用的参考运行 (FLAT) 相比, 早晨和傍晚的GSW最小可减小60%以下, 最大也可增加60%以上, 比一天中其他时间和平均值大得多.在江淮流域一次梅雨锋降水过程中, 坡地辐射参数化方案的引入对降水模拟有较明显的影响, 特别在高分辨率 (6 km) 情况下, 降水的增加和减小不仅发生在GSW改变比较大的地区, 且与复杂地形有较好的相关性.另外, 由于地形坡度和坡向引起地表温度的改变与地表热通量的变化一致, 且也发生在地形起伏的多山地区.因此, 当水平分辨率较高且地形陡峭起伏时, 应当包含坡地辐射. 相似文献
18.
An Examination of ENSO’s Effect on the Monthly and Seasonal Climate of Hong Kong from a Statistical Perspective 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 This study aims to examine the effect of El Nino and La Nina on the monthly and seasonal climate of Hong Kong against the ENSO-neutral situation from a statistical perspective. Monthly and seasonal temperature and rainfall of Hong Kong and monthly number of tropical cyclones (TCs) coming within 500 km of the city over the 59-yr (1950-2008) period are examined under three ENSO situations, namely El Nino, La Nina, and ENSO-neutral. It is found that, compared with the ENSO-neutral situation, El Nino tends... 相似文献
19.
COMPARISON OF SINGLE-STATION LIGHTNING LOCATION WITH THREE-STATION MEASUREMENTS AND RADAR DATA 下载免费PDF全文
下载免费PDF全文 A single-station or monostatic lightning detection and ranging system (M-LDARS),that is based on Wait's wave propagation theory and arrival-time differences between sky- and ground-wave atmospherics,has been developed by the University of Science and Technology of China (USTC).Lightning location by the system was compared with a three-station lightning location (TLL) system during July and August 1991 in Beijing,under the support of Chinese Academy of Meteorological Sciences (CAMS).The experimental results show that M-LDARS system can be used to observe direction,distance,intensity and polarity of cloud-to-ground strokes with good confidence for ranges less than about 250 km.90 percent of M-LDARS location points were within radar echoes,i.e.about 90% of the points were inside of the 0 dB isoline or outside,but within 10 km of the 0 dB isopleth.Average direction deviation and relative average deviation of distance between the single- and three-station measurements are respectively 12.8° and 14.1%. 相似文献
20.
何吉成 《气候变化研究进展》2011,7(4):281-287
基于中国民航部门逐年统计数据,计算了1960—2009年中国民航飞机的CO2逐年排放量,分析了中国民航飞机CO2排放强度及其变化特点。结果表明:中国民航飞机CO2总排放量由1960年的12.0万t增至2009年的4144万t;CO2排放强度呈明显的降低趋势,由1960年的2.9 kg/换算吨公里降至2009年的0.96 kg/换算吨公里,年均降低0.04 kg/换算吨公里。中国民航飞机的CO2排放量占整个交通运输仓储和邮政行业CO2排放量的比例较低,仅占6.6%,占全国化石燃料燃烧CO2排放量的比例也很小,平均只有0.25%。 相似文献