Air transport cruise altitude restrictions to minimize contrail formation

Abstract

While quantification of the effects of NO _x and water vapor is still at an early stage there is evidence that contrail formation could make a significant contribution to global warming. This paper builds on previous research that analyzed a policy of restricting air transport cruise altitudes to eliminate contrail formation. Our previous work [Transport. Res. D 7(6) (2002) 451], examined altitude restrictions in European airspace and concluded that this could be a beneficial policy for reducing climate change impacts from aviation. Since most of the flights in European airspace are short-haul flights, this paper evaluates the trade-offs between altitude restrictions, fuel burn and journey times for longer haul flights of up to 6000 nm. Our focus is on the North Atlantic and US airspace and we examine potential contrail fraction to determine optimal cruise altitudes for reducing contrail formation. Changes in fuel burn and travel times associated with flight levels of 18,000 and 31,000 ft for different aircraft types are analyzed. We find that, in most cases, CO₂ emission increases would be unlikely to entirely counteract the benefit of possible reductions in contrail formation. For some aircraft types, the percentage increase in emitted CO₂ was found to be strongly dependent on journey length. In general, journey times appear not to be a major issue except for some aircraft types. Our results suggest that reducing aircraft cruise altitudes could be a beneficial policy for mitigating climate change impacts from the aviation sector. This is clearly dependent on aircraft type and the distances traveled, but more importantly on ambient atmospheric conditions which can vary significantly between regions and due to daily variation. This suggests that real time flight planning to minimize contrail formation should be investigated as a possible climate mitigation policy.     

用高度订正方法确定区域自动气象站气候界限值

广西区域自动气象站建站的时间最长不到7年,大部分站点分布在不同高度的丘陵,因资料时间序列短,利用本站资料直接统计气候界限值,无法真实代表本站的气候界限值范围.为此,引入高度差订正来解决这个问题.先选取与之临近的国家气象站点作为参考站,统计出参考站点的气候界限值,再根据气温、气压、风速随高度变化的相关规律,对参考站的气候界限值进行高度订正,得出区域自动气象站点的气候界限值,经过比较,通过高度差订正后,各要素的气候界限值更具有代表性和可用性.该方法的统计值已在广西区域自动气象站实时数据质量控制系统中使用,取得很好的效果.     

贵州省分月太阳辐射参数模型计算

利用贵州省2011—2015年10个太阳辐射站观测资料,采用最小二乘法分月拟合太阳辐射计算参数a、b,结合相应站点的地理信息(纬度和海拔高度),建立参数随地理位置变化的分月模型,进行1962—1990年威宁站独立样本检验,利用2001—2010年贵阳站数据与海拔分区法进行比较;结合1981—2010年85个常规气象站日照时数资料和相应站点的地理信息推算累年各月太阳总辐射量,并探讨其空间分布规律。结果表明:用分月参数模型计算贵州省太阳辐射误差更小、精度更高,提高了太阳辐射计算的准确率;贵州省气象台站年平均太阳总辐射在3415.76~4737.04 MJ·m~(-2)之间,西部和西南部多,北部少,其中年总辐射最大值出现在威宁,最低值出现在务川。     

Air transport cruise altitude restrictions to minimize contrail formation

While quantification of the effects of NO_x and water vapor is still at an early stage there is evidence that contrail formation could make a significant contribution to global warming. This paper builds on previous research that analyzed a policy of restricting air transport cruise altitudes to eliminate contrail formation. Our previous work [Transport. Res. D 7(6) (2002) 451], examined altitude restrictions in European airspace and concluded that this could be a beneficial policy for reducing climate change impacts from aviation. Since most of the flights in European airspace are short-haul flights, this paper evaluates the trade-offs between altitude restrictions, fuel burn and journey times for longer haul flights of up to 6000 nm. Our focus is on the North Atlantic and US airspace and we examine potential contrail fraction to determine optimal cruise altitudes for reducing contrail formation. Changes in fuel burn and travel times associated with flight levels of 18,000 and 31,000 ft for different aircraft types are analyzed. We find that, in most cases, CO₂ emission increases would be unlikely to entirely counteract the benefit of possible reductions in contrail formation. For some aircraft types, the percentage increase in emitted CO₂ was found to be strongly dependent on journey length. In general, journey times appear not to be a major issue except for some aircraft types. Our results suggest that reducing aircraft cruise altitudes could be a beneficial policy for mitigating climate change impacts from the aviation sector. This is clearly dependent on aircraft type and the distances traveled, but more importantly on ambient atmospheric conditions which can vary significantly between regions and due to daily variation. This suggests that real time flight planning to minimize contrail formation should be investigated as a possible climate mitigation policy.     

区域自动气象站质量控制参数值高度订正的方法

根据区域自动气象站质量控制方法,结合广西区域自动站分布特点和业务需要,对温度、气压、风要素的质量控制参数进行高度订正,经过比较,通过高度差订正后,各要素的质量控制参数更具有代表性。     

Minor Constituent Concentrations Measured from a High Altitude Aircraft Using High Resolution Far-Infrared Fourier Transform Spectroscopy

Far-infrared emission spectroscopy has beendemonstrated to be a valuable method for remotesensing of trace species in the stratosphere, with theability to simultaneously detect a number of keychemical species. SAFIRE-A is a new far-infraredFourier Transform (FT) spectrometer which has beenspecifically designed to operate on board of a highaltitude aircraft in the lower stratosphere and uppertroposphere regions where relatively few remotesensing measurements have been made. Using newtechnology, the sensitivity of the FT spectrometermethod has been substantially improved for the longwavelength region. Results are reported formeasurements of O₃, HNO₃ and N₂O at 17and 19 km using a detection window near 23 cm^-1.Geographical and altitude variability of the volumemixing ratio of these constituents and their relativecorrelation are discussed. Ozone measurements agreewell with in situ measurements, except in regions ofstrong stirring and mixing associated with deformationof the northern vortex edge. Whilst SAFIREmeasurements of trace gases do not capture all of thelocal variability seen by rapid in-situ techniques,they can indicate horizontal variability close to, butnot intercepted by, the aircraft's flight path. Apossible detection of ClO at the low background levelsexpected outside the polar vortex is also reported.     

探空高度与雷达高度的比较研究

利用2009年1月南京探空站L波段高空探测的试验记录,以GPS所测的高度数据作为标准,分别从探空高度和雷达高度作了详细分析.结果表明:探空高度与GPS高度的差值随着探测高度的升高而增大,并且随着高度升高,增大的幅度越快;雷达高度与GPS高度的差值有正有负,随着探测高度的升高,总体上高度差值变大,且差值变化幅度出现较大起伏,其稳定性较差.100 hPa以下,探空高度比雷达高度的可信度大,选取探空高度较好;100hPa以上,雷达高度比探空高度可信度大,选取雷达高度较好.     

浅谈斜距不合理时的正确处理方法

在使用L波段高空探测系统时,由于探空仪受地物同波或其他因素的影响,经常出现斜距跟踪不好的情况,为了确保探测记录的准确性,必须掌握正确的处理方法。文章将自己工作中遇到的实际情况处理的方法,加以总结．与大家分享,共同提高探测质量。