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A hybrid regression/time series modelling was used to relate the total daily punctuality (TOTP) at Frankfurt Airport, Germany, to weather, the traffic flow and the airport system state. The selected modelling approach is applied to the annual, the multi-annual and seasonal data of the years 2001–2006. Reduction of the initial variables system dimension is achieved through the application of the principal component analysis (PCA) method. The portion of the variability that can be explained by the model after correction of autocorrelations in the residuals using autoregressive (AR) models, is between 60 and 69%. A slight year-to-year variability in the number of statistically significant model parameters is detected. Upon identification of the terminal-specific delay impact factors, the possibility of the 24 h punctuality forecast for the interval of 1 year was discussed. Copyright © 2008 Royal Meteorological Society

During four consecutive days in May 2001, convectively forced short-period (6–45 min) gravity waves were observed with a 482 MHz wind profiler, which is continuously operated by the Deutscher Wetterdienst (German Weather Service) at the Lindenberg observatory, 60 km south-east of Berlin. The objective of this campaign was to investigate onset and development of convectively forced gravity waves in the lower and middle troposphere. The wave character could be unambiguously identified by simultaneous vertical wind and temperature measurements and their respective phase shift of π/2. In accordance with previous findings, convection waves were found to be generated at the top of the convective boundary layer. They propagate predominantly horizontally with a slow but clearly recognizable vertical increase of wave activity. The layer with significant wave activity reached the upper detection range at 7.0 km within a couple of hours on each of the observational days. Gravity wave activity started to decay after 16 UTC with a slower rate than the simultaneously decaying forcing convection. Some wave activity remained during the night but at low amplitude levels. The vertical wind energy component of the free atmosphere was found to be about 30% of the corresponding convective boundary layer (CBL) energy, which is much more than previously reported values from numerical simulations. The wavelet analysis of highly resolved wind profiler vertical velocity data (Δt = 16 s, Δz = 250 m) in the boundary layer and free troposphere gives new insights into the temporal and vertical development of very-short-period convection waves through the troposphere. At the CBL top, a broad spectrum of wave scales with intrinsic periods between 6 and 45 min is generated. With increasing height, shorter scales (T ≤ 13 min) disappear and only longer ones remain. Wave trapping, which is confirmed by vertically orientated phase lines, is an important mechanism here. Copyright © 2004 Royal Meteorological Society

It is a well-known fact that adverse weather significantly influences the safety and operating efficiency of air traffic, particularly in the terminal area. The unavoidable consequences of reduced operating efficiency are delays, diversions and cancellations of flights. In this paper the impact of thunderstorms on landing aircraft at Frankfurt Airport (Germany) during 1997 and 1998 is analysed. Thunderstorms are among the major weather phenomena affecting airport operations. Weather and operating conditions permitting, Frankfurt Airport is operated at more than 100% of its nominal capacity, which in turn lowers the actual capacity during periods of adverse weather. To the authors' knowledge this is the first quantitative study of weather impact on aviation in Germany. To identify thunderstorms as the unambiguous cause of delays, days without thunderstorms were used for reference and the difference in delay time was determined. The study shows that in 1997 thunderstorms increased the accumulated regular delay time by a factor of 6.3 and in 1998 by a factor of 1.1. On average, a thunderstorm typically caused about 740 delay minutes in addition to the 280 regular delay minutes for a sum of 100 arriving aircraft within four hours of average impact time. Copyright © 2003 Royal Meteorological Society

A 2D-cloud model with spectral microphysics including ice physics and aerosol particle scavenging effects is used to simulate the 19 July 1981 CCOPE thunderstorm case. The net vertical transport of a chemically inert tracer between 30 respective levels by a single thunderstorm was determined in terms of a transilient matrix. Additionally, the redistribution of sulfur which was assumed to be initially present in aerosol particles was investigated. Beside transport with the mean wind, nucleation scavenging, particle scavenging, and wet deposition contribute to the observed redistribution. — The simulations show that even a moderate thunderstorm may reduce the pollution in the boundary layer by 50%. Trace species may be transported in less than half an hour from the ground to the upper troposphere and, in contrast, trace species originating from the upper troposphere may not have the change to be transported down to the ground. Net mixing strongly depends on the detailed dynamical and microphysical structure of the investigated thunderstorm. The hypothesis that thunderstorms play an important role in redistribution and wet deposition of airborne aerosol particle mass is confirmed.