Search

Abstract: We propose a submillimetre-wave atmospheric emission sounding instrument, called Far-InfraRed Experiment (FIRE), for the Japanese Martian exploration programme “Mars Exploration with Lander-Orbiter Synergy” (MELOS). The scientific target of FIRE/MELOS is to understand the dust suspended meteorology of the Mars. FIRE will provide key meteorological parameters, such as atmospheric temperature profiles for outside and inside dust storms, the abundance profile of the atmospheric compositions and their isotopes, and wind velocity profiles. FIRE will also provide the local time dependency of these parameters. The observational sensitivity of FIRE/MELOS is discussed in this paper. FIRE will explore the meteorological system of the Martian atmosphere including the interaction between its surface and atmosphere. [Copyright &y& Elsevier]

Abstract: GOMOS (Global Ozone Monitoring by Occultation of Stars) and MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) are remote sensing instruments on board the European Space Agency’s Envisat satellite. GOMOS and MIPAS have been designed for observations of stratospheric and mesospheric constituents, including ozone and nitrogen dioxide. Both instruments have a good global coverage of observations and can provide data also from the polar regions. In this paper, we compare night-time data from GOMOS with those from MIPAS. We present statistics of selected sets of data spanning from the year 2003 to 2006. The results for low-to-mid latitudes show that the two instruments are in a good agreement in the middle stratosphere, the differences being typically less than 5%. In the upper stratosphere, GOMOS observations generally show 15% higher values than those from MIPAS. The bias is in virtually all cases smaller than the combined systematic error of the measurements, giving great confidence in the GOMOS and MIPAS data quality. The result for high mesospheric mixing ratios observed in the polar regions during winter times indicate a good agreement between GOMOS and MIPAS. In the mesosphere, the difference is less than 35% and smaller than the systematic error. Due to the high mesospheric signal, MIPAS sensitivity decreases in the stratosphere which results in larger differences between the two instruments. [Copyright &y& Elsevier]

A hybrid regressiontime 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 multiannual 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 yeartoyear variability in the number of statistically significant model parameters is detected. Upon identification of the terminalspecific delay impact factors, the possibility of the 24 h punctuality forecast for the interval of 1 year was discussed. Copyright © 2008 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Lowlevel turbulence can bring about rapid bumps and jolts to an aircraft. In severe turbulence, the aircraft may suffer momentary loss of control. In accordance with the practice of the International Civil Aviation Organization ICAO, turbulence intensity is expressed in terms of the cube root of the eddy dissipation rate EDR. Measurement of the EDR is an important component in the provision of turbulence alerting services for arriving and departing aircraft at an airport. This article describes a method to calculate the EDR profile using the wind measurements from a groundbased minisodar located near the Hong Kong International Airport HKIA. The method makes use of the vertical wind data at 0.25 or 0.5 Hz provided by the minisodar depending on the maximum measurement range and searches for the inertial subrange in the frequency spectrum of the vertical wind. The accuracy of the wind and EDR measurements of the minisodar is first established by comparison with meteorological tower data in a field experiment. The potential application of the EDR profiles in terraindisrupted airflow at HKIA is then demonstrated through two case studies. The EDR profiles obtained from the minisodar are found to be of good quality and could be useful in the monitoring of lowlevel turbulence for aviation applications. Copyright © 2008 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Deriving accurate time-series of cloud cover from satellite sensor data still remains a challenging task. The instruments onboard polar orbiting NOAA satellites offer the opportunity to prepare cloud climatology on a global scale; however, the orbital drifts of these satellites can introduce uncertainty when deriving such cloud climatology. The aim of this letter is to point out the importance and to estimate the impact of orbital drift on long-term time-series of the observation of convective cloud frequency of occurrence. The 20 years of daytime AVHRR data from over the Indian subcontinent for the summer monsoon season is used in this study. All four AVHRRs onboard NOAA-7, -9, -11, and -14 satellites show positive correlation between increased cloud frequency and the delay in equator crossing-times during their lifetime. This increase is significant over land, but over the ocean, there is no discernible effect. This effect should be considered to avoid spurious trends in cloud cover. Further in-depth investigations are needed to make possible corrections. [ABSTRACT FROM AUTHOR]

Abstract  This paper investigates the third-order residual range error in the dual-frequency correction of ionospheric effects on satellite navigation. We solve the two-point trajectory problem using the perturbation method to derive second-approximation formulas for the phase path of the wave propagating through an inhomogeneous ionosphere. It is shown that these formulas are consistent with the results derived from applying perturbation theory directly to the eikonal equation. The resulting expression for the phase path is used in calculating the residual range error of dual-frequency global positioning system (GPS) observations, in view of second- and third-order terms. The third-order correction includes not only the quadratic correction of the refractive index but also the correction for ray bending in an inhomogeneous ionosphere. Our calculations took into consideration that the ionosphere has regular large-scale irregularities, as well as smaller-scale random irregularities. Numerical examples show that geomagnetic field effects, which constitute a second-order correction, typically exceed the effects of the quadratic correction and the regular ionospheric inhomogeneity. The contribution from random irregularities can compare with or exceed that made by the second-order correction. Therefore, random ionospheric irregularities can make a significant (sometimes dominant) contribution to the residual range error. [ABSTRACT FROM AUTHOR]

The article reports on the features of an unmanned aircraft system (UAS) which the scientists at the Cooperative Institute for Research Environmental Sciences have launched. The author argues that aircrafts have been a significant tool in the collection and gathering of atmospheric data. With the advent of new technology related to aviation; the necessity of aircrafts in atmospheric studies and experiments has become significant. As a matter of fact, there have been two successful missions that were able to monitor California wildfires.