Data Mining for Atmospheric Gravity Waves (Lee Waves)
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Chapter 2 Aviation Weather Hazards
NUNAVUT-E 11/12/05 10:34 PM Page 9 LAKP-Nunavut and the Arctic 9 Chapter 2 Aviation Weather Hazards Introduction Throughout its history, aviation has had an intimate relationship with the weather. Time has brought improvements - better aircraft, improved air navigation systems and a systemized program of pilot training. Despite this, weather continues to exact its toll. In the aviation world, ‘weather’ tends to be used to mean not only “what’s happen- ing now?” but also “what’s going to happen during my flight?”. Based on the answer received, the pilot will opt to continue or cancel his flight. In this section we will examine some specific weather elements and how they affect flight. Icing One of simplest assumptions made about clouds is that cloud droplets are in a liquid form at temperatures warmer than 0°C and that they freeze into ice crystals within a few degrees below zero. In reality, however, 0°C marks the temperature below which water droplets become supercooled and are capable of freezing. While some of the droplets actually do freeze spontaneously just below 0°C, others persist in the liquid state at much lower temperatures. Aircraft icing occurs when supercooled water droplets strike an aircraft whose temperature is colder than 0°C. The effects icing can have on an aircraft can be quite serious and include: Lift Decreases Drag Stall Speed Increases Increases Weight Increases Fig. 2-1 - Effects of icing NUNAVUT-E 11/12/05 10:34 PM Page 10 10 CHAPTER TWO • disruption of the smooth laminar flow over the wings causing a decrease in lift and an increase in the stall speed. -
Orographic Rainfall
October f.967 R. P. Sarker 67 3 SOME MODIFICATONS IN A DYNAMICAL MODEL OF OROGRAPHIC RAINFALL R. P. SARKER lnstitufe of Tropical Meteorology, Poona, India ABSTRACT A dynamical model presented earlier by the author for the orographic rainfall over the Western Ghats and based on analytical solutions is modified here in three respects with the aid of numerical methods. Like the earlier approxi- mate model, the modified model also assumes a saturated atmosphere with pseudo-adiabatic lapse rate and is based on linearized equations. The rainfall, as coniputed from the modified model, is in good agreement, both in intensity and in distribution, with the observed rainfall on the windward side of the mountain. Also the modified model suggests that rainfall due to orography may extend out to about 40 km. or so on the lee side from the crest of the mountain and thus explains at least a part of the lee-side rainfall. 1. INTRODUCTION tion for vertical velocity and streamline displacement from the linearized equations with the real distribution of In a previous paper the author [6] proposed a dynamical f (z) as far as possible, subject to the assumption that (a) model of orographic rainfall with particular reference to the ground profile is still a smoothed one, and that (b) the the Western Ghats of India and showed that the model atmosphere is saturated in which both the process and the explains quite satisfactorily the rainfall distribution from environment have the pseudo-adiabatic lapse rate. the coast inland along the orography on the windward side. However, the rainfall distribution as computed from We shall make another important modification. -
Airbus Perlan Mission II Soars to Over 62,000 Feet, Setting Second Altitude World Record and Crossing Armstrong Line
Airbus Perlan Mission II soars to over 62,000 feet, setting second altitude world record and crossing Armstrong Line EL CALAFATE, Argentina, 27 August, 2018 – Airbus Perlan Mission II, the world’s first initiative to pilot an engineless aircraft to the edge of space, made history again yesterday in El Calafate, Argentina, by soaring in the stratosphere to a pressure altitude of over 62,000 feet (60,669 feet GPS altitude). This set a new gliding altitude world record, pending official validation. The pressurized Perlan 2 glider, which is designed to soar up to 90,000 feet, passed the Armstrong Line, the point in the atmosphere above which an unprotected human’s blood will boil if an aircraft loses pressurization. This marks a second glider altitude world record for Jim Payne and Morgan Sandercock, the same two Perlan Project pilots who soared the Perlan 2 to 52,221 feet GPS altitude on Sept. 3, 2017, in the same remote region of Argentine Patagonia. The 2017 record broke a previous record that was set in 2006, in the unpressurized Perlan 1, by Perlan Project founder Einar Enevoldson and Steve Fossett. “This is a tremendous moment for all the volunteers and sponsors of Airbus Perlan Mission II who have been so dedicated to making our nonprofit aerospace initiative a reality,” said Ed Warnock, CEO of The Perlan Project. “Our victory today, and whatever other milestones we achieve this year, are a testament to a pioneering spirit of exploration that runs through everyone on the project and through the organizations that support us.” “Innovation is a buzzword in aerospace today, but Perlan truly embodies the kind of bold thinking and creativity that are core Airbus values,” said Tom Enders, Airbus CEO. -
Stratospheric Gravity Wave Fluxes and Scales During DEEPWAVE
JULY 2016 S M I T H E T A L . 2851 Stratospheric Gravity Wave Fluxes and Scales during DEEPWAVE 1 RONALD B. SMITH,* ALISON D. NUGENT,* CHRISTOPHER G. KRUSE,* DAVID C. FRITTS, # @ & JAMES D. DOYLE, STEVEN D. ECKERMANN, MICHAEL J. TAYLOR, ANDREAS DÖRNBRACK,** 11 ## ## ## ## M. UDDSTROM, WILLIAM COOPER, PAVEL ROMASHKIN, JORGEN JENSEN, AND STUART BEATON * Department of Geology and Geophysics, Yale University, New Haven, Connecticut 1 GATS, Boulder, Colorado # Naval Research Laboratory, Monterey, California @ Naval Research Laboratory, Washington, D.C. & Utah State University, Logan, Utah ** German Aerospace Center (DLR), Oberpfaffenhofen, Germany 11 National Institute of Water and Atmospheric Research, Kilbirnie, Wellington, New Zealand ## National Center for Atmospheric Research, Boulder, Colorado (Manuscript received 27 October 2015, in final form 25 February 2016) ABSTRACT During the Deep Propagating Gravity Wave Experiment (DEEPWAVE) project in June and July 2014, the Gulfstream V research aircraft flew 97 legs over the Southern Alps of New Zealand and 150 legs over the Tasman Sea and Southern Ocean, mostly in the low stratosphere at 12.1-km altitude. Improved instrument calibration, redundant sensors, longer flight legs, energy flux estimation, and scale analysis revealed several new gravity wave properties. Over the sea, flight-level wave fluxes mostly fell below the detection threshold. Over terrain, disturbances had characteristic mountain wave attributes of positive vertical energy flux (EFz), negative zonal momentum flux, and upwind horizontal energy flux. In some cases, the fluxes changed rapidly within an 8-h flight, even though environ- mental conditions were nearly unchanged. The largest observed zonal momentum and vertical energy fluxes were 22 MFx 52550 mPa and EFz 5 22 W m , respectively. -
THREE-DIMENSIONAL LEE WAVES by T. Marthinsen Institute Of
THREE-DIMENSIONAL LEE WAVES by T. Marthinsen Institute of mathematics University of Oslo Abstract Linear wave theory is used to find the stationary,trapped lee waves behind an isolated mountain. The lower atmosphere is approxi mated by a three-layer model with Brunt-Vaisala frequency and wind velocity constant in each layer. The Fourier-integrals are solved by a uniformly valid asymptotic expansion and also by numerical methods. The wave pattern is found to be strongly dependent on the atmospheric stratification. The way the waves change when the para meters describing the atmosphere and the shape of the mountain vary, is studied. Further, the results predicted by the theory are compared with waves observed on satellite photographs. It is found that the observed wave patterns are described well by the linear theory, and there is good agreement between observed and computed wavelengths. - 1 - 1 Introduction Three-dimensional lee waves have received little study compared to the two-dimensional case. They are, however, often observed on satellite photographs, and four such observations were presented and analysed in~ previous paper, Gjevik and Marthinsen (1978),referred to here as I. Some photographs taken by the Skylab crew have been presented by Fujita and Tecson (1977) and by Pitts et.al. (1977). A review of satellite observations of lee waves and vortex shedding has been given by Gjevik (1979). It is clear from the investigations in I that the observed waves presented there are trapped lee waves, i.e. waves with no vertical propagation. A condition for such waves to exist is that the Scorer parameter, which is the ratio between the Brunt-Vaisala frequency and the wind velocity, decreases with height. -
Analysis of Mountain Wave 3D Wind Fields in the Andes Derived From
Analysis of mountain wave 3D wind fields in the Andes derived from high-altitude sailplane flights Rick Millane1, Ni Zhang1, Einar Enevoldson2 and James Murray2 [email protected] 1Department of Electrical and Computer Engineering University of Canterbury, Christchurch, New Zealand 2NASA Armstrong Flight Research Center, Edwards, CA, USA Abstract Mountain lee waves are of importance in meteorology since they produce drag that affects the general circula- tion, and can influence windstorms, clear-air turbulence and ozone abundance. Since mountain waves are used routinely by sailplane pilots, data collected during wave flights are potentially useful for studying the structure of mountain waves. We have previously described methods for determining 3D wind velocities in mountain waves from limited sailplane flight data. These methods are applied to data from a high-altitude sailplane flight in the lee of the Andes that reached an altitude of over 15,000 m, well into the stratosphere, allowing a unique kind of in-situ observation of stratospheric mountain waves. The derived wind fields show parts of the wave structure in the troposphere and the stratosphere, and are compared with other observational data. Thus, a minimally instrumented sailplane can provide useful data for mountain wave research. Introduction from the mountain range. For the case of these trapped waves in the troposphere, the wavelength is typically between 2 km Gravity waves are perturbations in the atmosphere that are and 20 km [1, 2]. The wave crests may be marked by station- driven by gravity and buoyancy [1, 2]. Net forces on a par- ary lenticular clouds where the rising air cools to the dew point. -
2.1 ANOTHER LOOK at the SIERRA WAVE PROJECT: 50 YEARS LATER Vanda Grubišic and John Lewis Desert Research Institute, Reno, Neva
2.1 ANOTHER LOOK AT THE SIERRA WAVE PROJECT: 50 YEARS LATER Vanda Grubiˇsi´c∗ and John Lewis Desert Research Institute, Reno, Nevada 1. INTRODUCTION aerodynamically-minded Germans found a way to contribute to this field—via the development ofthe In early 20th century, the sport ofmanned bal- glider or sailplane. In the pre-WWI period, glid- loon racing merged with meteorology to explore ers were biplanes whose two wings were held to- the circulation around mid-latitude weather systems gether by struts. But in the early 1920s, Wolfgang (Meisinger 1924; Lewis 1995). The information Klemperer designed and built a cantilever mono- gained was meager, but the consequences grave— plane glider that removed the outside rigging and the death oftwo aeronauts, LeRoy Meisinger and used “...the Junkers principle ofa wing with inter- James Neeley. Their balloon was struck by light- nal bracing” (von Karm´an 1967, p. 98). Theodore ening in a nighttime thunderstorm over central Illi- von Karm´an gives a vivid and lively account of nois in 1924 (Lewis and Moore 1995). After this the technical accomplishments ofthese aerodynam- event, the U.S. Weather Bureau halted studies that icists, many ofthem university students, during the involved manned balloons. The justification for the 1920s and 1930s (von Karm´an 1967). use ofthe freeballoon was its natural tendency Since gliders are non-powered craft, a consider- to move as an air parcel and thereby afford a La- able skill and familiarity with local air currents is grangian view ofthe phenomenon. Just afterthe required to fly them. In his reminiscences, Heinz turn ofmid-20th century, another meteorological ex- Lettau also makes mention ofthe influence that periment, equally dangerous, was accomplished in experiences with these motorless craft, in his case the lee ofthe Sierra Nevada. -
Talking Points for “Satellite Interpretation of Orographic Clouds / Effects”
Talking points for “Satellite Interpretation of Orographic clouds / effects” 1. Title page 2. Objectives 3. Topics 4. Gap wind event over New Mexico. Strong winds affect Albuquerque and introduce moist airmass which may impact convective forecast the next day. 5. Topography of New Mexico. In easterly flow, winds may be funneled through Tijeras gap east of Albuquerque and produce locally strong winds in the city. 6. Surface observations (METARs) from 00:00 – 12:00 UTC (3 hour increments) 12 June 1999. At 00:00 UTC we observe a warm and dry air mass and southwest flow over most of central New Mexico (including Albuquerque). As time goes on, the easterly flow advects westward. Eventually, the easterly flow makes it to Albuquerque where the dewpoint goes from the 20’s to the low 50’s. The gap wind effects are very localized, at the Albuquerque airport winds gusted up to 30 mph, while on the west side of town at Double Eagle airport winds were southeast at 10 mph. 7. Fog Product 02:46 – 10:30 UTC 12 June 1999. This loop shows the origin of the easterly flow which helped produce the gap winds in Albuquerque. Deep convection on the plains of eastern New Mexico produced strong outflow that moved westward. Since this loop is at night, we can utilize the fog product to identify the outflow boundaries readily. The fog product is good at distinguishing low-level outflow boundaries at night. The outflow pushes westward towards Albuquerque, as it reaches the Tijeras gap the gap wind event begins. The fog product can be used in this way (at night) to determine when the conditions favorable for gap winds will begin. -
Perfect 10X? Pioneer Enevoldson P34 What to Expect from Dassault’S Greatest Falcon P12 705371327 770015 9 £4.99
FlightGlobal.com June 2021 Airbus nears narrowbody rate rise Freighter conversions deliver the goods p16 Remembering Perlan Perfect 10X? pioneer Enevoldson p34 What to expect from Dassault’s greatest Falcon p12 9 770015 371327 £4.99 Firm ground Power shift Boeing seeks How engine stability before makers see next project the future 06 p50 p69 Comment Plus ca change? Forming up Apparent accord between three European nations on their future fighter project is positive, but a lack of detail on the agreement’s practicalities leaves many unanswered questions Bundeswehr or a while it had seemed NGF’s prime contractor, it has UK-led Tempest future fighter pro- doubtful that an accord seen its share of the project fall gramme continues to go quietly might ever be reached be- from 50% to 33%, while its rival’s about its business. tween France, Germany and has risen to 66%. In contrast with its FCAS rival, FSpain to allow their Future Com- Although the defence ministries the Tempest effort, which also bat Air System (FCAS) to progress of the three nations say that their includes Italy and Sweden, has so to the next stage of development. differences are resolved, it is so far far has been notable for a lack of There had seemed too many unclear how that translates to the public discord. obstacles to progress, notably the industrial level. It is hard to pinpoint the reason thorny issues of workshare and Further hurdles remain, of for that apparent harmony – and it intellectual property. course: the Bundestag still needs may well not last for the duration Dassault Aviation was particularly to give its assent to this next step; of the programme – but perhaps outspoken about the potential di- elections in Germany this year and it is simply that all the parties are lution of its role in the process. -
Einar Enevoldson NA
Volume 27: Issue 3 ● April 2012 A Publication of the Pine Mountain Lake Aviation Association April 7th – Einar Enevoldson NASA's High Flying Test Pilot and Current Sailplane World Altitude Record Holder presenting "Soaring Beyond the Clouds" at 6:00 PM at a pot luck at Norm and Patty Peebles' hangar ur April speaker is Einar Enevoldson. Einar served as a jet fighter pilot and test pilot in the Currently retired from NASA, but still flying at US Air Force at Edwards AFB in the late '50s. In O 79 years young, Einar 1959, he was awarded the DFC for his record flights is hot after his own sailplane in the F-104 Starfighter. Later he served as an world altitude record of exchange officer with the Royal Air Force where he 50,724 feet. In 2006 Einar was a test pilot on the Hawker Hunter, Electric set the record with Steve Lightning and Javelin fighter aircraft at Farnborough. Fossett far south in the In 1968, Einar joined NASA where he was involved Argentine Patagonia above in numerous programs as a test pilot with the Dryden the Andes mountains in the Flight Research Center. He was awarded the NASA wind field of the Exceptional Service Medal for his work on the F-111 stratospheric polar night jet. Supercritical Wing Program and a second NASA Now, Einar is shooting for 100,000 feet. Yes, it's ESM on the F-14 stall and spin test program. possible says Einar under the right conditions in the right location with the right machine. -
A Report on Glider-Pilot Activities to Document Leewave-Events In
A Report on Glider Pilot Activities to document Lee wave-Events in Northern Germany and their Aims Jörg Dummann An der Alten Warte 20, D-34127 Kassel [email protected] Presented at the XXIX OSTIV Congress, Lüsse-Berlin, Germany, 6 August – 13 August 2008 Abstract A brief outline of the orographical, meteorological and infrastructural circumstances of wave flying in the re- gion of the lower mountains of northern Germany is given and completed by a short historical overview. Aims and methods of a glider pilot initiative for gathering information on atmospheric waves are presented. Some ef- fects are mentioned that intrinsically affect the resulting observations by using gliders for the exploration of the phenomenon. Statistical summaries of the gathered data are given as well as descriptions of some significant observations. Finally, a summary of possible future activities of the glider pilot initiative is provided. Introduction popular aeronautic sport. Glider pilots come from all walks of The orography of northern Germany is characterized by life; their qualifications and motivations reflect this variety. extended plains. This landscape shows negligible differences Aiming at a historical backdrop, some reports on out- in heights, smoothly formed by the glaciers and rivers of the standing aeronautical achievements resulting from the de- Quaternary. Southwards, lower mountains dominate the scene. scribed environment up to now can be given. For example, in The valleys and heights developed as layers of trias, which the 1960’s some pilots reached altitudes around 5000m MSL form the surface of the northern lee wave region, were folded in resonant waves of the Hasselberg-Süntel-Deister system, during later geological periods. -
Impact of Weather on Aviation
International Journal of Emerging Science and Engineering (IJESE) ISSN: 2319–6378, Volume-4 Issue-8, February 2017 Impact of Weather on Aviation Suad Mohammad Ali Abdullah Abul Abstract: This paper presents the effects of climate change and One system uses temperature and rates of temperature weather conditions on the air transport sector. And also changes. Another uses the changes in the content of the examined turbulent weather conditions and their relationship to gases in the atmosphere, and yet a third deals with the aircraft operations as well as the influence of dry and wet seasons on weather parameters of rainfall, thunderstorm and fog functions of these various layers. [2] these layers provide. In at the Port Harcourt International Airport. The aim was to this system, the atmosphere is divided into two distinct identify which weather parameter affects aircraft operations layers, the lowest of which is the ozonosphere. This layer which entails flight delay, cancellation and diversion. lies approximately between 15 and 50 kilometers (10–30 Keywords: Introduction Atmosphere-Climate-Weather- mi) above the surface. The ozonosphere is another name for Winds- Visibility- Ceiling-Steam Fog-Ice Fog- Thunderstorms- the ozone layer mentioned previously. Again, ozone Snow-Icing and conclusion effectively filters the UV energy from the sun and gives off heat energy instead. As we have noted, although ozone is a I. INTRODUCTION toxic pollutant at Earth’s surface, aloft, it serves a vital function for Earth’s life systems. From about 60–400 This chapter explains basic weather theory and offers kilometers (40–250 mi) above the surface lies the layer pilots backgro Weather is an important factor that influences known as the ionosphere.