Reconnaissance Flight Research Articles

OBSERVATIONS: The First Successful Typhoon Eyewall-Penetration Reconnaissance Flight Mission Conducted by the Unmanned Aerial Vehicle, Aerosonde

OBSERVATIONS: The First Successful Typhoon Eyewall-Penetration Reconnaissance Flight Mission Conducted by the Unmanned Aerial Vehicle, Aerosonde

Isomer Energy Source in Hybrid Jet Engines for High Altitude Reconnaissance Flight

An investigation was performed on the possibility of employing a triggered isomer heat exchanger (TIHE) as part of a hybrid heat source in an otherwise conventional turbojet engine. Reported is the application of such a long duration engine in a high-altitude long endurance surveillance and reconnaissance mission. Two-phase operation would include a switchover point, that is, an altitude and Mach number at which conventional combustion is replaced by the TIHE. A comparison of conventional and hybrid engines indicates a hybrid mixed-stream turbofan engine flying a part conventional and part TIHE mission, with a switchover at a Mach number of 0.4 at 40,000 ft, could provide weeks of endurance. Takeoff weight would be reduced by 20% due to lower fuel requirements.

Aerial sketch-mapping of the 1998 ice storm in eastern Ontario

The 1998 ice storm in eastern Ontario was quantified using aerial mapping to determine the geographic area affected, and the severity of damage to the forests. Prior to mapping a reconnaissance flight was used to establish methodology. Mapping was accomplished by experienced technicians flying in a helicopter, 60–100 m above the canopy. Damage was sketch-mapped onto topographic maps then digitized using a geographical information system. Remotely sensed ground cover data were used to remove non-forested and sparsely forested areas from map polygons, to better estimate the area of affected hardwood forests. Damage to conifers was sporadic and occurred as small pockets of 1–5 ha. These were mapped as point data. Comparisons to ground plot measurements made in the spring showed the aerial mapping to be accurate. Key words: sketch-mapping, aerial survey, ice storm

Elephant status and conservation in the Upper Bandama Game Reserve, Ivory Coast

Upper Bandama is the largest game reserve in the Ivory Coast. About 80 elephants were estimated to live in Upper Bandam GR's woodland savannah habitat during the 1980s, but no elephant were observed during a reconnaissance flight in 1996. However, between 1995 and 1999 several people observed elephant when flying over the area, and since large patches of forest are still present inside the Reserve elephant may still exist, but to locate them ground observation may be necessary. During the 1990s the estimate normally given for this area was 40 elephant, but the author suggests that now a more realistic estimate would be 20. Hunting pressure is high. The animals, if there are any, would have stayed in the Reserve area for protection from hunters and because of increasing conflict with human settlements and domestic stock in the surrounding area.

Inner Core Strength of Atlantic Tropical Cyclones

Abstract The evolution of the wind field beyond the radius of maximum winds is studied for 18 Atlantic tropical cyclones (TCs) with 989 research and reconnaissance flight legs. Inner core strength, defined as the storm relative mean tangential wind from 65 to 140 km from the circulation center for a given flight leg, is shown to be linearly correlated with tropical cyclone intensity. Inner core strengthening coincides with deepening, but as a hurricane decays, the inner core may exhibit a wider range of behavior. During an eyewall replacement cycle inner core strength and intensity become out of phase. Inner core strength tends to be axisymmetric as no quadrant maintains a higher inner core strength than the other quadrants for more than a day. Increases of inner core strength occur throughout the entire 65–140-km radial distance and, thus, are not due to the higher winds found in rainbands alone. The authors speculate that inner core strength, being relatively close to the circulation center, responds ef...

The Systematic Reconnaissance Flight (SRF) as a tool in assessing the ecological impact of a rural development programme in an extensive area of the Lowveld of South Africa

Land use cover and the current ecological condition of the natural resources of a 71,300 ha area were assessed quantitatively and qualitatively. The Systematic Reconnaissance Flight (SRF) was used to achieve the above within severe time constraints set by the terms of reference for the project. North–south grid lines, spaced 1 and 2 km apart, were flown using a helicopter. Changes in land use classes along flight transects were documented using a Global Positioning System. The co‐ordinates were transformed within a Geographic Information System into land cover values. The SRF with sampling intensities ranging from 5.13 to 9.89% yielded a difference of only 0.2% between the estimated cover of sugar cane compared to the known area under sugar cane. The other land cover classes were considered adequately quantified. The qualitative assessment shows the natural resources to be under severe strain, in particular within the riparian zone. Recommendations as to future agricultural expansion are made. The SRF was highly cost‐effective in achieving the stated objectives of the project.

The detection of hurricane asymmetries from aircraft reconnaissance flight data: Some simulation experiments

A series of observational system simulation experiments designed to investigate the data requirements for determining the flow asymmetry of a hurricane are described. Of particular interest is the azimuthal wave-number-one component of the asymmetry, which, together with the mean flow across the storm, is responsible for the storm motion. A principal finding is that the accuracy of retrieval of this component from wind data obtained from airborne omega dropwindsonde soundings depends on the orientation of aircraft flight patterns relative to that of the asymmetry. Since the orientation of the asymmetry is not known in advance, there will be an inherent uncertainty in the accuracy with which the asymmetry is determined. The simulation experiments enable one to estimate probable errors in the determination of the asymmetry and their implications for hurricane track errors. The track errors are assessed by comparing the vortex track in a high-resolution control experiment with those that result from initial analyses based on simulated data sets of varying data density and quality. In some of the experiments, an increase in resolution along the flight tracks, or additional data in the storm environment, does not lead to an improvement in the forecast track, in contrast to increased data coverage on a regular grid. This at first sight surprising result is likely to be a consequence of the constant influence radius used in the objective analysis scheme, a factor which is currently being investigated. The addition of random wind-measurement errors to the simulated data, comparable in magnitude to those in dropwindsonde measurements, does not lead to significantly inferior analyses or track forecasts based on them, suggesting that such errors are not the major cause of inaccuracy in diagnosing the vortex asymmetry. Moreover, the accuracy of the analysis is nearly independent of whether the data are taken at an instant of time, or over a typical nine-hour flight duration and then corrected to a storm-centred coordinate system.

The detection of hurricane asymmetries from aircraft reconnaissance flight data: Some simulation experiments

AbstractA series of observational system simulation experiments designed to investigate the data requirements for determining the flow asymmetry of a hurricane are described. Of particular interest is the azimuthal wave‐number‐one component of the asymmetry, which, together with the mean flow across the storm, is responsible for the storm motion. A principal finding is that the accuracy of retrieval of this component from wind data obtained from airborne omega dropwindsonde soundings depends on the orientation of aircraft flight patterns relative to that of the asymmetry. Since the orientation of the asymmetry is not known in advance, there will be an inherent uncertainty in the accuracy with which the asymmetry is determined. The simulation experiments enable one to estimate probable errors in the determination of the asymmetry and their implications for hurricane track errors.The track errors are assessed by comparing the vortex track in a high‐resolution control experiment with those that result from initial analyses based on simulated data sets of varying data density and quality. In some of the experiments, an increase in resolution along the flight tracks, or additional data in the storm environment, does not lead to an improvement in the forecast track, in contrast to increased data coverage on a regular grid. This at first sight surprising result is likely to be a consequence of the constant influence radius used in the objective analysis scheme, a factor which is currently being investigated.The addition of random wind‐measurement errors to the simulated data, comparable in magnitude to those in dropwindsonde measurements, does not lead to significantly inferior analyses or track forecasts based on them, suggesting that such errors are not the major cause of inaccuracy in diagnosing the vortex asymmetry. Moreover, the accuracy of the analysis is nearly independent of whether the data are taken at an instant of time, or over a typical nine‐hour flight duration and then corrected to a storm‐centred coordinate system.

Persistent Suppression in Dwarf Birch after Release from Heavy Summer Browsing by Caribou

The Rivibre George Caribou Herd (RGCH), in northern Quebec, erupted during a few decades to culminate at approximately 800,000 animals by 1990. The RGCH appeared regulated by competition for summer forage. Repeated browsing and trampling reduced summer range productivity to 50% compared to ungrazed areas, lichens and dwarf birch having been mostly responsible for this reduction. A reconnaissance flight in 1991 and intensive field work the following two summers suggested that caribou use of dwarf birch leaves was light following the period of peak numbers. We hypothesized that birch stands would show signs of rapid and vigorous recovery in 1993-1994. We surveyed five heavily browsed birch stands, and two inaccessible, lightly browsed ones. Although utilization of birch leaves by caribou ranged between 0 and 6% during the 1994 growing season, heavily browsed stands exhibited no signs of rapid and strong recovery. Young plants did not abound in heavily browsed stands compared to lightly browsed ones, neither was wood accumulation faster in the former than in the latter. Stem density and height were similar in heavily browsed and lightly browsed stands. However, the leaf/wood ratio and the percent dry weight of leaves and wood were higher in lightly browsed than in heavily browsed stands, which resulted in approximately twice as high leaf biomass in lightly browsed than in heavily browsed stands. We hypothesized that previous intense caribou browsing caused a persistent suppression of dwarf birches, and that stems could not accumulate sufficient reserves during a growing season to deploy more leaves in the next spring in order to return the leaf/wood ratio to a normal value. We discuss the consequences of such a reaction of dwarf birch to herbivory on the demography of the RGCH.

Persistent Suppression in Dwarf Birch after Release from Heavy Summer Browsing by Caribou

The Rivière George Caribou Herd (RGCH), in northern Québec, erupted during a few decades to culminate at approximately 800,000 animals by 1990. The RGCH appeared regulated by competition for summer forage. Repeated browsing and trampling reduced summer range productivity to 50% compared to ungrazed areas, lichens and dwarf birch having been mostly responsible for this reduction. A reconnaissance flight in 1991 and intensive field work the following two summers suggested that caribou use of dwarf birch leaves was light following the period of peak numbers. We hypothesized that birch stands would show signs of rapid and vigorous recovery in 1993-1994. We surveyed five heavily browsed birch stands, and two inaccessible, lightly browsed ones. Although utilization of birch leaves by caribou ranged between 0 and 6% during the 1994 growing season, heavily browsed stands exhibited no signs of rapid and strong recovery. Young plants did not abound in heavily browsed stands compared to lightly browsed ones, neither was wood accumulation faster in the former than in the latter. Stem density and height were similar in heavily browsed and lightly browsed stands. However, the leaf/wood ratio and the percent dry weight of leaves and wood were higher in lightly browsed than in heavily browsed stands, which resulted in approximately twice as high leaf biomass in lightly browsed than in heavily browsed stands. We hypothesized that previous intense caribou browsing caused a persistent suppression of dwarf birches, and that stems could not accumulate sufficient reserves during a growing season to deploy more leaves in the next spring in order to return the leaf/wood ratio to a normal value. We discuss the consequences of such a reaction of dwarf birch to herbivory on the demography of the RGCH.

Options for aerial surveys of elephants

In most areas where elephants occur, aerial surveys are the only means used to establish their numbers. The most common methodology is the systematic reconnaissance flight or the transect sample count, which, however, has been criticised as being inadequate. Other methods to supplement the standard methodology are reviewed.

THE KATINA OIL SPILL 1982, COMBATING OPERATION AT SEA

ABSTRACT At about 15 km north-northwest of the Hook of Holland, the Greek tanker M.S. Katina collided with the French ore carrier Pengall on the afternoon of Monday, June 7, 1982. The collision caused a gash below the waterline in the No. 4 port cargo tank of the Katina which was loaded with 6,300 m3 heavy fuel oil. It was estimated during the first reconnaissance flight at eight o'clock in the evening, that between 1,000 and 2,000 m3 of oil must have been released from the Katina. Later, when the oil had been cleared up, it appeared that the total amount of leaked oil had been 1,630 m3. The dredger oil combat vessels Cosmos and Hein were in full action beginning at noon Tuesday, June 8, sweeping the oil from the sea surface. The Cosmos and the Hein swept up 800 m3 and 300 m3 of oil respectively (i.e., weathered oil with 30–50 percent seawater included). Especially on Tuesday a fairly large amount of oil was recovered by the Cosmos and the Hein. After that, it became more and more difficult to combat the oil, which became more and more scattered. As the viscosity of the oil became increasingly higher due to evaporation of the more volatile components, pumping became increasingly difficult and the capacity of the sweeping system decreased accordingly. After the Cosmos was dismissed, the Hein and the Smal Agt continued to combat the scattered oil slicks. In total, approximately 1,440 m3 were eventually removed from the sea surface, of which approximately 790 m3 was pure water-free oil. No further oil of significance was observed on Saturday June 12 and the opinion was that the combat activities had been effective at sea and the coast had been protected from extensive oil pollution. However, that Sunday oil washed up on the Dutch coast. The submerged oil, due to its higher specific gravity, floats invisibly under the water surface and was driven toward the coast by strong on-shore winds and currents.

Planetary Imaging: Past, Present, and Future

Recent exploration of the planets has been highlighted by the development of visual imaging systems carried on board the spacecraft. This paper describes the evolution of planetary camera systems from the earliest reconnaissance flight to Mars in 1965 (Mariner 4) through the planned mission to Jupiter and Saturn in 1977. Advances in telecommunication performance, mission planning and operations, and digital processing of images are also discussed. Science objectives and changes in the imaging systems required to meet these objectives are discussed for the Mariner Mars 1971 (Mariner 9), Mariner Venus-Mercury (Mariner 10), Viking 1975 (Mars Orbiter), and Mariner Jupiter-Saturn 1977 missions. The last section of the paper describes future plans for imaging experiments based on cameras using solid-state sensors, particularly charge-coupled devices.

A CENSUS OF ELEPHANT AND OTHER LARGE MAMMALS IN THE MKOMAZI REGION OF NORTHERN TANZANIA AND SOUTHERN KENYA

SUMMARY 1. An attempt has been made to census elephant by a method which will enable the reliability of the results to be assessed. 2. The method used was a system of stratified random samples. 3. Stratification was based on the positions of elephant clumps recorded on a reconnaissance flight. 4. Strip samples were selected at random for the various strata and elephant and other large mammals were counted in a strip of 440 m width from an aircraft travelling 100 m above the ground at 130 km/h. 5. The problems of maintaining a fixed height above the ground and counting animals in a strip of constant width are acknowledged. 6. One stratum was totally counted for purposes of comparison. 7. Elephant, eland, kongoni, Grant's gazelle, buffalo, oryx, zebra, impala, ostrich and giraffe have been counted. 8. The results are set out in a series of tables and estimates and confidence intervals have been computed. 9. A discussion is held on the influences of various factors on the width of sample strips observed from the aircraft. 10. The total count and sample count of stratum 1 are observed to be in fairly close agreement. 11. The re-stratification of stratum 1 to take advantage of the observed clumps of elephant reduced the standard error of the estimate proportionally. The estimate was increased because the samples were no longer valid for the new strata. 12. The elephant population is of the order of 9,000 animals, as was predicted from observation flights, and the confidence interval of ±1,974 is acceptable for a first attempt at a sample count for elephant. The Mkomazi elephant were observed in three distinguishable groups, this being a distribution pattern frequently recorded since 1965. 13. Estimates and confidence intervals for other mammals do not refer to the whole region. It is observed that standard errors as a proportion of estimates are proportional to the degree of clumping shown by the species. 14. The census took 45 h, and cost K£800. It was accomplished in 7 d by a single pilot and observer. The Mkomazi region covers some 10,857 km2.

Position Determination from Radio Bearings

A new, simpler derivation is presented for Stansfield's formulas for the most likely position ion and the distribution of its error when a number of bearings are measured from known locations. The simplification results from the use of complex numbers. Simple results are obtained for the case in which bearings are measured at regular, short intervals along a straight reconnaissance flight path, providing asymptotes for Butterly's curves.

Observations of Musk Oxen on Banks Island, Northwest Territories, Canada

Notes summer 1963 observations of <em>Ovibos moschatus</em>. On a reconnaissance flight over the northern third of the island on Aug. 2 nearly sixty were seen, indicating greater abundance than hitherto supposed. Only two were seen south of the reconnaissance area during a two-month period; apparently they concentrate in the northern part at least during the summer.

The McCall Glacier Project and Its Logistics

Describes the establishment and supply of two camps for this United States IGY micrometeorological and glacier-movement survey program, 1957-58. The McCall, an accessible valley glacier in the Romanzof Mts., eastern Brooks Range, northern Alaska, was chosen for the study during a reconnaissance flight in Aug. 1956. Transport was by air: prefabricated buildings, 34 tons of fuel and 18 tons of supplies and rations for the four-man party were parachuted from U.S. Air Force C-119 cargo planes during the 18-month program. Personnel, scientific instruments, and delicate apparatus were flown in by ski-equipped light planes; the glacier surface made an excellent landing field.

An Ice-area Navigation on the North Pacific Ocean

Recently, with the increasing frequency ship-wrecks by the driftice on the North Pacific Ocean contained the Okhotsk Sea and the adjacent sea of Kurile Islands, the establishment of ice-area navigation has become a matter of urgent necessity.For purpose to preserve these wrecks, it is intended in the present study to details a practical method to passage through ice-area over this sea-region, based on the lessons brought those shipwrecks and the experimences for many years of the navigators.In chapter 2 details of the methods to foretell an existance of ice-area at outside of the field of vision, make use of the atmospheric phenomena (ice-blink, water-sky and mirrage of drift-ice, etc.), sea state, distribution of sea surface temperature and radar, etc.…The practical method of ice-area navigation breaking through the ice-strips lied between the open waters, and the requisite measures in the case of beseted into very close ice-area (for example, quotating the exploding technics of hummocked ice-floes carried out at the entrance of Abashiri harbor in 1956) are discussed in chapter 3.In chapter 4 mentions the counter-measures ought to take for ice-area navigation before the departure.Finally, it is explained that the adoption of reconnaissance flight is very efficacy to ice-area navigation. (chapter 5)

1955 MEAN MONTHLY WIND SUMMARY ALONG RECONNAISSANCE TRACK NORTHWEST OF HAWAIIAN ISLANDS AT 500 MB.

Abstract The mean 1955 monthly variation of the zonal and meridional wind components, and the wind steadiness are presented for the 500-mb. level, from 20°–40° N. in the longitude of the Hawaiian Islands. The basic wind information used in the construction of these charts was obtained from the daily weather reconnaissance flight on the track designated “Petrel Foxtrot.” Mean monthly 500-mb. wind charts were also prepared for the Hawaiian Islands area from the same wind sample.

The Winter Mid-Troposphere Circulation Near the North Pole

With the aid of observations at 500 mb taken by the Ptarmigan reconnaissance flight to the North Pole the mean fields of temperature, height, and wind for the region from the northern edge of the North American Continent to the North Pole for the first three months of 1949 are computed. The resulting picture is compared with previous concepts of upper-air conditions in the Far North. The 500-mb charts for the days with lowest and highest elevations of that surface are given. Profiles of temperature, height, and wind from near the Equator to the North Pole for these days are also given. An attempt is made to determine the rate of subsidence of the air at 500 mb in the vicinity of the North Pole.