Wind Movement Research Articles

Storm tracking using rain gauge data

The unknown spatial distribution and kinematics of short-term rainfall are recognised as the most important reasons for errors in runoff simulation on urban catchments. Since the storm movement influences the shape of the runoff hydrographs, the modern rainfall input should include patterns of this movement. In order to be able to take rainfall kinematics into account in runoff simulation, rain movement parameters must be extracted from the rainfall data itself or taken from other phenomena such as wind movement at high altitude. The paper presents the results of the application of three different storm tracking methods on a set of rainfall data from the 12-gauge network in Lund, Sweden. The main conclusion is that a really objective and reliable storm tracking method does not exist yet. When more than one rainfall cell is simultaneously present over the rain gauge network, all so-called objective methods fail or must lose their objectivity. On the other hand, when the rainfall data are good, the storm movement pattern can be easily, though subjectively, recognized. Then, simple methods based on triangulation work equally well as more sophisticated methods based on spatial correlation. The existence of a relation between rainfall and high-altitude wind movement parameters is now well documented. However, further studies subjected to derivation of storm movement parameters from gauge data are still important in order to quantify this relationship better and to explain eventual regional differences.

Observations of winds above and below a forest canopy located near a clearing

Measurements of wind movements have been made within and above a forest canopy located near a 0.5 km 2 clearing. They showed the existence of complex wind systems characterized by strong horizontal jets of air and large vertical velocities beneath the canopy during unstable atmospheric conditions. Under stable situations wind flows seemed to be less complex with both horizontal and vertical winds being greater above the canopy than below.

MADDSAP-l, a Versatile Remotely Piloted Vehicle for Agricultural Research

A remotely piloted vehicle (RPV) was redesigned and constructed as an agricultural research tool. The RPV was a biplane aircraft (2.44 m wingspan by 2.04 m fuselage length) powered by a 50-cm3 4.0 hp modified chainsaw engine. The aircraft was controlled by a seven-channel FM radio control system augmented with a quasielectrodynamic autopilot. The RPV has been fitted with both an ultra-low-volume spray system and an electrostatically charged dust system for applying high concentrations of entomopathogenic bacteria, fungal spores, or viruses. The RPV also utilizes an oil vaporization system to observe wind movement. The RPV is also fitted with systems to sample airborne insect, spore, and pollen populations via remotely controlled traps.

Drift Comparisons Between Aerial and Ground Orchard Application

Applications of carbaryl, captan, or both were made by fixed-wing aircraft and by low-volume ground air blast sprayer to the same orchard site. Over the course of 2 years, a total of eight applications was made, four by air and four by ground equipment. The effect of two climatic parameters was evaluated. The first was under relatively calm conditions with a temperature inversion present and the second without a temperature inversion and with wind movement up to 12.9 km/h. Regardless of wind or atmosphere stability, carbaryl deposits from aerial application were found at the furthest sampling distance (500 m downwind). Ground applications under similar conditions left deposits at 150 m during a temperature inversion but provided no detectable levels at 50 m or further in the absence of an inversion. Differences between captan drift were not as clearly defined; generally, captan did not appear to drift as readily as carbaryl.

The Martian Dust Storm of Sol 1742

After nearly five Earth years on Mars, the Mutch Memorial Station (Viking Lander 1) finally witnessed a local dust storm that eroded trenches, conical piles, and other disturbed surfaces in the sample field and near the lander. The event, called the Dust Storm of Sol 1742, occurred late in the third winter of lander observations between Sols 1728 and 1757. Analyses of tiny new wind tails and movement of materials indicate that the eroding winds were variable but more northeasterly than those that had previously shaped the surface. Pebbly residues and movement of 4–5 mm clods suggest drag velocities or friction speeds of the winds were about 2.2–4.0 m/s. Wind speeds at the height of the meteorology boom (1.6 m) were probably about 40–50 m/s. Much of the observed erosion could have occurred in a few to several tens of seconds, but somewhat longer times are suggested by analogy with the erosion of terrestrial soils. Most of the erosion occurred where preexisting equilibrium conditions of surface configurations and surface material properties had been altered by the lander during landing and during surface‐sampler activities, but thin layers of bright fine‐grained dust were also removed and redistributed. Surfaces where preexisting equilibrium conditions were unaltered appeared to be uneroded.

Potato early dying—A serious threat to the potato industry

Potato early dying (PED) is characterized by a loss of plant vigor during mid to late summer followed by senescence and death of the crop a few weeks prior to normal maturity. This disease is of serious importance in areas of long-term or intensive potato production and is largely uncontrolled. Symptoms of PED, which are difficult to distinguish from normal senescence, especially in early-maturing cultivars, are uneven chlorosis and necrosis of vines and tan discoloration of vascular tissues. The basic cause of PED is the soil fungusVerticillium. Two species are involved—V. alboatrum predominating in cooler areas andV. dahliae in warmer areas. Both fungi commonly occur in cultivated soils and persist as melanized hyphae or microsclerotia, respectively. Infection occurs through roots followed by colonization of the vascular system. Contamination of uninfested fields can occur by wind or mechanical movement of soil-borne propagules or introduction of infested seed stock. AlthoughVerticillium is the primary pathogen in potato early dying, other soil organisms are involved, resulting in a “disease complex.” Research is under way in many areas to further our understanding of these pathogenic interactions and to exploit this knowledge for use in new systems of prediction and control.

Nonlinear natural rubber bearings for seismic isolation

This paper summarizes the results of a ten-year joint research program on base isolation carried out by the Malaysian Rubber Producers' Research Association in England and the University of California at Berkeley. Special rubber bearings have been developed which protect buildings and their contents from earthquake damage without requiring additional mechanical devices to enhance damping or to avoid problems of wind movement. The lack of complexity in the system makes prediction of response more certain and reduces cost so that in many designs the additional protection will be achieved at a cost lower than that for conventional protection. The principles of design are explained and results given for the many experimental investigations of the system which have included measurements of the response of both the building and its internal equipment. Practical aspects of the use of the system are discussed with reference to a large structure at present being constructed on nonlinear natural rubber bearings in a highly seismic area.

Cotton Plant Response to Wind and Water Stress

ABSTRACT COTTON plant phenology was observed in a sheltered environment for six different planting dates and compared to cotton grown in an unsheltered area. The shelters consisted of a snow fence and provided a 35% reduction in wind velocity 0.2 m above the crop for the season. Increased plant height, earlier squaring, earlier boll set and more bolls and biomass were observed for sheltered cotton when compared to the unsheltered cotton. The unsheltered cotton used less water than the sheltered cotton. Regression equations were developed to predict plant height and the change in plant height as a function of age of the plant, wind movement, daytime temperature and nighttime temperature.

Cotton phenology parameters affected by wind

Abstract Cotton plant ( Gossypium hirsutum L.) phenology was observed in a sheltered environment for six different planting dates and compared to cotton grown in an unsheltered area to isolate the effects of wind movement on cotton phenology and plant stress. The shelters consisted of a snow fence which provided a 35% reduction in wind velocity 0.2 m above the crop for the season. Partially sheltering the cotton from wind resulted in increased plant height, earlier squaring, earlier boll set and more bolls and biomass when compared to the unsheltered cotton. The increase in biomass and plant growth for the sheltered cotton required more water as the season progressed than the unsheltered cotton produced without supplemental irrigation. The study shows that wind and water uptake should be considered in crop models.

Dynamic Properties of Rainfall in Lund

The shape of a runoff hydrograph depends on the dynamic properties of the rainfall. The possible range of impact of the rainfall movement on runoff generating process can only be judged if the rainfall volocity and direction are known in statistical terms. This paper gives the statistical characteristic of the rainfall movement in the city of Lund. The probability distribution of rainfall velocities and relative frequencies of the rainfall direction are given, based on the analysis of 400 rainfall events observed in the city of Lund. A simple program for determination of the velocities and the directions of storm movement has been developed and tested. Results show that there are two main storm directions in Lund: the first, generally oriented to the East, is prevalent throughout the year except summer; the second, oriented to the North-North-East, occurs primarily during summer months. During summer rainfall velocity is lower and intensity higher than during the rest of the year. Rainfall velocity is lognormally distributed. A strong correlation between wind movement parameters at 700 mb height and storm velocity and direction was observed.

Soil Water Change as Related to Position of Wheat Straw Mulch on the Soil Surface

AbstractA field study was conducted in the Central Great Plains to determine the effects of the position of wheat straw mulch on soil water change of a silt loam soil (a montmorillonitic, mesic Aridic Paleustoll) during three 14‐month fallow periods. Treatments of 4600 kg/ha of wheat straw mulch flat on the soil surface, ¾ flat and ¼ standing, or ½ flat and ½ standing (normal position following standard combine harvesting) were compared with bare soil. Standing stubble was 0.46 m tall. Soil water content of one 1‐m3 hydraulic lysimeter within each treatment was measured daily and changes summed for each week, and at a distance of 2 m from each side of the lysimeter a neutron depth probe was used to determine soil water content weekly except when the soil was frozen. The relationship of soil water change for each weekly period with weekly values of total precipitation, total open‐pan (U.S. Weather Bureau Class A) evaporation, average daylight‐hour vapor pressure deficit, average maximum air temperature, average daily air temperature, average daylight‐hour air temperature, total solar radiation, and average daily wind movement, was determined by single and multiple‐correlation techniques. Soil water increases were related only to precipitation events with the highest correlation resulting from the ½ flat ½ standing wheat straw position treatment. Soil water losses were best correlated with wind movement with r2 values of 0.55, 0.41, 0.41, and 0.32 for bare soil, flat ¾ flat‐¼ standing, and ½ flat‐½ standing treatments, respectively. Soil water loss occurred from both bare soil and where the mulch was flat with winds of 0.08 MS−1. When ¼ or ½ of the mulch was standing, a wind of at least 0.55 MS−1 was needed before soil water loss occurred. Standing wheat straw does not function as a wick for loss of water from the soil.

Trail of the Crab progenitor star

It is proposed that the jet which has been observed protruding from the northern rim of the Crab Nebula is a tubular trail of material lost by the presupernova star during its red giant phase. The movement of the red giant's stellar wind is analyzed to show that the mass profile downstream should be concentrated within a narrow cylinder. The parameters of the tube predicted by this model are presented and an observational test of the model based on the hydrogen-to-helium abundance ratio in the jet and in the Nebula as a whole is suggested; the model predicts that the ratio in the jet should be larger.

Food dehydration by solar energy.

Solar driers that are currently being investigated for drying of agricultural products can be divided into two major divisions, depending upon how they transfer the incident solar energy to the product to be dried. These two divisions are direct and indirect drying, with some work also being done on combination drying procedures. In direct solar driers, the product to be dried is usually either inside a tent, greenhouse, or a glass-topped box, where the product to be dried is heated by the direct rays from the sun and the moist air is removed by ambient wind movement. These dryers do accelerate moisture loss rate and the product is usually safe from inclement weather. These dryers usually do not require fans for forced air circulation. With indirect drying, the opposite is true, where most require powered fans for forced air circulation. With this type of dryer, both flatplate and inflated tube solar heat absorbers are used, with each offering certain advantages. Also, combination dryers have been built that utilize both direct and indirect principles. Product evaluation of solar dried foods indicate that in most cases the physical properties, flavor, and vitamin A and C retention were as good as, or better than, conventional dried foods. The economics of the solar systems indicate that most drying procedures are economically feasible for use in small-scale operations only, with the exception of grain drying.

Equation for Estimating Cotton Preharvest Losses

ABSTRACT A quasi-theoretical equation was developed to pre-dict cotton preharvest losses as a function of ac-cumulated wind movement, rainfall and boll age. Cotton preharvest loss data were gathered in the field in 1978, 1979, and 1980 in the hill areas of Mississippi. These data, along with the accompanying weather events, were used to determine the parameter values in the derived equation. The equation performs well when significant weather events occur after the bolls are 57 days of age; however, some difficulty develops when the weather event occurs between 45 and 57 days of age.

Forage Plantings on Six Arizona Pinyon-Juniper Subtypes

Forage Plantings on Six Arizona Pinyon-Juniper Subtypes

Parallel encoding of direction of wind, head, abdomen, and visual pattern movement by single interneurons in the dragonfly

1. The self-movement detectors whose detailed properties are introduced here are among the largest interneurons in the ventral nerve cord of the dragonflyAnax junius. They combine information from a wide variety of sensory structures including the compound eyes, mechanosensory frontal hairs, antennae, neck proprioceptors, and wind sensitive hairs in the neck region (Fig. 6). They fall into 8 classes, each with a specific pattern of multimodal inputs (Fig. 1). 2. Their visual receptive fields are large, anteriorly weighted, and selective for animal rotation in a given direction (Figs. 1, 2). 3. They show directionally selective responses to air puffs delivered to the front of the head and to shifts in direction of a stream of air onto the head (Fig. 8). 4. They show directionally selective responses to air puffs from the sides, above, and below the animal into the neck region (Figs. 3, 4, 5). 5. They respond directionally to rotations of the head in still air in the dark (Figs. 3, 4, 11). The receptors mediating these proprioceptive responses are probably different from those mediating the responses to air puffs to the neck. 6. Four of the eight classes respond when the animal actively flexes its abdomen (Fig. 12). 7. Within each modality, they are inhibited by stimulation in the non-preferred direction. Pairwise presentations of stimuli to different inputs showed that each sensory channel is capable of inhibiting self-movement-detector responses to stimulation through any other channel (Figs. 13, 14). 8. For each class, the receptive fields of the various inputs are all aligned to detect rotation of the animal or the head within the same plane in space (Figs. 3, 4, 5). Two classes are aligned in the horizontal plane, and the other six in oblique planes (Fig. 1). 9. The precise alignment of directional selectivity of several input modalities within the same plane, combined with the finding that individual self-movement detectors drive adjustments in wing position (Olberg 1978) indicates that these interneurons are critical elements of a feedback control system for flight control.

Vegetation Stagnation in Three-Phase Big Game Exclosures

The allocation of range forage for deer and livestock is an important range management problem. Utilization of the threephase exclosure technique for such evaluations is complicated by the response of plants to nonuse. Protection from browsing can cause ''stagnation to occur as early as the second year after the exclosure is established. Nonuse of bitterbush resulted in an average reduction in production of 70%. Temporary exclosures moved each year are required for accurately determining annual forage production. Resource managers lack methods that will give reliable estinmates of site productivity and its relationship to carrying capacity for either livestock or big game. One procedure often tollowed for partitioning forage has been the use of three-phase exclosures. This paper reports a 6 year study to determine site productivity (i.e.. pounds of vegetation produced per hectare) thrluIyh the use of three-phase exclosures and temporarily erected movable exclosures. Production refers to the total ainnual dry matter increment of grasses, forbs, and browse. Etft'ects of different species, plant density and dispersion charactelristics. vegetation stagrnation caused by lack of grazing, and site differences within three-phase exclosure all tend to contounld range production and utilization data. Factors considered to intluence these results are precipitation, past utilization, conidition and trend of the vegetation, and the period of pr-otection from grazing. Sttigniationi can be defined as the [hCe authors are professor of range ecology and graduate fellow. University of Nevada Renii. Tlo%\er is nom% Rangte Consersationist LJ.S. Forest Service. Phoenix. Arizona. I he autihilors S ish to recognlize the lunding assistance given by the Bureau of Land Manacemleltll and the Nevada Fishi anid Gamie Departimient. who also constructed the exclosuIres. I his report is al conitribuitioll ol the Nevada Agricultural Experimiient Station. Journal Series Nuimiber4 1. Mlanuscrilpt received May 17. 1978. reduction in productivity of range plants resulting from a lack of grazing. Use of exclosures for rangeland evaluation has received wide acceptance. Daubenmire (1940) defined the exclosure as any experimental area which is protected from the activities of a particular class of animal by a barrier such as a fence or screen. They have some drawbacks, such as the barrier effect which will influence wind movement, precipitation, and seed collection. Three-phase exclosures were used as early as 1932, to discover and demonstrate the food preferences of animals (Young 1955). Each phase should be I acre (.405 hectare) or larger to have the least effect on the probability that deer will enter and should be located so that all phases are located on a single vegetatively homogeneous and representative part of the rangeland (Young 1958). Jones (1965) and McMahon (1966) have used the exclosure technique to study relative utilization, cover and conmpositional changes, and other effects.

Irrigation Water Conservation Using Wide‐spaced Furrows

AbstractFurrow irrigation studies comparing water applications to narrow and wide‐spaced furrows were conducted on three crops at thee locations in Oklahoma over eight growing seasons. Wide‐spaced‐furrow irrigation usually required about half the water of narrow spacing. In 9 of 11 studies, no yield reductions were noted. In the seasons where yield reductions were noted, the atmospheric evaporative demand was high. A simple test was devised to indicate if a season in progress shows high atmospheric demand. The evaporative demand test involves measurement of rainfall and daily wind movement. Using standard National Weather Service instruments, daily average of rain > 1.6 mm between 15 July and 31 Aug. combined with daily wind movement < 155 km in August caused no yield reduction in wide‐spaced‐furrow irrigation. Wind was measured at the standard height of a “Class A” evaporation pan (51 cm). Conservation of water from wide‐spaced‐furrow irrigation should be possible on medium to fine textured soils in many semiarid regions of the world.

Color and feature changes at Mars Viking lander site

Analysis of three component color pictures taken by the Viking lander camera on Mars has established color differences for the background material, the rocks and spots on the rocks. Changes in the location of greenish rock patches and ground patterns have been observed over time. A combination of wind movement of dust and dirt dropped by sampler arm operations could have produced the slight changes in pattern and position. However, the observed patches, patterns and changes could also be attributable to biological activity. Analysis of six component color data on the same scene confirms the observations including the greenish color of the rock patches.

Physiological and Ecological Correlates of Tunnel Nesting in the European Bee-Eater, Merops apiaster

Bee-eaters excavate tunnel nests to a depth sufficient to blunt the impact of wide variations in surface temperatures on the thermal environment in the nest chamber. Thermal environment of the inhabitants is maintained within or near their thermal neutral zone. High chamber humidity, minimal thermal stress, and succulent insect food combine to stabilize water balance of nestlings. Diffusion of gases through soil and along the nest tunnel can account for maintenance of tolerable levels of O₂ and CO₂; however, the absence of nest sanitation and presence of microorganisms causes significant periodic elevations in NH₃ and CO₂ and a decrease in chamber O₂. This latter circumstance is associated with windless conditions. Wind movements rapidly improve internal conditions by the formation of gas vortices which penetrate via the nest tunnel to the chamber while displacing chamber gas to the exterior. The piston effect of adult birds moving along the tunnels and thermally induced density currents further augment g...