Showing papers on "Sea breeze published in 1981"

The Role of the Winter Land Breeze in the Formation of Great Lake Snow Storms

Abstract: Radar and aircraft data are presented, in the form of case studies, for three shoreline-parallel snow bands that occurred over Lake Michigan. In all three cases a winter land breeze from one or both shores is shown to have an important role in organizing the low-level convergence and convective motions. These cases are compared with earlier studies of lake-effect snow bands on Lakes Erie and Ontario.

Effects of Frictionally Retarded Sea Breeze and Synoptic Frontal Passages on Sulfur Dioxide Concentrations in New York City

Abstract: Temporal changes in the spatial distribution of sulfur dioxide concentrations in New York City resulting from the passage of sea breeze and synoptic fronts were studied using data from the New York University/New York City Urban Air Pollution Data Set. Results show that upwind portions of New York City experience decreasing concentrations with the passage of sea breeze fronts, while downwind portions experience increasing concentrations. Synoptic fronts produce increasing concentrations in the less urbanized areas to the east and west of Manhattan and decreasing concentrations in Manhattan. The one synoptic front which moved extremely slowly showed extreme frictional retardation and produced the opposite effects on the concentration field.

Lake Kinneret (Sea of Galilee) and its exceptional wind system

Abstract: From 1973–1976, research was performed around the Sea of Galilee, aimed at examining the wind regime in the area and whether the area develops a land-sea breeze despite its particular topographical location. The main conclusions were: (1) During the summer mornings a lake breeze develops, blowing towards the shores of the lake. It ceases at the peak of its development when a westerly wind, originating in the development of a breeze along the Israeli Mediterranean coast, plunges towards the lake. (2) Late at night, a wind flow develops from the land towards the lake, which combines with the katabatic winds that blow along the steep slopes surrounding the Kinneret. (3) The stations at the upper level, at a height of 400–500 m above the Kinneret, are not affected by the lake breeze during the day or by the land breeze at night. (4) In winter, the Kinneret lake breeze is almost as developed as in summer, because the westerly winds, originating in the Mediterranean sea breeze which hardly develops in this season, do not plunge into the Kinneret.

Models for estimating offshore winds from onshore meteorological measurements

Abstract: To understand and estimate wind speed differences across the coastal zone, two models, one theoretical and another semi-empirical, have been developed and verified by available data sets. Assuming that: (1) mean horizontal motion exists across the coastal zone; and (2) the geostrophic wind does not change appreciably at the top of the planetary boundary layer (PBL), the equation of motion in the direction of the wind can be reduced so that 341-01, where U, H, and CD are wind speed, height of PBL, and drag coefficient over the sea and land, respectively. For practice, CD SEA has been modified from a formula with ULAND as the only input. HSEA may be estimated routinely from known HD LANDLAND and the temperature difference between land and sea, which can be provided by such means as remote sensing from meteorological satellites. For a given coast, Cmay be estimated also. This formula is recommended for weather forecasters. The semiempirical formula is based mainly on the power law wind distribution with height in the PBL. The formula states that 341-02. Simultaneous offshore and onshore wind measurements made at stations ranging from Somalia, near the equator, to the Gulf of Alaska indicated that values of a and b are 2.98 and 0.34 with a correlation coefficient of -0.95. For oceanographic applications, a simplified equation, i.e., 341-03, is also proposed.

Sea breezes along the Canterbury coast in the vicinity of Christchurch, New Zealand

Abstract: Observations are presented suggesting the significance of sea breezes in producing distinctive diurnal boundary layer oscillations over Christchurch. Sea breeze effects are shown to be an all-year phenomenon reaching their maxima in summer. The interaction of onshore wind components with south-westerly gradient winds (even under cloudy conditions) appears to produce a distinctive all-seasons diurnal rhythm in the gradient wind. The development of shallow north-easterlies blowing into an orographically-induced lee trough, preceding the onset of ground north-westerlies, is shown to produce a complicated system of onshore airflow when combined with the sea breeze. Under such conditions it is argued that a sea breeze return current may be discerned. Canterbury sea breezes are an important feature of the local climate and correspond in many respects to classical sea breeze models. Notwithstanding, it is their site-specific characteristics that render them of particular interest.

Characteristics of local winds in northwest Hawaii

Abstract: During the period 22–29 June 1978, meteorological data were collected at six stations arranged in nearly linear transection extending from the coast at Anaehoomalu, Hawaii to Waimea Airport, 25 km inland and 800 m higher Sea breeze response to synoptic-scale weather patterns was documented Within the six days of 24 h measurements, two disturbances embedded in the prevailing trade winds passed over the island Three different types of sea breeze development ensued Sea breeze variability appears to be related to both synoptic-scale cloud and wind distributions and to the thermal properties of lava surfaces situated within the transection Days of maximum insolation corresponded to minimum sea breeze advance through the network It is suggested that numerical models be employed with this data set to test the sensitivity of sea breezes to soil and cloud conditions

Large Mesoscale Convection and Sea Breeze Circulation. Part I: Linear Stability Analysis

Abstract: The interactions between the sea breeze circulation and trapeze instability are investigated using a set of linearized equations. The results show that mesoscale waves associated with trapeze instability can be easily triggered by the sea breeze circulation and can propagate far inland, but no mesoscale waves are observed over the ocean. The wavelength is a few hundred kilometers. The period of the waves, which depends on the Coriolis parameter, eddy viscosity and the strength of land-sea contrast, can be either one day or two days, or a combination of one and two days. The waves obtained here are similar to the cloud bands observed in West Africa and South America.

Convective Downmixing of Plumes in a Coastal Environment

Abstract: This paper describes the results of an atmospheric tracer study in which sulfur hexafluoride (SF_6) was used to investigate the transport and dispersion of effluent from a power plant located in a coastal environment. The field study demonstrated that material emitted into an elevated stable layer at night can be transported out over the ocean, fumigated to the surface, and then he returned at ground level by the sea breeze on the next day. At night when cool stable air from the land encounters the warmer ocean convective mixing erodes the stable layer forming an internal boundary layer. When the growing boundary layer encounters an elevated plume the pollutant material, entrained at the top of the mixed layer, can be rapidly transported in ∼20 min to the surface. Various expressions for the characteristic downmixing time (λ = Z_i/w_*) are developed utilizing the gradient Richardson number, the Monin-Obukhov length and turbulence intensifies. Calculations using these expressions and the field data are compared with similar studies of convective mixing over the land.

Further Studies of a Lake Breeze Part I: Observational Study

Abstract: The three-dimensional structure and behavior of a lake-land breeze circulation system induced by Lake Ontario for a selected 24 h period is presented. The structure is determined from observations made during the International Field Year of the Great Lakes. The case which has been studied occurred when the large-scale prevailing flow was blowing from the south at relatively low speeds. The study shows that the lake induces a broad belt of easterlies over the take in the afternoon and the early evening. It also indicates that the lake breeze is more likely to occur over the southwestern coastal regions than over the southeastern coastal regions. During the early morning hours, surface wind convergence occurs over the northeastern shoreline but not over the northwestern shoreline.

Incidence of mesoscale convergence lines as input to spruce budworm control strategies

Abstract: On occasion Greenbank et al. (1980) in their 1973 to 1976 study on spruce budworm moth dispersal in New Brunswick, Canada, detected intense line concentrations of airborne moths crossing special radar observing sites located about 100 km inland from both the Bay of Fundy and the Northumberland Straits. Line concentrations of insects reflect the presence of atmospheric convergence lines. Data from a surface mesonetwork and wind and temperature soundings up to 2 km collected in New Brunswick from 1976 to 1978 around the period of spruce budworm moth activity has revealed sea breeze fronts to be the meteorological origin for the line concentrations of moths. Analysis has shown sea breeze fronts penetrating 80 to 100 km inland in New Brunswick can be expected once or twice each year during the moth dispersal period. An equation for maximum inland penetration was developed which gave a correlation coefficient of 0.78 between predicted and observed inland penetrations with a standard error of 17.5 km. Predicted sea-breeze frontal penetrations of 100 km or more were considered likely to produce a line concentration of moths observable at the radar sited. Using this criteria the prediction scheme delineated four out of the five nights when line concentrations of moths were observed and only over-predicted on one occasion. Thus meteorological data can be used to predict the appearance of line concentrations of spruce budworm moths and so provide input into population redistribution studies and into the development of control strategies directed at the adult budworm.

Large Mesoscale Convection and Sea Breeze Circulation. Part II: Nonlinear Numerical Model

Abstract: The nonlinear equations are applied to study the interactions between the sea breeze circulation and trapeze instability in low latitudes. The well-developed sea breeze circulation produced by the nonlinear model at coast is not so affected by the trapeze instability as shown in Part I of this study. However, the waves over the land are quite similar to those of Part I, but with a smaller growth rate. This study suggests that a strong diurnal temperature variation over the land and/or the latent heat may be required to produce the observed cloud bands in the tropical continental region.

Observations of nighttime winds using pilot balloons in Anderson Creek Valley, Geysers, California

Abstract: Nighttime drainage or downslope winds along the east-facing slope of Anderson Creek Valley located in the Geysers area of northern California are examined using pilot balloons as air parcel tracers. Observations made over four nights show a persistent pattern of winds. Before sunset strong westerly winds blow into the valley. These winds are believed due to the late afternoon sea breeze. Drainage winds become fully developed within 2 h after sunset. The drainage wind has an average speed of approx.3 m s/sup -1/ regardless of the speed of the ambient wind. The drainage layer thickness grows at a rate of approx.80 m per kilometer of downwind distance. Balloons in the drainage current quickly spread throughout the shallow, sidewall canyon containing Anderson Creek. The transition from the local valley wind system to the free, ambient wind occurs at about ridge height, i.e., /sub 5/00 m above the valley basin, for weak ambient winds, and at /sub 3/00 m above the valley basin for strong ambient winds.

Sulfate and nitrate concentration in aerosol above kanto area

Abstract: The concentration of sulfate and nitrate in aerosol above Kanto area was measured by aircraft on 6 th and 7 th August 1980 as a survey of photochemical smog. The concentration variation of both ions coincided with that of ozone throughout the field observation. This phenomenon is explained that the formation mechanism of sulfate and nitrate is closely concerned with that of ozone formation. The transport of ozone, sulfate and nitrate is governed mainly by Sagami Bay sea breeze and Kashima Nada sea breeze.

Sea Breeze Detection with Acoustic Radar

Abstract: ]. Introduction The sea breeze arises from strong local pressure gradients due to differential heating of land and sea by the sun. Naturally, the sea breeze is strongest on clear and hot summer days 1. A front-like sea breeze occurs at coastal stations when there is a moderate to strong ofTshore gradient wind to form a front-like boundary over the sea, between the warm land air and cool sea air; and when the land-sea temperature difference is strong enough to overcome this gradient wind, the front crosses the coast resulting in changes in wind, temperature, humidity and pressure2• Several attempts have been made to describe sea breeze mathematically. Estoque3 produced a model describing the formation of the circulation, its intensification, the movement of the whole pattern inland and its subsequent decay. Subsequently, much attention has been directed towards modelling of the sea breeze and much quantitative information concerning the development of the sea breeze has bee:! derived from these studies4•5. Changes in the atmospheric stability due to land-sea breeze phenomena are important from the view point of air pollution, specially, for developed coastal urban areas like Visakhapatnam. An elevated inversion is often created with the passage of the sea breeze front, following the movement of the cool moist marine air over the land, which may fumigate and trap the pollutants. Stephens6 has described a situation where a sea breeze caused the formation of photo-chemical oxidants and smog. Several workers demonstrated the potentiality of the acoustic radar technique to study the sea breeze and

A study of the land and lake breeze in the lake biwa basin

Abstract: A land and lake breeze is very important to understand local climate and the pattern of air pollution in the Lake Biwa basin. Detailed features of the land and lake breeze in the basin, however, have not been elucidated, due to the small water area, complicated topography and other wind systems. This paper intends to make clear occurrence frequency and geographycal distribubution of the land and lake breeze, and to discuss effects of the above mentioned factors on them, by analyzing the hourly wind data at s stations in this area (Fig. 1) during the period from January 1 to December 31, 1979. The method of selecting the occurrence days of the land and lake breeze is as follows : In the first place, the day when an on-shore wind blew in the daytime, and an off-shore wind in the nighttime at Imazu and Hikone located in plains near the shore of the Lake Biwa is noticed. In the second place, frequency distribution of the start and the end time of the on-shore wind at Imazu and Hikone was counted (Fig. 2). In the third place, criterion for judging the land and lake breeze was determined (Table 1), and the day when the on-shore wind at Imazu and Hikone started and ended within the time ranges shown in Table 1 was determined as the occurrence day of the land and lake breeze on the shore of the Lake Biwa. The results obtained are summarized as follows: 1. The occurrence days of the land and lake breeze in the Lake Biwa basin amounted to 60 days in warm season and 45 days in cold season in 1979 (Table 2). They were classified into two main types, type I and II (Table 4), on the basis of the general wind direction and the existance of the mountain and valley wind at Tsuchiyama in the eastern mountainous part of the Lake Biwa basin (Table 3). 2. The type I prevails when the general wind is westerly to north-westerly (Fig. 3), In this type, the land and lake breeze on the shore penetrates inland and is combined with the mountain and valley wind which has the same direction. Consequently, the combined wind diverges from the lake to the boundary of the Lake Biwa basin in the daytime and converges in the opposite direction in the nighttime (Figs. 4 and 6). 3. On the other hand, the type II is connected with the general wind of which direction is south-east to south (Fig. 3). In this type, the mountain and valley wind is not seen in the eastern part of the Lake Biwa basin. Moreover, the penetration of the land and lake breeze toward inland is limited, and effects of the general wind on the land and lake breeze is intensified in the eastern part of the Lake Biwa (Figs. 5 and 7). 4. A feature common to two types is that the lake breeze changes its direction clockwise on the eastern shore, but counter clockwise on the western shore of the Lake Biwa.

Sea Level Variations in Gulf of Thailand.

Abstract: : From a study of low-pass filtered hourly sea levels for Sattahip and Ko-Lak in the northern Gulf of Thailand during the period 1960 through 1966, the sea level variations due to meteorological effects are found. The mean annual variation of the filtered sea level, which averages 0.5 meters, is consistent with the climatological mean annual wind variations. This sea level change appears to be a response to the Ekman transport which would be expected from the seasonal monsoon wind regimes. Sea level response to atmospheric pressure is negligible compared with response to wind. Analyses performed to find relations between the filtered sea level and the gulf-wide geostrophic wind and local surface wind show that the sea level slopes upward across the gulf in the same direction as the local wind blows, the response being coherent in the frequency band 0.083-0.117 cycles per day (period 8 to 12 days). This wind set-up effect is clearly secondary to the Ekman transport in inducing the seasonal sea level variations observed in the gulf.

The sea breeze and internal gravity waves

Abstract: The sea breeze is considered as an initial-value problem in which the heating in the atmosphere excites internal gravity waves. For a uniformly heated layer there are three contributions to the field: one from the point of nonzero vertical gradient of the heat flux, one from its mirror image below the ground and the third from the ground. When rotation is included, asymptotic analysis shows that the sea breeze is confined close to the coast.

Vertical structure and turbulent properties of wind field observed at a coastal complex site

Abstract: Six experimental campaigns have been performed at the site of La Spezia Gulf (Northern Italy) from 1974 to 1977 jointly by three Italian research groups. Previous papers analysed various aspects of the collected data. The present paper deals with three topics not covered by preceding analyses. In studying the pibal data set, the statistics of wind field from ground level to free atmosphere has been studied; then an empirical expression, relating sea breeze flow to geostrophic circulation, is proposed; finally, examining no-lift balloon trajectories, turbulent properties, such as diffusion coefficients, turbulence intensities and so on, have been evaluated. The effects of the different surfaces, sea and land, on the turbulent parameters have been evidentiated.