Westerly Wind Directions Research Articles

The Influence of Meteorological Factors and the Time of Day on the Concentration of Ammonia in the Atmosphere Measured Using the Photoacoustic Method near a Cattle Farm—A Case Study

Influences of animals, time of day, air temperature and relative humidity, wind speed and direction on ammonia concentrations were investigated. A case study on a typical summer day from 7:00 to approximately 24:00 CEST (moderate wind speed, variable cloudiness and maximum global radiation higher than 950 W/m2) in west–central Poland is presented. Concentrations of this gas were measured at four heights (0.1–1.5 m), which were changed every 5 min, using a Nitrolux 1000 photoacoustic spectrometer. A micrometeorological station was established to also measure the surface energy budget components. The results presented are the average for each hour and for the entire day. The fine structure of concentration profiles, plume detection and uncertainty of ammonia flux calculation are also presented. The highest NH3 concentrations were at a 0.5 m height between 16:00 and 17:00 h when cows were grazing, but the lowest concentrations were between 23:00 and 24:00 h at the height of 1.5 m. The ammonia concentration increased with increasing air temperature and was the highest with a westerly wind direction and decreased with increasing air relative humidity. The greatest influence on the ammonia concentration was related to the presence of cows and the time of day, while a slightly smaller influence was noted in terms of air temperature and wind direction. A case study is suitable for presenting local effects, inhomogeneities and quantifying uncertainties in the bidirectional ammonia flux calculation.

Tracking westerly wind directions over Europe since the middle Holocene

The variability of the northern westerlies has been considered as one of the key elements for modern and past climate evolution. Their multiscale behavior and underlying control mechanisms, however, are incompletely understood, owing to the complex dynamics of Atlantic sea-level pressures. Here, we present a multi-annually resolved record of the westerly drift over the past 6,500 years from northern Italy. In combination with more than 20 other westerly-sensitive records, our results depict the non-stationary westerly-affected regions over mainland Europe on multi-decadal to multi-centennial time scales, showing that the direction of the westerlies has changed with respect to the migrations of the North Atlantic centers of action since the middle Holocene. Our findings suggest the crucial role of the migrations of the North Atlantic dipole in modulating the westerly-affected domain over Europe, possibly modulated by Atlantic Ocean variability.

Evaluation of an operational air quality model using large-eddy simulation

Abstract The large-eddy simulation (LES) model uDALES is used to evaluate the predictive skill of the operational air quality model SIRANE. The use of LES in this study presents a novel approach to air quality model evaluation, avoiding sources of uncertainty and providing numerical control that permits systematic analysis of targeted parametrisations and assumptions. A case study is conducted over South Kensington, London with the morphology, emissions, meteorological conditions and boundary conditions carefully matched in both models. The dispersion of both inert (NOx) and reactive (NO, NO2 and O3) pollutants under neutral, steady-state conditions is simulated for a south-westerly and westerly wind direction. A quantitative comparison between the two models is performed using statistical indices (the fractional bias, FB, the normalised mean squared error, NMSE, and the fraction in a factor of 2, FAC2). SIRANE is shown to successfully capture the dominant trends with respect to canyon-averaged concentrations of inert NOx (FB = −0.08, NMSE = 0.08 and FAC2 = 1.0). The prediction of along-canyon velocities is shown to exhibit sources of systematic error dependant on the angle of incidence of the mean wind (FB = −0.18). The assumption of photostationarity within SIRANE (deviations from equilibrium of up to 170% exist close to busy roads) is also identified as a significant source of systematic bias resulting in over- and underpredictions of NO2 (FB = −0.18) and O3 (FB = 0.14) respectively. The validity of the assumed uniform in-canyon concentration is assessed by analysing the pedestrian, leeward and windward concentrations resolved in uDALES. The use of canyon-averaged concentrations to predict pedestrian level exposure is shown to result in significant underestimations. Linear regression is used to effectively capture the relationship between pedestrian- and canyon-averaged concentrations in uDALES. Correction factors are derived ( m ≈ 1.62 and R 2 = 0.92 for inert NOx) that are capable of significantly improving SIRANE's ability to assess pedestrian level exposure for the conditions investigated in this study. The prevalence of intersections and advective nature of the shear layer are highlighted as important differences between modelling real heterogeneous urban morphology and idealised infinite canyons.

Reconstruction of Late Pleistocene paleoenvironments in southern Germany using two high-resolution loess-paleosol records

Two loess-paleosol sequences from the Heilbronn Basin in southwestern Germany, Frankenbach and Talheim, have been investigated to gain information about environmental conditions during the last interglacial-glacial cycle. Since paleoenvironmental research on terrestrial archives is crucial for a better understanding of past climatic and environmental conditions, the profiles were studied using a multi-proxy approach. Applied methods include the analyses of grain-size distribution, element contents, sediment color, rock magnetism, micromorphology, and black carbon (BC) via benzene polycarboxylic acids (BPCA). The data reveal that the two profiles show large variations in conservation due to their different geomorphologic positions. Moreover, the results imply a subarctic climate with stable conditions during the Middle Pleniglacial (MIS 3) in-situ soil formation phase while the Lower Pleniglacial (MIS 4) was characterized by erosion and reworking of Eemian and Early Glacial (MIS 5) material but also by accumulation of aeolian material during the late Lower Pleniglacial (MIS 4) in Frankenbach. The results further suggest that the Rhine River floodplain has been a major source for the accumulated material in the two profiles, which indicates westerly wind directions during the time of accumulation. The low GSI and U-Ratio of Upper Pleniglacial (MIS 2) sediments, supported by the overall high content of fine material, imply a larger distance to the source area. We give an overview of loess in the Heilbronn Basin and place it in a wider context of loess in Western Europe.

The Long distance wake behind Horns Rev I studied using large eddy simulations and a wind turbine parameterization in WRF

The aim of the present paper is to obtain a better understanding of long distance wakes generated by wind farms as a first step towards a better understanding of farm to farm interaction. The Horns Rev I (HR) wind farm is considered for this purpose, where comparisons are performed between microscale Large Eddy Simulations (LES) using an Actuator Disc model (ACD), mesoscale simulations in the Weather Research and Forecasting Model (WRF) using a wind turbine parameterization, production data as well as wind measurements in the wind farm wake. The LES is manually set up according to the wind conditions obtained from the mesoscale simulation as a first step towards a meso/microscale coupling.The LES using an ACD are performed in the EllipSys3D code. A forced boundary layer (FBL) approach is used to introduce the desired wind shear and the atmospheric turbulence field from the Mann model. The WRF uses a wind turbine parameterization based on momentum sink. To make comparisons with the LESs and the site data possible an idealized setup of WRF is used in this study.The case studied here considers a westerly wind direction sector (at hub height) of 270 ± 2.5 degrees and a wind speed of 8 ± 0.5 m/s. For both the simulations and the site data a neutral atmosphere is considered. The simulation results for the relative production as well as the wind speed 2 km and 6 km downstream from the wind farm are compared to site data. Further comparisons between LES and WRF are also performed regarding the wake recovery and expansion.The results are also compared to an earlier study of HR using LES as well as an earlier comparison of LES and WRF. Overall the results in this study show a better agreement between LES and WRF as well as better agreement between simulations and site data.The procedure of using the profile from WRF as inlet to LES can be seen as a simplified coupling of the models that could be developed further to combine the methods for cases of farm to farm interaction.

Characteristics of total gaseous mercury concentrations at a coastal area of the Yangtze Delta, China

ABSTRACTIn this study, we report on total gaseous mercury (TGM) field observations made in the rural area of Shanghai, Chongming Island, China, from September 2009 to April 2012. The average TGM was 2.65 ± 1.73 ng m−3 in Chongming Island, which is higher than the TGM background value of the Northern Hemisphere (1.5–1.7 ng m−3); this indicates that to some extent, the Chongming area has been affected by anthropogenic mercury emissions. The observed TGM follows a seasonal pattern; concentrations are highest in winter, followed by autumn, summer, and spring. There is also a clear diurnal variation in TGM. All peak values appear between 7:00 and 9:00 in all four seasons; this appears to be the result of the height change in the atmospheric boundary layer that occurs between day and night. TGM concentrations in Chongming remain high in the westerly wind direction, especially in the southwest direction because of its low frequency, so the greatest source contribution to TGM in Chongming lies to the northwest. Wind speed is also a significant factor affecting TGM, and was negatively correlated with TGM concentrations. TGM is also closely related to carbon monoxide (CO) concentrations, indicating that TGM is impacted by human activities. The slope of the linear fitting of TGM and CO demonstrates that the contribution of noncoal source emissions to TGM in summer is greater than in autumn, mainly because the high temperature and intensive sunlight in summer increase mercury emissions from natural sources.Implications: Except for some studies in the coastal areas (e.g., Kang Hwa Island by Kim et al., 2006, An–Myun Island by Kim et al., 2002, and Okinawa by Chan et al., 2008), data specifically for coastal areas are lacking. Monitoring of total gaseous mercury (TGM) in the rural area of Shanghai, Chongming Island, can help us understand mercury distribution.

Research of Sand Drift Potential and Wind Conditions in Xilamuren Grassland

Using the wind data in Xilamuren desert grassland by wind erosion monitoring system to record the years of 2011-2013 as the research foundations, through the statistics of wind and sand transport potential research, from aspect of the characteristics of blown sand environment Xilamuren desert grassland which can be shown the research area are mainly affected by the westerly, Northwest westerly wind or northwest wind three group interaction. The study area of annual sediment potential had mainly effected by westerly and Northwest westerly wind direction ,with wind direction variability index in 0.51°~ 0.61°, belonging to the intermediate ratio range of direction. Annual sediment potential was between 135.95VU ~214.1VU,belongs to the small and medium-sized wind environment. The spring sand transport potential and the resultant sand transporting potential than the other three seasons of sediment transport potential and the resultant sand transporting potential, the main direction of resultant sand transporting potential to Northwest westerly direction, wind direction variability index is relatively large. For spring grassland vegetation coverage rate is lowly, wind speed is large, characteristics of sand is belong to rich material, which should we to retain sand material through the appropriate protective measures to reduce wind erosion. So analyzing the wind regime and the theory of sediment transport potential calculation, provide scientific theoretical basis for the prevention and treatment of sand and harm to the Xilamuren grassland sand flow process.

Effects of the water level on the flow topology over the Bolund island

We have analyzed the influence of the actual height of Bolund island above water level on different full-scale statistics of the velocity field over the peninsula. Our analysis is focused on the database of 10-minute statistics provided by Risø-DTU for the Bolund Blind Experiment. We have considered 10-minut.e periods with near-neutral atmospheric conditions, mean wind speed values in the interval [5,20] m/s, and westerly wind directions. As expected, statistics such as speed-up, normalized increase of turbulent kinetic energy and probability of recirculating flow show a large dependence on the emerged height of the island for the locations close to the escarpment. For the published ensemble mean values of speed-up and normalized increase of turbulent kinetic energy in these locations, we propose that some ammount of uncertainty could be explained as a deterministic dependence of the flow field statistics upon the actual height of the Bolund island above the sea level.

Modeling large offshore wind farms under different atmospheric stability regimes with the Park wake model

We evaluate a modified version of the Park wake model against power data from a west-east row in the middle of the Horns Rev I offshore wind farm. The evaluation is performed on data classified in four different atmospheric stability conditions, for a narrow wind speed range, and a wide range of westerly wind directions observed at the wind farm. Simulations (post-processed to partly account for the wind direction uncertainty) and observations show good agreement for all stability classes, being the simulations using a stability-dependent wake decay coefficient closer to the data for the last turbines on the row and those using the WAsP recommended value closer to the data for the first turbines. It is generally seen that under stable and unstable atmospheric conditions the power deficits are the highest and lowest, respectively, but the wind conditions under both stability regimes are different. The ensemble average of the simulations does not approach the limits of the infinite wind farm under any stability condition as such averages account for directions misaligned with the row.

The formation and evolution of Hule and Río Cuarto maars, Costa Rica

The Hule and Río Cuarto maars are respectively located 11 and 18 km northward of the active crater of Poás volcano, on the Caribbean side of the Central Volcanic Range of Costa Rica. They lie on the northern part of Poás volcano massif, along a N–S trending, ~ 27 km-long volcanic fracture crossing the Poás volcano. The volcanic products from Hule maar (2.3 km × 1.8 km, area ~ 3.5 km 2) are mainly pyroclastic surges (poorly vesiculated andesites with very small plagioclases), silica-rich andesitic pumice flows, air-fall deposits, ballistic blocks, and reworked deposits that overlie the regional Pleistocene volcanic basement. They were produced during three main explosive phases. Two overlapping pyroclastic cones have developed within the Hule maar, and at least three lava fields are related to them (high-Al basalt to basaltic andesite). Another maar, Pata de Gallo (400 m across), is located less than 1 km off the SE rim of Hule. Río Cuarto is a nearly circular maar (700–850 m across) with a surface area of 0.33 km 2. Río Cuarto products include surges, ballistics and air-fall tephra, produced during three main explosive phases. These deposits show a narrow fan oriented westward, according to westerly wind direction. They indicate a westerly-directed surge (first 2 km), followed by air-fall deposits (up to 5 km away). Radiocarbon dating has shown that Hule was formed ~ 6.2 ka ago and Pata de Gallo probably formed ~ 2.8 ka ago, while the intra-maar products could have ages of ~ 1.7 ka or ~ 0.7 ka, indicating that Hule is a polygenetic maar. There are no radiocarbon ages yet for dating the formation of Río Cuarto maar, but archaeological data suggest that it erupted between 3–4 ka ago. The volume of pyroclastic deposits associated to Hule maar is estimated to be 0.51–0.53 km 3, from which ~ 20% is juvenile material, therefore 0.07–0.08 km 3 of new dense rock equivalent (DRE) magma, after subtracting 20–30% of porosity. The tephra from Río Cuarto is estimated to be 4.4 × 10 7 m 3, of which 0.008 m 3 correspond to DRE magma. The Hule and Río Cuarto maars are occupied by lakes and, in the last decades, several lake-overturn events have taken place, with a repeat cycle of six to seven years. The main outcome of these events has been the mass death of fish accompanied by changes in the lake color. In these systems, the hazard related to the possible occurrence of Nyos-type gas eruptions can be considered negligible or very local, but significant for tourists who camp by the lakes.

Loess failure in northeast Afghanistan

Mass movements in northeastern Afghanistan include large-scale rockslides and complex slope failures, as well as failures in loess. The loess region in northeastern Afghanistan occurs in the Badakhshan and Takhar provinces and was likely created by dust blown to the east from the Karakum Desert and the alluvial plains of northern Afghanistan. This loessic dust was deposited against the Hindu Kush mountain range which rises up along the eastern half of Afghanistan as a result of transpressional tectonism. It overlies less permeable crystalline and sedimentary bedrocks such as Triassic granite, Proterozoic gneiss, and Miocene and Pliocene clastics in the area with the largest concentration of slope failures. Thirty-four loess slides and flows were mapped and analyzed using remote satellite imagery over digital elevation models on Google Earth™. This source enabled location, classification, and measurement of failures. Findings revealed that most failed slopes faced north, west, and northwest. This trend can be explained possibly as different moisture contents resulting from the primarily westerly wind direction, which may cause more precipitation to be deposited on west-facing slopes, and sun position during the hottest part of the day. Additionally, the easterly rising Hindu Kush range may cause more slope area to face west in the study region. Other contributing factors could be the very high seismicity of the area, which may cause rapid dry fluidized loess flows, and landscape modification by humans. Several loess slope failures appear to be generated by water concentration through irrigation ditches and possible rutted tire tracks, which can create tunneling between the loess and its less permeable bedrock. Causes and effects of loess failure in Afghanistan need to be investigated in more depth. Further study may lead to the adoption of more sustainable and safe farming practices and more informed housing locations, which may prevent loss of property, crop, and transport routes.

Waves in shallow water off west coast of India during the onset of summer monsoon

Abstract. The wave growth characteristics during the onset of summer monsoon in a swell dominated open ocean at a location off the west coast of India at 14 m water depth are studied. 67% of the measured waves are due to the swells arriving from south and south-west and the balance was due to the seas from south-west to north-west. Wave age of the measured data indicates that the measured waves are young sea with presence of swells. Even when the wind speed reduced to less than 3 m/s, significant wave height more than 2 m is present due to the swells in the Arabian Sea. The maximum wave height increased from 2 to 8 m within 60 h. The mean wave directions at the high frequencies align with the westerly wind direction and gradually shift to south-westerly swell direction at low frequencies during the wave growth. The strong westerly winds present between longitude 72° and 72.5° at latitude 12.5° has created the high waves (Hm0 upto 5.65 m) during the measurement period.

Towards understanding the relationship between wind conditions and plankton patchiness

We used (1) water temperature (a proxy for water movement), (2) chlorophyll (a proxy for phytoplankton), and (3) zooplankton (bulk, small, and large size classes) to investigate the relationship between changing wind conditions and spatial patterns along linear transects (n 5 150) in two basins, South Arm and Annie Bay, of Lake Opeongo (Ontario, Canada). The basins have similar biological characteristics, but South Arm is larger and is oriented along the prevailing westerly wind direction. Large‐scale patterns (.1 km) were described with an accumulation index, and wavelet analysis was used to describe small‐scale patterns (≪1 km). Spatial descriptors were correlated with five descriptors of wind conditions: (1) wind force, (2) scalar wind speed, (3) vector wind speed, (4) wind persistence, and (5) wind direction. Persistent westerly winds in South Arm resulted in more downwind accumulation of warm water and total and large‐bodied zooplankton than in Annie Bay, while chlorophyll and small zooplankton did not show consistent downwind accumulation. The predominance of small‐scale variability, particularly in large zooplankton, increased in the South Arm as the persistence and strength of westerly winds blowing parallel to the sampling transects increased. Only temperature showed such a pattern in the smaller Annie Bay. These patterns were not related to winds blowing at the time of sampling but rather to those blowing up to 12 h before sampling. Our observations provide a basis for future consideration of how simple surface winds may actually shape the nature of trophic interactions in lake ecosystems.

Coupling of urban street canyon and backyard particle concentrations

Differences in particle mass and number concentrations between a busy urban street canyon (north-south orientation, about 50,000 vehicles 24 h -1 ) and an adjacent backyard were measured with optical particle counters. The influence of meteorological quantities, especially turbulent flow within the urban canopy layer, was also studied. Particle mass concentrations PM 10 and PM 1 were consistently larger within the street canyon due to enhanced emission and resuspension. For the study period this resulted in higher concentrations in the canyon of on average 30 % (PM 10 ) and 22 % (PM 1 ). Although elevated transport of submicrometer particles was related to easterly wind directions, the largest relative concentration differences between both sites were associated to cross-canyon flow from westerly wind directions. This is due to the canyon vortex being able to direct polluted air masses to the measurement site during flow being directed perpendicular to the canyon axis. For less polluted air within the backyard the backyard vortex is of minor influence. We found different influence of thermal and mechanical turbulence on the temporal evolution of concentration differences at both sites. Thermal turbulence was positively correlated with particle concentrations, while the latter was characterised by negative correlation coefficients.

Large-scale-flow interactions with the Alps and their impact on the low-level temperature field in the northern foreland

Numerical simulations are presented to investigate the impact of large-scale-flow interactions with the Alps on the temperature field in the northern Alpine foreland. The simulations use realistic topography but idealized large-scale conditions that allow for changing the wind direction without creating systematic temperature advection effects. The results show that the dependence of the surface temperatures on the wind direction differs substantially between the morning and the afternoon. In the afternoon, temperatures tend to be higher for southerly flow directions than for northerly ones, as might be expected from the fact that subsidence in the lee of the Alps causes warming while upslope flow is related to cooling. In the morning, however, the lowest temperatures are found for easterly directions while northwesterly flow shows the highest temperatures, followed by westerly flow. Part of this behaviour is related to the fact that in the northern Alpine foreland, westerly wind directions tend to be associated with higher wind speeds than easterly directions, which in turn is caused by the fact that the flow around the Alps is asymmetric. As a consequence, turbulent mixing tends to be stronger for westerly directions. For northwesterly flow, turbulent mixing is particularly strong because a barrier jet forms along the Alps. Another important contribution arises from the friction-induced wind turning in the surface layer, which causes a northerly (southerly) component for easterly (westerly) flow. Thus, the radiatively cooled near-surface air is piled up along the northern rim of the Alps for easterly flow but is advected away from the Alps for westerly flow.

Modeling dispersion at distances of meters from urban sources

This paper describes the evaluation and improvement of dispersion models for estimating ground-level concentrations in the vicinity of small sources located in urban areas. The models were evaluated with observations from a tracer study conducted at the University of California, Riverside. This experiment simulated a non-buoyant release from the top of a small source in an urban area. The tracer, SF 6 , was sampled at several receptors within 20 m from the source. Several receptors were located upwind of the dominant westerly wind direction. Model estimates from ISC-PRIME and AERMOD-PRIME were evaluated with hourly observed concentrations. The evaluation indicated that the highest concentrations were overestimated by these models. At the same time, the lower range of concentrations was underestimated. A diagnostic study with a simple Gaussian dispersion model that incorporated site specific meteorology indicated that these errors could be reduced by accounting for the lateral meandering caused by increased horizontal turbulence in urban areas. While AERMOD incorporates lateral meandering, it switches it off in the near field affected by PRIME estimates. This study found that using onsite turbulence information in a simple model for meandering can lead to adequate estimates of observed concentrations even when downwash effects are not modeled explicitly.

Climatological analysis of wintertime extreme low temperatures in São Paulo City, Brazil: impact of sea‐surface temperature anomalies

AbstractA diagnostic climatological study of winter cold temperature extremes in the Metropolitan Area of São Paulo (MASP) is presented. This diagnosis is based on temperature data collected at the Meteorological Station of Parque Estadual das Fontes do Ipiranga (IAG/USP) from 1950 to 2000. The persistence of synoptic and climatological patterns has been studied through principal component (PC) analysis and the results are compared with monthly anomalies in sea‐surface temperature (SST) of the eastern Pacific and South Atlantic. The extreme cold air temperatures, on a monthly basis, have shown no significant change since 1950. On the other hand, the mean monthly air temperatures have shown a slight warming trend, in agreement with the South Atlantic Ocean warming trend. The PC indicates significant loadings of two SST anomaly types: a cold anomaly of the South Atlantic Ocean, and a warm anomaly off the southern Brazilian coast. The latter could also be responsible for some extreme cold events (for daily minimum temperatures) in the MASP, and to a dominant westerly wind direction (southwest to northwest). Both the cold events and the westerly wind direction were evident in such winters as 1953, 1975, 1978, 1981, and 1994. On the other hand, the cold mean monthly temperatures are very well correlated to a broad cold pool anomaly in the South Atlantic at around 25 to 35° S and 15 to 55° W—sometimes narrower (such as in 1979 and 1988), and sometimes broader (such as 1964 and 1990). Where there was a narrowing or a widening, the prevailing wind direction was from the south–southeast. Therefore, the conclusion of these results is that the SST anomalies in the South Atlantic Ocean have a dominant effect on the São Paulo winter temperature climatology. Copyright © 2002 Royal Meteorological Society.

Expected effect of climate change on Sylt island: results from a multidisciplinary German project

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 18:141-146 (2001) - doi:10.3354/cr018141 Expected effect of climate change on Sylt island: results from a multidisciplinary German project Kai Ahrendt* GEOMAR Research Center for Marine Geosciences, Wischhofstraße 1-3, 24148 Kiel, Germany Fig. 1. Overview of study area ABSTRACT: Climate change (i.e. increasing mean sea level and storm activity) will influence the coastal development of sandy islands such as Sylt. To estimate the influence of climate change, a numerical model was used to predict the development of the coastline of Sylt island. Data for coastal retreat are available from 1876 to 1997 and were measured every 500 m longshore (~70 profiles). Wave data are available from 1986 to 1997. The model was calibrated and verified with these data. Coastal retreat was calculated to the year 2050 under the following scenarios (IPCC 1990): mean sea level +25 cm; tidal range +25 cm; wave height +10%; wave direction ±10°. Little change in the configuration of the coastline of Sylt is expected over the next 50 yr if the present strategy of western shore protection is maintained. No additional measures seem to be necessary. In contrast, if shore protection is not maintained, significant changes in coastline configuration (both west and east coasts) may occur, due in part to dramatic shore retreat by erosion, in the case of a 10% increase in wave height and a 10° change in all westerly wind directions toward the north. Only moderate changes in coastline configuration and weak shore retreat through erosion can be expected if wind direction is turned 10° to the south and wave height is maintained. KEY WORDS: Climate change · Coastline development · Modelling Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 18, No. 1-2. Online publication date: October 18, 2001 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2001 Inter-Research.

SANGICOCCUS SP., A NEW RECORD OF PEST DEVASTATING COCONUT PALMS IN PALAWAN, PHILIPPINES

Sangicoccus sp. nr. truncatispinus (Reyne) (Eriococcidae: Homoptera) is recorded for the first time as a major pest of coconut palms in the Philippines. It is also the first record among the coconut growing areas in the world. It sucks the plant sap resulting to chlorosis of leaves. Furthermore, honeydew droplets exuded by the pest accumulated on upper leaf surfaces become substrate for sootymolds.
 
 The severe infestation observed in late 1980’s already spread to 6 out of 8 municipalities of the southern second district of Palawan. Presently, crop losses are estimated to reach 53% of the nut yield. The prevailing easterly and westerly wind directions of 1-5 m/sec coupled with the dense manner of planting enabled first instar nymphs (crawlers) to spread to other palms. The long dry spell also favored the proliferation of Sangicoccus sp.bv.
 
 Controlling the spread and outbreak of this pest seems to be difficult as it thrives on eleven alternate hosts. Ant attendance contributed to dispersal and protection from natural enemies. Moreover, field population of ten predatory species remained minimal. Possible strategies for its control are presented.

The wind directions of the pleistocene dunes near Essaouira, Morocco

The dominant easterly and the westerly wind directions observed in the dune section exposed south of Essaouiria, Morocco, are interpreted as reflecting formation during a time characterized by a greater north-south seasonal displacement of the Azores High. It is further suggested that this is more characteristic of a cold rather than a warm period in the Early Pleistocene.