Meteorology

The design of flood control structures requires rainfall intensity estimation for design discharge computation. To make the rainfall intensity values easily available in Warri, Delta state of Nigeria, this research developed rainfall models. Rainfall intensity data were collected and analysed. The statistical method of least squares was used to fit the curves generated. Intensityduration models were developed and presented in graphical curves. Quotient method was adopted in the modeling. Another set of models developed are intensity-frequency models which gave correlation coefficient values of between 0.8694 and 0.9689 showing good fit. These models were used to produce rainfall intensity values for durations of 30, 60, 90 and 120 minutes and some return periods between 5 years and 30 years.

The Increasing pace of Industrialization throughout the world has brought with It a serious, and ever Increasing threat from air pollution. It Is true that this threat Is being taken seriously, and that many responsible research workers, government advisers and others are working towards Its reduction. But air pollution seems to have something of the nature of a hydra-headed monster: tackle one problem and another immediately grows to take its place. Actions taken sometimes have results that are far from what was envisioned, sometimes even seeming to make the problem worse.

In "The Forgotten Pollution", Roos shows clearly and In an often entertaining way, how many of the "unexpected" side effects of pollution by waste gases and particles can be explained by paying attention to the electrical activity of the atmosphere and the earth.
Using an Instrument, which he has developed the Electrostatic Charged Aerosol Monitor (ECAM), together with other instruments and reference to the literature, much of it dating back to the early days of science, when electrostatics was appreciated as a science more than It Is today, Roos has succeeded In explaining many hitherto "puzzling" phenomena in a clear, simple and intellectually satisfying way.

Artificial neural networks (ANNs) are useful alternative techniques in modelling the complex vehicular exhaust emission (VEE) dispersion phenomena. This paper describes a step-by-step procedure to model the nitrogen dioxide (NO 2 ) dispersion phenomena using the ANN technique. The ANN-based NO 2 models are developed at two air-quality-control regions (AQCRs), one, representing, a traffic intersection (AQCR1) and the other, an arterial road (AQCR2) in the Delhi city. The models are unique in the sense that they are developed for 'heterogeneous 1 ' traffic conditions and tropical meteorology. The inputs to the model consist of 10 meteorological and 6 traffic characteristic variables. Two-year data, from 1 January 1997 to 31 December 1998 has been used for model training and data from 1 January to 31 December 1999, for model testing and evaluation purposes. The results show satisfactory performance of the ANN-based NO 2 models on the evaluation data set at both the AQCRs (d = 0.76 for AQCR1, and d = 0. 59 for AQCR2).

Every day in the news it seems like there are more and more stories about record-breaking weather. Kevin Kloesel is a Texas Ex and Director of the Oklahoma Climatological Survey, working right in the heart of Tornado Alley. He will talk about the science behind extreme weather events such as tornadoes and super storms, and how meteorologists deal with uncertainty in their forecasts. His talk will include demonstrations of extreme weather phenomena, and comparisons between shooting three-point baskets and climate change.

The horizontal flow of SO2 gas from day side to night side of Io is calculated. The surface is assumed to be covered by a frost whose vapor pressure at the subsolar point is orders of magnitude larger than that on the night side. Temperature of the frost is controlled by radiation. The flow is hydrostatic and turbulent, with velocity and entropy per particle independent of height. The vertically integrated conservation equations for mass, momentum, and energy are solved for atmospheric pressure, temperature, and horizontal velocity as functions of solar zenith angle. Formulas from boundary layer theory govern the interaction between atmosphere and surface. The flow becomes supersonic as it expands away from the subsolar point, as in the theory of rocket nozzles and the solar wind. Within 35 ° of the subsolar point atmospheric pressure is less than the frost vapor pressure, and the frost sublimes. Elsewhere, atmospheric pressure is greater than the frost vapor pressure, and the frost condenses. The two pressures seldom differ by more than a factor of 2. The sublimation rate at the subsolar point is proportional to the frost vapor pressure, which is a sensitive function of temperature. For a subsolar temperature of 130°K, the sublimation rate is l0 ~5 molecules/cm2/sec. Diurnally averaged sublimation rates at the equator are comparable to the 0. l cm/year resurfacing rate required for burial of impact craters. At the poles where both the vapor pressures and atmospheric pressures are low, the condensation rates are 100 times smaller. Surface pressures near the terminator are generally too low to account for the ionosphere discovered by Pioneer 10. The possibility of a noncondensable gas in addition to SO: must be seriously considered.

Design traffic volumes, vehicle emission factors and meterological data are used to assess the impact of a suburban limited-access highway segment. Mesoscale effects are determined by emission inventory techniques. Microscale effects are determined using a pollutant dispersion model developed by the California Division of Highways. The air pollution impact of the highway segment is small, and should not be considered a significant criteria for decisions concerning construction of the highway.

Designing a fuel-sampling program that accurately and efficiently assesses fuel load at relevant spatial scales requires knowledge of each sample method’s strengths and weaknesses. We obtained loading values for six fuel components using five fuel load sampling techniques at five locations in western Montana, USA. The techniques included fixed-area plots, planar intersect, photoloads, a photoload macroplot, and a photo series. For each of the six fuels, we compared (1) the relative differences in load values among techniques and (2) the differences in load between each method and a reference sample. Totals from each method were rated for how much they deviated from totals for the reference in each fuel category. The planar-intersect method, which used 2.50 km of transects, was rated best overall for assessing the six fuels. Bootstrapping showed that at least 1.50 km of transect were needed to obtain estimates that approximate the reference sample. A newly developed photoload method,...

Periodicity mining is used for predicting trends in time series data. Discovering the rate at which the time series is periodic has always been an obstacle for fully automated periodicity mining. Existing periodicity mining algorithms assume that the periodicity rate (or simply the period) is user-specified. This assumption is a considerable limitation, especially in time series data where the period is not known a priori. In this paper, we address the problem of detecting the periodicity rate of a time series database. Two types of periodicities are defined, and a scalable, computationally efficient algorithm is proposed for each type. The algorithms perform in Oðn log nÞ time for a time series of length n. Moreover, the proposed algorithms are extended in order to discover the periodic patterns of unknown periods at the same time without affecting the time complexity. Experimental results show that the proposed algorithms are highly accurate with respect to the discovered periodicity rates and periodic patterns. Real-data experiments demonstrate the practicality of the discovered periodic patterns.

The detailed topological or 'connectivity' properties of the clusters formed in diffusion limited aggregation (DLA) and cluster-cluster aggregation (CCA) are considered for spatial dimensions d = 2,3 and 4. Specifically, for both aggregation phenomena we calculate the fractal dimension d,,, = i-' defined by e -R d m l n where e is the shortest path between two points separated by a Pythagorean distance R For CCA, we find that dmin increases monotonically with d, presumably tending toward a limiting value dmi, = 2 at the upper critical gimensionality d, as found previously for lattice animals and percolation.

This paper was finished and distributed May 7, 1991 to several people in the Eugene, Oregon area, including John Moseley, the vice president of research for the University of Oregon.  He once greeted me enthusiastically on the street after my Peace Economics book had come out.  This is the 54 year cycle documented to come from the temperature records of key sections of the earth.

Complementary analysis of satellite mission data (altimetry, Moderate Resolution Imaging Spectroradiometers (MODIS)) and climate fields over 2000–2009 was conducted to investigate the variability of the water cover surfaces and the geographical source of water inflowing into the Lake Poopó system. The results suggest that over the time span of 2000–2009 a great part of the variability of the Poopó system originates from geographic sources other than Lake Titicaca. Possible alternative causes include climate change inducing increased temperatures and greater evaporation rates along the Altiplano; increased glacier and snow melting over the Andes Cordillera; and a potential increased anthropogenic water use (such as irrigation, minery, etc.) throughout the path of the Desaguadero River (which connects lakes Titicaca and Poopó). This change in the hydrology of this region could lead to a collapse of water supplies and endanger the already fragile Poopó system as well as the regional socioeconomic system, which closely depends upon it.

Understanding the impact of aerosols on the earth's radiation budget and the long-term climate record requires consistent measurements of aerosol properties and radiative fluxes. The Clouds and the Earth's Radiant Energy System (CERES) Science Team combines satellite-based retrievals of aerosols, clouds, and radiative fluxes into Single Scanner Footprint (SSF) datasets from the Terra and Aqua satellites. Over ocean, two aerosol products are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) using different sampling and aerosol algorithms. The primary, or M, product is taken from the standard multispectral aerosol product developed by the MODIS aerosol group while a simpler, secondary [Advanced Very High Resolution Radiometer (AVHRR) like], or A, product is derived by the CERES Science Team using a different cloud clearing method and a single-channel aerosol algorithm. Two aerosol optical depths (AOD), A1 and A2 , are derived from MODIS bands 1 (0.644 m) and 6 (1.632 m) resembling the AVHRR/3 channels 1 and 3A, respectively. On Aqua the retrievals are made in band 7 (2.119 m) because of poor quality data from band 6. The respective Ångström exponents can be derived from the values of . The A product serves as a backup for the M product. More importantly, the overlap of these aerosol products is essential for placing the 20ϩ year heritage AVHRR aerosol record in the context of more advanced aerosol sensors and algorithms such as that used for the M product.

Urban flooding is an inevitable problem for many cities around the world. In the present paper, modelling approaches and principles for analyses of urban flooding are outlined. The paper shows how urban flooding can be simulated by one-dimensional hydrodynamic ...

Les conditions de température de l'air sont parmi les paramètres les plus importants du climat d'une région ou d'un pays. Trois aspects de la température sont traités, à savoir les températures minimales, les températures maximales et l'amplitude thermique. Des cartes ont été créées à l'aide de données d'observation issues de la Direction de la Météorologie Nationale. Les résultats ont montré qu'il existe une certaine variabilité entre les différentes zones du Maroc, principalement en raison des différences d'altitude (présence de séries de montagnes), de la proximité de la côte et d'autres aspects météorologiques. Une carte de vulnérabilité a été élaborée à partir des résultats précédents et analysée. Les résultats ont montré que les villes les plus vulnérables sont Béni Mellal, Ouarzazate et Rachidia. Cela implique par exemple que les planificateurs nationaux des secteurs de l'agriculture et des transports / infrastructures dans la partie centrale du pays doivent prendre en compte les vulnérabilités liées à la température lorsqu'ils élaborent des stratégies et des plans sectoriels.

Despite the availability of the sensor and smartphone devices to fulfill the ubiquitous computing vision, thestate-of-the-art falls short of this vision. We argue that the reason for this gap is the lack of an infrastructure to task/utilize these devices for collaboration and coordination. We propose that Twitter can provide an "open" publish-subscribe infrastructure for sensors and smartphones, and pave the way for ubiquitous crowd-sourced sensing and collaboration applications. We design and implement a crowd-sourced sensing and collaboration over Twitter, and showcase our system in the context of two applications: a crowd-sourced weather radar, and a participatory noise-mapping application. Our results from real-world Twitter experiments give insights into the feasibility of this approach and outlines the research challenges in sensor/smartphone integration to Twitter.

The parameter terms (second column) for log (Aerial shrub cover + 1) × scale and log (Aerial tree cover + 1) × scale were incorrectly given positive rather than negative values. The correct values are: log (Aerial shrub cover + 1) × scale = −0.005 (0.002) log (Aerial tree cover + 1) × scale = −0.002 (0.001)

The potential of a ground-based microwave temperature profiler to combine full tropospheric profiling with highresolution profiling of the boundary layer is investigated. For that purpose, statistical retrieval algorithms that incorporate observations from different elevation angles and frequencies are derived from long-term radiosonde data. A simulation study shows the potential to significantly improve the retrieval performance in the lowest kilometer by combining angular information from relatively opaque channels with zenith-only information from more transparent channels. Observations by a state-of-the-art radiometer employed during the International Lindenberg Campaign for Assessment of Humidity and Cloud Profiling Systems and Its Impact on High-Resolution Modeling (LAUNCH) in Lindenberg, Germany, are used for an experimental evaluation with observations from a 99-m mast and radiosondes. The comparison not only reveals the high accuracy achieved by combining angular and spectral observations (overall, less than 1 K below 1.5 km), but also emphasizes the need for a realistic description of radiometer noise within the algorithm. The capability of the profiler to observe the height and strength of low-level temperature inversions is highlighted.

This paper presents some of the findings of the European project, RUROS, concentrating on the effect of microclimatic conditions on the use of open spaces in an urban Mediterranean environment. The findings confirm that there is a strong relationship between microclimatic conditions and use of open spaces. Regarding the users of open spaces, a sensitivity to the summer heat was apparent for the age category >65. The spatial distribution of the interviewees demonstrates that in summer, visitors prefer to sit in shaded areas, whereas in autumn and winter sunlit areas are more popular. Observations of the use of space revealed that air temperature and solar radiation were found to be the most dominant parameters in relation to the use of space, with wind speed and relative humidity having a weak effect. In general, people prefer shaded areas at higher air temperatures. However, as high air temperature is a factor contributing to discomfort, overall presence is reduced when air temperature rises significantly. The preference of sun, differs from season to season, depending on the activities taking place in the areas (either designated or not). The diurnal pattern of the use of space also reveals a strong dependency on meteorological parameters. Regarding the time of maximum attendance, this is found in the evening during summer, while there is a transition of the time of maximum attendance towards noon as the season progresses from summer to winter. Daytime attendance figures of autumn and winter are 300-400% higher than in the summer. The need open spaces cover and the social ties provided may also be traced by analyzing the social composition of the interviewees and the reasons bringing them in the space.

The geographical area of Northeastern Bulgaria boasts a specific climate conditions. They are a prerequisite for the expression of adverse and hazardous natural phenomena. This report analyses the genesis and location of the adverse and dangerous meteorological, climate and hydrological phenomena within the Northeastern Bulgaria, which determined by climate conditions.

Positive cloud-ground lightning is considerably more complex and less studied compared to the negative lightning. This paper aims to measure and characterize the significant parameters of positive return strokes electric field, namely, the zero-to-peak rise time, 10–90% rise time, slow front duration, fast transition rise time (10–90%), zero-crossing time, and opposite polarity overshoot relative to peak. To the best of the authors’ knowledge, this is the first time such detailed characteristics of positive lightning in Malaysia are thoroughly analyzed. A total of 41 positive lightning flashes containing 48 return strokes were analyzed. The average multiplicity is 1.2 strokes per flash. The majority of positive lightning was initiated from the primary positive charge rather than as a byproduct of in-cloud discharges. The cumulative probability distribution of rise time parameters, opposite polarity overshoot relative to peak, and slow front amplitude relative to peak are presented. ...

The first part of this note provides all trigonometrical formulas which allow the direct spectral analysis and the computation of those long-term variations of the earth's orbital elements which are of primary interest for the computation of the insolation. The elements are the ...

An unsupervised method that utilizes a combination of statistical and machine learning techniques is presented in order to classify statistically independent rainstorm events and create a limited number of design hyetographs for the Water Division of Thrace in Greece. The whole process includes the necessary steps from importing raw precipitation time series data to producing the initially unknown optimal number of representative design hyetographs. These hyetographs can be used for stochastic simulation, water resources planning, water quality assessment and global change studying. The present type of analysis is applied for the first time on data from a Greek region and, in addition, it presents certain characteristics of a more general applicability. Namely, the method employed is fully unsupervised, as no empirical knowledge of local rainfalls is implicated or any arbitrary introduction of quartiles for grouping. Also, the critical time duration of no precipitation between rainstorm events is not defined in advance, as is the case in the pertinent literature.

The author conducted a ground damage survey after riding out Hurricane Elena in Pensacola, FL.  We drove the Mississippi coast just after the storm and documented high wind and storm surge damage.  High water marks were obtained using a level from known benchmarks.  This HAAG ENGINEERING paper summarizes our findings.

This work discusses the continuous movement of water on, above and below the surface of the earth. Brought into focus are the processes of the hydrologic cycle. This study is a useful starting point on the study of hydrology. The cycle begins with the evaporation of water from the ocean due to the heating of the water by the sun's radiation, thereby making it to change to water vapour and driven by air current in the atmosphere to form clouds which later condenses as rain. Processes of hydrological cycle takes place simultaneously at different rates and time. A concise history of the hydrologic cycle was also captured. Evaporation is seen as the major player in the hydrologic cycle.

The impact that volcanic eruptions may have upon environments far from the volcanic source is conventionally assumed to depend on climatic modification by emitted gases. However, recent research has suggested that the damage caused by the direct impact of volcanic gases, mainly H 2SO 4, may be profound. This paper highlights the severity of this mechanism by reference to human sickness and death in France and contiguous with the eruption of the Laki fissure in Iceland in 1783. This work demonstrates the gains which may be made by interdisciplinary teams of researchers and illustrates the valuable knowledge that remains to be revealed by further research in the French historical record. To cite this article: J. Grattan et al., C. R. Geoscience 337 (2005).

Mesosphere-Stratosphere-Troposphere (MST) Radar wind data for the period June through September 1996 have been examined to study vertical variation of Madden-Jullian Oscillations in wind and eddy kinetic energy (eke) in the normal monsoon season. The domain of analysis in the vertical is from 6 to 20 km with a height resolution of 150 m. Fast-Fourier-Transformation (FFT) has been applied to zonal (u), meridional(v) components of wind to extract the Madden-Jullian oscillations and eke. There are three dominant modes viz., 50±70, 30±40 and 10±20 day periodicity, which contain considerable fraction of energy and show high degree of vertical variability. The peak amplitude of 50±70 day mode in u, 30±40 mode in v and eke were observed at 16±17 km just below the tropopause level. The peak amplitudes of 30±40 day mode in u and 50±70 day mode in v were found in the height region of 13±16 km. To understand the origin and propagation of these waves, wave energy is calculated. The wave energy is higher at tropospheric heights than at lower stratospheric heights indicating that the origin of these waves is in the troposphere, and a part of the energy leaks into the stratosphere.

A numerical study is performed to elucidate the dominant turbulent processes that occur in urban areas. Comprehensive data from direct numerical simulations (DNS) over idealized three-dimensional arrays of buildings are analysed to study the unsteady and organized aspects of the turbulent flow. The accuracy of the DNS is evaluated by comparing turbulence statistics with a high quality wind-tunnel dataset. The simulation results are studied using flow visualization as well as statistical methods including quadrant analysis, space-time two-point correlations and conditional averaging. Three regimes of the flow are identified. First, the rough wall flow above the buildings has turbulent organized structures that resemble the 'hairpin vortices' and 'low momentum regions' that are well known to occur in the turbulent boundary layer over smooth walls. These hairpin-like vortices contribute dominantly to vertical momentum transport. Secondly, shear layers develop over the tops of the buildings and shed structures that may sometimes impinge upon downstream buildings and drive a robust recirculation within the building canopy. These unsteady canopy-top shear layers and their interaction with the larger eddies above provide important mechanisms for coupling with the flow within the canopy. Thirdly, the flow within the building canopy is the result of complicated interactions between the above and eddies shed off the vertical edges of the buildings, and their distortion caused by impacting buildings. Mean flow patterns around the buildings are important and lead to significant dispersive stresses. Implications for scalar transport and dispersion are briefly discussed.

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The daily rainfall over India during the monsoon season (June-September) is governed by the interplay of the large-scale, synoptic and mesoscale disturbances, many of which are sporadic rainfall spells and extremely intense. These spells often bring extreme amounts of rain over only a few days, which can have sizable impacts on the estimated seasonal mean rainfall. The record rainfall of over 100 cm/day in Mumbai on 26 th July, 2005 is an outlier/extreme at over 20 standard deviations for activity of typical June-September average rainfall of 18 mm/day with daily standard deviation of 28 mm/day. While such outliers are not uncommon in India during the monsoon season, they pose serious challenge to even the high resolution forecast models. The statistics of these outlier events are examined both for observed and model-forecast daily rainfall for recent seven monsoon seasons (2007-2013). Some of the extreme one day rainfall events (over the plains of eastern India) contribute up to 30% of the seasonal total rain. This study presents rainfall verification over India using traditional verification scores such as Probability of Detection (POD), Equitable Threat Score (ETH), Critical Success Index (CSI) etc. for various categories. Further, the statistical challenges associated with the verification of the extreme events are discussed. A brief review of the new methods suggested in literature for verification of the extreme events, such as Odds Ratio (OR), Extreme Dependency Score (EDS), Symmetric Extreme Dependency Score (SEDS), Extremal Dependence Index (EDI) and Symmetric EDI (SEDI) is provided with example application to Indian context.

Advances in earth observation technology over the last two decades have resulted in improved forecasting of various hydrometeorological-related disasters. In this study the severe tropical cyclone Gonu (2-7 June, 2007) was investigated using multi-sensor satellite data sets (i.e. AIRS, METEOSAT, MODIS and QSCAT data) to monitor its overall structure, position, intensity, and motion. A high sea surface temperature and warm core anomalies (at 200 hPa and above) with respect to the pressure minima in the central core were found to have influenced the pattern of development of the tropical cyclone. High relative humidity in the middle troposphere was aligned with temperature minima at 850 hPa and 700 hPa; high winds (above 120 knots) and closed pressure contours were observed during the intensification stage. A contour analysis of outgoing longwave radiation (OLR) provided an explanation for the direction of movement of the cyclone. The translational movement and velocities (ground speed) of the tropical cyclone were calculated using the surface pressure of the cyclone's central core. Statistical analyses revealed a strong correlation between the maximum wind speeds within the cyclone and various atmospheric parameters. We conclude with a discussion of the significance of these findings with regard to cyclone forecasting within the framework of early warning and disaster management.

La preocupacion del hombre en observar el cielo para conocer la influencia de los astros en los ciclos vegetativos ha existido desde siempre. El saber popular nos ha dejado en la tradicion una rica y variada metodologia para pronosticar el tiempo a traves de la observacion del clima en determinados dias del ano. Con diversas variantes, entre las que destaca la observacion de los ciclos de la luna, las Cabanuelas se nos presentan como el metodo popular de prediccion meteorologica por antonomasia, abarcando una interesante riqueza costumbrista que esta presente en todas las civilizaciones y en todos los momentos de la Historia, hasta nuestros dias. Al margen de comprobaciones mas o menos cientificas, las Cabanuelas se encuentran tan arraigadas en nuestra cultura popular que merecen, al menos, el respeto de los escepticos.

This paper describes the architecture of a data level comparative visualization system and experiences using it to study computational fluid dynamics data and experimental wind tunnel data. We illustrate how the system can be used to compare data sets from different sources, data sets with different resolutions and data sets computed using different mathematical models of fluid flow. Suggested improvements to the system based on users' feedback are also discussed.

To gain occupational legitimacy, workers depend on claims of accuracy. How
are these claims assessed? Organizations judge competence and effectiveness
using metrics, which can be massaged. Using a case study of operational meteorology,
the author examines the organizational and self-presentational politics
whereby meteorologists verify their predictions. Forecasts of future events
are central to occupational work in operational meteorology. However, assessing
what really happened “on the ground” is not unproblematic. So, meteorologists
and their employers construct measures for assessments, even though
these assessments are social and organizational routines.Verification statistics
are signals whereby local offices are judged on effectiveness, and as a result,
workers develop strategies to increase their verification scores. The author
examines the production of verification at three local offices of the National
Weather Service using ethnographic observations and in-depth interviews.
Similar strategies operate when workers are judged in accountability systems,
leading to forms of organizational impression management to demonstrate
competence.

In January 2002, the Inter-Agency Space Debris Coordination Committee (IADC) promoted a fourth reentry test campaign, choosing an old Russian upper stage as a study case. As in the past, ISTI -formerly CNUCE -was involved, acting as the Italian Space Agency (ASI) technical contact, in the modeling aspects of the reentry predictions, while other IADC members, namely NASA, Rosaviakosmos and ESA, also provided periodic orbits determinations based on ground sensor data. The test campaign took place in a period of high solar activity, during the second peak of the cycle 23 maximum. This was a good opportunity to investigate the behavior of the models available or developed at ISTI, in terms of atmospheric density description, extreme ultraviolet radiation input, ballistic parameter estimation and orbit propagation. In order to evaluate the intrinsic reentry prediction uncertainties, the orbital decay of the test object was fitted, and predictions were made for it, using three different thermospheric density models and two independent sets of orbit determinations (American and Russian two-line elements). The results obtained were compared in order to provide a quantitative assessment of the level of accuracy that may be expected in similar situations.

This paper presents the measurement and analysis of the consistency of rain induced impairment on Line-of-sight links in middle belt region of Nigeria. The experiment was carried out at the Globacom switch house, Jos Plateau state (9.9565° N, 8.8583° E; 1258 meters). Rain rate data were obtained for the period of eight months (April, May, June, July, August, September, October and November 2017). The Davis Vantage Vue weather station was used to measured and recorded one-minute rain-rates. Microsoft Excel application package was used to analyze the obtained rain rate data through which the frequency and exceeded frequency percentage of time was calculated. Results obtained shows that the rain induced impairment within the study area are cause mostly by widespread (>5-25mm/hr) and shower (>25-120mm/hr). Higher rainfall intensities were obtained between 0.01 and 0.001% exceeded percentage of time where maximum rain induced impairment can best be estimated. Keyword: Line-of-sight link, rain rate, rain induced impairment

Wildland fuelbeds are exceptionally complex, consisting of diverse particles of many sizes, types and shapes with abundances and properties that are highly variable in time and space. This complexity makes it difficult to accurately describe, classify, sample and map fuels for wildland fire research and management. As a result, many fire behaviour and effects software prediction systems use a generalised description of fuels to simplify data collection and entry into various computer programs. There are several major fuel description systems currently used in the United States, Canada and Australia, and this is a source of confusion for many in fire management. This paper (1) summarises the challenges of describing fuels, (2) contrasts approaches (association, classification and abstraction) for developing fuel description systems and (3) discusses possible future directions in wildland fuel description and science to transition to a universal fuel description system. Most discussio...

Mingo Creek is located just east of Tulsa, Oklahoma. The creek flows northward from rolling hills to a shallow flood plain. Over the last three decades, the watershed has been highly commercialized with large subdivisions and industrial parks. Over half the watershed is now urbanized. Bermed highways and interstates bisect the floodplain. The rapid growth and extensive development of the watershed has altered the floodplain environment and hydrology.  This paper summarizes the effects of urbanization which led to extreme flooding of the area during heavy rains.

The emission and scattering from desert surfaces are analyzed using simulations and measurements from the Special Sensor Microwave/Imager (SSM/I) and the Advanced Microwave Sounding Unit (AMSU) microwave satellite instruments. Deserts are virtually free of vegetation, so the satellite radiometers are able to observe the emissivities of different minerals, such as limestone and quartz. Moreover, since deserts contain little moisture, the thermal emission originates below the surface at a depth of many wavelengths. At high frequencies, where the penetration depth of radiation is smallest, the radiometric measurements display the large diurnal variation in surface temperature, which reaches its maximum at around 1 P.M. Conversely, at low frequencies, where the penetration depth is largest, the radiation measurements display the small diurnal variation of subsurface temperature, which reaches a minimum at around 6 A.M. In addition to these emission signals, sand particles also scatter microwave radiation. Volume scattering causes the measurements to decrease as the frequency increases; although compared to other scattering media (snow cover and precipitation), the larger absorption and fractional volume (i.e., solidity) of sand reduce the scattering. Although the scattering effect is small, SSM/I measurements between 19 and 85 GHz show that deserts scatter the upwelling microwave radiation in a manner similar to light precipitation, which makes it difficult to uniquely identify precipitation over arid regions. Interestingly, the higher frequency AMSU measurement at 150 GHz is nearly the same as at 89 GHz for deserts, whereas the 150-GHz measurement is much lower than at 89 GHz for precipitation. These different spectral features at high frequencies can provide a means of separating the scattering from desert surfaces from that of precipitation.

Although a few studies on rainfall spatial and temporal variability in the UAE have been carried out, evidence of the impact of climate change on rainfall trends has not been reported. This study aims at assessing the significance of long-term rainfall trends and temporal variability at Sharjah City, UAE. Annual rainfall and seasonal rainfall extending over a period of 81 years (1934–2014) recorded at Sharjah International Airport have been analyzed. To this end, several parametric and nonparametric statistical measures have been applied following systematic data quality assessment. The analyses revealed that the annual rainfall trend decreased from −3 mm to −9.4 mm per decade over the study periods. The decreasing annual rainfall trend is mainly driven by the significant drop in winter rainfall, particularly during the period from 1977 to 2014. The results also indicate that high probability extreme events have shifted toward low frequency (12.7 years) with significant variations i...

Fog is a significant factor affecting the Air Traffic Control (ATC). Significant limitations of the airport capacity are due to fog that causes the reduction of the visibility (Runway Visual Range, RVR). Today METAR (Meteorological Aviation Report

This work describes the results of research into a source-oriented pollen concentration forecasting technique. Tests were conducted using the National Center for Atmospheric Research/ Penn State Fifth Generation Mesoscale Model (MM5), the National Oceanographic and Atmospheric Administration (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT_4) Model combined with the locations of oak trees and their aerial coverage from biogenic emissions land cover database version 3.1 (BELD3). Daily forecasts of pollen concentrations via MM5 and HYSPLIT_4 were made with 30-min increments and tested against 30-min oak pollen data collected by the St. Louis County Department of Health in Clayton, Missouri, for the month of April 2000.

Electric radiation fields produced by lightning cloud flashes have been analyzed using Fourier methods to obtain amplitude spectra for frequencies in the range of 20 kHz to 20 MHz. Time to thunder measurements were used to extract the distances to the cloud flashes from the measurement site. The spectra were generated by analyzing the first 10 ms time window of cloud flashes with 10 ns sampling resolution, and they show f-1 frequency dependence up to 2 MHz followed by f-2 dependence and higher for frequencies above 2 MHz. The results agree very well with previous measurements carried out for individual pulses produced by various lightning processes. By utilizing digital filters, it has been shown that measurements taken with narrowband filters agree with the results produced under wideband measurements