Dynamics and physical processes involving extreme temperatures in the Iberian Peninsula and Iraq

The occurrence of heat waves and cold spells has received special attention in recent years due to their impact on human health, ecosystems and economy. In the context of climate change, there is evidence that extreme temperature episodes, and not only the mean temperature, are changing in response to anthropogenic radiative forcing. This thesis focuses in the study of the dynamics and the physical processes leading to temperature extremes in two regions located at the west and the east sides of the Mediterranean Sea: the Iberian Peninsula (IP) and Iraq. The 12–hourly 2–m height maximum/minimum temperatures obtained from the 1º¿1º ERA–Interim database in the period 1994–2013 are used. At each grid point, hot/cold extremes are defined as those events in which T2MAX/T2MIN was above/under its 99.9th/0.1th percentile. The results in both study areas show that there is a positive trend in the occurrence and persistence of both hot and cold events. By using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the 10-day back-trajectories of the air masses producing the extremes are analysed. Rather than meridional advection, the primary cause behind the occurrence of hot extremes seems to be progressive diabatic warming, which becomes accentuated the days before the episode. The extremes are caused by air masses with long residence times and by recirculation processes during summer days of weak baric gradient. The air masses producing the extreme cold events have faster trajectories. Cold events are mainly associated with advection of air-masses from northeast and north Europe for IP and from Siberia and East Europe for Iraq. In the IP, Principal Component Analysis of the pressure and geopotential fields has also been carried out to identify the associated synoptic scale configurations, showing that advection during cold episodes is induced by the presence of a relative low in the central Mediterranean and a blocking high in the North Atlantic and/or in northeast Europe. We analyse the correlations between temperature extremes and the modes of climatic variability affecting the Mediterranean basin: North Atlantic Oscillation (NAO), Western Mediterranean Oscillation (WeMO), Arctic Oscillation (AO) and East Atlantic Oscillation (EA). In the IP, a significant positive correlation (p < 0.01) is found between the annual average of the extreme hot temperatures and annual WeMO. Significant negative correlation (p < 0.01) is found between the number of cold days and the annual index for NAO. In Iraq, significant positive correlation (p < 0.01) between the annual average of the extreme hot temperatures and annual EA is found. The mechanisms underlying the occurrence of hot extreme temperatures for specific events occurred in IP have been analysed by using both HYSPLIT and the Weather Research and Forecast (WRF) mesoscale model. For the event that occurred on 10 August 2012, that affected the highest number of grid points of the series, the synoptic situation shows an omega blocking system and local recirculation of warm air masses. The analysis of the only hot extreme event recorded just at one single grid point, on 15 August 2012, shows that not synoptic or mesoscale conditions substantially different from those of the neighbours grid point were given.L'estudi de les causes de les onades de calor i fred ha tingut una atenció especial en els últims anys a causa del seu impacte en la salut humana, els ecosistemes i l'economia. En el context del canvi climàtic, hi ha evidències que mostren que els episodis de temperatura extrema, i no només la temperatura mitjana, estan canviant en resposta al forçament antropogènic. Aquesta tesi se centra en l'estudi de la dinàmica i els processos físics que condueixen a temperatures extremes en dues regions situades a l'oest i l'est del mar Mediterrani: la Península Ibèrica (PI) i Iraq. S'utilitzen les temperatures màximes/mínimes a 2 m d'altura, obtingudes a partir de la base de dades ERA-Interim en el període de 20 anys 1994-2013. En cada punt de la malla que cobreix les dues àrees d’estudi, cada 12 hores (03 i 15 UTC) amb resolució 1ºx1º, es defineixen els extrems càlids/freds com aquells episodis en què T2MAX/T2MIN es troba per sobre/sota del percentil 99.9/0.1. Els resultats en ambdues àrees d'estudi mostren que hi ha una tendència positiva en l'ocurrència i persistència d'episodis tant càlids com freds. Mitjançant l'ús del model Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), s'analitzen les trajectòries, endarrere en el temps, de 10 dies de durada, de les masses d'aire que produeixen els extrems. La causa principal que explica l'aparició d'extrems càlids sembla estar associada a un escalfament diabàtic progressiu, que s'accentua els dies anteriors a l'episodi, i no pas a l’advecció de masses d’aire des d’àrees més càlides. Els extrems càlids són produïts per masses d'aire amb temps de residència llargs sobre la PI i per processos de recirculació que tenen lloc durant dies d'estiu amb un feble gradient bàric. Les masses d'aire que produeixen dies de fred extrem tenen associades trajectòries més ràpides que les masses d’aire càlides. Els episodis freds a la PI es relacionen principalment amb advecció de masses d'aire procedents del nord-est i el nord d'Europa, i per l’Iraq, procedents de Sibèria i l'Est d’Europa. A la PI també s'ha realitzat l'anàlisi de components principals dels camps de pressió i geopotencial per identificar les configuracions d’escala sinòptica associades; aquestes mostren que l'advecció durant els episodis de fred és induïda per la presència a la Mediterrània central d'una baixa relativa i un alta de bloqueig a l'Atlàntic Nord i/o al nord-est d'Europa. S’analitzen també les correlacions entre l’ocurrència de temperatures extremes i els principals modes de variabilitat climàtica que afecten la conca mediterrània: Oscil·lació de l'Atlàntic Nord (NAO), Oscil·lació de la Mediterrània Occidental (WeMO), Oscil·lació Àrtica (AO) i Oscil·lació de l'Atlàntic Oriental (EA). A la IP es troba una correlació positiva significativa (p <0,01) entre la mitjana anual de les temperatures extremes càlides i l’índex anual de WeMO. També es troba una correlació negativa significativa (p <0,01) entre el nombre de dies freds i l'índex anual de NAO. A Iraq, s’ha obtingut una correlació significativa positiva (p <0,01) entre la mitjana anual de temperatures extremes càlides i l’índex anual de EA. Els mecanismes subjacents a l'aparició de temperatures extremes càlides per a episodis extrems específics ocorreguts a la IP s'han analitzat utilitzant el model a gran escala HYSPLIT i el model mesoescalar Weather Research and Forecast (WRF). Per a l'episodi que es va produir el 10 d'agost de 2012, que va afectar simultàniament al nombre més gran de punts del període, l’estudi sinòptic mostra una situació de bloqueig associada a una configuració ‘omega’, que provoca recirculació de massa d’aire. L’anàlisi de l’únic episodi càlid que va afectar a un sol punt de la malla, el 15 d’agost de 2012, mostra que les condicions sinòptiques i/o mesoescalars no van diferir substancialment de les que es van donar en els punts circumdants al punt de l’extrem càlid

Fully Stable Banach Algebra Module

The object of this paper is to introducea class of module which is a fully stable Banach Algebra module.

Dynamics and physical processes involving extreme temperatures in the Iberian Peninsula and Iraq

The occurrence of heat waves and cold spells has received special attention in recent years due to their impact on human health, ecosystems and economy. In the context of climate change, there is evidence that extreme temperature episodes, and not only the mean temperature, are changing in response to anthropogenic radiative forcing. This thesis focuses in the study of the dynamics and the physical processes leading to temperature extremes in two regions located at the west and the east sides of the Mediterranean Sea: the Iberian Peninsula (IP) and Iraq. The 12–hourly 2–m height maximum/minimum temperatures obtained from the 1º¿1º ERA–Interim database in the period 1994–2013 are used. At each grid point, hot/cold extremes are defined as those events in which T2MAX/T2MIN was above/under its 99.9th/0.1th percentile. The results in both study areas show that there is a positive trend in the occurrence and persistence of both hot and cold events. By using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the 10-day back-trajectories of the air masses producing the extremes are analysed. Rather than meridional advection, the primary cause behind the occurrence of hot extremes seems to be progressive diabatic warming, which becomes accentuated the days before the episode. The extremes are caused by air masses with long residence times and by recirculation processes during summer days of weak baric gradient. The air masses producing the extreme cold events have faster trajectories. Cold events are mainly associated with advection of air-masses from northeast and north Europe for IP and from Siberia and East Europe for Iraq. In the IP, Principal Component Analysis of the pressure and geopotential fields has also been carried out to identify the associated synoptic scale configurations, showing that advection during cold episodes is induced by the presence of a relative low in the central Mediterranean and a blocking high in the North Atlantic and/or in northeast Europe. We analyse the correlations between temperature extremes and the modes of climatic variability affecting the Mediterranean basin: North Atlantic Oscillation (NAO), Western Mediterranean Oscillation (WeMO), Arctic Oscillation (AO) and East Atlantic Oscillation (EA). In the IP, a significant positive correlation (p < 0.01) is found between the annual average of the extreme hot temperatures and annual WeMO. Significant negative correlation (p < 0.01) is found between the number of cold days and the annual index for NAO. In Iraq, significant positive correlation (p < 0.01) between the annual average of the extreme hot temperatures and annual EA is found. The mechanisms underlying the occurrence of hot extreme temperatures for specific events occurred in IP have been analysed by using both HYSPLIT and the Weather Research and Forecast (WRF) mesoscale model. For the event that occurred on 10 August 2012, that affected the highest number of grid points of the series, the synoptic situation shows an omega blocking system and local recirculation of warm air masses. The analysis of the only hot extreme event recorded just at one single grid point, on 15 August 2012, shows that not synoptic or mesoscale conditions substantially different from those of the neighbours grid point were given.L'estudi de les causes de les onades de calor i fred ha tingut una atenció especial en els últims anys a causa del seu impacte en la salut humana, els ecosistemes i l'economia. En el context del canvi climàtic, hi ha evidències que mostren que els episodis de temperatura extrema, i no només la temperatura mitjana, estan canviant en resposta al forçament antropogènic. Aquesta tesi se centra en l'estudi de la dinàmica i els processos físics que condueixen a temperatures extremes en dues regions situades a l'oest i l'est del mar Mediterrani: la Península Ibèrica (PI) i Iraq. S'utilitzen les temperatures màximes/mínimes a 2 m d'altura, obtingudes a partir de la base de dades ERA-Interim en el període de 20 anys 1994-2013. En cada punt de la malla que cobreix les dues àrees d’estudi, cada 12 hores (03 i 15 UTC) amb resolució 1ºx1º, es defineixen els extrems càlids/freds com aquells episodis en què T2MAX/T2MIN es troba per sobre/sota del percentil 99.9/0.1. Els resultats en ambdues àrees d'estudi mostren que hi ha una tendència positiva en l'ocurrència i persistència d'episodis tant càlids com freds. Mitjançant l'ús del model Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), s'analitzen les trajectòries, endarrere en el temps, de 10 dies de durada, de les masses d'aire que produeixen els extrems. La causa principal que explica l'aparició d'extrems càlids sembla estar associada a un escalfament diabàtic progressiu, que s'accentua els dies anteriors a l'episodi, i no pas a l’advecció de masses d’aire des d’àrees més càlides. Els extrems càlids són produïts per masses d'aire amb temps de residència llargs sobre la PI i per processos de recirculació que tenen lloc durant dies d'estiu amb un feble gradient bàric. Les masses d'aire que produeixen dies de fred extrem tenen associades trajectòries més ràpides que les masses d’aire càlides. Els episodis freds a la PI es relacionen principalment amb advecció de masses d'aire procedents del nord-est i el nord d'Europa, i per l’Iraq, procedents de Sibèria i l'Est d’Europa. A la PI també s'ha realitzat l'anàlisi de components principals dels camps de pressió i geopotencial per identificar les configuracions d’escala sinòptica associades; aquestes mostren que l'advecció durant els episodis de fred és induïda per la presència a la Mediterrània central d'una baixa relativa i un alta de bloqueig a l'Atlàntic Nord i/o al nord-est d'Europa. S’analitzen també les correlacions entre l’ocurrència de temperatures extremes i els principals modes de variabilitat climàtica que afecten la conca mediterrània: Oscil·lació de l'Atlàntic Nord (NAO), Oscil·lació de la Mediterrània Occidental (WeMO), Oscil·lació Àrtica (AO) i Oscil·lació de l'Atlàntic Oriental (EA). A la IP es troba una correlació positiva significativa (p <0,01) entre la mitjana anual de les temperatures extremes càlides i l’índex anual de WeMO. També es troba una correlació negativa significativa (p <0,01) entre el nombre de dies freds i l'índex anual de NAO. A Iraq, s’ha obtingut una correlació significativa positiva (p <0,01) entre la mitjana anual de temperatures extremes càlides i l’índex anual de EA. Els mecanismes subjacents a l'aparició de temperatures extremes càlides per a episodis extrems específics ocorreguts a la IP s'han analitzat utilitzant el model a gran escala HYSPLIT i el model mesoescalar Weather Research and Forecast (WRF). Per a l'episodi que es va produir el 10 d'agost de 2012, que va afectar simultàniament al nombre més gran de punts del període, l’estudi sinòptic mostra una situació de bloqueig associada a una configuració ‘omega’, que provoca recirculació de massa d’aire. L’anàlisi de l’únic episodi càlid que va afectar a un sol punt de la malla, el 15 d’agost de 2012, mostra que les condicions sinòptiques i/o mesoescalars no van diferir substancialment de les que es van donar en els punts circumdants al punt de l’extrem càlid.Postprint (published version

Analysis of threats and security issues evaluation in mobile P2P networks

Technically, mobile P2P network system architecture can consider as a distributed architecture system (like a community), where the nodes or users can share all or some of their own software and hardware resources such as (applications store, processing time, storage, network bandwidth) with the other nodes (users) through Internet, and these resources can be accessible directly by the nodes in that system without the need of a central coordination node. The main structure of our proposed network architecture is that all the nodes are symmetric in their functions. In this work, the security issues of mobile P2P network system architecture such as (web threats, attacks and encryption) will be discussed deeply and then we propose different approaches and we analysis and evaluation of these mobile P2P network security issues and submit some proposal solutions to resolve the related problems with threats and other different attacks since these threats and attacks will be serious issue as networks are growing up especially with mobility attribute in current P2P networks

On (ɱ,ɳ)-Strongly Fully Stably Banach Algebra Modules Related to an Ideal of Am ×ɳ

في هذا البحث تم دراسة مفهوم مقاسات بناخ الاجبرا تام الاستقراية من النمط (ɱ,  ) بالنسبة الى مثالي Am ×ɳ و دراسة بعض خواصه.قد تم برهنت العديد من العلاقات منها يكون المقاس X  تام الاستقرارية من النمط (ɱ,ɳ) بالنسبة الى مثالي  اذا وفقط اذا لاي محموعتين جزئيتين من العناصر من النمط ɱ  و  من Ӽɳ و ادا كان  لكل j = 1, …, ɱ,  i = 1,…, ɳ و  و  يؤدي الى Ạɳ( ) Ạɳ(The aim of this paper is introducing the concept of (ɱ,ɳ) strong full stability B-Algebra-module related to an ideal. Some properties of (ɱ,ɳ)- strong full stability B-Algebra-module related to an ideal have been studied and another characterizations have been given. The relationship of (ɱ,ɳ) strong full stability B-Algebra-module related to an ideal that states,  a B- -module Ӽ is (ɱ,ɳ)- strong full stability B-Algebra-module related to an ideal  , if and only if  for any two ɱ-element sub-sets and of Ӽɳ, if , for each j = 1, …, ɱ,  i = 1,…, ɳ  and   implies Ạɳ( ) Ạɳ(  have been proved.

Improving HiperLAN/2 Physical Layer Model Based Multiwavelet Signals by using Block Turbo Codes System

The progress of broadband wireless communication systems should cope with different performance restrictive challenges that include channel fading as well as size and power limitations at the mobile units.  In this paper, the Block Turbo Codes (BTC) is evaluated for the HiperLAN/2 OFDM system based multiwavelet signals. Matlab software-simulated physical layer performance results are presented show that Packet-Error- Rate (PER) performance is improved when using block turbo codes in the HiperLAN/2 system. We also show that the frequency interleaver has a big impact on the performance of the turbo decoding process and that increasing its size lead to good performance when compared to the convolutional code Keywords: HiperLAN/2, OFDM, DMWT, IDMWT, BTC, PER

Seasonal dynamics of heavy metal uptake in some aquatic plants of the Tigris River

This work aimed to study the accumulation of heavy metals Cadmium, Lead, Chromium, and Nickel in different aquatic plants along the Tigris River. The research focused on the seasonal variations in heavy metal uptake by Phragmites australis, Typha domingensis, Persicaria salicifolia, Azolla filiculoides, and Ceratophyllum demersum. Samples were collected from three distinct locations along the river, each characterized by varied environmental conditions. Using Atomic Absorption Spectrophotometry, the quantified metal concentrations were measured, revealing significant differences across seasons and locations. The study provides crucial insights into the dynamics of heavy metal accumulation in riverine ecosystems, underscoring the role of environmental factors and plant species in metal uptake

Best Quadratic unbiased Estimator for Variance Component of One-Way Repeated Measurement Model

The studies of analysis of variance components is one of the important topics in mathematical statistics for this subject of wide application. In this paper given best quadratic unbiased estimator of variance components for balanced data for linear one-way repeated measurement model (RMM). We computed the quadratic unbiased estimator, which has minimum variance (best quadratic unbiased estimate (BQUE)) by using analysis of variance (ANOVA) method of estimating the variance components

Modelling the spatiotemporal change of urban heat islands and influencing parameters

This study identifies the spatial and temporal change of three types of Urban Heat Island (UHI). The Surface Urban Heat Island (SUHI) and Canopy Urban Heat Island (CUHI) are common UHI phenomena; however, the Radiant Urban Heat Island (RUHI) is proposed as a new type of UHI. Surface temperature, air temperature, and mean radiant temperature are used as indicators to measure the SUHI, CUHI, and RUHI respectively. Visual, statistical and microclimate approaches are carried out to increase the spatial and temporal resolution of the UHI modelling. The modelling approaches employ the integration of remote sensing, GIS, and ground measurements to improve the 2D and 3D representation of the UHI. Furthermore, the influencing parameters on the formation of the three types of UHI are investigated. The research aim is to produce an integrated approach that improves the low spatial or temporal coverage of UHI models in the literature. Moreover, it quantifies the causative parameters on the formation of UHI, and proposes mitigation strategies accordingly. London, Baghdad and Birmingham are the study areas of the SUHI, to test the variability of the size, population, Land Use/Cover (LULC), geometry, microclimate, geography, and level of development. Birmingham is chosen to study the CUHI and RUHI, because of the availability of the required data to model these UHIs. The SUHI is carried out between (2000- 2015) by the Land Surface Temperature (LST) of the thermal bands of Landsat, ASTER, MODIS and other auxiliary data. The CUHI, on the hand, is undertaken for two years (June 2012- June 2014) using high density air temperature measurements (HiTemp data), and the RUHI is simulated based on the mean radiant temperature (Tmrt) for four seasonal days that are part of the HiTemp. The integrated approach of the research employs three indictors (LST, air temperature, and Tmrt) to model the UHI which is unprecedented in the literature. Furthermore, within the use of each indicator there is a novel approach. The LST is acquired for three different cities using thermal bands from 1 m to 1000 m spatial resolution by employing diverse satellite and airborne images for about 15 years. The air temperature is hourly measured for two years by over 100 ground stations to produce high spatial and temporal thermal maps, and some of the ground stations are used to simulate the Tmrt. The Tmrt is used for the first time to model the UHI as a new indictor, which upgrades the 2D UHI using LST and air temperature to 3D UHI simulation. The influencing parameters on the formation of three types of UHI derived from the three indicators are identified, and they include many potential factors not investigated together in the literature. The findings of such topic might be useful for decision-makers when building new cities or modifying the existing ones, even the public can know more about their environment. The results show that, London and Birmingham core area usually work as SUHI during the day and night-time. However, Baghdad city exhibits low LST in the daytime except for high density residential area as well as indusial and commercial units. Similarly, Baghdad city becomes a SUHI in the night-time, and the water bodies have high LST during the cold nights for the three cities. Despite the higher diurnal, daytime and night-time LST of Baghdad compared to London and Birmingham, the London SUHI intensities were higher than those of Baghdad. The temporal change of the average LST and SUHI for Birmingham did not show significant change over the study period just like London; however, they both gave high spatial variability. The diurnal averages of SUHI are 9.41, 11.29, and 7.63 ºC for Baghdad, London, and Birmingham (during 2003-2015) respectively. The CUHI appear daytime and night-time in Birmingham urban and suburban areas throughout the different seasons for 56% of the total hours of two years, to reach 13.53 ºC. The simulation of Tmrt show the presence of daytime Radiant Urban Cool Island (RUCI) in the City Centre of Birmingham, while, the night-time induced the development of RUHI. Various influencing parameters contribute to the different types of UHI. The land cover types and anthropogenic heat are the main contributors to the SUHI. Fourteen controllable and uncontrollable predictors control the CUHI development. On the other hand, the radiation fluxes and shadow patterns direct the RUHI formation. Overall, the spatial and temporal behaviour of UHI varies for the different types of UHI. Each type of UHI is controlled by a set of causative parameters, and these might differ based on the type of UHI as well as where and when it occurs