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Establishment of IDF-curves for precipitation in the tropical area of Central Africa - comparison of techniques and results
B. Mohymont,G. R. Demarée,D. N. Faka
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2004,
Abstract: The establishment of Intensity-Duration-Frequency (IDF) curves for precipitation remains a powerful tool in the risk analysis of natural hazards. Indeed the IDF-curves allow for the estimation of the return period of an observed rainfall event or conversely of the rainfall amount corresponding to a given return period for different aggregation times. There is a high need for IDF-curves in the tropical region of Central Africa but unfortunately the adequate long-term data sets are frequently not available. The present paper assesses IDF-curves for precipitation for three stations in Central Africa. More physically based models for the IDF-curves are proposed. The methodology used here has been advanced by Koutsoyiannis et al. (1998) and an inter-station and inter-technique comparison is being carried out. The IDF-curves for tropical Central Africa are an interesting tool to be used in sewer system design to combat the frequently occurring inundations in semi-urbanized and urbanized areas of the Kinshasa megapolis.
A Novel Approach for the Joint Use of Rainfall Monthly and Daily Ground Station Data with TRMM Data to Generate IDF Estimates in a Poorly Gauged Arid Region  [PDF]
Ayman G. Awadallah, Nabil A. Awadallah
Open Journal of Modern Hydrology (OJMH) , 2013, DOI: 10.4236/ojmh.2013.31001
Abstract: In poorly gauged regions, rainfall data are often short or even absent, hindering the possibility of estimating Intensity-Duration-Frequency (IDF) relations with operationally acceptable accuracy. In this research, a novel idea is presented for the use of three separate rainfall datasets: maximum annual daily data, monthly data and Tropical Rainfall Measuring Mission (TRMM) satellite data to develop robust IDF in Namibe, south ofAngola. TRMM data is used to derive relations between maximum monthly and maximum daily rainfall and between sub-daily and daily rainfall depths. Frequency analysis is undertaken on the mixed daily record using several distributions and the best fitting is selected based on discriminant plots of the distribution tails and the moment ratio diagram as well as Bayesian criteria. The IDF curves are derived based on the estimates of daily rainfall at various return periods, with the derived sub-daily rainfall duration ratios. Robust IDFs are thus developed for a scarce data region inAfrica.
Regionalization of Rainfall Intensity-Duration-Frequency (IDF) Curves in Botswana  [PDF]
Berhanu F. Alemaw, Ron T. Chaoka
Journal of Water Resource and Protection (JWARP) , 2016, DOI: 10.4236/jwarp.2016.812088
Abstract: A regional analysis of design storms, defined as the expected rainfall intensity for given storm duration and return period, is conducted to determine storm Rainfall Intensity-Duration-Frequency (IDF) relationships. The ultimate purpose was to determine IDF curves for homogeneous regions identified in Botswana. Three homogeneous regions were identified based on topographic and rainfall characteristics which were constructed with the K-Means Clustering algorithm. Using the mean annual rainfall and the 24 hr annual maximum rainfall as an indicator of rainfall intensity for each homogeneous region, IDF curves and maps of rainfall intensities of 1 to 24 hr and above durations were produced. The Gamma and Lognormal probability distribution functions were able to provide estimates of rainfall depths for low and medium return periods (up to 100 years) in any location in each homogeneous region of Botswana.
Lawfare: The Legal Front of the IDF
Avihai Mandelblit
Military and Strategic Affairs , 2012,
Abstract: Lawfare is closely linked to the theme of this issue of Military and Strategic Affairs: the challenges facing the regular armies of law-abiding nations engaged in asymmetrical confrontations in densely populated civilian urban areas. Therefore, as part of its preparations for the challenges it may have to face in the future, particularly in this type of fighting, the IDF must give the proper weight to the legal front that is likely to develop as an integral part of the same confrontation.
Impact of Global Warming on Intensity-Duration-Frequency (IDF) Relationship of Precipitation: A Case Study of Toronto, Canada  [PDF]
Erick Carlier, Jamal El Khattabi
Open Journal of Modern Hydrology (OJMH) , 2016, DOI: 10.4236/ojmh.2016.61001
Abstract: Annual maximum rainfall intensity for several duration and return periods has been analyzed according to the Gumbel distribution. The Intensity-Duration-Frequency (IDF) curves before and after 1980 have been computed and compared. For the city of Toronto, it is shown that the rainfall intensities after 1980 are lower than those from before this date. This is especially clear for those of short duration. Comparing our results with those of other authors, it appears that, for the moment, no general law on the impact of global warming on the curves intensity duration frequency cannot be made. It appears that the impact of global warming on rainfall varies with geographic location and that it is not possible to draw some general conclusions across the planet.
Development of IDF-curves for tropical india by random cascade modeling
A. Rana,L. Bengtsson,J. Olsson,V. Jothiprakash
Hydrology and Earth System Sciences Discussions , 2013, DOI: 10.5194/hessd-10-4709-2013
Abstract: Efficient design of urban drainage systems is based on statistical analysis of past rainfall events at fine time scales. However, fine time scale rainfall data are usually lacking in many parts of the world. A possible way forward is to develop methods to derive fine time scale rain intensities from daily observations. This paper applied cascade-based disaggregation modeling for generation of fine time scale rainfall data for Mumbai, India from daily rainfall data. These data were disaggregated to 10-min values. The model was used to disaggregate daily data for the period 1951–2004 and develop intensity-duration-frequency (IDF) relationships. This disaggregation technique is commonly used assuming scale-invariance using constant parameters. For the Mumbai rains it was found better to use parameters dependent on time scale and rain volume. Very good agreement between modeled and observed disaggregation series was found for the time scales larger than 1/2 h for the 1/2-yr period when short term data were available. Although the parameters were allowed to change with time scale, the rain intensities of duration shorter than 1/2 h were overestimated. When IDF-curves had been established, they showed that the current design standard for Mumbai city, 25 mm h 1, has a return period of less than one year. Thus, annual recurring flooding problems in Mumbai appear evident.
The Test of Consciousness: The Crisis of Signification in the IDF
Nadir Tsur
Military and Strategic Affairs , 2010,
Abstract: Conclusions drawn by the IDF from the post-Second Lebanon War debrie ngs and investigations about the language and validity of the documents on doctrine, the applicability of operative plans and their assimilation, and the clarity of commands and their rationale, all point to a crisis of signi cation. This crisis, which has dogged the security establishment as well as its civilian and military foundations, began its slow growth in the early 1990s. Many sectors within the public were tired of war and of internal struggles, especially in the security-political arena. New approaches adopted in the art of war were not always properly adjusted to Israel’s reality, with concessions to post-modern, global ideas imparting a transition to peace-seeking militarism or re ecting new de nitions of old military goals. The two intra-military dimensions of the crisis of signi cation that engulfed the IDF were not approved by the top command structure and emanated without prior warning from command and control bodies, with the exception of the State Comptroller. They stemmed in part from the failure to formulate a concept of the use of force and combat doctrines that would provide a response to the new complex reality facing Israel and give clear, goal-oriented meaning to the understanding of the enemy and its methods.
Force Deployment Planning in the IDF General Staff
Gabi Siboni
Military and Strategic Affairs , 2011,
Abstract: IDF General Staff planning processes relate to two primary areas: force buildup and force deployment. The fundamentals of military doctrine of any army, and particularly the IDF, necessitate full synchronization between the two, and the element that underlies all planning processes is what is needed for force deployment. Upon the establishment of the IDF, these processes were assigned to a single framework: the General Staff Branch. However, more than sixty years later, planning in the General Staff today has been decentralized among various bodies in a way that complicates effective processes. Of the signi cant dif culties posed by this situation, three should be singled out. The rst is the weakness of planning for force deployment, which ostensibly is the responsibility of the IDF Operations Branch.The second dif culty concerns weak planning for force buildup, which must be based on force deployment needs. The third dif culty is the absence of synchronization in the planning processes. This article seeks to examine operational planning within the IDF command in three ways. The rst avenue of approach describes the evolution of operational planning and its implementation in the IDF over the years; the second analyzes the principles of operational planning and the limitations of the current situation in the IDF; and the third presents a possible model that could obviate some of the anomalies that exist today in the IDF. The scope of this article dictates a focus on the General Staff’s operational planning for force deployment. The limitations involved in planning processes related to force buildup should be discussed in a separate framework.
On the semantics of merging  [PDF]
Thomas Meyer
Computer Science , 2000,
Abstract: Intelligent agents are often faced with the problem of trying to merge possibly conflicting pieces of information obtained from different sources into a consistent view of the world. We propose a framework for the modelling of such merging operations with roots in the work of Spohn (1988, 1991). Unlike most approaches we focus on the merging of epistemic states, not knowledge bases. We construct a number of plausible merging operations and measure them against various properties that merging operations ought to satisfy. Finally, we discuss the connection between merging and the use of infobases Meyer (1999) and Meyer et al. (2000).
The Challenges of Warfare Facing the IDF in Densely Populated Areas
Gabi Siboni
Military and Strategic Affairs , 2012,
Abstract: Current assessments are that fighting in densely populated areas will be one of the main types of combat the IDF will face in the foreseeable future. This essay will focus on three points: one, the change in threats facing the State of Israel; two, the main characteristics of the military response necessitated by the change in the threat; and three, some components of the necessary method of action in such confrontations.
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